www.elektor.com SEPTEMBER 2007 £ 3.80 qet a move on PC Gamepad has tilt sensors added on the testbench ... 11 Audio amplifier bricks Wireless Household Energy Monitor Ultrasound & Bat Receiver based on SDR FM Superreg Receiver Four-channel Logic Analyser 770268 45112 8 I . F yL.ii W 675 Visit us at www.jaycarelectronics.co.uk and obtain your free copy of our 430+ page, full colour catalogue. We have an extensive range of electronics kits and the best in innovative gadgets. L E m. i Ml II If -■J Universal Speaker Protection and Muting Module Kit KC-5450 £8.75 + post & packing Protects your expensive speakers against damage in the event of catastrophic amplifier failure such as a shorted output transistor. In addition, the circuit also banishes those annoying thumps that occur when many amplifiers are switched on or off, especially when the volume is set to a high level. The design also incorporates an optional over temperature heat-sensor that will disconnect the speakers if the Water Level Indicator Kit KC-5449 £10.25 + post & packing This simple circuit illuminates a string of LEDs to quickly indicate the water level in a rainwater tank. The more LEDs that illuminate, the higher the water level is inside the tank. The input signal is provided by ten sensors located in the water tank and connected to the indicator unit via-light duty figure-8 cable. Kit supplied with PCB with overlay, machined case E output stage gets too hot. Configurable for supply voltages between 22VDC-70VDC. Supplied with a silk screened PCB, relay and all electronic components. ft yv with screenprinted lid and all electronic components. • Requires: 8mm (OD) PVC hose/pipe (length required depending on depth of tank) Requires 9-12VDC or AC wall adaptor (Maplin JC91Y £14.99) re str!cff ^ ? 9' eat fc lt 7 ">« \ NN" POST AND PACKING CHARGES: Order Value Cost Order Value Cost £20 - £49.99 £5 £200 - £499.99 £30 £50 - £99.99 £10 £500+ £40 £100 -£199.99 £20 Max weight 121b (5kg). Heavier parcels POA. Minimum order £10. Note: Products are dispatched from Australia, so local customs duty and taxes may apply. How to order: Phone: Call Australian Eastern Standard Time Mon-Fri on 0800 032 7241 Email: techstore@jaycarelectronics.co.uk Post: PO BOX 6424, Silverwater NSW 1811. Australia Expect 10-14 Days For Air parcel delivery r 4 Channel Guitar Amplifier Kit KC-5448 £28.75 + post & packing The input sensitivity of each of the four channels is adjustable from a few millivolts to over 1 volt, so you can plug in a range of input signals from a microphone to a line level signal from a CD player etc. A headphone amplifier circuit is also included for monitoring purposes. A three stage EQ is also integrated, making this a very versatile mixer that will operate from 12VDC. Kit includes PCB with overlay and all electronic components. • ^proved 2007 Stereo VU and Peak Meter Kit KC-5447 £20.50 + post & packing Accurately monitor audio signals to prevent signal clipping and ensure optimum recording levels. This unit is very responsive and uses two 16-segment bargraphs to display signal levels and transient peaks in real time. There are a number of display options to select, and both the signal threshold and signal level calibration for each segment are adjustable. Kit supplied with PCBs, LCD and all electronic components. Accuracy within 1 dB for signals above -40dB. • Case not included use HB-6082 £2.95 IR Remote Control Extender MKII KC-5432 £7.25 + post & packing Operate your DVD player or digital decoder using its remote control from another room. It picks up the signal from the remote control and sends it via a 2-wire cable to an infrared LED located close to the device. This improved model features fast data transfer, capable _ m of transmitting Foxtel digital remote control signals using the Pace 400 series decoder. Kit supplied with case, screen printed front panel, PCB with overlay and all electronic components Requires 9VDC wall adaptor (Maplin #GS74R £10.99) 2 Channel USB Oscilloscope QC-1930 £83.75 + post & packing Using Plug 'n Play USB technology and providing full optical isolation from the computer, this oscilloscope is easy to setup and use, as well as providing protection for the computer. The software is a fully featured chart recorder, function generator, logic generator, logic analyser, and spectrum analyser all in one easy to use package. See website for specifications. Fuel Cut Defeat Kit KC-5439 £6.00 + post & packing This simple kit enables you to defeat the factory fuel cut-out signal from your car's ECU and allows your turbo charger to go beyond the typical 15-17psi factory boost limit. Note: Care should be taken to ensure that the boost level and fuel mixture don't reach unsafe levels. Kit supplied with PCB, and all electronic components. J *. At j, '■* - *a. - -- 1 - “ j -' =, "?■“ \ ’-py ■ft ■- Requires 9-12VDC wall adaptor (Maplin #JC91Y £14.99) Log on to ww.jaycarelectronics.co.uk/ for your FREE catalogue! 0800 032 7241 (Monday - Friday 09.00 to 17.30 GMT + 10 hours only) For those who want to write: 100 Silverwater Rd Silverwater NSW 2128 Sydney AUSTRALIA IjM >,#7e these | / / ^ . c onib two kit* * ni °st cost ° Pc et th *e Peif 0rma|j feff ect|Ve 0,1 Variable Boost Kit for Turbochargers KC-5438 £6.00 + post & packing It's a very simple circuit with only a few components to modify the factory boost levels. It works by intercepting the boost signal from the car's engine management computer and modifying the duty cycle of the solenoid signal. Kit supplied in short form with PCB and overlay, and all specified electronic components. r Minimum order now » X All All prices in £ Stg 4T 'year v J Free 430+ page ^ Catalogue. jnycor www.jaycarelectronics.co.uk Analog + Digital Digital Storage Oscilloscope Dual Channel Digital Scope with industry standard probes or POD connected analog inputs. Fully opto-isolated. Mixed Signal Oscilloscope Capture and display analog and logic signals together with sophisticated cross-triggers for precise analog/logic timing. Multi-Band Spectrum Analyzer Display analog waveforms and their spectra simultaneously. Base-band or RF displays with variable bandwidth control. Multi-Channel Logic Analyzer Eight logic/trigger channels with event capture to 25nS. DSP Waveform Generator Built-in flash programmable DSP based function generator. Operates concurrently with waveform and logic capture. Mixed Signal Data Recorder Record to disk anything BitScope can capture. Supports on-screen waveform replay and export. User Programmable Tools and Drivers Use supplied drivers and interfaces to build custom test and measurement and data acquisition solutions. USB Mixed Signal Oscilloscope ...or a BitScope BS100U Mixed Signal Storage Scope & Analyzer Innovations in modem electronics engineering are leading the new wave of inventions that promise clean and energy efficient technologies that will change the way we live. It's a sophisticated world mixing digital logic, complex analog signals and high speed events. To make sense of it all you need to see exactly what's going on in real-time. BS100U combines analog and digital capture and analysis in one cost effective test and measurement package to give you the tools you need to navigate this exciting new frontier. Opto-isolated USB 2.0 12VDC with low power modes BitScope DSO Software for Windows and Linux BS100U includes BitScope DSO the fast and intuitive multichannel test and measurement software for your PC or notebook. Capture deep buffer one-shots, display waveforms and spectra real-time or capture mixed signal data to disk. Comprehensive integration means you can view analog and logic signals in many different ways all at the click of a button. The software may also be used stand-alone to share data with colleagues, students or customers. Waveforms may be exported as portable image files or live captures replayed on another PC as if a BS100U was locally connected. www . b i tscope . com 9/2007 - elektor electronics lektor lectronics i + 1 +1 +1 + Elektor = 1 50,000 With this edition we're proud to present, for the first time in the history of Elektor, a ready-assembled circuit board secured on the front cover of the magazine; for all language editions distributed across the globe, including, as of this month, Spanish! The board is not an existing com- mercial product — it was custom made for Elektor. About a year ago it struck us that the PREMA PR4401 chip would be great for a LED driver board to give away to our readers. We told PREAAA representatives of our idea at the 'electronica' exhibition in November 2006. Not without success as a few weeks later PREAAA promised us 1 50,000 ICs. For the inductor in the circuit, we secured the equally kind cooperation of Wurth Electronic. After extensive research at PREAAA the optimum SAAD case and inductance were established, while the PCB design came from the Elektor labs. All we needed at that point were companies to manufacture and stuff the PCB. No problem if you disregard the hard fact that PCB manufacturers these days are fully booked and the cost of 1 50,000 pieces of the board we had in mind is about as much as we spent on build- ing four new websites (see p. 1 8). The solution to the problem was found on an electronics trade shown in the Netherlands, where an Elektor- designed all-SAAD WiFi Sniffer board was produced 'live' using a dozen or so high-end machines and other specialised equipment from different companies. About 2,500 of these boards were successfully produced in one day and given away to visitors to the show. The resounding success enabled us to find in Eurocircuits (the guys running The PCBShop) a 'cost- sharing partner' for the LED driver board. Too late, we thought, for our September 2007 issue. But then Wurth and ECS seemed to bend over backwards in respect of component supply and manufacturing times and we received confirmation — liter- ally when these words are written — that 150,000 populated PCBs were ready for transporting to our magazine binders. I hope you have your PR4401 LED driver on your desk as you read this. Jan Buiting Editor The new Elektor website 22 Good and Occasionally Favourable You might think that amplifiers are like sand on the beach. But if you restrict your search for fully assembled amplifier modules to hi-fi appli- cations and omit modules for other applications, the range of available products shrinks quite quickly. For this test, we selected eleven different modules from various manu- facturers, with an output power range extending up to nearly half a kilowatt. CONTENTS In conjunction with PREMA Semiconductor and Wurth Electronics (who provided the components). Eurocircuits and ECS Electronics (who manufactured and populated the printed circuit board), Elektor is pleased and proud to include a free gift with this issue: a board containing an LED booster circuit which you can try out for yourself. 38 42 46 50 58 65 66 80 72 ilyser is compact and can be bat- tery powered. The maximum sampling rate is 2 MHz and lory to store 1 024 samples ignal. The dot-matrix display with a resolution pixels shows a clear representation of the digital signals. 74 National Instruments/ Elektor Seminar 32 62 6 7 8 12 16 76 Using a balanced mixer, we can make an ultrasound receiver that allows us to hear bat sounds. The Software Defined Radio (SDR) previously described in 77 Elektor Electronics May 2007 makes an ideal starting point. Volume 33 September 2007 no. 369 projects Digital Inspector Tilt Gamepad Ultrasound Receiver SDR and VLF FM Superregenerative Re- ceiver The Anatomy of Hex Files Watchdog in the Meter Cabinet Automating the R8C Starter Kit Profiler Tips & Tricks Design Tip technology PR4401 LED Driver Waiting for Zigbee info & market Colophon Hands-on Seminar Mailbox News & New Products Adding Security to Remo- vable Mass Storage Media Elektor's New Website Good and Occasionally Favourable Racing under the Sun Elektor SHOP Sneak Preview infotainment Hexadoku Philips '60'-series NORbits (1968) Advertisement lektor lectronics Volume 33, Number 369, September 2007 ISSN 0268/45 1 9 Elektor Electronics aims at inspiring people to master electronics at any personal level by presenting construction projects and spotting developments in electronics and information technology. Publishers: Elektor Electronics (Publishing), Regus Brentford, 1 000 Great West Road, Brentford TW8 9HH, England. Tel. (+44) 208 261 4509, fax: (+44) 208 26 1 4447 www.elektor.com The magazine is available from newsagents, bookshops and electronics retail outlets, or on subscription. Elektor Electronics is published I I times a year with a double issue for july & August. Underthe name Elektor and Elektuur, the magazine is also published in French, Spanish, German and Dutch. Together with franchised editions the magazine is on circulation in more than 50 countries. International Editor: Mat Heffels (m.heffels@segment.nl), Wisse Hettinga (w.hettinga@segment.nl) Editor: Jan Buiting (editor@elektor.com) International editorial staff: Harry Baggen, Thijs Beckers, Ernst Krempelsauer, Jens Nickel, Guy Raedersdorf. Design staff: Antoine Authier, Ton Giesberts, Paul Goossens, Luc Lemmens, Jan Visser, Christian Vossen Editorial secretariat: Hedwig Hennekens (secretariaat@segment.nl) Graphic design / DTP: Giel Dols, Mart Schroijen Managing Director / Publisher: Paul Snakkers Marketing: Carlo van Nistelrooy Customer Services: Anouska van Ginkel Subscriptions: Elektor Electronics (Publishing), Regus Brentford, 1000 Great West Road, Brentford TW8 9 H H , England. Tel. (+44) 208 26 1 4509, fax: (+44) 208 26 1 4447 Internet: www.elektor.com Email: subscriptions@elektor.com Rates and terms are given on the Subscription Order Form Head Office: Segment b.v. PO. Box 75 NL-6 1 90-AB Beek The Netherlands Telephone: (+3 I ) 46 4389444, Fax: (+3 I ) 46 4370 1 6 1 Distribution: Seymour, 2 East Poultry Street, London EC I A, England Telephone: +44 207 429 4073 UK Advertising: Huson International Media, Cambridge House, Gogmore Lane, Chertsey, Surrey KTI 6 9AR England. Telephone: +44 1932 564999, Fax: +44 1932 564998 Email: p.brady@husonmedia.com Internet: www.husonmedia.com Advertising rates and terms available on request. International Advertising: Frank van de Raadt, address as Head Office Email: advertenties@elektuur.nl Advertising rates and terms available on request. Copyright Notice The circuits described in this magazine are for domestic use only. All drawings, photographs, printed circuit board layouts, programmed integrated circuits, disks, CD-ROMs, software carriers and article texts published in our books and magazines (other than third-party advertisements) are copyright Segment, b.v. and may not be reproduced or transmitted in any form or by any means, including photocopying, scanning an recording, in whole or in part without prior written permission from the Publishers. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. Patent protection may exist in respect of circuits, devices, components etc. described in this magazine. The Publisher does not accept responsibility for failing to identify such patent(s) or other protection. The submission of designs or articles implies permis- sion to the Publishers to alter the text and design, and to use the contents in other Segment publica- tions and activities. The Publishers cannot guarantee to return any material submitted to them. Disclaimer Prices and descriptions of publication-related items subject to change. Errors and omissions excluded. © Elektor International Media B.V 2007 Printed in the Netherlands Your price conscious PCB supplier EURO Online price emulation Online ordering Online order tracking Online 24/24H and 7/70 Interested? Contact us: 444 2088 187 DOS E-mail: euro @ c u rod rco i ts . com www.eurocircuits.com A la carte j On demand pooling for standard boards up to 6 layers from 1 to 1000 pieces from 3 working days onwards - pooling with more options - up to 8 layers - from 1 tu 1000 pieces - from 3 working days onwards - your boards our challenge A - up to 16 layers - from 1 piece onwards - from 3 working days onwards ClmSccm 5 USB Scon Tool Diagnose any car with EOBD Based on the ELM327 1C Supports all EOBD and OBD-II protocols ^ ISO 1 5765-4 (CAN) S ISO 1 4230-4 (Keyword 2000) s IS09 141-2 S JI850 VPW s JI850 PWM 9600 or 38400 baud Supported by more software than any other OBD interface Inexpensive Full Speed USB 1.1 Automatic protocol detection Package includes cables, software CD, and Quick Start Guide Buy from your local UK distributors! www.ElmScan5.com/elekfor 6 elektor electronics - 9/2007 SEMINAR ANNOUNCEMENT INFO & MARKET Hands-On Seminar Jointly organised by Elektor Electronics and National Instruments Electronics Workbench Group ^7 NATIONAL f INSTRUMENTS ELECTRONICS WOfikBEkEil GfiOUP In cooperation with National In- struments Electronics Workbench Group, Elektor Electronics is orga- nising a hands-on seminar for its readers, to be held on 27 Septem- ber 2007. This seminar will focus on using Multisim 10 to design, simulate and measure electronic circuits. Participants will be given ample opportunity to obtain per- sonal experience with using these techniques on a PC. At this seminar, several specialists from National Instruments Electron- ics Workbench Group will show you how simulation and virtual instruments can assist you in the design process and enable you to reduce development time. Ap- plication of SPICE models and ad- vanced analysis methods such as Monte Carlo analysis are also on the agenda. All of this will be il- lustrated using the versatile Multi- sim 1 0 program. The seminar will also feature sev- eral demonstrations of National In- struments instrumentation products to show how they can be used to make measurements on circuits and how to set up measurement procedures. Several computers will be availa- ble at the seminar so participants can try out all of this 'hands-on'. Topics The following topics will be ad- dressed during the seminar: - Introduction to SPICE model- ling in Multisim for developing schematics; - Using LabVIEW and virtual in- strumentation to create interac- tive simulations; - Entering real stimulus data for use in simulations; - Various types of analysis (AC, DC, Monte Carlo, etc.); - Design verification of proto- types, in which simulation results are fed into real circuits; - Using Ultiboard to design PCB layouts; - Using LabVIEW and Nl instru- mentation hardware to set up hybrid prototyping systems; - Using Nl Educational Laborato- ry Virtual Instrumentation Suite (ELVIS) to create a circuit and link it to a PC. Registration If you're interested in attending the seminar, you can sign up by com- pleting the registration form found on the Elektor Electronics website (www.elektor.com). The number of seminar par- ticipants is limited to 30. If more than 30 people sign up for the seminar, participants will be se- lected by Elektor Electronics. No correspondence will be conducted in this regard. Seminar participation is free of charge for readers of Elektor Elec- tronics who are professionally in- volved in designing and develop- ing electronic circuits. The hands-on seminar will be held on 27 September 2007 at the National Instru- ments Office in Newbury, Berkshire. A route description for travel by car or public transport will be sent to the participants in good time. ( 070492 - 1 ) Programme 8.30-9.00 Reception and registration of participants 9.30 Start of the morning session 12.30 Catered lunch 13.15-15.15 Afternoon session 15.30 Informal discussion with NIEWG specialists Advertisement Electronics Engineers - Join A Winning Team! UK and Czech Republic We are looking for Engineers for the United Kingdom & Czech Republic. The Lektronix Group of Companies are the worlds leading provider of Industrial Automation repairs with an enviable reputation for the best in technical excellence and customer service. Due to the huge demand for our services we need to employ additional engineers at our three UK workshops (West Midlands, South Wales and Northern Ireland) to keep pace with the work we are receiving. Also, due to future expansion throughout Europe we are looking for English speaking engineers to train and work in the UK with eventual relocation to our workshop in Brno, Czech Republic. We are looking for Electronic Repair Engineers, Electronic Repair Technicians and Electronic Component Level Repair Engineers. Do you have an interest in electronics? Have you any experience in the field of practical electronics? Have you experience in Radio/Television/Home Electronics? Does your hobby/interest include electronics? Are you willing to learn new tricks - electronic engineering? Do you want work in an exciting and challenging environment? Do you have any experience with Machine Tool Systems - PLC's - Servo Drives - Servo Motors - Monitors-VDU's - AC Drives - DC Drives - Temperature Control - Digital Electronics - Analogue Electronics? Please Contact: Mr Brian Stewart Lektronix Ltd, Unit Cl, Anchor Brook Ind Park, Wharf Approach, Aldridge, West Midlands, WS9 8EQ, United Kingdom. We offer a competitive salary and all the other benefits normal with a go ahead company. Telephone +44 (0)1922 455555 for an application form or apply on line at www.lektronix.net 6/2007 - elektor electronics 7 INFO & MARKT MAILBOX Solution to Hexadoku May 2007 5 4 C 2 1 B 7 8 9 E 0 D 3 6 F A A 6 E B C F 9 4 3 1 2 5 8 0 D 7 9 1 8 7 D 2 0 3 6 C A F 4 E B 5 3 D 0 F 6 A E 5 7 B 8 4 2 9 1 C 8 3 9 5 F C 6 1 2 4 D 0 B A 7 E C B A 4 0 7 8 D F 3 6 E 1 5 9 2 D 7 1 6 E 9 5 2 A 8 B C F 3 4 0 F E 2 0 4 3 A B 5 7 1 9 6 D C 8 B 9 6 A 7 0 F C 4 D 3 2 5 8 E 1 7 2 D C 5 8 3 9 E A F 1 0 4 6 B 0 5 4 8 A 1 D E B 6 C 7 9 2 3 F E F 3 1 2 4 B 6 0 9 5 8 7 C A D 4 C F D B E 2 7 8 5 9 6 A 1 0 3 2 A B 9 8 6 1 0 D F E 3 C 7 5 4 6 8 7 E 3 5 C F 1 0 4 A D B 2 9 1 0 5 3 9 D 4 A C 2 7 B E F 8 6 Solution to Hexadoku June 2007 A F E 5 2 4 0 B 9 D 7 8 C 3 1 6 6 C B 3 7 D A 9 5 0 4 1 8 E 2 F 0 9 8 D C 1 5 F 6 3 E 2 B A 7 4 4 7 2 1 8 6 E 3 F C A B 9 0 D 5 F 6 4 0 A C D 7 B 5 1 9 2 8 E 3 7 D 9 E B 8 F 1 2 4 3 6 0 5 A C 1 B A 8 5 3 2 0 E F C D 6 4 9 7 5 3 C 2 E 9 4 6 8 7 0 A F D B 1 E 5 1 9 4 7 8 C A 6 2 0 3 B F D 8 A D 7 9 F 3 E C 1 B 4 5 6 0 2 3 2 6 F 0 5 B A D 9 8 7 1 C 4 E B 4 0 C 1 2 6 D 3 E 5 F A 7 8 9 C 8 7 6 D A 1 4 0 2 F 5 E 9 3 B 9 1 F 4 3 B C 8 7 A 6 E D 2 5 0 2 0 3 B F E 9 5 4 8 D C 7 1 6 A D E 5 A 6 0 7 2 1 B 9 3 4 F C 8 Crypto Puzzle winners The Crypto Puzzle published in the March 2007 issue of Elektor Electronics as part of the Microchip/Labcenter Explorer-16 article series has drawn a good response from our inter- national readership. In fact, the number of correct entries received was such that there was no need for the authors to post clues in instalment 4 or the Explorer-16 forum on the Elektor website as originally planned. To compensate initial problems with the 'secret' email address resolved from the puzzle, the competition rules were changed from 'the first three correct entries for each Elektor national edition are winners' to: '12 winners drawn at random from all entries received'. One method of solving the puzzle was described in Part 4 of the Explorer-16 article series. All participants received a free Microchip pen and wallet. The winners received an ICD- 2 debugger kit from Microchip and a copy of Proteus VSM for the PIC24FJ1 28GA01 0. Congratulations to all! United Kingdom John Tuckett (Cleveland); Colin Wilkinson (Wareham) Germany Christian Heiland (Olbersdorf); Marc Neujahr (Lahstedt/Munstedt) Belgium Christophe Kaut (Burg-Reuland); Simon Saenen (Holsbeek); Hans Ameel (Kortrijk) France Sebastien Larcher (Carcassonne); Frederic Linard (Me zieres sur Seine) Denmark Klaus Klug Christiansen (Kokkedal) Netherlands Marco van Nieuwenhoven (Eindhoven); Dennis Vermoen (Capelle aan den Ijssel) Freescale samples (2) (they came from afar...) I was just wondering whether anyone else had tracked their order of Freescale microcon- trollers (ref. 'g-Force on LEDs', EE April 2007, Ed.) and if so if theirs had travelled as far as mine? I have posted the route, plotted on Google Earth, they took on my blog ( http:// britishengineeringsystems. com/2007/03/21 /what-a- long-way-for-free/ ) for anyone who wants to see the 5,000+ mile trip. As someone has already asked, what is the carbon foot print of these? (ac- cording to the box they were made in China too!) 'binraker' (on EE forum) Microwave ovens and SMD Dear Editor — I do not own and have never used a microwave oven for cooking food. However, as a result of technical progress in electron- ics (SMD use) I feel forced to consider the purchase of a unit. My local MIGROS store have an offer of a 1 000W Mio Star MWG 8000 21 litre microwave oven with 5 power steps between 80 W and 800 W. Included is a 27cm 8 elektor electronics - 9/2007 dia turntable and a grill unit. I understand that you are going to update your article on 'Electronic Cooking' ('SMD Reflow Oven', January 2006, Ed.) and I would like to know if the unit which I have described could be used as an SMD tool? As I am unlikely to use the unit for cooking food and I would have no other application for it I decided not to purchase it until I had some guidance from EE. Unfortunately, the store would not allow me to examine the contents of the carton so I am unable to describe the circuit board but I do know that the whole unit complies with the Swiss safety standards. By the way, when is the next article on SMD frying? David Stafford (by email) Give thatMio Star a miss , David \ and look out for an oven with a grill only. Even a 'student edi- tion' the size of a large toaster will work better. Most combined microwave / grill ovens hove poor temperature control of the electrical heater elements used for baking and grilling. The up- dated SMD Oven article is in the pipeline and will appear later this year. In it we will recom- mend a suitable low-cost oven. New lithium batteries Dear Editor — I cannot entirely understand the sense of euphoria radiated by the 'Tough and Powerful' article in the April 2007 issue of Elektor Electronics. The main advantage of LiPo cells, which is their low self- discharge rate, is matched by modern NiMH cells such as Eneloop and Ready4you from Sanyo and Varta. For equip- ment that uses AAA or AA cells, this makes them consider- ably more attractive in terms of price, compatibility and availably than lithium batter- ies, which are expensive and not readily available. NiMH batteries can even be used to replace primary batteries in watches and IR remote controls, and the Eneloops also score bonus points with an improved voltage level. Hans-Konrad Unger (Germany) Ernst Krempelsouer, the article editor ; replies : The lithium cells with nonophosphote cathodes described in the article ore intended to be used in a com- pletely different application area than the NiMH cells you mention , which we have also de- scribed in an article (see inset). They are not standard equipment batteries , but instead distinctly high-performance , high-current batteries intended for the ap- plications mentioned in the arti- cle , such as power tools , hybrid cars , electric airplanes , electric bicycles , etc. We certainly did not intend to create the impression that these batteries would be advanta- geous for normal consumer ap- plications, and in any case this would be excluded by their con- struction and voltage level. The 'improved voltage level' is only claimed by Sanyo (for Eneloop ), and even there the 'improve- ment' in the average full-dis- charge voltage is only slightly less than 50 mV (0.05 V). Mains filter for audio Dear Jan — in the specialist press, you hear a lot about mains filters that are supposed to extract the last ounce of refinement from high-end audio equipment. Specialist suppliers then respond by plac- ing ads for sinfully expensive outlet strips. Is this all simply hocus-pocus? Since I've started to hear stories of this sort from people in my circle of ac- quaintances, I wonder whether there's actually something to it. I thus have this question for you: wouldn't a filtered outlet strip of this sort be a worthwhile DIY project for a Fairchild Anniversary Quiz winners In the May 2007 issue of Elektor we reported on the double anniversary of semiconductor pioneers Fairchild, celebrating their founding 50 years ago and, in the same year (2007), having been an independent company again for the last 10 years. To celebrate the double anniversary, Fairchild and Elektor published a quiz with 10 power inverter/ motor driver kits and associated asynchronous motors as prizes, worth £ 200 each. The quiz questions were not too difficult, it turned out as over 300 correct answers were received. The correct answers are shown in brackets. 1 . Who developed the planar transistor at Fairchild in 1958? (Jean Hoerni). 2. How many integrated com- ponents comprise and IGBT? ( 2 ) 3. What is the phase angle between any two of the 3-phase outputs of a fre- quency inverter? ( 120 ) The lucky winners drawn at random are: Harry Coolen (Weert, NL); Sanitate Donato (Ars sur Moselle, F); Christian Fasthuber (Weis, A); Michael Greiff (Dresden, G), Leslie Hadden (Ballygawley, UK), Pierre Lefebvre (Morlanwelz, B), Erich Lienhart (Buhl, G); Viktor Riediger (Bielefeld, G); Ko Visser (Nijverdal, NL); Manfred Weder (Halle, G). Congratulations to all winners and thanks to all who have participated! 9/2007 - elektor electronics 9 INFO & MARKT MAILBOX Corrections & Updates Satnav for Robots July/August 2007, p. 78-80, ref. 070350-1 The circuit diagram in Figure 1 was erroneously shifted out of its box. The correct rendering is shown here. +5V © R23 K1 +5V 0- +5V RXD TXD GND 10 03 « , 8 , 6 lOOn i 1 4 2 — K2 O o o o o o o o o ISP “1 GPS or programmer cable K3 target OK right left R14 R15 MISO SCK RST MOSI RXD TXD R16 S3 I RESET R24 S2 14 15 16 17 18 19 R17 oMo PRG 20 R18 D6 21 R22 D5 32 10 30 AREF VCC AVCC RST IC1 PB0(XCK/T0) PB1(T1) PB2(INT2/AIN0) PB3(OCO/AIN1) PB4(SS) PB5(MOSI) PB6(MISO) PB7(SCK) (ADCO)PAO (ADCI)PAI (ADC2)PA2 (ADC3)PA3 (ADC4)PA4 (ADC5)PA5 (ADC6)PA6 (ADC7)PA7 ATmega32 PDO(RXD) (TOSC2)PC7 PDI(TXD) PD2(INT0) PD3(INT1) PD4(OC1B) PD5(OC1 A) PD6(ICP1) PD7(OC2) (TOSC1)PC6 (TDI)PC5 (TDO)PC4 (TMS)PC3 (TCK)PC2 (SDA) PCI (SCL) PCO GND XTAL1 XTAL2 GND D3 SYSTEM RUN ii 13 X 1 12 < h > C2 Cl 22p 16MHz 22p DRIVE SIGNAL- READOUT TT 40 39 38 o> 00 CO o CM CC CC IT cc cc IT cc 37 36 35 34 33 10 11 12 29 28 27 26 25 24 23 l 2 C - Bus to main controller trackpoint assignment +5V " 16 © P0 SDA PI SCL IC2 — P2 INT P3 PCF8574 P4 P5 A0 P6 A1 P7 A2 K4 15 14 13 +5V SDA SCL GND +5V © K5 O 22 l 2 C - Bus +5V SDA SCL GND K6 O +5V © 2k2 2k2 R1 R2 10k 10k 10k R5 R4 R3 CO 0 . ADR W 31 compass l 2 C LCD 16x4 IC3 +8V ... +15V lot of readers? In contrast to ready-made products, you could adapt it to your specific situation and needs (such as building it into a home-built rack), and you could save cou- ple of quid at the same time. A unit dimensioned for 1 kW or so, with supplementary filtering for digital equipment, would probably suit most users. I already suspect that even the slick ready-made products are built using only standard parts, so the material should be avail- able. This also reminds me of the Class D final amplifier de- sign you published. However, I cannot judge whether the filter board for this amplifier would fulfil this purpose. What do you think about this? G. Barth (Netherlands) This is on interesting question. On the one hond , we hove long since stopped devoting ony ot- tention to discussions of how dif- ferent types of copper olloy ef- fect the sound of o system. This a/so opplies in principle to the system performonce enhance- ments attributed to mains filters , regardless of whether they are built using standard components or electronic dowsing rods. On the other hond ', a 'clean' power source is certainly not a bod idea, and it con at least im- prove the signal to noise ratio. And considering that our mains networks are becoming dirtier all the time (with a wealth of in- terference ), the utility of a mains filter cannot be entirely denied. We are already tossing around some ideas for a project in the Elektor Electronics lab. A tile saw comes in handy Dear Editor — I would like to briefly share some experience with sawing PCBs. If you start making them on your own again, it's always difficult to get the board dimensions right. Of course, an sheet metal shear is quite handy for this, but if you don't have one you have to use a saw. Cutting PCBs with a hacksaw is actually not all that bad, but if you have to saw quite a few boards it's easier to use a MailBox Terms •Publication of reader’s orrespondence is at the discretion of the Editor. •Viewpoints expressed by correspondents are not necessarily those of the Editor or Publisher. •Correspondence may be translated or edited for length, clarity and style. •When replying to Mailbox power tool. Although a tile cut- ting saw is probably not some- thing that most people have lying around, it makes cutting boards very easy. It's probably not the first thing you would think of, but it works very well. After a bit of touching up with a belt sander, you're all set to go, Mac. Mac (by email) Thanks a lot for this handy tip. We're sure that other readers will wont to give this a try. But we do hope that they ore care- ful, since it's quite easy to cut off a finger too! correspondence, please quote Issue number. •Please send your MailBox correspondence to: editor@elektor-electronics.co.uk or Elektor Electronics, The Editor, 1000 Great West Road, Brentford TW8 9HH, England. 10 elektor electronics - 9/2007 Does your company spend too much time, money and effort developing and testing embedded systems? Would you like to have access to an integrated suite of cost-effective tools which support the rapid development and testing of reliable embedded systems using off-the-shelf processors with an ARM™ core? Would you like to be able to use the same tool set with a range of FPGA platforms, using "soft core" processors? Have you tried fcfryiji'Xl tj ? info@tte-systems.com www.tte-systems.com Rapid development of reliable embedded systems 9/2007 - elektor electronics 11 30-day free trial now available - please visit www.tte-systems.com INFO & MARKET NEWS & NEW PRODUCTS Lascar move to new offices in Hong Kong Lascar Electronics' Hong Kong sub- sidiary have moved to new premis- es within the city to facilitate the continued expansion of the compa- ny's Far Eastern operation. Lascar (HK) Ltd. is vital in the deliv- ery and success of the custom de- sign & manufacture service offered by Lascar in the UK. This service provides a route to Far Eastern manufacturing for European com- panies, bringing together the best in UK design and sourcing, kitting and manufacturing in the world's most important growth market. The new 2950 sq ft. offices are located in the Futura Plaza build- ing in Kowloon at the heart of Hong Kong's business area. www.lascar.co.uk ( 070321 - 2 ) BitScope BS100U USB Mixed Signal Scope and Waveform Generator BS100U is the newest member of BitScope's popular family of PC based mixed sig- nal oscilloscopes. Like all BitScopes, it has an analogue input band- width of 100 MHz and supports real-time simul- taneous analog and log- ic capture to 40 MS/s. Unique to BS100U is its opto-iso- lation decoupling it from the PC. You can ground reference it in- dependently and USB drop-outs due to ground-loops or glitches when looking at high power electrical or automotive systems are never a problem. Another feature to make its de- but in BS100U is a powerful DSP based flash programma- ble waveform generator. Op- erating independently of the scope's capture engine it allows complex waveforms to be syn- thesised concurrently with wave- form capture. LT'^w 1 * * * t BS1 00U has 4 in- puts feeding 2 analogue channels plus 8 concurrent logic channels, a ±5 V adjustable external trigger in- put, a calibration output, and low power modes for extended use on battery power in the field. The premium BitScope DSO soft- ware package is included with BS100U for a complete set of integrated virtual instruments on Windows or Linux PCs. Standard functions include mixed signal and digital storage scopes, a logic an- alyzer, baseband spectrum analyz- er, X-Y phase plotter and an inte- grated data recorder. With ^ BS1 00U the DSO in- troduces 2 GS/ s equivalent time sampling with phase coherent full speed dual channel capture for HF eye dia- grams, ISI and modulation analy- sis, a multi-band spectrum analyz- er for RF and narrow-band signal analysis and sophisticated transfer function analysis applications using the built-in waveform generator. BS1 00U is also well suited to many data acquisition applications with the inclusion of a DSO based tran- sient recorder as well as drivers for use with third party software tools such as Microsoft Excel, Math- works MatLab and National Instruments LabVIEW. Open source software solutions are also available and the exter- nal trigger and POD based connectivity supports the con- struction of multi-scope data ac- quisition systems. To meet specialised needs the programming API is published to support the development of custom applications and the BS100U POD interface provides full access to the analog and log- ic signals as well as data, control and power lines making the de- velopment of new BS1 00U pow- ered POD devices easy. ( 070490 - 1 ) BitScope Designs, Suite 3, 28 Chandos St., St. Leonards, NSW 2065, Australia. Tel: +61 2 9436 2955; tax: +61 2 9436 3764. www.bitscope.com High performance register supporting ddr3 memory modules IDT™ (Integrated Device Technol- ogy, Inc.) announces the industry's fastest JEDEC-compatible integrat- ed register and phase-locked loop (PLL) for DDR3 registered dual in- line memory modules (RDIMMs). The device's integrated PLL sup- ports the industry's widest range of operating clock speeds, from DDR3-800 to DDR3-1600 with a propagation delay of less than 1 nanosecond. Designed for a new generation of high performance servers and workstations, the IDT 74SSTE32882 offers twice the speed of today's DDR2 solution with a 30 percent reduction in power consumption. The integration of the register and PLL into a single device enables RDIMM vendors to develop a sim- plified design and board layout. In addition, the 74SSTE32882 supports an internal PLL feedback loop to reduce trace routing and spread spectrum clocking to re- duce EMI. The supply voltage for the 74SSTE32882 is reduced to 1.5V, limiting power consump- tion and heat generation. These features are valuable to RDIMM vendors because they enable sig- nificant cost savings through the reduction of board real estate and the elimina- tion of external components. The IDT 74SSTE32882 is designed to be fully compatible with the most cur- rent JEDEC specifi- cation. The guide- line set by JEDEC ensures interopera- bility for all JEDEC compatible DDR3 solutions and will help facilitate the growth of the DDR3 market. www.idt.com ( 070321 - 5 ) 12 elektor electronics - 9/2007 Infratec SpeedUp Partner Programme Infratec AG presents its new Spee- dUp Partner Programme. Not only does it offer interesting lucrative conditions and services, but above all it offers the SMS Alarm System which controls both PC as well as Server; for instance, in case of damage, an alarm is sent via SMS or via email. The SpeedUp Partner Programme offers three categories: Partner, Silver Partner and Gold Partner, which do not focus solely on max- imising annual turnover on Infratec products. Certification depends es- sentially on training courses relat- ing to the products. In order to achieve the Silver Partner status, training on the Remote Monitoring System and on Power Monitoring Products is required. The Gold Part- ner status can be obtained once training on NMS 1000 software for general control is undertaken. Infratec AG's range of products in- cludes individual components and complete solutions for the range of KVM Switches, KVM Extender, cabinet monitors and even power distribution units and serial console servers. Thus an excellent oppor- tunity in auxiliary business opens up to traders with an expertise in information technology and to sys- tem houses. The SpeedUp Partner Programme offers lucrative conditions: Every new distributor will receive a spe- cial bonus of 5% with the first or- der. The standard margin for a Sil- ver Partner with an annual turnover of 25.000 EUR is 24% while that for a Gold Partner with an annual turnover of € 35,000 is 27%. An- other important aspect of the Spee- dUp programme: on every total amount of at least 25 units an ex- tra unit is included for free. With their SMS-Alert Platform and the NMS Line, Infratec offers a tool for the immediate notification not only of server breakdown or dam- age. With the NMS Line, worksta- tions, server and all other SNMP enabled devices can be controlled. It can also be combined quite easi- ly with all control units and sensors of Infratec's RMS Line. Thus the NMS Line is a powerful software suite which not only alerts immedi- ately in cases of hardware break- down but also if incidents such as temperature rise, fire, smoke, vi- brations, water leakages and un- authorized access occur, simply through an SMS or an email. In developing the NMS Line, it has been ascertained above all that expensive investments such as for an SMS Gateway, could be saved. Instead, the NMS Line ac- cesses the portal www.sms-alert.de which is managed by Infratec, in order to feed the relative informa- tion through SMS into any mobile network. (070490-11) www.infratec-ag.de Introduction to Microcontrollers on CD-ROM An mlmduclmn tu inicrufitintrullur pftigrliiTmiirig by R.in Hiiyifc-MiiL ..in Jcrtin Onti'.rn This new course from Matrix Multi- media contains an introduction to microcontroller programming and system development and is suitable for complete novices. One version of this product is avail- able free of charge online on the Matrix Multimedia website. Stu- dents working at home can use this free version - and the free version of Flowcode - to learn about microcontrol- ler development. This free version is not licensed for ed- ucation use and is missing key items - worksheets and the grading scheme. 'An introduction to microcontroller pro- gramming' has a re- tail price of £ 100 for institutions and this version includes the worksheets and grading scheme. However it is availa- ble free of charge to education customers who buy a PICmicro solution based on E-blocks (EB1 1 0 or EB215). The new product will also be included in all educational solutions like the E-blocks CAN bus solution, mobile phone solution etc. (070490-III) www.matrixmultimedia.com jr Wcift Rn;ul EEeHL«t t, IVflflt Mmit, h Dfrlphtni m SKi? frHK, UK out PflOftft indUdflUK VAT: 9/2007 - elektor electronics 13 INFO & MARKET NEWS & NEW PRODUCTS Slimline hand-held enclosures The popular 1455 family of ex- truded aluminium enclosures from Hammond Electronics has been extended with the addition of the A and B sizes, slimline units de- signed to accept one or two cir- cuit boards respectively, mounted horizontally directly into slots in the walls of the unit. The rounded profile fits comfort- ably into the hand or pocket and the units are fitted with plastic bez- els at each end that incorporate a flat panel area for switches, indi- cator lights and other front panel furniture. The units are available in lengths of 100 mm, the A size is 70 mm wide and the B size is 71 .7 mm in width. The 12 mm high A size, which accepts a single PCB, has flat top and bottom surfaces while the 19mm high B size, provided with two PCB mounting slots, has a recessed area, suitable for a mem- brane keyboard, on one face. The units are available with a clear or black anodised finish; the end bezels are moulded in black poly- carbonate as standard with translu- cent blue and IR transparent trans- lucent red available as optional alternatives. (070490-IV) www.hammondmfg.com BV51 1 32 Bit ARM Microcontroller with Operating System New from ByVac is their easy to use BV51 1 32 bit microcontroller board for education and real appli- cations. The system comes with full documentation, is easy to start and no external tools are required. All communication is via the built-in operating system based on Forth. A 100+ page user manual and tutorial shows how to interface a host of devices. User programs can be saved to Flash to produce a standalone system. BV51 1 is an upgrade path from 8 bits to 32 bits; this is in fact easier to use than most 8-bit microcon- trollers and much more powerful, yet small enough to be built into user applications. The possibilities are endless, from driving robots, milling machines; making a weath- er station, controlling heating to ex- perimenting with light and audio. No tools need to be installed on the PC and so this can be pro- grammed and used with any PC, ideal for students, no need to be tied to the computer lab. The BV51 1 has a 32-bit ARM LPC21 32, real time clock with bat- tery backup; 64 k Flash (OS uses 20k); 16 k RAM; ADC, DAC (10 bit), I2C, SPI, IASI; 2 x 32-bit tim- ers; 2 x UARTs (OS uses 1 15,200 baud); In-Application Programming (easily upgradeable). The board is powered by USB, with 5-V and 3.3V regulated outputs for exter- nal equipment. Processor clock is troller Foundation Book. 60 MHz and size approx. 80mm x 32mm x 14mm high The kit comprises a Processor, USB www.byvac.com Lead, CD-ROM and the Microcon- (070490-X) Multicore processor for telematics, consumer and industrial applications Freescale Semiconductor has intro- duced a highly integrated system- on-chip (SoC) processor optimized for high-performance, power-sensi- tive applications requiring complex graphics, multimedia and real-time audio processing. Built on Power Architecture™ tech- nology, the MPC5121e SoC de- vice is the latest member of Frees- cale's mobileGT processor fam- ily-the most widely used platform solution for telematics. Manufac- tured on advanced 90 nanometer low-power CMOS technology, the MPC5121e is designed to deliver exceptional multimedia perform- ance and feature-rich user interfac- es within a low power envelope, without sacrificing flexibility and robustness. The primary processing engine of the MPC5121e microprocessor is the e300 core built on Power Ar- chitecture technology, scaling to 400 MHz. The MPC5121e com- bines the e300 core with an inte- grated 2D/3D graphics core and a fully programmable 32-bit RISC- based multimedia acceleration core optimized for audio process- ing. Freescale also plans to offer a version of the MPC5 1 2 1 e without the 2D/3D graphics core. The MPC5121e processor is au- tomotive-qualified, making it ide- al for telematics, connectivity and driver interactive vehicle applica- tions. The device meets the reliabil- ity requirements of the AEC-Q1 00 standard and TS 14969 specifica- tion and is designed to withstand harsh environmental conditions. In addition to addressing telemat- ics, the MPC5121e device can be used in a broad range of em- bedded applications, such as net- worked industrial control and se- curity/surveillance systems, net- worked patient monitoring systems, 14 elektor electronics - 9/2007 gaming and digital home applica- tions, such as media gateways and set-top boxes. The MPC5121e processor's high level of on-chip integration helps reduce BOM costs and provides a flexible processing platform for a variety of embedded applica- tions. The device offers a rich set of integrated peripherals, includ- ing 10/100 Ethernet, PCI, SATA, PATA, two USB 2.0 On-The-Go (OTG) with an integrated high speed PHY, four CAN modules and 12 programmable serial con- trollers. The integrated display con- troller provides cost-effective sup- port for liquid crystal display/thin film transistor (LCD/TFT) displays. The 128 kByte of on-chip SRAM and numerous embedded memory buffers help ensure balanced sys- tem performance and system bus throughput while reducing latency demands. Processing performance is enhanced by well balanced sys- tem resources for the e300 core, graphics core and multimedia acceleration core, as well as the DDR-l/DDR-ll/mobileDDR memory controller with integrated 64-chan- nel DMA support. For more information about the MPC5 1 2 1 e processor, visit www. freescale.com/files/ pr/ mpc5 1 xx. html. (070490-V) www.freescale.com MonCon range Compact Control De- sign announces the launch of a product range intended for use in stand-alone and bench-top equipment such as ATE, scientific instruments and pro- duction equipment. The range includes boards for controlling/driv- ing motors, valves, so- lenoids, digital and analogue I/O boards, relay and interface boards. MonCon has been designed for ease of integration especially with wiring loom require- ments and can provide a compact, very cost effec- tive and rapid solution. The design enables cus- tom boards to be devel- oped quickly and we can supply complete systems or you can manufacture under license. (070490-VI) Compact Control Design, 77 Woolston Avenue, Congleton, Cheshire CW12 3ED. Tel. +44 (0)1260 281694. Web: High power 500mW narrow-band RF module targets long range applications Radiocrafts AS, a leading RF mod- ule supplier, now expands their product line with a high power narrowband RF module for the Eu- ropean market. The RC1 280HP, offering up to 500 mW output pow- er for increased range, is based on the RC 1 280 RF Transceiver Module for FSK operation with embedded proto- col. When used with quarter- wave antennas a line-of-sight range of 5-6 km can be achieved. The new RC1280HP module uses the same protocol and channels as the RC1280. Interoperation be- tween RC1280 and RC1280HP is therefore possible in a network with both long- and shorter range modules. The module is pre-certified and CE marked for operation under the European radio regulations for license-free use in the 868 MHz band, operating in 3 chan- nels in the sub-band at 869.400 - 869.650 MHz. Up to 1 0% duty- cycle (transmission ratio) is allowed in this band. The new high power module can also be used outside this sub-band if the power amplifi- er is disabled, reducing the output power to less than 1 0 mW. The RC1280HP module contains a multi-channel transceiver with a receiver sensitivity of -108 dBm at 4.8 kbit/s. With 30 dB adja- cent channel rejection, 40 dB al- ternate channel selectivity and outstanding blocking properties, the module offers exceptional per- formance even in a crowded and noisy environment. The new module measure only 1 9.5 x 60.5 x 6.0 mm, and comes in a DIL-style package with 2.00 mm pin pitch made for low pro- file board-to-board connection. Data buffering, addressing and error check are all handled by the embedded RC232™ proto- col. A standard UART serial bus is the interfa ce to the host for both data com- munication and configuration. Typical appli- cations include long range te- lemetry and re- mote control, automatic meter reading (AMR), fleet and asset management, home-, building- and industrial- automation, wireless security and alarm systems. (070490-VIII) www.radiocrafts.com 9/2007 - elektor electronics 15 INFO & MARKET SECURITY SYSTEMS Adding Security to Ren Mark Schultz (Applications Engineer Principal; Cypress) As portable media proliferates into more and more consumer products, data security is becoming increasingly important. New products need to be secure in order to protect confidential information from theft. Biometric security offers an economical solution that doesn't add significant user burdens such as extra pass- words or additional log-in steps. Biometric security meth- ods include fingerprint sensing, retina and iris scanning, signature analysis and hand geometry. Consider the case of fingerprint sensing. With a simple swipe of a finger, a user can authenticate himself to gain access to data on a portable storage device. Identification and security issues Identification comes in different forms ranging from pass- words to dongles to biometrics. These days, there is a password for everything. Remembering passwords usually involves storing them somewhere, which, in the security sense, is self defeating. Dongles are expensive to manu- facture and are prone to being misplaced. Biometric ap- plications need no passwords, require small and relatively inexpensive hardware, and fingerprints are never lost. There are various methods used to keep data secure from an unauthorized user. These include encryption and drive manipulation, among others. Encryption comes in two forms: software and hardware. Hardware encryption adds cost and size to a design. Software encryption is slow when used on larger drives. Drive manipulation in- volves hardware locking of the drive to prevent access to unauthorized users. One such locking mechanism is ATA Security, a feature available on all new hard drives. Here, a 32-byte password is sent to the drive electronics to put it into 'Secure' mode. After being power cycled, the drive comes up in a locked state until a password is provided. Since only the microcontroller in the enclosure knows the password, moving the drive to an unprotected enclosure won't make the drive readable. Sensor Types Some sensor solutions require image processing on the PC while other solutions use a co-processor to process image data. Different sensors also employ differing USB interfaces for getting data back to the PC. Such interfaces include Printer Class, Storage Class and Human Interface Device (HID) Class. There are pros and cons for all three, but they all share the advantage of using only native Win- dows drivers, making device installation unnecessary. On the hardware side, there are various interfaces rang- ing from SPI to Parallel bus. The type and speed of inter- face is related to the method of image processing. The sensor with the co-processor requires only a few hundred kilobits per second while the sensor that uses the PC for image processing requires a 6.5-Megabit per second throughput. The sensor used in the implementation de- scribed here is available with either an SPI or a Parallel bus interface. System Requirements Removable storage is generally made up of a 2.5" or smaller hard disk drive (HDD), a drive enclosure, power supply and a USB-to-ATA bridge. This solution allows for a very modular design. Adding a fingerprint sensor, as will be seen, is not that difficult. The USB-to-ATA Bridge for this design will be the Cypress EZ-USB FX2-LP. The following section will detail the addition of the Authentec AES2510, a slide type of fingerprint sensor, to an existing USB Mass Storage device. The AES251 0 does not have a coproc- essor, so the interface between it and the USB controller needs to support data burst rates up to 6.5-Mbps to keep up with the data coming from the sensor during a finger swipe. This isn't a problem since the FX2-LP can already keep up with Hard Drives using UDMA-100 transfer rates. Since image processing will be done on the PC, there will be instances where the USB controller will be required to rapidly switch its interface back and forth between an ATA interface and a fingerprint sensor interface. This is easily accomplished by modifying the FX2-LP's interface on the fly. Following is a block diagram of the USB-to-ATA Bridge with the fingerprint sensor added. 16 elektor electronics - 9/2007 Implementation For this design, the sensor interface will be added to a stand- ard USB-to-ATA Bridge reference design using the Cypress EZ-USB FX2-LP, see Figure 1 . The FX2-LP contains a USB 2.0 Serial Interface Engine (SIE), an enhanced 8051 micro- processor and a General Purpose Interface (GPIF). The GPIF is a state-machine based interface capable of data transfers of up to 96 Mbps. The GPIF can be configured for various interfaces including ATA, NAND, Utopia, EPP and Com- pact Flash. Since the GPIF is a RAM based state machine, multiple sets of control waveforms can be copied in and out, making the GPIF a reconfigurable interface under firmware control. Since the GPIF is directly connected to the FX2-LP / s USB FIFOs, there is no need for firmware to do any data manipulation on the sensor data stream. For this design, the GPIF waveforms will include PIO Read and Write as well as UDMA Read and Writes for the ATA interface. Additional waveforms for reading from and writing to the fingerprint sensor will be added to the project. The firmware for the hard drive functionality will be from the CY461 1 Mass Storage reference design. Firmware for the fingerprint sensor will be taken from a code library supplied by the sensor manufacturer. The AES2510 is available with either an SPI or a parallel bus interface. Since our existing hardware already uses a parallel interface, we have chosen the parallel ver- sion of the AES25 10. I/O requirements include an 8-bit data bus, plus six control bits - RD, WR, CS, AO, INT and PWR_CTRL. We can share the lower byte of the ATA bus for data if we are careful with the chip select inputs to both the sensor and the ATA bus. For the control and sta- tus, we can use Port C of the FX2-LP. Communication between the sensor and the application software is accomplished via the SCSI Pass Thru interface, an extension to the Windows Mass Storage Driver. Use of SCSI Pass Thru enables the sensor to use the same USB interface as the Mass Storage Device, so no additional device drivers are required for this device. When a Pass Thru command is received, firmware from the sensor library is used to process the command. The very first thing that the firmware does is to overwrite the GPIF waveform memory, replacing the ATA waveforms with sen- sor waveforms. Then the firmware acts upon the Pass Thru command performing the required reads and writes to the sensor. When the pass thru cycle is complete, the ATA waveforms are copied back into GPIF memory. User Interface A typical secure drive will contain three partitions as shown in Figure 2. One partition will contain the Biomet- ric Application Software. This partition will usually emu- late a CD-ROM for two reasons: 1 . CD-ROM offers a better AutoRun response than a disk drive in Windows; 2. CD-ROM is write protected so the Biometric applica- tion cannot be accidentally erased. One of the two remaining partitions will be for un-secured storage. The user will be able to access this data at any Figure 1. Proposed connection of the EZ-USB FX2-LP unit to its peripherals. time. The last partition will contain the protected data area. The user will not be able to access the data in this partition without first verifying ownership via his fingerprint. A biometric application will Auto-Run from the emulated CD-ROM partition on drive start up. The application will process fingerprint image data sent via the Pass Thru in- terface for the purposes of both user enrollment and user verification. Verification is based on a comparison of the user's swiped fingerprint to their enrolled fingerprint im- age. Once the user is verified, the public partition will be 'unlocked' and its data will be available to the user. If the drive is disconnected from USB or if power is removed, the protected area will once again become inaccessible to the user. Cost of components to add the biometric option is under $7.00. Solutions for other media such as NAND-Flash are currently under development. ( 070422 - 1 ) Further information Cypress EZ-USB FX2-LP: www.cypress.com AES2510 fingerprint sensor: www.authentec.com Biometric Application via AutoRun Public Storage Area Protected Storage Area Figure 2. Mapping the available memory. 9/2007 - elektor electronics 17 INFO & MARKET A BRAND NEW SITE Elektor's New Surfer-readers, our strength lies in Denis Meyer (Elektor webteam) Elektor has spared no effort in bringing its readers a brand new website that's better suited to their needs. And before starting, we collected different people's wishes to try and find the best way to reconcile them. The new website went online on 26 June 2007. Here are the main thrusts of the changes with respect to the previous version (active since May 2005): • freshened- up, clearer presentation; • simplified, faster navigation, particularly for easier searching; • each visitor's identity and personal status is now taken into account (if they so wish) — although of greatest benefit to our magazine subscribers, non-subscribing but regular visitors will find this helpful too; • articles and other files are no longer downloaded using phone surcharge, but are paid for using Elektor credits (E-cre- dits) on the site itself; • the secure payment methods have been improved and extended to include PayPal; • the professional tools now in place for sending out our free electronic 'E-weekly' newsletter will let us improve distribution. It's actually quite hard for the individual to truly appre- ers in East Midlands as for those in Bangalore or further ciate the scale of the new Elektor website (Figure 1). afield still, it's a site with four faces, in four languages Designed to be equally convenient to use for our read- (German, English, French, and Dutch). And it's also your Figure 1. This screen grab from the new Elektor website gives an idea of the organization of your electronics platform. A good balance has been struck between physical and virtual products. ft ‘IT wof Id-lead iivg * rvilweik Apr etaci; eta ci ionic* Ha me Hi W! Hngfljire Suawr.fc-t! nev- farum- f.rm QDlliCZEiMH I- ■! 1 1 lkj i. ■? an aulnir -1 Ariirln u hitariiidCiva dr£n£r^ Fra d u c !■* U ttoak*- «l Cb L Runii V ■ (■ "yJUfls V f Ihkn Li > V Ui CiWtIf !!|li-ri U n&aaiift#* W l lelrtof ■ Cntdrts L If Met La a in Lm&il / Lvfl iff) "ip-Rirni rm'Ktralir-F Inf CVDON TtafliKonunr? 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I>: 1 1 1 f l^arr '0 O flakier I'.'idfi .‘i> ■ • 18 elektor electronics - 9/2007 ebsite diversity! personal shop counter on a worldwide scale, where every Internet user, wherever they are, can pay for their purchases in the currency they’re used to, whether that’s €uros, pounds sterling, Swiss francs, or US dol- lars, using the payment method they prefer. Add to this the number of options in terms of shipment methods, and you'll get some idea of just how complicated it all is. Ele- ktor readers, our strength lies in your diversity! www.elektor.com Homepage Whilst the domain name www.elektor-electronics.co.uk continues to exist, with the launch of our new websites you are automatically switched through to www.elektor. com. The various menus and tabs on the homepage show a variety of services on offer from various Elektor depart- ments including sales, subscriptions and of course editorial. These include our famous PCBs, kits and modules supplied through mail order. There's also information on conven- tional physical media, printed documents, CD-ROMs, etc. On the same site you can also find virtual information ac- cessible online directly from your own home: downloads of magazine articles in PDF format, project software, extra documentation, free software, news items, and responses to questions in the forum. On the German and Dutch ver- sions of the Elektor site you can also find special lectures (masterclasses), workshops, seminars - all activities that Elektor is getting ready to develop for the UK market too. In the same way that the horizontal menu bar doesn't change, the contents of the left-hand column also stays the same wherever you are on the site. The other blocks change, not just with the page you're on, but according to your visitor status. The website content is adapted to your status, so what you actually see may depend on whether you're logged in or not, or are an Elektor maga- zine subscriber or not. My Elektor Interactivity between Elektor and visitors to its website has been developed in such a way that people who just drop in don't remain 'just another' anonymous visitor, but can - if they so choose - be recognized individually. Logging in to our new site is a personal thing between you and us. Magazine subscribers are the first to see the benefit of this recognition - as soon as they sign up on the new website, they get a welcome gift of 30 Elektor credits (Figure 2). Subscribers enjoy other advantages too (see 'E-credits' below). From now on, you won't need to use a nickname to log in to the site (although you'll still use it in the forum), just your e-mail address. Each visitor is invited to create their own profile on the site, Ny FI "lei nr L-U i| 114 Email / Username- lag in a T n J ,E DVnr.l l‘-il M«i>iE«c ^hcififi mig f.irt PtUfv CwHa: & Figure 2. Your way in to the site and your control panel. which can remember their delivery (and/or billing) ad- dress. This profile also allows regular customers to define a preferred payment method (credit card, PayPal, etc.). In this same 'My Elektor' block (bottom left of all website pages) you'll have direct access to your shopping cart, as well as your E-credits balance - we'll be coming back to that later. Didn't we tell you the site would be more convenient? Products The Elektor range of products and publications also ap- pears in the left-hand column of the website and so re- mains within mouse range at all times. Wherever you are on the site, you can go directly to any category of prod- uct (Figure 3). f 1 ril ill SI i • m w fiue&i v CP’E*m* -W km ft Mn rliifi-s tl V tantroltor-i tl M ag-sj ie s VOff* r* V f li'-S-t-nr C.r>riiC-i Figure 3. To allow direct access to any product category, this list remains visible wherever you are on the site. www.elektor.com/credit E-credits One of the great new features on the site is the introduc- tion of Elektor credits (Figure 4) for our paid downloads. You can buy E-credits just like any other product or publi- cation on the site, your personal balance is credited, and then you can use them as you wish to pay for downloads. One of the advantages of this new system is the consider- able reduction of the standard charge for an article pdf or PCB artwork pdf - now only £ 0.80 (€ 1 .20) per file, Elektur-CreJilSi hlcklor Credit h; Huy :a Lie-ktor Lrcdita £ [],$[) Mnrt inform Mian P r-CrsditR: RiibsfTib^rs only Huy £>U LJektor trcditi / ,F.n Mart mfdfm-i’jon o Huy i/n Flrktar Crtidlt-s L T.ni Mura ml uf niVjiju & Figure 4. Elektor credits (E-credits) make downloading from the new site considerably easier. The special rates are exclusive to magazine subscribers. 9/2007 - elektor electronics 19 INFO & MARKET A BRAND NEW SITE Figure 5. A website is only as good as the speed and accuracy of its search engine. I.Olf tho wof I rf-l ii 3 d i ncj IwIVIW ■ n#|WQi-lH fjsr ■ j E ■ j P- ■- AFjtfc^/Vidflo/PhpEagr-iSi h r "riirqiLilF r/^nitwflrr/lnlpii ii-ipI MbhifajP BF l>iC Hi.i in w tdutbtionfEftffflrhiiCinn iirr 1 mnrit Mira-p^htrnllnrt PokM Supply Miin l flll'infl«iii! F '■iiF'.r riffc T | F n Choo-ir an loptirm 70D7 zou*.< 30fH ^rjijj | 10 EM 1 im 1 ■Lhnetfl qn ftpbrir. ■ »n Hrfi rii l r- Jin nfrtieirv ii ■>n*iK V U-9 A H c n r 0 £L as against £ 1 .00 on the old site (which did not offer the € currency). Elektor magazine subscribers benefit from a special rate for buying bulk credits (in 60s or 1 20s) at a preferential rate - provided, of course, they have duly logged in to the site at least once using their subscriber number and personal code. Non-subscribers can buy bulk credits too, simply by using the 'quantity' box. Improved searching Also permanently available through the left-hand column are the new site's greatly improved search functions. The Search box covers the entire website, while magazine ar- ticles can be searched separately, using a two-step filter, first for the Subject Area, then deeper for Year Vol- ume and/or Alphabet (actually, alphanumerical order), see Figure 5. Searching is fast and the results are very easy to read. www.elektor.com/magazines The Magazine page has been revamped. Tabs now make it possible for the information to be presented even more Figure 6. The new magazine article presentation brings together all the relevant details onto a single page with tabs and links. Iluirir *■ ■"’Pjijv mi 1 % > if i..i! i F * June ■ SL-Jiid ■ Al-u ihz UBU" if Pin a l#s c r Stand- Alone OUD Artdlly*er Iivte rpret 'Ir&ubfa codsi ' mttHritrl fir, P.ih iihF-il in i-hua 2(6, May ?I1Q? Tlhif hdndf -in-blvf&r rrh&ktf * fimpl* |ob rummaging llirl$iiyli Ihr in! i : r :nnl mil iliirnl Lt Ihn -CAviU^-aiuuns-s-iljl? part *ul yC nr n vbmE Fi> a ihf vii.mi lIaIiiiii . tom pPAAhRl S-rlr -m .1 rihiAi!" Fi r'O di I ■p 2 IL r ; 3 i:' - I lid J :u:. - I .. rra,y j 31-3= " ►'hCm =: SIL-S irc&y Cmpm ■l-ir-fuJ. ^IbCS.tJ-ClC * iQQn.*- MhiTy rnri i+f n-^i i-Wi louiblishtd >n ERfekur •vsju 1 * idd^iwnP avlliirg Mrt'U-ur l . Ktliv ►'rt pi-s-durti dpplic:4bl*) ifrcim ih* ri*k?nj shop ark r>iUd abova. 20 elektor electronics - 9/2007 1 1 on it- i- E'j-o.hn t-i i- U d □ k -i- books Search fan 3 eer ch in; I ta*hf 3 LFook-t ElwLftrcmM | Computer "] Audio- | Nkva&CiMrell#rE | -'r>>yr j -i 'iwmj Recently published In the Spotlight Vmi.il r,i-cif Inr F I-pt trnnil-r t F nqini-rt'ing ftjl |l III =llllil i*. H U - V IJ ■ j / IJT-. - 1 u - : J "i £ 27. M Msn inform-ilicfi Q Bestsellers Vnuil Dj-mc fo€ I k-itronis-f- Engfcnre-rjviq ApfllFillBni 10 -9(13705-^3} L 27 .'J 0 Mown mlumi-sfliu-'i A Hi l >u 'll pm II u r 8 T in ffl-HKiTK-t?'*) jf ]ft.7£| Mote mfc'im-Yuori s® FL InCc-rfiice-* under Window* in *oe?(k . 3 } f j'S.o*, M&r?i infnrrnAriiMi €3 M-udc-ni Mi-jEi feiil *\ii \rn AuijihlMT' t Jiii-d Hit InroidLbl output trftrwferrner* U n ! v r ill ii|>lrFinr -i nri- c riiiirdril Fif rrm-* Fit- Iw; tin: no pluf ulfrd whtn it oomei ba pro<«-fi aud-c- ■iigrili. Thu ns mh in. irvin M ri.iviic.il tr-rihnfi I .iMil inudnrn mcr^im-ini il\ Iiai i p i‘> :l ■! ji ipv 3 v.iI of tho vaJyfi -fimptifmr. 1 ho use of tonoid-d-ooro output tTMis-foTmars , developed by the author nvnrttir pin IB feMV, h.iv nnnfenfMrtAri 1w rhi nroivjil. Thn irni'-i i p tiimtIi «!>!■■ Fh jTI> irm ill Huiun •b-Qr-ahsTFivcri- -dpc fttv Entmmljf wida Fps-quciKV ra/ige-i Mid ttirur wiry low level* at linear vuwl ii^iiIiiiom d^urfeiun., & Microc n-irtrollor Uo»ic« MtrriftfifiHfrattftrv hjwn hervimr mi inrii-cperuialilr [ml id iiHiihm pT-hi J rom. TIip? 1 1 1 .* k f llini-j 1 . Figure 7. In the E-shop too, the use of tabs makes for easier browsing. clearly, components lists, hyperlinks, related articles, cor- rections, supplementary information, related shop prod- ucts - all this can amount to a great deal of information, which is now much more clearly structured (Figure 6). The publication month is shown for each article, with a link to take you straight to the corresponding magazine issue. www.elektor.com/faq FAQs (frequently asked questions) have been added in par- ticular about the new log-in procedure. FAQs for published projects may also appear here in due course, but for the time being they remain under the relevant forum topics (for example, the June 2005 'GPS Receiver on USB'). www.elektor.com/shop Presenting the products via tabs means several categories can be shown side by side and lets you move quickly be- tween them without getting lost. The specific search function within each subject area make it possible to target searches better (Figure 7). You'll find the same presentation and interdependent links between the products in all the Elektor product and pub- lication categories: bare PCBs, kits, modules, CD-ROMs, books, E-blocks, special offers and more. It's well worth paying a visit! www.elektor.com/forum The Elektor forum contents have been transferred to the new website in their entirety. This is a substantial treas- ure-house of valuable information on many projects and background articles published in Elektor. We're quite sure this new version of the forum site will soon once again be seeing the lively level of activity of the early months of 2007. Amongst the new features, the RSS feed lets you follow the flow remotely. Another very effective improvement for browsing the website is the trail or 'breadcrumb' that helps you find your way back up the forum tree (Figure 8). Once you've realized how it works, this hierarchical line of links can save you a lot of time moving from one dis- cussion to another in the forum. www.elektor.com/subs Amongst the other key functions of the site is also the possibility of taking out a subscription online - one page that's really worth a visit, especially as there are now more advantages than ever for Elektor subscribers. And that's just for starters! www.elektor.com/news Not only have news items on the website been brightened up with one or more illustrations (where available from our sources), but they now appear as a constantly-chang- ing display on the home page. What's more, when visitors come across a news item they find interesting, they can click on a link to share the infor- mation automatically with one or more friends. The old site's news access restriction has been lifted - from now on, recent news items are also accessible to visitors who are not logged-in. Login is only required for retrieving archived news items. Conclusion Ffaving seen the scale of the changes, it's no surprise the new Elektor website was longer than planned in gesta- tion - in spite of all our efforts. Just like eternity, it always seems longest near the end - but we think you'll agree, the finished result was well worth the wait. (070155-1) Mfiiw ;■ r irk TUR mmiM F PrnHIrr MilMing Mni-hlnr * W hirr hi JI? Figure 8. Click on the hierarchical links to move back up the forum tree. 9/2007 - elektor electronics 21 INFO & MARKET AUDIO Rolf Hahle Building a good-sounding amplifier on your own is not as easy as it may seem at first glance. Using fully assembled, aligned and guaranteed modules can increase your chance of success significantly, while still leaving ample room for creative freedom. Our test reveals that the available products differ in many regards. You might think that amplifiers are like sand on the beach. But if you restrict your search for fully assembled ampli- fier modules to hi-fi applications and omit modules for motor controllers, RF transmitters and all other industrial ap- plications, the range of available prod- ucts shrinks quite quickly For this test, we selected eleven different modules from various manufactur- ers, with an output pow- er range extending up to nearly half a kilowatt. They can be classified as linear or switch-mode amplifiers, depending on their operating principle. The representatives of the ‘linear’ category in our test group include rather simple types as well as extremely sophisticated models. Three of the modules are sim- ple IC -based designs, while one is ful- ly encapsulated and thus keeps its se- crets to itself. The most elaborate modules come from manufacturers of the switch-mode am- plifiers, all of which belong to the class of PWM amplifiers. Amplifiers in this class, which is also called Class D, are being used more and more often as hi-fi amplifiers, where they are sold as ‘dig- ital amplifiers’. Of course, most of them do not actually operate in digital mode (due to the absence of an A/D convert- er), but they have never- theless ignited a religious war among technology adherents. One of the con- tentious issues here - and a subject of heated de- bate in various forums - is whether overall negative feedback in a Class D am- plifier should be tapped off before or after the output filter. All variations are rep- resented in the test group. NewClassD leaves the pre/ post choice to the user and ColdAmp employs global 22 elektor electronics - 9/2007 j About the author Rolf Hahle has been actively involved in building amplifiers and loudspeakers since the age of 1 2. While he was studying for a degree in me- I chanical engineering, he accumulated a wealth of experience in electronics and electroacoustics by repairing hi-fi equipment, building and sell- i 1 ing various DIY loudspeakers, and installing 'carnival-proof' public address systems in a variety of pubs in Cologne. After several years as an editor at Elektor Germany and a tour in the PR department of a manufacturer of PC-based measuring equipment, he has been in charge of the i measuring laboratory of the hi-fi magazine Stereo for the last 10 years. I ___________________________________________________ ______ j feedback in combination with a fixed switching frequency and a notch filter. Test procedure In order to subject the amplifiers to proper evaluation, we of course loaded them adequately. As we wanted to test the capability of the amplifier instead of the capability of the power supply, we used a pair of stabilised labora- tory power supplies made by Delta Electronics to avoid any issues in that area. For each supply voltage, we had access to a maximum voltage 70 VDC at up to a whopping 45 A if necessary. That’s what you call a sustainable DC source. We only used a specific mains transformer for our measurements if the manufacturer recommended or offered it, and this is also noted in the results. We measured the output power using non-inductive 8-ohm and 4-ohm resis- tors with adequate power ratings. All other results listed in the table were measured using a 4-ohm load. The readings and all signals necessary for making the measurements were ob- tained from a Rohde & Schwartz model UPL Audio Analyzer. The same meas- urement procedure and sequence was used for all the amplifiers. Exceptions were only made where they were un- avoidable (for example, there’s little point in trying to measure intermodu- lation distortion using 8-kHz and 60-Hz signals with an output stage that has a built-in low-pass filter with a 2.6-kHz cutoff frequency). For each sample module that we test- ed, the complete results and a frequen- cy response curve with a sweep range of 20 Hz to 100 kHz are shown in the large table. ( 060322 - 1 ) Manufacturer Website Module Price* (incl. VAT) * rrp (approx.) Options Amplimo www.amplimo.nl A120 £ 62 (€ 90) Power supply kit (transformer, rectifier and electrolytic capacitor) (£ 48 / € 70); speaker relay (£ 4 / € 6) Coldamp www.coldamp.com BP4078 £ 86 (€ 125) Switch-mode power supply (£ 1 30 / € 1 90) Ground Sound www.groundsound.com PA3CC £ 1 34 (€ 1 95) PSU4SA power supply module (£ 1 62 / € 235) Hypex www.hypex.nl UCD400ST £ 83 (€ 120) Power supply module: standard (£ 55 / € 80) or high-grade (£ 1 37 / € 200); transformers Marchand www.marchandelec.com PM224 U$ 200 Power supply incl. transformer (U$ 100 and up); heat sink (U$ 20) Monacor www.monacor.de 1 PA-50 £41 (€60) NewClass D www.newclassd.com NCD1 £ 196 (€ 285) Power supply module (£ 1 1 0 / € 1 60 and up); soft-start circuit (£ 27 / € 40) Newtronics www.newtronics.net available from www.lautsprechershop.de Verstarkermodul AMP 7293 £ 66 (€ 95) Power supply module (£ 92 / € 133); transformers Sitronik www.sitronik-industrie.de VP 703B £ 48 (€ 70) Transformers (£ 21/ € 30) Thel www.thel-audioworld.de Accusound 100 £ 172 (€ 250) Smoothing filter (£ 65 / € 95 and up); mains filter (£ 26 / € 38 and up); heat sink (£ 26 / € 38 and up); VU meter; transformers Velleman www.velleman.be VM100 £ 35 (€ 50) * Preisempfehlungen/ungefahre Preise 9/2007 - elektor electronics 23 INFO & MARKET AUDIO 1 Amplimo A120 Amplimo in the Netherlands produces a whole series of amplifier modules co- vering a power range of 30 W (A30) to 1 80 W (A1 80). Our text example, a model A1 20, is only 8 cm wide by 5 cm high including the heat sink. Its depth of 1 2 cm is mainly due to the long fins of the heat sink on the rear of the module. Nothing can be seen here of the electronics, since they are entirely encapsula- ted. The plastic that surrounds the electronic components is linked to cutouts in the extruded heat sink to create a module that makes a very robust impression. Eight tinned metal terminals stand at the end of the module opposite the heat sink. Besides two terminals for the balanced supply voltage (±47 V), they include a ground terminal in the middle and the signal input. The RELAY output pin swit- ches to ground a few seconds after the supply voltage is applied. This allows a relay to be used to eliminate loudspeaker clicks during switch-on and switch-off. The module is ready to use without any additional circuitry. An integrated limiter is activated automatically if the module is overdriven, The LED output provides a constant current to drive a LED indicator when the limiter is restricting the signal. The limiter can be disabled by connecting the LIM pin to ground. Coldamp BP4078 This module has a typical 'industrial' open-frame construction with the PCB fitted in a length of U-shaped aluminium channel, offering adequate cooling for nor- mal use. This suggests mechanical solidity, although the ring-core choke at the output, which is supported only by its leads, clouds the picture somewhat. The BP4078, which has a balanced input and operates in PWM mode, makes an exceptionally robust impression in the electrical domain. It delivers 400 W into 4 £2 or 240 W into 8 £2, and it can also be operated with a 2-£2 load. This modu- le measures just under 8 by 1 0 cm, and with a height of 39 mm it occupies only one height unit in a 19-inch rack. Unlike most PWM amplifiers, it has an overall negative feedback arrangement that causes the frequency response to be largely independent of the load impedance. The supply voltage and loudspeaker are connected using 6.3-mm spade connec- tors, and all other signals are connected via a single-row pin header. The modu- le has over/undervoltage protection and overcurrent protection. A fault condition - even if it is only transient - is indicated on a separate output for at least 2 s. There is also an output for a LED to serve as a clipping indicator, as well as a clock pin (CLK) that can be used to synchronise a group of modules. Thanks to a remote control port, a (normally jumpered) connector for a volume control, and the option of powering the driver stage separately, the module can be used for practically any application. The very ex- tensive documentation (in English) is easy to understand, and there application notes for optional configurations are included. Ground Sound PA3CC This conventionally designed power amplifier with bipolar transistors operating in Class AB comes from Denmark. The manufacturer rates the output power at 300 W, but in our measurements the limit was reached at 380 W. The entire cir- cuit is built using discrete components. The aluminium profile on the long edge has three output transistors for each supply voltage fitted on top, with the dri- ver transistors fitted on the bottom. The PCB is double-sided and through-hole plated, with SMD components on the top and conventional components on the bottom. All connections are provide by adequately dimensioned solder eyes. There is a Mute input that can be pulled to ground to eliminate clicks when swit- ching the output stage on or off. The module shuts down reliably if it reaches a temperature above 90° C, and it resumes operation automatically after cooling down. Two conventional fuses (5 x 20 mm, 6.3 AT) in the supply voltage lines are located conveniently on top of the board. The manufacturer specifies the mi- nimum allowable load as 2 ohms. We made our measurements at 4 ohms, and we had no doubts at all regarding electrical or thermal stability. This was done with the module attached to a heat sink (not included with the mo- dule) rated at 0.6 K/W. The operating instructions are comprehensive and provide some suggestions and explanations for optimum cabling. 24 elektor electronics - 9/2007 Hypex UCD 400 These amplifiers with their characteristic blue anodized T-shaped aluminium ex- trusions come from the Netherlands. The extrusion is used to attach the module to a heat sink, to secure the power transistors mechanically, and to bond them thermally. Hypex can supply modules rated at 180, 400 and 700 watts output power in two different versions. We tested a 400-watt module in the standard version. An Advanced Version' with a higher-spec input opamp is also available. The modules operate properly from unregulated supply voltages in the range of ±45 V to ±65 V. Overall negative feedback is integrated into the circuit design. It taps off the feedback signal after the output filter, which minimises the effect of load impedance on the gain. This was verified in practice: the frequency res- ponses with 4-ohm and 8-ohm loads are the same within 0.5 dB. That's hardly a matter of course with a Class D amplifier. A balanced input and a remote control input are available at a four-way pin header, while the supply voltage and loudspeaker connections are made via broad, readily accessible spade terminals at the front. In our test with 430 W into 4 £2 and 226 W into 8 £2, the amplifier yielded slightly higher figures than the values specified by the manufacturer. With dimensions of 8 x 3 x 9 cm, this module is one of the smallest of the tested units, but it sailed through the entire measurement procedure without any supplementary cooling and without shutting down. Marchand PM224 I This Rochester, New York (USA) based manufacturer makes a power amplifier built with discrete components that occupies an area of 1 0 by 1 4 cm and fits on a Euroboard PCB with room to spare. With the appropriate supply voltage, the PM224 can deliver 200 W into 8 £2 or 4 £2. Marchand recommends supply vol- tages in the range of ±45 V to ±65 V, or less for Class A operation. The input is a balanced design, but it can be driven single-ended without any problems by tying the unused input line to ground. There are two 2-way pin headers on the board that can be used to jumper out the input coupling capacitors. This allows the module to be operated with AC or DC coupling. The supply voltages and loudspeaker are connected via PCB-mounted screw terminals. There are sepa- rate supply voltage terminals for the driver and output stages. The advantage of this is that powering the driver stage with a higher voltage allows a greater vol- tage swing in the output stage and thus better overall efficiency. As the module can also be purchased as a DIY kit, it is supplied with complete circuit documentation consisting of a schematic diagram, component layout and components list. The assembly instructions (in English) include detailed descriptions of the operational configuration options (individual or bridge) and possible adaptations. Component values for gain values between 20 dB and 40 dB are provided in two tables, and different quiescent current settings are shown for operation in Class AB or Class B mode. We measured the module operating in Class AB with the recommended heat sink (0.8 K/W). Monacor (Monarch) IPA-50 The smallest module in our test implements the standard application circuit for the SGS Thomson TDA7296. Monacor recommends ±22 V for operation with a 4-ohm load or ±29 V for an 8-ohm load. This corresponds to an sinusoidal out- put power of 45 W, but the small heat sink included with the module is definitely not adequate for this. The data sheet recommends using a small fan for continu- ous operation. The compact module (with dimensions of only 7x5x8 cm) has short-circuit and overtemperature protection. Despite the small size of the circuit board, it in- cludes a bridge rectifier and electrolytic smoothing capacitors. However, 2200 yU F I per supply voltage is on the small side in our opinion, so we measured the mo- dule using the laboratory power supply as well as with the recommended trans- former. Using a separate power supply was no problem, since all connections are accessible on the front of the module via solder posts. This makes it possible to power the module from an AC source or connect a DC source after the built-in smoothing capacitors. As could be expected, distortion and intermodulation are distinctly worse with the module operating from the transformer, but transient performance is distinctly better thanks to the higher no-load voltage. Despite the simple design, the measured results are not just OK, but in fact quite good. The only thing that stands out is the rapid roll-off in the bass region. Maybe the input capacitor (470 nF) is too small. The module comes with concise but adequate multilingual documentation, including a schematic diagram. 9/2007 - elektor electronics 25 INFO & MARKET 1 AUDIO Newtronics AMP 7293 The AMP 7293 module comes from Germany. It is the only module in the test that is available in two mirror-image versions. If you use an enclosure with heat sinks on the sides, this allows the wiring between a power supply located in the middle and the two amplifier boards to be kept very short. Three SGS Thom- son 7293 amplifier ICs are wired in parallel on the compact PCB (dimensions 5x14 cm). The manufacturer claims that this arrangement ensures that loads with a impedance as low as 1 .4 can be supplied with adequate current. Sol- der-mount 6.3-mm spade terminals are provided for the loudspeaker and power supply connections, and two solder eyes are provided for the unbalance audio input. This module is very easy to use. No settings are necessary, you don't have to fit any jumpers, and there are no details to take into account. The Class AB ampli- fier can operate from a mains transformer with dual secondary windings rated at 22 V or 30 V each (rms AC), which yields an output power of just under 1 00 W or just under 190 W, respectively, into an 8-ohm or 4-ohm load. The manufacturer recommends a heat sink rated at 0.8 K/W for 8-ohm opera- tion or 0.5 K/W for 4-ohm operation. r NewClassD NCD1 The circuit board, which measures only 11x5 cm and has components on both sides, houses a switch-mode amplifier that according to the manufacture ope- rates in a special mode called 'Nano Alignment', which is not further described. The efficiency is slightly lower than with a typical Class D amplifier. Consequently, an aluminium plate with a thickness of 4 to 6 mm and dimensions of at least 10x15 cm is recommended for cooling a pair of amplifier modules. The layout is very straightforward, and all control and power inputs and outputs are availa- ble on a 7-way pin header on one of the narrow edges of the board. The very informative documentation discusses many aspects of hi-fi. For example, the sound depends on whether the negative feedback signal is tapped off before or after the output filter (pre-filter or post-filter mode). This can be con- figured on the PCB by means of a solder bridge. The input opamp (a LM61 72) is socket-mounted, so you are free to experiment with the opamp of your choice. A special feature of the switch-on procedure for the NCD1 can lead to inconsi- stencies if a supplementary soft-start circuit is used in the power supply. A microcontroller in the amplifier measures the actual value of the supply voltage approximately 2 seconds after switch-on and stores the measured value as a reference. If the supply voltage does not reach its nominal level before this time, the module will shut down due to the presumption that the voltage is too low. We used ±45 V for the test, but the maximum rated voltage is ±63 V (with a rated output power of 400 W into 4 ohms). Sitronik Industrie VP 703 This fully assembled and cabled module is a complete backplane amplifier with two channels and a filter circuit, which is designed to drive the tweeter and woo- fer of a two-way speaker. It has a balanced input with an XLR connector and an unbalanced input with a Cinch connector. The input can be selected using a tog- gle switch. The levels of the two channels can be set using two potentiometers. The corner frequencies of the third-order high-pass filter and the low-pass filter (also third-order) are fixed at the practical value of 2.6 kHz (-5 dB). The ma- nufacturer can also configure other frequencies on request. The filter response can also be changed (up to seventh-order) by means of a daughterboard. The VP 703 is a conventional design. The filter circuit is implemented entirely using NE5532 ICs, and the output stages use two TDA 7294s for the treble channel and two TDA 7294s (operating in bridge mode) for the bass channel. A 4-ohm tweeter and an 8-ohm woofer must be used in order to achieve the maximum output music power (70 W treble and 1 30 W bass). The power supply is adequa- tely dimensioned with a 220-VA toroidal transformer and two 10-mF capacitors. The amplifier ICs have internal short-circuit, overtemperature and DC offset protection. The module makes a very robust impression, and with di- mensions of 31 .5 x 1 9.6 cm it can hardly be called 'small'. An allowance of 1 2 mm on each side can be subtracted if the module is built into an enclosure, so a cutout in the loudspeaker enclosure with dimensions of 29.1 x 1 7.2 cm is adequate. 26 elektor electronics - 9/2007 Thel Electronic Accusound 100 Thomas Hartwig, the head of Thel Elektronik, kindly sent us a complete stereo amplifier with the latest-generation Accusound 1 00 modules for our test. This very elaborately finished module has an aluminium extrusion fitted along one of the long edges, with ten MOSFET power transistors screwed onto it. The smoot- hing capacitors, a DC protection circuit, and a pair of relays wired in parallel for switching the loudspeakers in or out are also fitted on the double-sided PCB. The module operates from balanced DC supply voltages in the range of 20 V to 80 V, with a maximum rated value of ±95 V. If you want to achieve the maxi- mum possible voltage swing from the output, the driver stage can optionally be powered with a voltage that is 5 to 7 V higher and possibly stabilised separately. The bottom of the circuit board is fitted with hefty copper strips to reinforce the PCB tracks in the region of the output transistors. The supply voltage connections and loudspeaker terminals are implemented as threaded studs. Instructions for operating the module in Class A or Class AB are available on the Thel website. Thel can also supply the module with the same technology under the designation Accusound 40, with only four power transistors and correspon- dingly reduced maximum power. Four different versions of the Model 100 are also available. They differ in terms of circuit design and the quality of the components used in their construction. Velleman VM 100 The traditional design of this power amplifier, which operates in AB mode, ma- nages to do its job with six small-signal transistors (one of which provides tem- perature stablisation for the quiescent current) and two bipolar power transistors. The circuit board, which measures slightly less than 7x11 cm, has room for the rectifier and smoothing capacitors, even though all the components are fitted on one side of the board. However, the smoothing capacitors are only 3300 jL/F, which is on the small side. A red LED serves as a supply voltage indicator. A 47- k£2 potentiometer can optionally be connected ahead of the unbalanced input to act as a volume control. The manufacturer recommends a mains transfor- mer with dual secondary windings rated at 25 V to 30 V AC, which is sufficient for 70 W into 8 T2 or 1 00 W into 4 T2. The concise but graphic data sheet (in German) specifies a minimum load impedance of 4 £2. Velleman explicitly re- commends against changing the preset quiescent current level, which can be adjusted using an easily accessible and extensively described trimpot. For our test, we powered the module with ±40 V DC connected to the PCB directly after the rectifier diodes. Spade terminals are provided for the supply voltages and loudspeaker, while the audio signal reaches the amplifier via two solder pins. This is a mechanically robust, compact and economi- cal amplifier. Summary All in all, we tested quite a wide assortment of modules. They ranged from simple but nevertheless good designs, which are open to user measurements, soldering and modification, to complex closed designs. If you simply want to amplify a signal, the Monarch module is certainly a good choice. The Velleman module undoubtedly has the best price/performance ratio, and it is also available as a DIY kit at an even lower price. Relatively demanding hi-fi fans will appreciate the elaborate circuitry of the Ground Sound, Marchand and Thel modules. If you are also looking for real power (400 W at 4 Q), you will find what you need with the Class D amplifiers, which now offer true hi-fi sound. The specifica- tions of the Coldamp, Hypex and NewClassD modules are quite similar. Of course, it's difficult to judge the sound of these three amplifiers from the measured results, so we would like to hear from readers who have experience with one or more of these modules. A few hundred pounds for a pair of modules is nothing to sneeze at, and that’s aside from the other components you have to provide (heat sink, transformer and enclosure), which also aren’t exactly cheap. However, with this approach you can build an amplifier that can hold its own against ready-made high-end equipment at a much higher price. And when you use pre-assembled modules in DIY con- struction, you can rest assured that the end result will work properly and sound the way it should. 9/2007 - elektor electronics 27 INFO & MARKET AUDIO m Measurement Condition(s) Unit Amplimo A120 Coldamp BP4078 Power, Distortion, Signal/Noise Ratio sine power T/oTHD, 1 kHz into 8 Ohm W 117 222 into 4 Ohm W 57 414 Power bandwidth 20 Hz - 20 kHz at 1 W into 4 Ohm dB -0.2 /-I -0.5/ -1.9 Output Resistance (40 Hz) mOhm 12 74 Distrortion (1 kHz / into 4 Ohm) at Pmax -1 dB % THD 0.012 0.58 at 1 W % THD 0.02 0.08 Intermodulation (8 kHz and 60 Hz, voltage ratio 4:1) at Pmax -1 dB % 6.8 4,5 at 1 W % 0.21 0.54 Signal/Noise Ratio (1 k termination) referenced to 1 W dB(A) 82 79 referenced to 50 mW dB(A) 58 51 Connecting values Input sensitivity for full power at 4 Q mV 684 940 Input resistance kOhm 116 13,8 Miscellaneous Upper frequency limit kHz 35 26 Supply voltage during test -Vcc/-Vss V 47 60 Module dimensions (approx.; rounded off) Width / Height / Depth cm 12/5/8 10/4/8 Sweep to 1 1 0 kHz at 1 W Fig. 1 Fig. 2 28 elektor electronics - 9/2007 Hersteller / Typ Ground Sound PA3CC Hypex UCD 400 ST Marchand PM 224 Monacor IPA50 m. Netzt. Newtronics AMP7293 NewClassD NCD1 Sitronic VP 703 Thel accusound 100 2 CH Amp, compl. Vellemann VM 100 202 226 127 44 96 99 85 2x 170 86 380 429 145 61 186 198 50 2x273 133 -0.1 / -0.1 -0.2/ -0.4 -0.4 /-l. 7 -3.2/ -0.1 -0.7/ -0.3 0/-1.3 - -0.35/ -0.1 0.2/0 39 12 22 123 31 43 12 24 424 0.041 0.55 0.009 0.1 0.67 0.4 0.006 0.66 0.14 0.052 0.0056 0.006 0.008 0.228 0.03 0.005 0.056/0.094 0.0074 0.1 1 1.07 0.09 0.14 1.25 1.5 - 3.77 0.32 0.147 0.023 0.083 0.046 1.06 0.047 - 0.63 0.039 82 98 80 87 89 81 83 85 100 58 72 54 60 64 55 57 60 75 3185 2097 607 488 353 602 280 1066 700 4,3 95.9 88 22.9 21.9 10 24 15.3 46.1 93 46 29 >110 78 38 - >110 >110 60 60 50 32 (PSU) 40 40 own PSU own PSU 40 (Lab PSU) 18/3/8 8/3/9 10/3/14 7/5/8 14/5/5 11/5/4 20/7/32 43/14/45 17/7/6 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9a/b Fig. 10 Fig. 1 1 9/2007 - elektor electronics 29 Elektor is now & tomorrow. lektor iusvt x] I1ECJK* 1 e m ct ., r _; EKf lO Sgft ' ' ruNiNi Prof UiHlH v^ >,JV 5*5 i X3K«- FAFF tc r^i «* ** Secure a head start in electronics with a subscription! Advantages to subscribers: Cheaper than 1 1 issues from the newsstand Subscribers get up to 40% discount on special Elektor products As a welcome gift you get a free 1GB MP3 player \A/r»rth P QzL RC\ worth £ 34.50 S £ec°* de * >|oV> e No queues, travelling, parking fees or ‘sold out’ Elektor is supplied to your doorstep every month Always up to date - read your copy before everyone else www.elektor-electronics.co.uk/subs Tel. +44 (0) 208 261 4509 Or use the subscription order form near the end of the magazine. the world-leading network for electronics mikroElektronika DEVELOPMENT TOOLS | COMPILERS | BOOKS CAN-1 Board - Interface CAN via MCP2551 . CANSPI Board - Make CAN network with SPI interface. RS485 Board - Connect devices into RS-485 network Serial Ethernet - Make ethernet network with SPI Interface (ENC28J60). lrDA2 Board - Irda2 serve as wireless RS232 communi- cation between two MCU’s. 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You can choose between USB or External Power supply. BIGAVR also supports Character LCD as well as Graphic LCD. EasyPSoC3 Development Board with on-board USB 2.0 programmer The system sup- ports 8, 20, 28 and 48 pin microcon- trollers (it comes with CY8C27843). Each jumper, element and pin is clearly marked on the board. EasyPSoC3 is an easy-to- use PSoC development system. On-board USB 2.0 program- mer provides fast and easy in-system programming. Please visit our website for more info http://www.mikroe.com SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD 9/2007 - elektor electronics 31 TECHNOLOGY POWER SUPPLIES Burkhard Kainka LED lighting is all the rage! Of course, that means there are now countless designs available for LED drivers: a particularly simple and practical solution is provided by the PR4401. In conjunction with PREMA Semiconductor and Wurth Electronics (who provided the components). Eurocircuits and ECS Electronics (who manufactured and populated the printed circuit board), Elektor is pleased and proud to include a free gift with this issue: a board containing an LED booster circuit which you can try out for yourself. Although tiny, the board contains a complete high-efficiency 500 kHz voltage converter which will light an LED even from an almost flat battery. Figure 1. The free LED driver board in use. All that remains for you to do is connect a single 1 .5-V battery (dry cell) to one side of the board and a white LED to the other side (Figure 1). Even an almost flat bat- tery will be fine, and the LED may also be a red or green type. It is even possible to connect two red, green or yel- low LEDs in series. Whatever components are used, it is important to make the connection wires on both sides as short as possible. ... observing the correct polarity The battery connections on the printed circuit board are marked '+' and / - / . One of the LED connections is marked with a 'C' to indicate the cathode pin. The legs of the LED usually have different lengths, and the leg that's cut shorter is the cathode (remember 'C' stands for 'cath- ode' as well as for 'cut'!). There is also a small flat on the flange of the LED's package indicating the cathode side: helpful if you have already chopped the leads to length! What will happen to the 1C if you reverse the battery po- larity? As you can demonstrate using an ohmmeter, there are diodes at the input to the 1C: with an input voltage of -1 .5 V these conduct, a current of 500 mA starts to flow, and the 1C gets rather hot. We tried this for a few sec- onds, and the 1C survived, but to be honest we might not have been so lucky if we had prolonged the test — don't push your luck and try it at home. The LED must also be wired the correct way round. Al- though the circuit should not be damaged by reversing the connection, the LED may well be, as it will be subject to high voltage pulses exceeding its rated reverse volt- age. In the course of making similar mistakes we have observed that some white LEDs are very fragile in the face of this kind of treatment. The result of so-called reverse breakdown in the LED is that its efficiency is considerably reduced, and a relatively low resistance can be measured in the reverse direction. There are also white LEDs that stand up rather better to high reverse voltages. Manufac- turers tend to be quiet on this topic, and all in all it is best just to make sure that you wire the LED correctly first time. For decoupling it is possible to connect an additional 1 00- nF ceramic capacitor across the battery connections on the printed circuit board (Figure 2). The capacitor improves the efficiency of the LED driver if the battery has a relative- ly high internal resistance or if long connection wires are used. Even with a 1 00-nF ceramic capacitor and 50 cm of wire between battery and 1C, we measured a ripple of 0.5 V pp at 500 kHz at the 1C input. At this frequency 32 elektor electronics - 9/2007 batteries! LED from only 0.9 V! a 1 00-nF capacitor has a reactance of 3 Q. When using long wires, it is better to use an even larger capacitor, for example a tantalum type with a capacitance of at least 1 yuF. Polarity is also very important here, as tantalum ca- pacitors cannot withstand reverse connection. A little theory Why do we need an LED driver circuit? Of course, if the supply voltage available were high enough, a simple series resistor would do the job: see the example LED character- istic curves shown in Figure 3. A modern red LED starts to light at a voltage of around 1 .5 V. For other colours, the forward voltage is rather higher, and a white LED generally requires approximately 3.6 V, and so at least this voltage is required in the driver circuit. For example, an LED can be powered from a series combination of three AA-size 1 .5-V cells giving a total voltage of 4.5 V. If we use rechargeable cells, a further problem arises. When the battery is deeply discharged the polarity on the flattest cell in the pack will be reversed and the resulting current flow sharply decreases its life. A more practical, more compact and more economical driver can be made if we run the LED from a single cell. One solution is presented by our tiny printed circuit board which replaces the series resistor by a PR4401 and an inductor, and which can work from a supply voltage from 1 .5 V all the way down to 0.9 V. Voltage converter To drive the white LED we need to provide a voltage of at least 3.6 V at a specified maximum current. For operation from an ordinary 1 .5 V cell or a 1 .2 V rechargeable cell (NiCd or NiMH) we therefore require a voltage converter with integrated current limiting circuit. PREMA Semicon- ductor produces just such an 1C, the PR4401 , which has only three pins and which requires the addition of a sin- gle external component, a miniature coil with an induct- ance of between 10 pH and 22 pH: see Figure 4. The device comes in a tiny SOT23 package which means that the total printed circuit board area occupied by the driver is minuscule, making the device ideal for use in hand torches and similar applications. The LED current is determined by the choice of coil. The device datasheet lists a selection of suitable coil values and the corresponding currents. For higher output currents a sister device, the PR4402, is also available. If a 22-pH coil is used, the PR4401 delivers a diode cur- Figure 2. Adding a decoupling capacitor. 3.5 4.0 070100 - 12 Figure 3. Typical characteristics of red, green and white LEDs. IC1 PR4401 LI 18|iH 070100 - 11 Figure 4. Basic circuit of the switching converter. 9/2007 - elektor electronics 33 TECHNOLOGY POWER SUPPLIES Figure 5. LED current and voltage. Figure 6. Simplified block diagram of the PR4401. Figure 7. Experimental LED driver using an NE555. To k JL MPOfiO Htti hC + "j Mh 1.S7V jJPuT 1 mm — m on CM OH ti 1 \ .'riW | ■ W dft 1 v u 1 Ts. ■ HATH cm CHI *Wrrj M4v-« M with LI = 22 uH rent of approximately 1 2 mA; with a 1 O-pH coil, the cur- rent is around 23 mA. Our printed circuit board comes fitted with an 1 8-piH inductor, which gives a good com- promise between LED brightness and battery life. LED brightness is practically constant over input voltages rang- ing from 0.9 V to 1.5 V; however, the input current does of course increase as the voltage drops. The oscilloscope trace (Figure 5) shows the LED voltage and current: as you can see, high-frequency pulses of energy are stored in the coil and then delivered at higher voltage to the LED. What makes the PR4401 tick? The basic principles of operation are discussed in the datasheet, although details of the internal circuit are not given. The circuit essentially consists of a switching transistor and associated control logic (Figure 6). To understand the circuit better, we replaced the LED with a 47 Q resistor and monitored the output signal at vari- ous input voltages using an oscilloscope. The NPN output transistor is turned on to start the storage of energy in the coil: the 'charge phase'. The length of this period deter- mines the total energy stored. Then, when the transistor is turned off the coil delivers this stored energy into the load: the 'discharge phase'. The comparator detects the end of the discharge phase when the output voltage V out falls below a threshold value of 2 V. A new charge phase then starts. As the battery voltage falls the length of the charge phase is increased so that on average the same power is delivered to the LED. But how does the device keep the LED brightness constant when it apparently does not have a way to measure the LED current? To help understand the IC's operation, we built a single squarewave generator around an NE555 for compari- son. The circuit drives an NPN transistor (see Figure 7). As far as T1 , LI and LED D1 are concerned the circuit is essentially the same as that using the PR4401 ; however, whereas the NE555 requires a relatively high supply voltage, PREMA have managed to replicate its control function in an integrated circuit that can run on just 0.9 V. Our reference circuit also does not take its supply voltage into account, with the result that as the battery voltage falls, the LED dims. For reasons we shall look at later, the switching frequency of our circuit is set to 50 kHz rather than 500 kHz. At 50 kHz and a (nominal) mark-space ratio of 50 % the charge phase lasts 1 0 |js. During this period the current through the coil l c rises linearly to a fi- nal value of 1 5 mA: l c = U x t / L l c = 1 .5 V x 1 0 |js / 1 mH l c = 1 5 mA Now, suppose that when the transistor is turned off the volt- age across the LED is 3 V and therefore the voltage across the coil is -1 .5 V. This current will fall linearly from 1 5 mA to zero in 1 0 |js. The average current drawn from the bat- tery is 7.5 mA, and the average LED current is 3.75 mA. So much for theory; in practice things are a little different. For example, if the input current is noticeably higher than expected, it might be that the coil is saturating for part of each cycle. This reduces its effective inductance and the current rises more rapidly, with an adverse effect on the efficiency of the circuit. Switching losses must also be taken into account. In the charging phase there will be a voltage between the collector and emitter of the transistor, with corresponding power dissipation in the transistor. The transition to the discharge phase will also not be instant: there will be a period during which a collector current will flow as the voltage starts to rise, resulting in further power losses. This is the reason that the NE555-based circuit works better at lower frequencies. Because the PR4401 is capable of operating at 500 kHz, it is able to make use of a smaller coil and deliver greater efficiency. Coil crisis The inductor has a reputation as the most fearsome com- ponent in electronics, although superficially one might think that winding a bit of wire into a helix could hardly give rise to any difficulties. However, air-cored coils are large and potentially have a high DC resistance, and so we need to move to a magnetic core to reduce the number of windings needed. Now we have to consider questions of correct dimensioning and selection of materi- als, as otherwise the losses will be great and the coil will heat up. The core material must be selected to suit the frequency being used; and if the core is too small, it is in risk of going into saturation. The fixed inductor that we use here is kindly provided by Wurth Electronics. Despite its small size it is in fact some- what larger than strictly necessary for this application. This means that the DC resistance is low, the saturation current is high and losses overall are low. After making an extensive series of measurements we selected the SMD 34 elektor electronics - 9/2007 PREMA Semiconductor PREMA Semiconductor began life in 1970 developing and manufacturing pre- cision instrumentation equipment. Since 1977 PREMA has been making inte- grated circuits in a dedicated facility in Mainz, Germany. A new 1 50 mm wafer line was installed in 1996 with a production throughput of up to 100 wafers per day. The line is used to produce custom ICs, or ASICs (Application-Specific Integrated Circuits), for industrial and domestic applications including barcode readers, motion detectors and audio amplifiers. Since spring 2006 PREMA has been making its devices available on the open market. This includes the LED driver 1C, manufactured using the ModuS U6 process, which employs eight production layers including a single metallisation layer. The first five layers involve the production of N- and P-doped regions in the raw silicon wafer to create diodes, transistors and resistors. The next layer provides an insulator between these and the metallisation that will follow. The wafer is then sputtered with aluminium, which is etched away to form the tracks. For complex projects two or three metal layers are possible, separated by insulating layers and interconnected by contact vias. Subsequent passivisation (normally using a silicon oxide layer) protects the cir- cuit from oxidation and impurities. The (unpassivated) pads are then bonded either to leads for packaging (in the case of the PR4401 an SOT23-3 package is used), or the die can be directly mounted on a printed circuit board. Depend- ing on the size of the circuit, between 2000 and 1 5000 dice are made on a single wafer. The wafer is sawn into the individual dice for packaging. Each die is tested against its specification both on the wafer and after packaging. At the moment PREMA is in the process of qualifying its new 200 mm wafer BiCMOS production line. Web Link: http://www.prema.com Wurth Electronics The name of Wurth has long been associated with screws, and fixings and mountings still form a central part of the operations of the company that started as a hardware shop run by Adolf Wurth and which now employs some 60000 staff worldwide. The Wurth Elektronik group now employs around 6700 staff in the fields of printed circuit board manufacture, power distribution, backplanes, solar technology and, last but not least, connectors and inductors. A particular milestone is the first mass production of so-called 'silicon free' multi-layer copper-indium-diselenide (CIS) solar cells in the world. Web Link: http://www.we-online.de The inductor used on the LED driver board is made by Wurth Electronics eiSos, a specialist in passive and electromechanical compo- nents, in particular in inductive components, connectors, and EMC and ESD protection. Wurth places a high value on 'designer friendliness', with free samples, small-quan- tity ordering, design support and design kits, free seminars and applications handbooks entitled 'ABC of Transformers' and 'Trilogy of Inductors', which are available in sever- al languages. As the only European man- ufacturer of chokes Wurth devices feature in reference designs by the major switching regulator manufacturers, including Linear Technology, National Semiconductor, Texas Instruments, ON Semiconductor, STMicro- electronics, Diodes, MPS, Maxim, Semtech and Sipex. 9/2007 - elektor electronics 35 TECHNOLOGY POWER SUPPLIES 200% Printed circuit boards, quantity 150,000 We started by designing the single-sided printed circuit board layout for the two SMD components (Figure 1) in our laboratories here at Elektor Electronics. With dimensions of 10 mm by 15.5 mm it was not practical to make 150,000 units individually: more on that below. Then we went to Eurocircuits. They performed initial checks on the board design (provided by us as a Gerber file): that the file could be read correctly, that the dimensions were accurate, and that the board was manufacturable. An extra sol- der mask was added to the unpopulated side of the board to increase the con- trast and hence legibility of the logo to be printed on it. To make populating the boards practical, a panel consisting of one hundred boards in a ten-by-ten array was laid out as a single large board with a border for reinforcement (Figure 2). The border also carried fiducial (reference) marks. The panel was scored in a horizontal and vertical grid using a V-cut machine to simplify separating it into individual boards after population. The boards were then manufactured in the Eurocircuits factory (Figure 3), and the result, 1,500 panels like the one shown in Figure 2, were sent to ECS for population. The copper surface of the boards went through a lead-free hot air levelling proc- ess using SnlOO. ECS then screen-printed a lead-free solder paste on to the board using an EKRAX1-SL machine and a 125-jL/m stainless steel screen. The next step was the automatic population of the boards using a Samsung SV20 pick-and-place machine (Figure 4), which can fit ten thousand 0603-style SMD components per hour. Before starting on each panel, the machine used a vision system to register the position of the fiducial marks so that the position of each board was exactly known. The machine at ECS is easily adapted to a new design and so is even suitable for short production runs and prototypes. Soldering was the next step, using a vapour-phase process which is ideal for SMD printed circuit boards. By enveloping the boards in a heated atmosphere of protective gas oxygen is removed from the joints and the solder temperature can be controlled very precisely, which prolongs the service life of the components and boards. After soldering the joints on each panel were checked using a Mantis optical inspection machine. Finally the panel came under the knife: 1,500 panels were chopped into 150,000 individual LED driver boards. And, assuming no accidents have happened on the way to your newsagent or doorstep, you should have received one with this issue, courtesy of Elektor, the world-leading magazine on electronics. Web links: http://www.eurocircuits.com http://www.ecsgeel.com The LED driver board was planned as a free gift with the editions of Elektor Electronics published worldwide (English edition), in Germany, France, the Neth- erlands, Spain and Greece, which have a total circulation of around 150,000 copies. How does a magazine publisher go about getting this many boards manufactured and populated? Of course, we needed not only the components from PREMA Semiconductor and Wurth Electronics, but also a printed circuit board manufacturer and assembler. Board manufacture was done by Eurocircuits, whose proven quality will be famil- iar to Elektor Electronics readers through The PCBShop service. ECS Electronics and Component Service in Geel, Belgium populated the boards. 36 elektor electronics - 9/2007 WE-PD2 choke with an inductance of 1 8 pH. The data sheet gives a typical DC resistance of 0.225 Q. The coil current may rise as high as 1 .1 A, compared to the satu- ration limit of 1 .29 A. The core is made of a nickel-zinc ferrite material which can operate with minimal losses even at high frequencies. A special enamelled copper wire permits high operating temperatures. With an input voltage of 1 .5 V the charge phase of the PR4401 lasts approximately 1 ps. From this we can work out the peak coil current: l c = Uxt/L L = 1.5 V x 1 p S / 18 pH l c = 83 mA Making the approximation that the LED voltage is 3 V, we arrive at an average LED current of approximately 20 mA and a battery current of approximately 40 mA. At the end of the charging phase the voltage drop across the coil is only about 1 0 mV. From this we can see that the chosen coil is capable of delivering considerably more current than it does in this circuit. According to the datasheet, the efficiency of the converter circuit is 80 % even when using a smaller coil; with the 1 8 /iH coil we have selected, we can expect even higher efficiency. Applications The LED driver is neither a constant voltage source nor a constant current source, but rather something in between. It can be thought of as a constant power source. For the given component values it will always deliver approxi- mately 70 mW into the connected load, to a large extent independent of the input voltage and of the load resist- ance. If the connected LED requires a higher voltage, the current will reduce accordingly; it is therefore possible, for example, to connect more than one LED in series to the output of the circuit. For example, a white and a green LED could be used in series with a total voltage of about 5.5 V. According to the data sheet the limit is at 15 V. Open-circuit operation is also possible, and meas- urements show that the output voltage is limited to about 1 8 V by a zener diode inside the 1C. The LED receives a pulsed current from the driver circuit. LED data sheets state that the expected efficiency of the LED is greater if a constant current is used. With the assistance of a rectifier diode and an electrolytic smoothing capacitor we can reduce the ripple in the LED current (Figure 8). It is not essential to use a Schottky diode here as the PR4401 will make up for the voltage drop across the diode by suit- ably increasing its output voltage. However, the power loss in a Schottky diode will be less than in a 1 N4148 (about 14 mW), but a difference of a few milliwatts will not make much difference to the brightness of the LED. A further possible application is to use the circuit as a battery charger (Figure 9). For example, a NiCd or NiMH cell (with a charge voltage of up to 1 .45 V) can be charged from two, or preferably three, solar cells with a total nominal voltage of 0.9 V or 1 .35 V respectively. Since the PR4401 automatically adjusts the output voltage up to a maximum of 15 V, it is possible to connect a 9-V or 1 2-V battery consisting of a number of NiCd or NiMH cells in series to the output. The current will be limited to approximately 20 mA, and so the circuit would be a good match for a small 3.6-V battery with a capacity of 200 mAh or a 9-V battery with a capacity of 1 50 mAh. For higher capacity batteries the PR4401 might be suit- able in a trickle-charging application, and for currents of 4 m 070100-16 up to 40 mA the PR4402, also made by PREMA Semicon- ductor, is worth considering. There are of course many other application possibili- ties for these two ICs. Let your imagination run free (and wild!) and with a little technical know-how and skill with the soldering iron you should be able to come up with plenty of creative ideas! We will publish the best ideas we receive on the Elektor Electronics website and in the pages of the magazine. ( 070100 - 1 ) Weblinks [1] PREMA PR4401 and PR4402 LED driver ICs: http://www.prema.com/Application/whiteleddriver.html [2] PR4401 data sheet: http://www.prema.com/pdf/pr4401 .ppdf [3] Wurth WE-PD2 SMD power inductors, including data sheet (order code 7447731 1 8): http://www.we-online.com/website/emc/eisos/alg/kat_layout. php?id = 28 Figure 8. Circuit using a rectifier diode and smoothing. Figure 9. Charging a battery from 1.2 V. 9/2007 - elektor electronics 37 LOGIC ANALYSER Digital I nspedor Four-channel logic analyser Ronald de Bruijn When checking digital signals a logic analyser is indispensable, especially since many circuits use microcontrollers these days. In this article we describe an easy to build circuit that can cope with most digital signals and also has a memory function. Specification Sample frequency: 200 Hz-2 MHz Channels: 4 Range: 0 to 5 V Memory: 1024 samples per channel Trigger levels: +Ve and -Ve Trigger pattern: can be set for each input Dot matrix LCD: 64 x 128 pixels Supply: 9 V PP3 battery The best way to inspect digital signals is with a logic analyser. Sometimes it’s useful to be able to do this on-site, or you may have to take a ‘floating’ meas- urement. The four-channel logic ana- lyser described here is suitable in both situations due to its compactness and because it can be battery powered. The maximum sampling rate is 2 MHz and the circuit has sufficient memory to store 1024 samples of the signal. The dot-matrix display with a resolution of 64 by 128 pixels shows a clear repre- sentation of the digital signals. Schematic At the heart of the circuit is IC2 (a PIC18F4850, see Figure 1). This PIC controller samples the signals and drives the display. It is controlled via five push buttons (SI to S5). The crystal (XI, 10 MHz) de- termines what the max- imum sampling rate is. The internal PLL of the microcontroller is used to give the controller an internal clock frequency of 40 MHz, which is the max- imum frequency recommended by Mi- crochip for this type of chip. Diodes D1 to D8 protect the inputs against too high or negative voltag- es. The input signals are fed to IC1, a 74HC04N, which is used as a buffer. The fact that the signals are inverted doesn’t matter in this case, since we can easily convert the signals back via the software. The signals go directly from the buffers into the controller via RA1 to RA4, where the software takes over (see Control). Preset PI is used to set the contrast of the display and T1 turns on the background light of the display. Bzl gives an audible warning when a new sampling cycle starts and when you change between run and hold mode. The five switches used to control the circuit don’t require a hardware de- bounce circuit, since this is taken care of by the software. The power supply for the circuit con- sists of two parts: a stabilised 5 V sup- ply and a 9 V supply for the display light. The source for these voltages can either be a 9 to 12 V mains adapter or a 9 V rechargeable battery. A simple charging circuit for the bat- tery is also included (T2, Rl, R17, D12), which comes into action whenever a mains adapter is connected. Assuming a standard LED with a forward voltage drop V t of 1.5 V is used, the charging current for the battery will be: (1.5 -0.6)/ 56 = 16 mA. A 9 V NiMH battery with a capacity C of 170 mAh is then charged at about 0.1 C, so no damage will occur if it is charged con- tinuously. The battery will be fully charged in about 10 hours with this circuit. During the charging LED D12 will be on. If an ordinary (non-rechargeable) battery is 38 elektor electronics - 9/2007 used, the circuit around T2 can be left out. Control Switch SI is used to select the sam- pling frequency. The rates that can be selected are 5/10/20/50/100/200/500 |i s/div and 1/2/5 ms/div. S2 selects the channel that is used to trigger the cir- cuit. S3 is used to tell the PIC if it is to trigger on a rising or falling edge and S4 can arm and stop the circuit, or clear the display. One short press of S4 arms the circuit. After the trigger signal oc- curs it will take 1024 samples per chan- nel and store them. Pressing S4 briefly again will make the circuit read in a new set of 1024 samples after the next trigger signal. When S4 is held down for longer the display is cleared. The last settings for the sampling frequen- cy, the trigger channel and the trigger condition are stored inside the EEP- ROM of the microcontroller. These set- tings are then used as the initial state when the circuit is next turned on. S5 turns the backlight on or off. After Figure 1. From the circuit diagram it is clear that the microcontroller takes care of just about everything. +9V © 0 — | 330 n h CH3 R6 0 1 330 Q | - CH2 R4 0 1 330 Q | - CH1 R3 0 1 330 Q h +5V © +5V R11 H 100k | - IC1.A 1 1 \2 3 R12 D5 D4 D1 D3 w 4x^M N4148 w D10 2x D9 1N4148 11 32 "^C5 ^^0 IC1.E 11 1 s 10 IC1.F 13 1 s 12 © © MCLR/VPP/RE3 RA0/AN0/CVREF RA1/AN1 RA2/AN2/VREF- RA3/AN3/VREF+ RA4/T0CKI RA5/AN4/SS/HLVDIN IC2 RC0/T1 OSO/T1 3CKI RCI/TIOSI RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX/CK RC7/RX/DT PIC18F4580-I/P RD0/PSP0/C1 IN+ RD1/PSP1/C1IN- RD2/PSP2/C2IN+ RD3/PSP3/C2IN- RD4/PSP4/ECCP1/P1 A IC1 = 74HC04 +5V IC1 © RB0/INT0/FLT0/AN1 RB1/INT1/AN8 RB2/INT2/CANTX RB3/CANRX RB4/KBI0/AN9 RB5/KBI1/PGM RB6/KBI2/PGC RB7/KBI3/PGD J. OSC1 RD5/PSP5/P1B RD6/PSP6/P1C RD7/PSP7/P1D RE0/RD/AN5 RE1/WR/AN6/C1 OUT RE2/CS/AN7/C20UT OSC2 J. 12 C2 22p 13 XI I I 20MHz 14 Cl 22p XT"* Dll 15 16 17 J 8 23 _24 25 26 19 20 21 22 27 28 29 30 10 31 R21 +5V © Pi * 20k \ K2 O R19 BZ1 BC337 X o o o o o o o o o o o o 0. CO Q o T1 R2 R2 ° i © © +5V +9V 12V X C6 lOOn i-O -o 060092 - 1 1 9/2007 - elektor electronics 39 LOGIC ANALYSER Components list Resistors R1 = 680D R2,R1 1-R16 = 10 kQ R3-R6 = 330Q R7-R10 = lOOkQ R17 = 56Q R19 = 1 kQ R20 = 47Q R21 = 220Q PI = 20I IC2 Xout ST ADXL322 Yout o o □ □ z z z z CD CD CD CD CO LO CO h— *~T GND 10 +5V o 12 — 21 IS 1 ^pOOn GND AVCC IC1 PC6 (RESET) PC5 (ADC5/SCL) PC4 (ADC4/SDA) PC3 (ADC3) PC2 (ADC2) PCI (ADC1) PCO (ADCO) VCC PD7 (AIN1) PD6 (AINO) PD5 (T1) PD4 (XCK/TO) PD3 (INTI) PD2 (INTO) PD1 (TXD) PDO (RXD) PB5 (SCK) PB4 (MISO) PB3 (MOSI/OC2) PB2 (SS/OC1B) ATmega8-16PI pbi (OCiA) AREF PBO (ICP) GND XTAL1 XTAL2 GND oo o> O CXI > [1 ^ CM < h » C3 C4 C5 lOOn 22 p 4MHz 22p 1 i i •— ►— < i GND 13_ 12 _ 11_ 6 _ 5_ 4_ 3_ 2 _ 19 +5V O K1 O 17 O 16 15 14 O t 0 GND 070233-11 Figure 1. Besides the acceleration sensor and microcontroller there are very few other components required. 42 elektor electronics - 9/2007 pled alternately, the 2.56 V reference for the A/D converter is produced on- chip and decoupled by capacitor C3 on Pin 21 (AREF). The I/O pins have good sink/source current capability which together with selectable internal pull- up resistors means that there is no re- quirement for additional drivers for the output signals. Simple circuitry It can be seen in the circuit diagram in Figure 1 that apart from the microcon- troller and sensor there are very few additional components required. The layout of the double-sided PCB shown in Figure 2 is therefore quite simple. Figure 3 gives the flow chart describ- ing the main software functions. The microcontroller ADC port is sampled every 10 ms, raw values of acceleration are converted into tilt values which are then filtered. The signals output by the gamepad depend on the direction of tilt and tilt angle. The 6-way pin header (Kl) is fitted to the PCB for all the connections to the gamepad. The circuit is powered directly from the USB interface ( + 5 V and ground). Putting it together The finished PCB can be fitted into the casing of a standard PC gamepad if sufficient space is available. In prin- ciple any gamepad can be used pro- viding the direction buttons are ‘active Low’ i.e., when you press a button the output signal goes from a high to a low. The author used a ‘Firestorm Digital 3’ while in the Elektor Electronics lab a ‘MAXFIRE G-08X4’ from Genius hap- pened to be available for conversion (it must have been used earlier by one of our team for some serious research work. . .). In addition to the gamepad and fin- ished PCB a short length of 6-core ca- ble is required and possibly a small plastic enclosure for the finished PCB if it will not fit in the gamepad case. Do not insert the programmed micro- controller in its socket yet. The micro- controller can be ordered ready-pro- grammed from the Elektor Electron- ics website. Alternatively, the hex file (object code) can be downloaded from the same website at no cost if you pre- fer to program the device yourself. The original source files are protected by licences and copyrights and are not freely available. Assembly begins by first dismantling the gamepad; undo the screws at the Figure 2. The double-sided PCB is supplied with the SMD-outline tilt sensor already mounted (near the bottom of the board). Components list Capacitors Cl / C2 / C3 = lOOnF C4,C5 = 22pF Semiconductors IC1 = Atmega8-1 6PI, programmed, Elektor SHOP # 070233-41* IC2 = ADXL322 Miscellaneous Kl = 6-way SIL pinheader XI = 4MHz quartz crystal PCB with ADXL322 sensor fitted, Elektor SHOP # 070233-91 * hex code file: free download # 070233-1 1 .zip from www.elektor.com 9/2007 - elektor electronics 43 GAMEPAD CONVERSION 070233-12 Figure 3. The software flow diagram. The sensor is sampled every 10 ms. back of the unit which hold the two parts of the shell together. Once inside it is necessary to find out which parts of the circuit are connected to +5 V and which are connected to ground. The simplest method is to trace wires from the USB connection, pin 1 (usu- ally black) is ground and pin 4 (usual- ly red) is + 5 V. Similarly check out the wiring to the gamepad buttons; a close inspection reveals that each of the di- rection buttons have two contacts, one of which is usually connected to ground (as in the Thrustmaster game- pad but some use +5 V for this connec- tion) the other contact goes to the mi- crocontroller. This contact will be used later to solder wires to the new PCB connector K1 pins 2 to 5. If it is neces- sary to mount the PCB externally in a small plastic enclosure (as is the case with the “Firestorm Digital 3”), a hole will need to be drilled in the rear of the gamepad housing (5 mm diameter Gamepad/sensor board connections Wiring between the gamepad and K1 on the sensor PCB using 6-core colour coded cable. K1 GND Up Left Down Right + 5 V Cable Black Orange Yellow Green Blue Red Gamepad Earth/Ground Up Left Down Right + 5 V should be sufficient) to run the multi- core cable through. Wiring between the tilt PCB connector K1 and gamepad can now begin by sol- dering the wires + 5 V, ground and the four direction button contacts. The pin assignment for K1 is detailed on the circuit diagram in Figure 1. Pins 1 and 6 carry the power sup- ply while 2 to 5 are the digital output signals wired to the direction button contacts (active low, the idle state is high). The Table below shows the wiring connections in detail and the cable col- ours. Printed arrows on the PCB next to connector K1 indicate the direction in which the PCB should be moved to produce an output at that pin. Once the wiring is complete the pre- programmed microcontroller can now be fitted in its socket on the PCB. The PCB can be secured in the gamepad using hot glue (roughen the internal surface of the housing for good adhe- sion) or if an external enclosure is used it can be attached externally to the rear of the gamepad again with hot glue. Screw the two halves of the gamepad together. The tilt gamepad is now finished! The PC has no way of knowing that the gamepad internals have changed so it’s not necessary to load any new soft- ware drivers. Revisit all your favour- ite games but this time experience a whole new level of intuitive control. ( 070233 - 1 ) 44 elektor electronics - 9/2007 How many nj equipment can you £ 99 ? With a PoScope USB instrument you get the features of an oscilloscope, spectrum analyser, chart recorder, logic analyser (with UART, SPI, l 2 C and 1 -wire serial bus \ nt decoding), pattern generator and square- wave/PWM generator. That’s equivalent to six pieces of test equipment for £99 including UK cfeWec/ and VAT. PoScope is a low-cost USB- based instrument that adds invaluable test equipment features to your desktop or notebook PC. Being PC-based, all measurements can be printed, copied to the clipboard and saved as text, bitmap or vector graphics for subsequent analysis or to import into other programs. PoScope is ideal for use by electronics hobbyists, students and engineers alike and is particularly suited to those developing with microcontrollers such as PIC and AVR. PoScope provides the following operation modes: • 2-channel oscilloscope with 100Hz to 200kHz sampling, -20 V to +20V input range, 10-bit ADC resolution, absolute, differential and external triggering, adjustable pre-trigger and marker measurements. • 2-channel spectrum analyser with klirr factor measurement, Hamming, Hanning, Blackman and Blackman-Harris FFT window functions. • 2-channel chart recorder with 0.01Hz to 200kHz sampling, maximum, minimum and average voltage measurements for each channel and waveform record over several tens of hours. • 16-channel (8 when pattern generator used) logic analyser with 1kHz to 8MHz sampling, versatile triggering with adjustable pre-trigger, external clocking, preset pulse miss, preset bit sequence/edge, decoding of UART, SPI, I2C and 1-wire serial interfaces. • 8-channel 1kHz to 1MHz pattern generator with tabular waveform formatting or direct timing chart plotting on the screen. • Square-wave/PWM (pulse width modulation) generator. Compatible with Microsoft Windows ME, 2000 and XP, PoScope is supplied with easy- to-use software and a USB cable. Oscilloscope probes and logic analyser test lead/clip sets are available separately. Order now on Freefone 0800 612 2135 or online at www.paltronix.com PALTROniK EQUIPMENT FOR ELECTRONICS DEVELOPMENT, TRAINING & EXPERIMENTATION Paltronix Limited Unit 3 Dolphin Lane, 35 High Street, Southampton SOM 2DF Telephone: 0845 226 9451 Facsimile: 0845 226 9452 Email: sales@paltronix.com Web: www.paltronix.com .■ftiSfcr-L'-vti Abesirfr vtsa i m VfSA EleCErfm All major credit and debit cards accepted ULTRASOUND WJ 'ahh^nh- lOCFivAuR^dL-C^S^rit UJJrtf rtvfH I r Ji* m/m n A^.b. n IrpJ KjW PI hpj ^ ; wpi&w Wti i lenten W .^ChifV* Htt< Eieis L v I I - Hi P Wtawr if Lhrr*t J? r . It Inw i“ IW I - _•**■- T*1 r l ■ HlJii ' - .rj. r L :-J rjfc- r«-s f'JUfc I WkhaUW I "i.- P VI Pi Burkhard Kainka Although bats are common animals, it is rare to actually catch a glimpse of one. In the dark they are practically invisible, and their ultrasonic sounds are inaudible. However, using a balanced mixer, we can make an ultrasound receiver that allows us to hear these sounds. The Software Defined Radio (SDR) previously described in Elektor Electronics May 2007 makes an ideal starting point. tM'.rilllL Iihu w i N * ’ 4 ii-* Hi RSiniHr IBP IHP S firw v u J i ' FrtCBfc ■ tt -'Wj: H-db 1MHN SWUM fW^fl Ul i > ¥ 5;."i 4uW< -V tW-W i'V*jp j p,v ■ (UwvfdtaH 4w S-FYiocrwi Among the living things that move upon the earth, the fowl of the air, and even among the creatures of the sea there are animals that can produce sounds with frequencies well in ex- cess of 100 kHz. The most well-known are of course bats, with their phenom- enal ability to navigate using ultra- sound. Dolphins, whales, mice and in- sects also make use of high-frequency sound signals. Many creatures also have a sense of hearing with a frequency response wider than that of humans. It is well known that household pets such as dogs and cats can hear frequencies of over 20 kHz and are more sensitive to sounds. Figure 1 gives a summary of the audi- tory capabilities of man and beast. The frequency range of the voice is gener- ally around 20 % to 30 % narrower than the auditory range. In the case of bats and marine mammals the sounds pro- duced are used not only for communi- cation, but also for navigation and for locating objects and prey: see the text box ‘Ultrasound radar’. Bat spotting In the past bats were surrounded by superstition and fear; these days, how- ever, they are seen as an indicator of a thriving environment. Unfortunate- ly thriving environments, and hence bats, are less common than they once were. The author, who lives in the heart of a bustling conurbation, had been search- ing for bats in his area for several years without success. And there the situa- tion was left, at least until last year when his neighbours reported a sight- ing of a bat. A little searching around with an acoustic sensor confirmed that indeed Batman and Bat woman had tak- en up residence: their ultrasonic calls could be heard loud and clear with the help of a suitable receiving device. Since then, monitoring the animals has become something of a hobby for the author. Unfortunately the scope for lis- tening in to the signals is restricted by buildings and by time constraints. To help overcome these, a wireless ultra- sonic microphone (using a radio link) was developed, and the processing of the resulting data was automated us- ing a PC running software originally developed for radio reception. A suita- ble PC program is the dream DRM soft- ware that will be familiar to many Ele- ktor Electronics readers. 46 elektor electronics - 9/2007 audible frequency range [kHz] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 1 I I I I I I I I I I I I I I I I I I I I 20Hz 20kHz man 7kHz 200kHz bat shrew dolphin locust cricket 7kHz 115kHz 4kHz 200kHz 5kHz 95kHz 3kHz 100kHz 070406-11 Figure 1. Human hearing covers frequencies of up to 20 kHz, a relatively narrow range compared to that of many creatures. Bat radio Is it possible to use a radio to listen to a bat? In principle the answer is yes, as long as we ensure that we cover the right frequency range. The Software Defined Radio (SDR) described in the May 2007 issue of Elektor Electronics will in theory operate down to very low frequencies, even just a few kilohertz. So, if we can use the radio in SSB mode tuned to a fre- quency of 40 kHz to 50 kHz and replace the antenna with an ul- trasonic microphone and match- ing preamplifier, the presence of any nearby bats will instantly be revealed. The original Software Defined Radio tuning facility is not able to work at the very low frequen- cies we require here; however, with a new extended version of the program we can adjust the oscillator frequency down to 20 kHz. The new software (Figure 2) covers the full range from 20 kHz to 30 MHz in steps of 1 kHz: see also the article ‘SDR and VLF’ elsewhere in this issue. Microphone plus preamplifier The ultrasonic microphone nor- mally used in commercially- available bat detectors is a ce- ramic ultrasound transducer covering frequencies around 40 kHz, of the type chiefly used in ultrasonic distance measur- ing devices. The UST-40R that we use here (available, for ex- ample, from Reichelt Electron- ics; www.reichelt.de) is a typi- cal device of this type. We also require a low-noise preampli- fier. One grounded-emitter am- plifier stage using a dead com- Figure 2. New tuning software for the SDR board allows reception at 45 kHz. 9/2007 - elektor electronics 47 ULTRASOUND R3 +5V R3 +5V Figure 3. Microphone preamplifier for a ceramic ultrasonic transducer. Figure 4. The microphone preamplifier can be used in conjunction with a long cable. Figure 5. Preamplifier for an electret microphone capsule suitable for operation in the ultrasound range. mon BC547C or BC549C (Figure 3) is sufficient in this case, giving a gain of around 40 dB. The output of the pream- plifier is connected to the spare anten- na input number 4 of the SDR board. This will allow us to use software to switch between normal radio mode and bat monitoring mode. The ultrasonic microphone we use has a relatively narrow response peak around 40 kHz, with a secondary peak around 80 kHz. It is relatively insensi- tive to all other frequencies between about 20 kHz and 100 kHz. If it is desired to use a longer micro- phone cable the circuit can be sepa- rated as shown in Figure 4 so that a two-core screened cable can be used to carry both power for the preampli- fier and the returned signal. Other microphones There are many alternatives to the relatively narrow-bandwidth ceramic 40 kHz ultrasound sensors. A few ex- periments have shown that an ordi- nary piezo sounder can be used as an ultrasound transducer. The flat discs generally have several resonance fre- quencies. A device with a diameter of 27 mm was found to have a natural resonance at around 30 kHz and an- other at 50 kHz. At these points the transducer has comparable sensitiv- ity to the ceramic 40 kHz ultrasound transducer. It is also worth experimenting with electret microphone capsules. Even if the response of the microphone is only given as extending to 20 kHz, the us- able frequency range is often much wider. And there are also profession- al microphones designed for use in in- strumentation with a wide frequen- cy response, but these are far from economical. When using an electret microphone it is worth noting that the response falls off at higher frequencies. So that the preamplifier is not driven into clip- ping by the lower- frequency signals, a small 1 nF (0.01 juF) coupling capacitor Ultrasound radar In order to help orientate themselves, bats emit brief bursts of ultra- sound, sometimes using constant frequency (CF) and sometimes with rapid frequency modulation (FM). The Greater Horseshoe bat spe- cies, for example, produces a tone at 83 kHz lasting for just 30 ms to 40 ms, which is initially at constant frequency but which towards the end has frequency modulation imposed upon it. Another species, Daubenton's bat, uses a purely frequency-modulated tone sweeping from 60 kHz down to 30 kHz over a period of 10 ms. By combining CF and FM tones the bat can determine the distance to the insect prey (using FM) and the relative speed (using CF). The reflected CF signal also provides information about the wing beat frequency of the insect, which helps the bat determine its species and size. Two physical effects play an important role in processing the reflected sound signal: the Doppler frequency-shift effect and interference. Doppler shift can be heard when any sound source moves of flies by (for example, a train, car or aeroplane). While the object is approach- ing, its sound is heard at a higher pitch, and while an object is reced- ing, the sound is heard at a lower pitch. The difference in frequency depends on the relative speed of the object and the observer. Interfer- ence can make this detectable as a beat frequency. When two tones are mixed together interference creates the perception of a new signal at the difference frequency. The bat processes this difference frequen- cy which is created in its auditory system by interference between the transmitted signal and the received echo signal. Primarily thanks to their specialised sonar system some species of bat are among the most effective hunters of insects in existence. A single Daubenton's bat can easily catch 60,000 gnats, midges and mosqui- toes in one season, enough to survive its hibernation. Note that bats should never be disturbed when they are hibernating or nesting. If disturbed while hibernating, a bat will invariably wake up, resulting in a life-threatening level of energy use. Bat watching should therefore be limited to open spaces. For communicating among themselves bats, like most other animals, use calls in the audible part of the spectrum, ranging from metallic clicks to a bee-like buzz. 48 elektor electronics - 9/2007 +3V ... +9V © JS 7 T1 [r3~ T2 < R2 o c » ( R4 < £ 3 1 ( i - A -J L ^^00n U 56p \ 9 < i ©) HH® 100n 2x BC547C „ V. © RF IN RF OUT MIX IN MIX OUT IC1 osc TA7358 RF BP OSC MON UST-40R 2(iH C4 33p C6 56p ANTI XI i i C5 33p 13.56MHz 070406- 15 Figure 6. Circuit diagram of a wireless ultrasound microphone with DSB transmitter. should be used. With the circuit shown in Figure 5 a small (5 mm diameter) electret microphone will be usable at frequencies of well beyond 50 kHz. Radio microphone Even the longest practically-usable ca- ble is too short for some applications, and we need to look at other ways to increase the distance between micro- phone and PC. If the SDR is already connected to a roof-mounted antenna or to a long-wire antenna in the gar- den, a tempting option is to connect the ultrasonic microphone preampli- fier output to a radio transmitter and let the signal be received by the SDR in the normal way. Figure 6 shows the very simple cir- cuit diagram of a small transmitter using DSB (double-sideband modu- lation) at 13.56 MHz. The transmitter can be clamped directly onto the end of the SDR antenna, avoiding any con- cern that a significant amount of pow- er might be radiated. If a significant range is wanted, there is no problem: the frequency of 13.56 MHz is reserved for industrial and scientific applications (including eavesdropping on bats!). The TA7358 integrated mixer used is primarily aimed at applications in FM input stages, and internally is very similar to the ubiquitous NE612 bal- anced mixer, which can also be used in this circuit. The TA7358 also includes an RF preamplifier, which we do not use in our design. The miniature trans- mitter (Figure 7) thus uses only a very small number of components. The bal- anced mixer produces an AM output signal with a suppressed carrier, also known as a DSB signal. At the receiv- er we can choose to listen to either the upper sideband (USB) or the low- er sideband (LSB). Depending on the ultrasonic frequency being monitored the receiver should be tuned to approx- imately 30 kHz to 50 kHz above or be- low the centre frequency. Although the carrier is to a large extent suppressed it is still of sufficient amplitude to al- low it to be located to simplify testing the operation of the transmitter and to help adjust the transmitter antenna cir- cuit for resonance. Results The tiny transmitter can be used to lis- ten to bats in conjunction with practi- cally any shortwave receiver capable of SSB reception, including, of course, the widely-used DRM receiver described in the March 2004 issue of Elektor Elec- tronics. Using the SDR we have made recordings of a bat, available for down- load as MP3 files from the Elektor Elec- tronics website. The call of this animal is at around 40 kHz to 50 kHz. The MP3 files include the received signal at its original speed as well as at one half and one quarter of the original speed, so that the structure of the call can be more clearly heard. More detailed investigations as to the nature of the signal can be carried out using the microphone and shortwave transmitter. The wide reception band- width of the SDR is a big advantage here. Most of the frequency compo- nents of the call of the animal in ques- tion lie between 41 kHz and 48 kHz (Figure 8). It is probably therefore a pipistrelle, as commonly found in build- ings during their breeding season from April to July. ( 070406 - 1 ) Web Links http://www.bats.org.uk (the UK Bat Conservation Trust) http://en.wikipedia.org/wiki/Bat Figure 7. Prototype of the miniature bat eavesdropper circuit shown in Figure 5. 9/2007 - elektor electronics 49 — BRUSSEL II TOULOUSE- — LIMOGES _ USSABGN — ATHENE ■ H1LVERSUM ■ p BRUSSEL I VIGR A BAA^dbF BERO — MUNSTER BOEDA— PEST N.^^iUNCHEN G, C. I AATSBG t BY - wx_l - flO\ ARSEIL - HOM | HC- KFtKFr i k he. KfcKN I II ANItMH|K*IWC FM qqHI 1 3 5 L'] » 1 R0W| £ i c m . ■ ■9VM Burkhard Kainka Almost as soon as the Software Defined Radio article was published in the May 2007 issue of Elektor Electronics, we started receiving requests for special-purpose receiver upgrades. The most commonly requested capability was extending the receiver range to include low frequencies. Tuning 30 kH? ... 3Q 19) and (Freq < 60) then begin DivlN := round (2500 / Freq) + 128; p := 1000; q : = 40 ; end; if (Freq > 59) and (Freq < 801) then begin DivlN := 125; p := Freq * 2; q : = 40 ; end; if (Freq > 800) and (Freq < 2001) then begin DivlN := 50; p := Freq ; Q : = 50; end; Listing 2 The empirical procedure for higher frequencies if (Freq > 20000) and (Freq < 30001) then begin DivlN := 4; Min := 10000; for Q := 100 downto 10 do begin for p := 500 to 2000 do begin VCO := 10000/Q*P; if abs ( 4*Freq-VCO/Di- vlN) < Min then begin Min := abs ( 4*Freq-VCO/DivlN ) ; Qout := Q; Pout := P; end; end; end; Q := Qout; P := POut; end; 9/2007 - elektor electronics 51 RECEIVERS GND 070389-13 Figure 2 A low-pass filter for signals below 150 kHz. were wound around the periphery of a cardboard box with dimensions of 18.5 cm by 25.4 cm (we used the box in which the bare receiver PCB was delivered). The large inductance of the antenna coil yields a natural low-pass effect, which is complemented by its considerable winding capacitance. The relatively flat resonant frequency is ap- proximately 150 kHz. Testing A suggested test signal for initial ex- periments with the receiver is DCF39 at 139 kHz, which is a telecontrol transmitter located near Magdeburg, Germany. You will see a carrier that is occasionally modulated using a two- tone modulation scheme. DCF49 at 129.1 kHz, which is located at Main- flingen, is a similar transmitter. The well-known DCF77 time signal trans- mitter, which operates at 77.5 kHz, is located in the same place. You can clearly hear the short and long seconds pulses, which are now used to trans- mit weather information in addition to the time of day. And of course there are also many other signals, including sig- nals that are actually the third or fifth harmonics of other signals that are in- sufficiently attenuated. If you tune us- ing 1-kHz steps and you find a signal that wanders through the spectrum in large steps, you have discovered such a signal. In the course of time, you can figure out what is actually happening on that frequency. You have to be care- ful not to be fooled by the signal corre- sponding to the horizontal scan rate of your monitor or other interference sig- nals from your surroundings. In many cases, you can recognize distant sig- nals by their slow fading. ( 070389 - 1 ) Web Links http://en.wikipedia.org/wiki/Longwave www.giangrandi.ch/electronics/dcf77/station. html Figure 4. A simple 100-turn loop antenna (approx. 18 by 25 cm). Publicity lektor lectronics Participate in the Elektor Readership Enquiry and win £ 35 (€ 50) ! Making a good and inspiring magazine for our readers is time and again our motive behind every new issue. We receive many positive reactions but we are convinced that there is always room for improvement. And that’s what we would like you to tell us. Participate in our online readership enquiry on www.elektor.com! Our end of the bargain Of course we appreciate your cooperation. We will therefore raffle 5 Elektor Vouchers worth £ 35 (€ 50) among all participants! Results The results of the enquiry as well as the names of the winners can be found on our internet site www.elektor.com after the enquiry is closed. We expect this will be around October. ~ > p www.elektor.com browse online now! More information? If you have questions concerning this Elektor Readership Enquiry please go to Service — ► Feedback on our website and select “Other” for the subject. 52 elektor electronics - 9/2007 oi Number One Systems for Windows The World Beating PCB design software Version 1 1 features ■ Design revision analysis ■ Star . 1 Delta points ■ Apply Jayoui pattern A groups ■ Design calculators ■ Electrical rules check f ERC) ■ Shape editing panel ■ Merged mb tract shape editing ■ Track analysis Plus many more exciting features. 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You're now convinced that it's your future, the future! You don't feel that excited about just any car. This one is just so special: it's really eye-catching and you can see the ambition and innovation that's gone into this solar-powered car. The design of a solar-powered car for taking part in the prestigious World Solar Challenge isn't just another as- signment, quite the opposite. It is an enormous project on which 1 6 students from the Saxion Polytechnic and the Uni- versity of Twente, The Netherlands, have been working for a good one and a half years. In a series of three articles well give you an insight to the project and the activities of the Solar Team Twente. In this first instalment well tell you about the race, the team and the origins of the project. Best newcomer comes back for more The World Solar Challenge is a race for solar-powered cars right across Australia. It is a prestigious race that now takes place every two years, where developments in the use of renewable energy take centre stage. Over 40 teams from about 20 countries take part. The race goes from Darwin in the North to Adelaide in the South, a distance of almost 1 ,900 miles, which take the solar-pow- 54 elektor electronics - 9/2007 av for the Solan The solar-powered car of Solar Team Twente in 2005 in Australia. This finished ninth and was the best newcomer. for all team members to get to know each other and was part of a team building exercise. There were also many discussions during this weekend. Agreements were made regarding the work to be done, the division of tasks were worked out and, most importantly, the objective was agreed. This was simply: 'We're seeking a podium finish, but aim to be first!' Large quantities of clay were used to make a few conceptual designs. The eventual design had a lot in common with one of the designs suggested during this weekend. ered cars about five days. The 21 st October 2007 sees the start of the next race. This year is the second time that the Solar Team Twente takes part. In 2005 the team from Twente finished an im- pressive ninth and was crowned the best newcomer. Joost Kuckartz, a student in Electronics Engineering at the Uni- versity of Twente, set up the first team in 2003. "Even be- fore The Netherlands took part in the World Solar Chal- lenge I was already infatuated by solar-powered cars. I wanted to find out everything about them and I followed all the races. When I started studying I had the opportu- nity to create a team myself. It's great that this project con- tinues to the present day." A new team was formed in June 2006. Team members from the Solar Team 2005 held a number of lectures and visits in order to whet the interest of potential new team members. Those interested could sign up before the usual application rounds. Sixteen students from the University of Twente and the (co-sited) Saxion Polytechnic were se- lected by the previous team members to make up a new team. In order to get started as quickly as possible, a kick- off weekend was organised. This was primarily meant Diverse team Since that weekend in September 2006 the team mem- bers have had their hands full with the project. All of them have put their studies on hold for one and a half years for the project. As a small financial compensation, during this period they'll still receive a percentage of their grant. Not only the standard working days, but also many eve- nings and weekends are taken up by work for the Solar Team. But it's worth it! To be part of a team of 1 6 and to see the culmination of all your hard work take shape is an incredible experience. For some of the team members this project is part of their studies, but for the others it's com- pletely voluntary. The project consists of much more than just the technical as- pects. The subjects studied by the students vary from Engi- neering to Psychology, and from Electronics to Medical Sci- ences. Five of the sixteen team members are involved with a non-technical side of the project, such as sponsorship, logistics and media. Although this is a pure student project, advice and help from several companies, local authorities, educational and some specialist institutions are vital. Adopting solar cells One of the challenges for the 2005 team was the financ- ing of the project, and they had to rely a lot on sponsor- ship. It's the same for the new team and finances play an important part in bringing the project to a successful conclusion. To have a serious chance of a top-3 finish you have to use the best solar cells. The cost of these solar cells alone takes up nearly half the budget for the whole project. Other big expenses are of course the construc- tion of the car, PR, and travel to Australia. The Solar Team Twente is therefore dependent on their sponsorship money. Sponsorship is looked for both in cash as well as in kind. In kind, sponsors are mainly technical firms who 9/2007 - elektor electronics 55 INFO & MARKET SOLAR TEAM The team members of Solar Team Twente with their SolUTra. agree to give, design or produce certain parts for the car. At this moment in time the Solar Team has the support of a large number of sponsors: over 100 sponsors are now involved with this project! The Solar Team has run several campaigns to attract spon- sors. One of the campaigns was called the 'Club of Thou- sand 7 . The team members picked up the phone and called about 1 ,200 firms during a two-week period, mainly from the region of Twente. These firms were asked if they want- ed to join the Club of Thousand, where each firm gave 1 .000 euros (approx. £ 700) in sponsorship. This initia- tive managed to finance a large part of the project. Apart from the Club of Thousand campaign, one was also set up with individuals in mind. For a relatively mod- est sum of 25 euros (£ 17) you can 'adopt 7 one of the 2.000 solar cells. In this way members of the public can show their support and involvement and the Solar Team Twente gets a helping hand. Almost 700 cells have been adopted to date. This campaign is still active and you too can adopt a cell via www.solarteam.nl. cars taking part were more like space shuttles on wheels and you couldn't ever imagine using one to do the weekly shopping or go on holiday with. However, this will change. In the framework of the twenty-year existence of the World Solar Challenge there is a new regulation this year. This distinguishes between two classes: the Ad- venture and the Challenge class. Most of the prominent teams, and hence Solar Team Twente, take part in the Challenge class. Several regulations have been adapted for this class, which make the cars look a bit more like road cars. For example, the driver now has to sit upright in the car, which completely changes the look of the car. Furthermore, the area that may be covered with solar cells has been restricted. In the past an unlimited number of cells could be used and winning became more a ques- tion of the money available. This year the area of solar cells has been limited to only 6 m 2 (1 8 sq. ft.). As a result of this, limitation ingenious ways have to be invented to capture as much sunlight as possible. The solar-powered car also has to be equipped with headlights, a horn and a steering wheel. These changes made the teams think 'outside of the box' and called upon the creative and innovative skills of the team members. At the start were many brainstorming ses- sions where many concept designs were proposed. The number of designs was continually reduced through criti- cal analysis by the technical team members. The path to the eventual concept design takes a tortuous route. Good use has to be made of external sources of knowledge and experience. A large list of design criteria had to be sounded out and agreed on. These included the speed, ease of construction, weight distribution, stability, reliabil- ity, cost and planning. In the end a daring concept was chosen and the actual design began. Two innovative ideas have been included in the design. The first relies on principles found in nature. Just like a sunflower, the solar cells follow the position of the sun. This keeps them pointed straight at the sun for as long as possible during the day. An ingenious system with lenses has also been used, for which a patent has been applied. In the next edition of Elektor Electronics we will take an extensive look at the design of the car. ( 070380 - 1 ) Space Shuttles on wheels Although sponsorship is an important part of the project, we shouldn't forget that the main aim is to build a win- ning solar-powered car. The design and development of a solar-powered car is an enormous task. It's more of a challenge this year due to some changes in the regulations. Up to now the A CAD drawing of the new solar-powered car. 56 elektor electronics - 9/2007 Take out a free subscription to E-weekly now Do you want to stay up to date with electronics and computer technology? Always looking for useful hints, tips and interesting offers? Subscribe now to E-weekly, the free Elektor Electronics Newsletter. Your benefits: * The latest news on electronics in your own mailbox each friday ■ Free access to the News Archive on the Elektor website • You’re authorized to post replies and new topics in our forum Register today on www.elektor-electronics.co.uk/newsletter £L£CTROniCS courses at Derby Do you love building kit and making things work? Do you want a career where you get paid for doing something you enjoy? If so, we've got the course for you. Study full time or part time and specialise in areas that interest you. Our staff have lots of industry experience and are passionate about their work. Our courses include: BSc (Hons) Electronics BSc (Hons) Electrical and Electronic Engineering HNC / HND Electrical and Electronic Engineering Find out more t: 01332 593216 e: adtenquiry@derby.ac.uk UNIVERSITY of DERBY www.derby.ac.uk/adt No Compromise Oscilloscope Other oscilloscopes in this price range force you to compromise on one of the key specifications: sampling cate, memory depth or bandwidth, The PicoScope 5000 merles Is a no compromise PC oscilloscope at a price every engineer can afford,. www . picotech . co m/sco pe4 28 0 480 396395 T^cIuioIoev tGS. s sampling rate 250 MHz bandwidth I28M sample buffer memory 1 25 MS/s 12 bit AWG bum in PrcoScope 5203 32M buffer £ 1195 PfCOStope 5204 I28M buffer £ (795 9/2007 - elektor electronics 57 Building an AM receiver is a simple project for a beginner, but building an FM receiver is rather trickier. However, with a little ingenuity we can get away with a very small number of components: our superregenerative 'audion receiver uses just two transistors, two coils and a few capacitors. A 'mini 7 project in the true sense of the word! MINI PROJECT FM Superregener Receiver I using only two transistorsl Burkhard Kainka Component count is not the only re- spect in which our superregenerative audion receiver design is economi- cal. As most readers will know, good grounded screening is essential in a ra- dio receiver. In our prototype we recy- cled the tin lid from a packet of coffee for this purpose: the ideal type of pack- et is one with sides made from card- board to which the lid is crimped, as the edge can simply be cut with a sharp knife. It is easy to bend to the desired shape, pro- vides a stable base for mounting and takes solder easily. For the circuit connections either plain perforated board or stripboard is suitable (see large picture). We also wind the coils ourselves. The oscillator coil is made from five turns of 0.8 mm (ideally, sil- ver plated) copper wire on a di- ameter of 8 mm. Short connec- tions are essential, especially to the tuning capacitor: we sol- dered a trimmer directly to the ground plane. The second coil in the circuit consists of 20 turns of 0.2 mm enamelled copper wire wound on a 10 kQ resistor. The rest of the circuit is constructed as shown in Figure 1 . The antenna should not be too long, as otherwise the circuit may cause interference: the su- perregenerative circuit is also a transmitter! Nevertheless the circuit is very sensitive and operates perfectly satisfactorily using a 10 cm length of wire for an antenna. The headphones should ideally have an impedance of at least 400 Q. The circuit will work with 32 Q stereo headphones, but the out- put will not be as loud. Figure 1. A handful of components go to make our FM receiver. Reception in practice When the receiver is switched on the output will consist of noise. The fre- quency can now be adjusted using a screwdriver: when an FM station is en- countered the noise will reduce in vol- ume or disappear altogether. The tun- ing must be adjusted so that it is just on the edge of the band occupied by the transmitted signal: this re- quires a little patience, luck, and skill with the screwdriver. Once you have found your favourite station, of course, there is no need to adjust the circuit again. The sound quality from this sim- ple receiver is admittedly some- what mediocre, although it is re- markable that it works at all giv- en that only two transistors are used. In the early days of radio the superregenerative audion receiver design was very widely used (although of course the cir- cuit was built using valves). The design subsequently fell from fa- vour as it became apparent that, since it also acted as a trans- mitter, it could interfere with a neighbour’s radio reception: this applies also to our design. It is doubtful whether such a radio could obtain its ‘CE’ certification mark today, and the radio is thus more of an interesting experi- ment than a potential challenge 58 elektor electronics - 9/2007 Figure 2. Circuit of an RF oscillator. R4 +9V I Figure 3. The capacitor in parallel with the emitter resistor makes the RF oscillator flip between 'oscillating 7 and 'not oscillating' states. to the tried-and-tested superhet de- sign. The superregenerative audion design still features in simple radio remote control receivers, remotely- controlled power sockets and re- mote temperature monitors. A little theory How does the receiver work? At first sight the circuit appears to be a simple oscillator. Figure 2 shows for comparison a well-known RF os- cillator design. The simple oscillator keeps the amplitude of its output constant. We now modify the circuit so that the amplitude of the oscillations is much greater, and so that the tran- sistor can be switched fully off. The value of the feedback capacitor has to be increased. It is important to use a transistor designed for radio frequency use (such as the BF494) as it is difficult to get the circuit to work using an ordinary audio fre- quency device such as the BC548B. The circuit shown in Figure 3 also includes a coil in the emitter con- nection. Finally, the capacitor in par- allel with the emitter resistor also plays an important part in the cir- cuit: as soon as oscillations start, it starts to charge. When the poten- tial difference between the base and the emitter of the transistor falls far enough, the transistor turns off and oscillations can no longer be sustained. The emitter capacitor Figure 4. The RF oscillation builds up practically from zero. Figure 5. The quenching gives rise to a very noisy sawtooth signal at the output. Figure 6. If a signal is received, the circuit flips between its two states more quickly and more regularly. discharges again, a collector cur- rent once again starts to flow, and the circuit starts to oscillate again. The circuit thus flips between two states: oscillating and not oscil- lating. At the output we obtain a sawtooth signal with a frequency of about 50 kHz. Each time the oscillator swings into action the amplitude of its oscilla- tion builds up practically from zero (Figure 4). Thermal noise in the cir- cuit helps to start the oscillations going, which means that the start- up time can vary considerably. This variation (Figure 5) leads to noise in the collector current, which in turn is heard when no station is be- ing received. To and fro If, however, a signal is received at the tuned frequency, this will help the amplitude of the oscillations build up more quickly each time (Figure 6) and the rate at which the oscillator starts up and stops (the ‘quench frequency’) increases. An unmodulated RF signal gives rise to a stable quench frequency and little noise at the output. If the sig- nal is amplitude modulated, this will affect the degree to which the it helps oscillations start up, which in turn will be reflected in the av- erage collector current. To demod- ulate an FM signal we adjust the tuning so that the centre frequency 9/2007 - elektor electronics 59 MINI PROJECT of the signal is on the edge of the range that will stimulate the oscil- lator: this makes the FM signal have the same effect as an AM signal. The whole process can be seen clearly on an oscilloscope. The saw- tooth signal on the emitter resistor will indicate whether a station is be- ing received. The receiver is so sen- sitive that it does not actually need an antenna: the oscillator coil can pick up enough energy directly. The circuit in Figure 3 has a further weakness in that its output con- sists of a high-amplitude sawtooth signal plus the desired signal at low amplitude. The cunning technique we use to avoid this is illustrated in Figure 7. The emitter capacitor is now wired not to ground, but to the output. As the collector current rises the collector voltage will fall and the emitter voltage will rise, and the emitter capacitor will now act to counteract this effect on the output. The amplitude of the sawtooth signal is reduced practically to zero, leaving just the desired demodulated R4 +9V Figure 7. If we take the emitter capacitor to the output the sawtooth signal is almost completely suppressed. Just the desired signal remains. audio output. This can be taken to an audio amplifier. The basic circuit is now essentially as shown in Figure 1. We have added the audio amplifier stage, and the base bias circuit for the oscillator transistor is slightly simplified. Con- necting one side of the tuning ca- pacitor to ground does not affect the circuit as far as radio frequencies are concerned, and for simplicity we wind the RF coil on a resistor. (070 044 - 1 ) Anzeige FORMULA FLOWCODE Incl. CD-ROM Ordering: Use the order form at the back or visit our online shop. Elektor Electronics (Publishing) Regus Brentford I 1000 Great West Road Brentford TW8 9HH I United Kingdom Tel. +44 208 261 4509 sales@elektor-electronics.co.uk Formula Flowcode Buggy USB-programmable robot vehicle ■ A complete solution: robot + software + curriculum ■ Line following and maze solving ■ High-tech specifications ■ Also programmable with C or ASM ■ E-blocks compatible Motivating for education and hobby Built and ready to use for only £ 85.00 / US$ 169.00 lectronics More information on www.elektor-electronics.co.uk 60 elektor electronics - 9/2007 QUASAR electronics Quasar Electronics Limit PO Box 6935, Bishops Stc CM23 4WP, Tel: 0870 241 United Kingdd 1826 ed rtford m Fax: 0870 460 1045 E-mail: sales@quasarele Web: www.QuasarElectro ctronics.com nics.com 08717 Postag^ 3-7 Day Europe SOrder We acc to Quas Call no 95 & Packing Op Delivery - £3. (EU) -£6.95; R4 online for reduc opt all major cr ar Electronics, for our FREE project^ modules and w ions (Up to 0.5 UK Mainland st of World - £! ed price UK P4 edit/debit cards Prices include CATALOGUE publications. : UK Standard jery - £8.95; I) ( 20 kb/s) applications. Try Googling 'home automation' and ZigBee and you will find any amount of technical information and news items but very little information on the availability of the radio modu- les or a finished ZigBee product (e.g. a remotely controlled mains outlet). The company Zensys have developed their own system si- milar to ZigBee called Z-wave. This system uses 868 MHz in Europe and 908 MHz in the USA. An attractive feature of the system is its low cost of components (< 3 $ for a radio module) and lowjL/W power consumption means that battery operation is feasible. Zensys is backed by a large part of the ZigBee alliance and has ensured that Z-wave capable devices from different manufacturers are interoperable which is not guaranteed with ZigBee devices. v-| r v r m. __ _ What's on the high street? We carried out a small survey to find just what systems are available from high street retailers and from build- ers markets for the home-owner or DIY enthusiast. In the majority of the larger superstores it is possible to pick up a fairly simple hand-held wireless remote controller which manages up to four switched mains outlets (usually three on/off and one dimmable). Along with these controllers it is also possible to find wireless doorbells, garage door openers, curtain opener/closer and security systems. All of these are manufactured by different companies so that they are operated by a single controller and cannot be integrated and switched by a centralised controller (in- deed they are generally designed to respond to the signal from one unique transmitter to avoid interference to/from neighbouring systems). The design philosophy of a home automation system is the reverse and seeks to integrate the operation of these sub-systems in a meaningful way. When it comes to buying the hardware for a home auto- mation system the picture across Europe seems to be the same; whether you look in a large DIY outlet in Maas- tricht, Holland or in your local branch of Homebase or B&Q in the UK. You are sure to find any number of stand- ard electrical outlets and manually operated switches as far as the eye can see (Figure 4) but when it comes to home automation there is sadly nothing to be seen; it would seem that the average homeowner is quite content to carry on turning things on and off by hand. Enquiries are met with the response that there has not been any call for such products. The picture across Europe in the DIY market seems to be the same — in another outlet there was evidence of re- mote controlled mains sockets as mentioned earlier and wireless thermostats which could be retro-fitted to existing heating systems and wireless PIR based movement detec- tors (Figure 5). When it comes to home automation there is no evidence at all that such systems have made any in- roads into the mainstream building and DIY market so far. With an ever increasing number of remote control units piling up on the coffee table we look forward to a time when a more integrated approach removes all the clutter and simplifies our lives but don't hold your breath, it looks like it may take another three or four years at least before it is a reality. ( 060324 - 1 ) Web Links [1 ] www.aec.at/en/archives/festival_archive/festival_catalogs/ festival_artikel.asp?iProjectlD = 8681 [2] http://depts.washington.edu/dmgftp/publications/html/ smarthouse98-mdg.html Further Reading [3] Zigbee with Xbee, Elektor Electronics November 2006 [4] Zigbee Transceiver, Elektor Electronics March 2007 64 elektor electronics - 9/2007 LABTALK HANDS-ON The Anatomy of HEX Files Luc Lemmens This month a story that really should not be necessary. When we develop software for a microcontroller, the compiler or assembler will, as final output, create a file that we need to program into the program memory of the controller. In the vast majority of cases this file will have the so-called Intel-HEX (Intellec) file format, a file that in addition to the machine code itself also includes the destination ad- dresses showing where this code has to be located. The file also incorporates checksums that allow the integrity of the code to be verified. In reality it should not be of interest to the pro- grammer to know the details of the file format, just program it in the memory and Bob's your uncle. But it is different if the assembler or compiler appears to generate something different from what we ex- pect. Sometimes you just cannot avoid browsing through the HEX-file to find out what exactly is going to end up in the program memory. Sometimes this file also contains configuration bits for the controller that configure the oscillator, watchdog, copy protection and related things. Because the need to unravel the inner workings of a HEX file are so infrequent, you either need to look up the details every time or try very hard to remember them. A HEX file is built up out of records. Each record contains a record- type, a record-length, the address at which the data has to be located and a checksum. There are six different types of records, not all of which are necessarily used all the time: • Data record (all formats) • End of File record (all formats) • Extended Segment Address record (not in 8-bit format) • Start Segment Address record (not in 8-bit format) • Extended Linear Address record (only in 32-bit format) • Start Linear Address record (only in 32-bit format) Every record appears as shown below. RECORD MARK j . j RECLEN LOAD OFFSET RECTYP INFO or DATA CHKSUM 1-byte 1-byte 2-bytes 1-byte n-bytes 1-byte The start is indicated with RECLEN indicates the number of data bytes. LOAD OFFSET indicates with 1 6 bits the offset of the destina- tion of the data bytes and only has meaning in data-records, in all other records this field is '0000'. RECTYP indicates the record type: '00' = Data record ' 00 ' = Data record ' 01 ' = End of File record ' 02 ' = Extended Segment Address record ' 03 ' = Start Segment Address record ' 04 ' = Extended Linear Address record ' 05 ' = Start Li near Address record The INFO/D ATA-field consists of a number of bytes (see RECLEN), the interpretation of which depends on the record type. The checksum is calculated from the two's complement of the bytes from the fields starting at RECLEN up to and including the last INFO/ DATA-byte. When you add the sum of these bytes to the checksum you will get a result of 'O'. Extended Linear Address Record (only in 32-bit format) RECORD MARK i . j RECLEN ‘02’ LOAD OFFSET ‘0000’ RECTYP ‘04’ ULBA CHKSUM 1-byte 1-byte 2-bytes 1-byte 2-bytes 1-byte In the 8-bit HEX-files two bytes (LOAD OFFSET) are available to in- dicate the address. In this record type the ULBA (Upper Linear Base Address) defines bits 16 to 31 of the address, the LOAD OFFSET of the subsequent data records then completes bits 0 to 15 to give the final absolute address. Extended Segment Address record (16- and 32-bit formats) RECORD MARK > . j RECLEN ‘02’ LOAD OFFSET ‘0000’ RECTYP ‘02’ USBA CHKSUM 1-byte 1-byte 2-bytes 1-byte 2-bytes 1-byte The 16-bit Extended Segment Address record specifies bits 4 to 19 of the Segment Base Address (SBA), bits 0 to 3 of the SBA are 'O'. The LOAD OFFSET of the subsequent data records then determines the final address. Data record (all formats) RECORD MARK i . j RECLEN LOAD OFFSET RECTYP ‘00’ DATA CHKSUM 1-byte 1-byte 2-bytes 1-byte n-bytes 1-byte This contains a maximum of 256 (RECLEN) bytes of data, LOAD OFF- SET determines (with or without ULBA or SBA) where the first data byte of the record will go in memory. Subsequent data bytes go se- quentially after this address at increasing address locations. Start Linear Address record and Start Segment Address record are not used with microcontrollers and are therefore outside the scope of this article. End of File record (all formats) RECORD MARK > . i RECLEN ‘00’ LOAD OFFSET ‘0000’ RECTYP ‘01’ CHKSUM ‘FF’ 1-byte 1-byte 2-bytes 1-byte 1-byte As the name already gives away, this record marks the end of the program file. Well, that ends the 'refreshment course'. And now just keep your fin- gers crossed that you will never or at most seldom need this knowl- edge! In the interest of full disclosure: there are many more HEX-file formats, but the Intel-format is the most common one. Engineers are fond of standards and that is why they can never in- vent enough of them... ( 075034 ) 9/2007 - elektor electronics 65 MODDING & TWEAKING Watchdog in the Meter C Jeroen Peters Many of us see our electricity consumption increasing, and with it our electricity bills. That's why it's useful to improve your insight into your consumption. But existing energy meters in the form of an adapter that you can plug a device into cannot be used to measure the consumption of ceiling lamps and other loads connected directly to the mains. The Wireless Energy Monitor (WEM) described here remedies this problem. Figure 1. Sensor circuits of the Wireless Energy Monitor, which is located in the meter cabinet. +5V The Wireless Energy Monitor consists of several sensors with a transmitter and a receiver. The transmitter and the sensors are placed in the meter cabinet next to the electricity meter and gas meter. You can use the door- bell transformer to power the transmitter. Thanks to the wireless link, the receiver can be used anywhere in the house to show your current power consumption on a LCD screen. You can thus use it in every room to see the effect on energy consumption of switching something on or off. The receiver is powered by a 9-V battery. The transmitter and receiver are both based on a PIC mi- crocontroller. Each circuit is fitted with an RS232 connec- tor for programming the PIC. The programmer for this is a very simple design that you can easily build yourself. Operating principle Most electricity meters in current use have a LED that flashes at a rate proportional to the amount of electric- ity that is being used. The number of pulses per kilowatt- hour (pulse/kWh) is stated on the meter. For example, the meter shown in the photo (Figure 7) outputs 600 pulses per kWh. These pulses are recorded using LDR R2 in Figure 1 . We also want to know whether the electric- ity will be billed at rate I (usually the High rate) or rate II (usually the Low rate). The designations for the High and Low rates may differ between countries and even be- tween electricity suppliers — we've seen Peak/Off-Peak, Normal/Reduced; Daytime/Other, to mention but a few. Anyway, for our purpose, we fit another two LDRs (R 1 0 66 elektor electronics - 9/2007 and R 1 1 ) to the electricity meter (see Figure 8). With the gas meter, we make use of the small reflecting dot in the '6' digit of the rightmost counter wheel of the gas meter. A reflective sensor (1C 5) shines a beam of in- frared light on this counter wheel. The phototransistor in the reflective sensor sees the reflective dot, which allows the gas consumption to be measured with a resolution of one hundredth of a cubic meter (m 3 ). The transmitter circuit measures the time between succes- sive pulses, looks to see which rate is currently applica- ble, and maintains the gas consumption count. It then sends this information via the radio transmitter module. The receiver converts the time interval between the last two pulses from the electricity meter into the current power consumption (watts). It then shows the result on the LC display, taking the currently applicable billing rate into account. It also shows the internally accumulated coun- ter values for the electricity gas meters on the display. These counters start at zero when the transmitter is first connected. This makes it easy to keep track of the energy consumption without having to check the meters. To make everything really easy, the receiver also has an RS232 connector that can output all this data to a PC or other equipment each time new data is received. Figure 2 shows how everything is linked together in schematic form. Transmitter circuit For description purposes, the transmitter circuit can be broken down into two functional parts: the basic trans- mitter section together with the power supply (which is tapped off from the bell transformer), as shown in Fig- ure 3 and Figure 1 1 , and three circuits for the sensors fitted to the electricity and gas meters (Figure 1). Figure 2. Block diagram of the transmitter and receiver of the Wireless Energy Monitor. The transmitter is built around a Microchip 1 6F84. This 1C is readily available and easy to program in a DIY envi- ronment without any need for an expensive programmer. A 4-way connector is provided in the circuit for program- ming the PIC. The complete transmitter circuit is powered from the bell transformer, which is usually located in the meter cabinet and does not have to supply any power most of the day. A power source salvaged from other equipment can also be used in place of the bell transformer. As the voltage is rectified by D1-D4 and then stabilised by IC1 , you can use almost any power source that can provide an AC or DC voltage in the range of 7.5 V to 20 V. The combined current consumption of the transmit- ter, sensors and LEDs will never exceed 1 00 mA. R1 pulls Master Clear Reset (MCLR) to +5 V. XI , C3 and C4 provide a stable 4-MHz clock signal for the PIC. The transmitter uses an 868-MHz set from Conrad Electronics (order # 1 90939). This set includes a transmitter mod- ule and a receiver module, and it has sufficient range 78L05 IC1 Figure 3. The schematic diagram of the transmitter unit consists of nothing more than a PIC and a quartz crystal. 9/2007 - elektor electronics 67 MODDING & TWEAKING Figure 4. The receiver circuit is also very simple. There are few components other than the PiC. K1 Figure 5. Pay careful attention to correct wiring of the programming cable. n i n i n i n 11 flashing LED on E-meter ±260 ms E TIME E RATE El COUNTER E2 COUNTER G COUNTER CRC 2_ (2 bytes) (1 byte) (2 bytes) (2 bytes) (2 bytes) (1 byte) start pulse start pulse 'O' 'O' 'O' T ‘O' ‘1’ '1' '1' '0' 'O' '1' 'O' ‘O' '1' 'O’ 'O' Figure 6. Structure of the message sent to the receiver by the transmitter. 1 ms 5 ms 200 800 ps 600 ps 400 ps M s ‘ | start pulse j | II -I’ 1 1 1 - 1 1 1 075075-15 for in-house use. The range can be extended somewhat by straightening out the curled antenna. You can also replace the supplied antenna with a straight piece of insu- lated wire exactly 8 cm long (quarter-wave antenna). The sensors are connected to RB0-RB2 of the PIC. The circuit shown in Figure 1 is used to detect the flashes that indicate the electrical power consumption. Fit LDR R2 on the electricity meter directly in front of the blinking LED (see Figure 8). In combination with R3, it forms a volt- age divider whose junction voltage rises when the LED of the electricity meter emits light. IC3a buffers this voltage, while C5 and R4 ensure that its quiescent value is 0 V. This makes the circuit considerably less sensitive to ambi- ent light, which is handy if the door of the meter cabinet happens to be open. IC3b amplifies the pulse by a factor of 1 1 , equal to (10 kQ + 1 kQ) -s- 1 kQ. The resulting pulse is large enough to cause comparator IC4a to switch states. A small signal is adequate for this purpose because the in- verting input of IC4a is connected to a reference voltage of only 0.1 6 V. This reference voltage is taken from volt- age divider R7/R8. When the LED of the electricity meter flashes, the output of the comparator goes low briefly and LED D 5 flashes briefly. The PIC also sees a short 'O' level on RB0. Many electricity meters have dual meter mechanisms (for daytime and nightime rates). The circuitry around LDRs R10 and R1 1 is used to see which mechanism is active, and thus which rate is currently applicable. They must be fitted above the LEDs of the electricity meter that indicate which meter mechanism is currently active (see Figure 8). As only one of the LEDs is on at any given time, the junc- 68 elektor electronics - 9/2007 tion voltage of this voltage divider will always be either higher or lower than the 2.5-V reference voltage set by R1 2/R1 3, which is applied to the inverting input of com- parator IC4b. When rate I is applicable, LED D6 is off and a '1 ' level is present on RB2, and when rate II is ap- plicable, LED D6 is on and an 'O' level is present at RB2. IC5 in Figure 1 is used to measure gas consumption. It senses the reflecting dot in the '6' digit of the rightmost counter wheel of the gas meter (see Figures 9 and 10). IC5 is a reflective sensor that shines a beam of infrared light on the dial and detects how much light is reflected back. When the reflective surface of the gas meter dial is in front of IC5, the transistor in IC5 conducts and the volt- age on the non-inverting input of comparator IC4c drops below the 0.45-V reference voltage generated by voltage divider R1 7/R1 8. The output of comparator IC4b will thus go low, and LED D7 will light up. The PIC processor will also see a 'O' level on RBI . Receiver circuit Another 1 6F84 is used in the receiver circuit (Figures 4 and 12). This circuit also includes a 4-way connector for programming the microcontroller. The receiver module from the Conrad set is used to receive the RF signal from the transmitter. Don't forget to fit an insulated wire exactly 8 cm long as an antenna. The circuit is powered by a 9-V battery. The combination of a 78L05 and Cl generates a stabilised 5-V supply volt- age from the battery voltage. If you use an LP2950CZ5.0 instead, the voltage regulator will be much more efficient and the battery will last almost 50% longer. The key player in this circuit is again the PIC1 6F84. It re- ceives the information from the electricity and gas meters via the Conrad radio receiver. Rl, C2, C3 and K1 have the same functions as in the transmitter circuit. The LCD is connected directly to the PIC and driven in 4-bit mode (see 'Software' below). The contrast of the LCD screen can be adjusted with R2. Finally, connector K2 is provided to allow the received data to be transferred directly to a PC via the COM port. The PIC will transmit the full set of data to the PC each time the electricity meter generates a light pulse. You can omit this connector if you do not plan to use a PC. LED D1 lights briefly each time a message is received correctly from the transmitter. Software The software for the transmitter and the receiver is avail- able as assembly-language source code and hex files, which can be downloaded from www.elektor.com and easily loaded into the PIC microcontrollers. You can use the NTPICPROG.EXE program from Andreas Hansson [1] for this. If you have to modify the source code, you can use the MPLAB IDE environment, which can be download- ed free of charge from the Microchip site [2]. The PICs are programmed via the COM port of the PC. You will need a simple programming cable for this (see Figure 5). Plug the 9-way D connector into the COM port of the PC, and slide the other connector over 4-way PCB connector K1 on the transmitter or receiver board. Make sure it is fitted correctly, which means with the GND lead on the proper side! Now you can program the PIC quite easily using NTPICPROG.EXE and the .hex file. You should use a desktop PC, since many notebook PCs only have 3.3-V levels on the signal lines of the COM port, and that's too O* Cm». fl nt* h . -np£ *.{.» 000467895? V 1 0 3 9 2 3 1 3003 9/2007 - elektor electronics 69 MODDING & TWEAKING low. Also make sure that power is applied to the PIC dur- ing programming. With the transmitter, you can temporar- ily connect a 9-V battery to the supply .lines that would otherwise be connected to the bell transformer. The software in the transmitter unit measures the time between successive pulses from the flashing LED of the electricity meter. It sends the following data to the receiver immediately after each measurement: • The time between two electricity pulses (E_TIME_2 and E_TIME_ 1 ) . The elapsed time between two pulses from the electricity meter (in milliseconds) is equal to E_TIME_2 x 256 + E_TIME_1 , with a maximum value of 65,535 ms. • Rate I/ll indicator (RATE). This byte is '1 ' for rate I and '2' for rate II. • Electricity meter rate I count (E 1 _2 and El_l). This count indicates how many pulses have been issued by the electricity meter for rate I since the transmitter was switched on. It is equal to E_1 _2 x 256 + E_1 _1 , with a range of 0 to 65,535. The count starts again at 0 after it reaches 65,535. The count must be divided by the number of pulses per kWh in order to determine the number of kilowatt-hours. • Electricity meter rate II count (E2_2 and E2_l). This is as described above, but for rate II instead. • Gas meter count (G_2 and G-l ). This is as described above, but for the gas meter instead, and the count rolls over to 0 after reaching 9,999. The counting unit is one- hundredth of a cubic metre (0.01 m 3 ). • A CRC control byte (CRC). Figure 6 shows the structure of the transmitted mes- sage. The receiver converts the time interval between two light pulses from the electricity meter into the amount of power currently being consumed in the house. As this conversion depends on the type of meter (number of pulses per kWh), this parameter must first be configured in the software. The default value in the software is 600 pulses/kWh. The photo of the LCD screen in Figure 13 shows the structure of the displayed information. The first line shows the power consumption and the count of the number of pulses of the first meter mechanism of the electricity meter. The second line shows the count for the gas meter and the count for the second meter mechanism of the electric- ity meter. All of the bytes received from the transmitter are also sent to the PC via the serial link. This data arrives at a rate of 9600 baud with no parity bit, 8 bits per byte, and 1 stop bit. Practical aspects The contrast of the LCD screen of the receiver can be ad- justed with trimpot R2. When you switch on the energy monitor, it will immediately start counting and recording the number of cubic metres of gas and electrical power consumption. When everything is switched off at night, you can see how much is still being used by 'surreptitious loads'. This is also a good way to see whether the PC is actually switched off or the heating is still on. You can also track down real energy gluttons and take suitable measures. For example, you can replace lamps that are often on by low-energy lamps, or switch off equipment instead of leaving it in standby mode. You can calculate the difference in electricity consumption from the data shown on the LCD screen. As all the data can be read in by the PC, you can cre- ate your own household energy consumption database to indicate whether your household is using energy more economically. A nice example of a system of this sort is shown in reference [3]. You can also see the times when energy consumption peaks occur. ( 075075 - 1 ) Web links: [1 ] http://home.swipnet.se/~w-24528/NTPicprog [2] www.microchip.com [3] www.bwired.nl [4] www.elektor.com About the author Jeroen Peters is a first-year student of Computer Engineering at HAN University in the Netherlands. He is interested in practical applications of electronics, especially in home automation. Jeroen created the basis for the circuit described here for his specific research project at the HAVO (senior general secondary school). 70 elektor electronics - 9/2007 Vex Robotics Kits Meccano” Compatible Computer Control Radio Control Tank Treads Hydraulics FUN FOR THE WHOLE FAMILY! Build your “Imagination is more important than knowledge” Albert Einstein E a f*OfcojKt Internet Technical Bookshop, 1-3 Fairlands House, North Street, Carshalton, Surrey SM5 2HW www.robotiq.co.uk sales@robotiq.co.uk 0208 669 0769 ANiiui UAMOTH* ' y riLJN i_£aj«n iJrrp-fiv-ti rep J-mLV to jju.'i r.< •no Dcctjdtw Yt pum o*?. V'chtc? Ca***: Comacm-e . 1 Dirtiqn ImpirMl by Eh* j ’ '^L. 500 2000. Sinclair 2X Spectrum. x || J| |T 1 41 J B ... J* . ™" J" Apo c H ft fA' 4FV»U k « fts, CM*jMttbk! '-r .L *frr t/DPS* 'IWS? - lotto, tv * uwnfei" ■ ■ CiMmt tnr MO Sljd*rtV j The Fit* ttifr »uvn ErriKOOM Sfrfwud ■ F-Ap HvrhM Kt* Mlpvfdflnn IM ' LinniMn SslEwlrv Up TfefTVTtanl KHl * f cn D^HHiTinu XCSCtvno Cl*-4d|l«Kq WWW. XG AM EBTATtO.N . CO M '!£*£ Rjc gas. 736^ -am^ FI I gup ptiht(^nuh vi;.net B II II \ IIU* lil-i U I Vi ih LJ U Jw.kLtfJ ~ T r ■ v_.- , rmi Pv^hrwy irs rwi 1 1 1 1 1 - 1 1 !i j. i >u-iirrill*r l> ) ~~U u www.componentbin.com +44 (0) 1354 778224 £l*ilGf l^TprtnKpn £ lectromcs ISBN 978-90-5381-214-3 £18.90 / US$ 37.90 ethernci CD-ROM Ethernet Toolbox Software Tools en Hardware Tips This CD-ROM contains all essential information regarding Ethernet interfaces! To help you learn about the Ethernet interfaces, we have compiled a collection of all articles on this topic that have appeared in Elektor Electronics and complemented them with additional documen- tation and links to introductory articles on Ethernet interfaces. •Controllers & Microcontrollers •Boards with Ethernet connectivity •Serial to Ethernet •CAN to Ethernet •Connectors •Physical Layer Tranceiver •IEEE 802® standard It includes a collection of datasheets for dedicated Ethernet interface ICs from many different manufacturers. To help you with your own projects, the CD-ROM provides a wealth of information about connectors and components for the physical layer (PHY) and specific software tools for use with the Ethernet (Software). All of the documents are PDF files. Order now using the Order Form in the Readers Services section in this issue. Elektor Electronics (Publishing) Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel. +44 208 261 4509 See also www.elektor-electronics.co.uk 9/2007 - elektor electronics 71 PROJECTS PROFILER MILLING MACHINE 'Profiler', a milling machine from a kit was published in the January and February 2007 issues of Elektor. Profiler is a joint undertaking of Elektor and Colinbus. At the time of writing, more than 900 people have placed orders for a Profiler kit. Some knowledgeable users have found the 'Profiler' topic on the Elektor forum suitable for exchanging all the latest on their machines. Here's a compilation of the best tips and tricks we came across. One of the best documents to read for budding Profiler users may be found on the web pages by Reece Robinson from New Zealand who kindly supplied the necessary url on our forum. A large section of this article should be credited to Reece! PCB tools When I ordered the Profiler I also ordered a number of tools so I could start making PCBs the minute I had assembled the kit. As I am a newbie at milling PCBs I researched what I could from the Internet and came up with the following initial list: A good construction procedure is to build the electronics first so as to be able to operate each of the axes once it is assembled up but not yet tightened, again, to allow easier access to the adjusting elements. Software 1 Ox PCB engraving tool - Normal Line Milling 36 mm, 0.2 -0.5 mm (ref. COLCT0001) Once I completed assembling the kit my attention turned to the two software applications ColiDrive and ColiLiner. Drill Bits 38 mm long 5x d = 0.80 mm (ref. COLCT0025) 5x d = 1 .00 mm (ref. COLCT0028) Contour Router 38 mm long 1 x d = 1 .00 mm (ref. COLCT00 1 3) lx d = 2.00 mm (ref. COLCT0015) End Mill 36 mm long 2x d = 1 .00 mm (ref. COLCT0007) lx d = 2.00 mm (ref. COLCT0008) Having milled my first PCB I think this was a good initial list. Not really IKEA When the kit arrived (all 30 kilograms of it!) my first task was to inventory all the parts. Everything was in order so I went about building it. I was initially concerned that the instructions were only a series of photos/pictures but once I got started my fear was not realised and it all went together very quickly. The one lesson I got from this phase is that it is very important that when building the Z assembly that you ensure there is no slack in the roller system. Make the adjustment to the eccentric wheel as necessary to ensure there is no play. Failure to do this in the early stage will leave you having to disassemble most of the Profiler later to access the adjustment mechanism. The mechanical construction is going to take you between 10 and 20 hours, depending on your level of experience - it's a bit more complicated than a unit from IKEA! Very rarely, parts are either missing, or replaced with others not described in the documentation. The drawing of the Z-axis limit switch is reversed. ColiLiner During the installation of ColiLiner (Standard 1 .0 Rev. 20070301 ) you are given the choice of install location. I recommend you don't choose anything other than the default location. It turns out that the installer does not update the folder locations in the CBPCBF.INI file located in the ColiLinerXSYS directory. The software does not function correctly with incor- rect settings here. Once all was working correctly I found that ColiLiner didn't require any changes to its configuration before I used it. This software is relatively simple to use for what I needed. As I currently only make single sided PCBs all I need to do here is load the bottom artwork layer Gerber file and the drill file then align the drill holes with the pads. This is a simple procedure that is described in the software manual. Once the design is 'Contoured' and the 'Fabrication Output' file has been produced then it's off to ColiDrive. Note: The software manual recommends that you use the 'mill as text' option for any text that appears in your design. There appears to be a bug with this feature as the results I get are unreadable. This feature sounds good but it just didn't work for me. ColiDrive ColiDrive (my version: 2.2.0. 1 9) is where you will spend most of your Profiling time. Tool Configuration The first task was to configure ColiDrive with the tools I have. The Tool database configuration is accessed from the Setup — ► Tools menu option. Here I selected the 'used tools' tab and entered the tools I had purchased (listed above). This list is 72 elektor electronics - 9/2007 then made available for ColiLiner. Refer to the software manual for more details. ColiDrive Machine Properties After hours of trial and error I think I have settled upon the machine settings that will give good milling results. In the 'Options' tab I selected the 'Line-by-line' file processing strategy. This gives you the ability to pause the machine or cancel the job. It does not unfortunately allow you to back up an arbitrary number of steps to repeat. In the Program Setup & Options dialog, accessed from the Setup — ► Machine Properties menu, I set the maximum X, Y and Z speeds all to 10000 micro m/s. I found this minimised the chance of the line milling tool skating on top of the copper instead of break- ing the surface and removing material. I also selected the 'Do Nothing' option in the 'When Finished Go To' section of the dialogue. This was handy because it gives you the option to repeat a whole segment of the process- ing using the same material origin. I found this useful in the trial and error learning phase. In the 'PCB Post Processor' tab you will see the settings for PU, PD and Drill. My settings are PU = -2000, PD = 300, Drill 2000. It is important to note here that when you load your PCB file and provided these values in the dialog that pops up — you cannot update these values from the Program Setup & Options dialogue. The software allows you to change them, but any changes here will have no effect on the currently loaded project. You must close the project and reload the file. I wasted some copper and tools learning that lesson. Settings ColiDrive v 2.2.0. 1 9 seems to be the most complete version at the time of writing. Windows 2000 with SP4 is reported to work correctly, but some problems have been reported with ATI or S3 cards. To avoid crashing (caused by data saturation in the controller when handling big files), ColiDrive must be configured as follows: follow Communication Setup Machine properties: on the second tab (options/strategy) select 'realtime communi- cation' instead of 'transfer file to controller'. If you want to send commands from a terminal, the communi- cation between the PC and the controller card needs to be con- figured thus: 38400,8,N,1 - but apparently ColiDrive simply needs a free communication port with Profiler connected up and initialized. Our Dutch friends are trying to make Profiler work with an Open Source application. Another correspondent says that, in the light of the huge demand, it is possible that the applica- tions running Profiler might in the future accept the much more commonly used G-Code. Z homing One thing I should explain is how I choose PD (pen down) to be 300. This value is very much tied to the manual procedure I perform for setting the Z home when asked by the ColiDrive software. Setting the Z home is one of the most critical steps to get right. Get this one wrong and you end up with a nice modern artwork and not a functional PCB. There are a few factors that I have found to impact this value: 1 . The flatness of the base board. I.e. is it exactly level? Mine is not and has a difference of about 1 00 pm from one side of a 6-inch PCB to the other when placed in the centre of the Profiler. Small but important difference. 2. The quality of the copper board. The copper board I have has small waves in one direction. This makes for perfect lines in one direction and wavey lines in the other. On diagonal lines the tool sometimes gets pushed a little by the waves and results in narrowing of the tracks. 3. How well is the material fixed to the Profiler board? I use the double-sided tape method shown in the Elektor video which seems to work well. 4. There are probably others that I have yet to discover... The manual procedure I use to set the Z home, given the fac- tors above, is to position the machine head over the centre of the copper material and lowering the tool until it makes electri- cal contact with the surface. I use a multimeter on the continu- ity setting with one lead touching the copper surface and the other on the tool. When I am close to the surface I reduce the Z increments to 0.025 and listen for the beep. Once I hear the continuity beep I back the head off 0. 1 00 to clear the surface. This is necessary to ensure the tool does not contact the copper surface when the drill is powered up or when it moves over the surface at this low level. Alternate method of Z homing There are two methods for adjusting the origin, based on either a dial gauge or a feeler gauge - the latter being suit- able for initialization and calibration when changing tools, but not for checking in various places on the part to be machined. Not all Profiler users will have access to a dial gauge or equivalent instrument, and tools for amateurs (drills, milling cutters, etc.) are not usually length-calibrated. Here's a simpler method: a strip of thin paper placed on the table is trapped between the table and the tool by carefully lowering it by hand. The tool is then raised by about 0.1 mm, releasing the paper, and this is taken as the Z-axis origin. Note: It is important you don't place any weight on the Profiler board or material when Z homing. Resting you hand on the board will impact the Z home value. It is also a good idea not to do this when the machine is operating. Placing material The base board may not be dead level so I place the material in the centre of the board to minimise any unevenness. Once the material is placed I position the drill head over the bottom left corner which will become the PCB origin. 9/2007 - elektor electronics 73 PROFILER MILLING MACHINE The next step is to load the PCB design into ColiDrive with the drill head where you placed it. This ensures that the PCB design is placed correctly on the software 'virtual' Profiler board. There are other ways you can achieve this but this is the easiest for me. Let's do it Before you start, ensure you have (in order): 1 . Set machine parameters. 2. Placed the material on the board. 3. Loaded your PCB design. Then, to make it: 1 . In the motor control panel, click the 'Make it' button. 2. Click the 'Start' button. The head will move to the tool change position and the 'Waiting to Continue' dialogue gives you the option to position the Z home. This option will initially be the default. 3. Insert the initial tool you need. 4. Click 'Continue' in the popup dialog. 5. Click 'OK'. 6. Manually drive the head into a good position for Z homing. I use the 'Go to Position' button and select a spot on the machine desktop window that is in the centre of my PCB design. 7. Perform the Z homing procedure outlined above. 8. Power up the drill and click the 'Finished zero setting' button in the 'Start Machining' dialogue and watch it go. Noisy If the phenomenon occurs even when stopped, this is a quite common problem with stepper motors driven from a PWM if the servo loop is unstable. If the problem only occurs when the motor is running, and the sound frequency is the same as the motor's stepping frequency, you may also need to look at mechanical reso- nances. But in any event, the movements will never be silent - stepper motors 'sing' so long as their drive signals and/or the PWM frequency are within the audible range. Jamming Jamming may be caused by 'stiff spots' caused by lack of lubrication, out-of-true runners or a shaft, build-up of debris, dust and foreign materials on these elements, areas of insuf- ficient mechanical play, poor alignment, or non-concentric coupling between motor and shaft. The cause is often screws that have been overtightened before alignment, or distortion caused by over-tightening, as the components supplied are of industrial accuracy, and so significantly better than even careful manual workmanship makes it possible to achieve. Axis-by-axis checking as you go is always best, and makes it easier to gain access to the settings. It's invariably best to always try realignment first, virtually leaving the parts to take up their own positions without forc- ing them, and only then tightening screws after checking. If these precautions prove fruitless, the simplest solution to solving a problem of eccentric coupling (and sometimes out-of-true shafts) is to make a 'flexible' coupling using a short piece of flexible tubing of suitable internal diameter (car hose, compressor air hose) and compressed air hose clips (less bulky than ordinary hose clips). However it's unreasonable to expect the machine to achieve impossibly high performance either - Profiler is only meant to be a tool for ' informed amateurs'. Tips and leads from experienced CNC users The Ferm motor suggested in the article and supplied with the machine is not very robust and the spindle bearing risks wear- ing out very quickly. So you need to consider buying a proper milling spindle, like the ones on offer from Kress (www.kress- elektrik.de/en/index. php). But watch out, as the fixing diameter is 43 mm and doesn't fit the existing bracket. According to one user of this type of equipment, a 900-watt motor seems a bit marginal for machining aluminium. As far as tools are concerned, you should use only tungsten-car- bide bits, with a standard 3.2 mm shank (make sure you have suitable 'collets'). Milling and cutting-out may be performed using tungsten-carbide cutters up to 3 mm diameter, high-speed steel up to 8 mm if you have the right collet (in theory, supplied as standard). Epoxy PCB can be milled using tungsten-carbide cutters only. Engraving can be done using a 'spear' type cutter, 22° for plastic and 35° for aluminium (distributors: Welleman). Feed rates are dependent on the size of the stepper motors, and above all, their drive voltage. At a single feed rate of 5 mm/s engraving requires 3.9-amp stepper motors driven from at least 30 volts. Board drilling is usually performed from 'Excellon' files gener- ated by most CAD applications. PCB production by engraving the insulating paths between the track areas is of interest for prototyping, but you do need to find a suitable drawing program or else draw the insulation layout yourself - fairly easy with a little practice. Any technical drawing program that allows exporting (or printing to a file in HPGL format) will allow you to design front panels and engrave text/images in 2D. Programs for creating PCB layouts need to permit the creation of the files for the track layout and the same files in Excellon format for the drilling. For 3D use, the 'Ninos' software performs very well and is not expensive - but is sadly not compatible with Profiler. The same goes for Galaad, more expensive, but possibly configurable? Of course there is Deskproto with a 'Lite' version, which does less than the aforementioned ones despite being twice the price of Ninos, but is recommended by Colinbus themselves (and so is presumably compatible). ( 070425 - 1 ) Further information Elektor forum: www.elektor.com/forum , go to the Profiler Milling Machine (January 2007) topic. Reece Robinson's 'Profiler Operational Notes': www.therobinsons.gen.nz/Profiler%20Lessons%20Learned.html 74 elektor electronics - 9/2007 DESIGN TIPS TECHNOLOGY Green USB switch Wolfram Winfera According to the Energy Saving Trust, if you add up all the cur- rent drawn in standby mode by items such as stereos, TVs, VCRs and DVDs over a year in the UK alone, it amounts to 3.1 million tonnes of C0 2 released into the atmosphere. This is without fac- toring in the current drawn by all the PCs, laptops and their associated peripherals left in standby mode. It is not necessary to spend a great deal of money or time to make a difference on a personal level. The circuit described here is designed for use by laptop or notebook computers. It will au- tomatically switch off all mains powered peripheral equipment including monitor, printer, scan- ner, TV tuner and USB hub etc when it detects that the notebook is switched off. The circuit is quite straightforward; in addition to an optocoupler it requires a 12 V double-pole relay with mains rated contacts and a small pow- er supply for the optocoupler. When the laptop is switched on 5 V appears at the USB socket, activating the relay and switch- ing through the mains supply on K3 and K4. The notebook's USB socket is still available to be used as normal but it's worth re- membering that the optocoupler takes a few milliamps from the USB supply and this may cause a problem if a high-current device is plugged into the USB socket. In the case where the laptop has more than enough USB sock- ets it may be worthwhile us- ing one of them solely for this circuit, the extension USB con- nector K2 would then not be required. The circuit is mounted into a mains plug enclosure which provides a socket where the mains extension strip will be plugged into. With any luck there will be sufficient space to fit the entire circuit into the mains extension strip enclo- sure and save the need for a separate enclosure. The slow- blow 6.3-A fuse (FI) protects the equipment plugged into the strip. In addition to the optocoupler and relay the circuit also has a 'freewheel' diode D1 and a relay driver formed by T1 and its base bias voltage divider network R2/ R4. The two 'snubber' networks C1/R3 and C2/R5 reduce the possibility of arcing which can occur when the relay contacts open (especially with inductive loads). Capacitors Cl and C2 must be class X2 types which can handle mains voltage plus any spikes. The power supply consists of a small mains trans- former (12 V, 50 mA), bridge rectifier and smoothing capaci- tor C3. The laptop's mains adaptor itself can also be switched by this cir- cuit when the laptop is fitted with its rechargeable battery which allows the computer to boot up without a mains supply. The en- tire USB switch circuit draws cur- rent even when it is off but this value is tiny compared to the combined standby current of all the peripherals. Note that parts of this circuit are connected to the (potentially le- thal) mains supply voltage; it is essential to provide protection to ensure that nothing can acci- dentally make contact with these parts of the circuit. It is also im- portant to observe correct sepa- ration between parts of the cir- cuit carrying low voltage and those carrying the high volt- age. Please observe the elec- trical Electrical Safety guide- lines which are reprinted in Elektor Electronics several times a year. The circuit is less suitable for use with desktop PCs be- cause the majority of these machines supply 5 V over the USB socket even though they have been shut down via soft- ware. The only way to turn off in this case is to reach around the back of the machine and switch off at the main switch. ( 060306 - 1 ) ■ Advertisement ■ Tel: 01 635 40347 Niamey Flalimiif. I NE I 31 : mE£] 3ET 47 Harf Bflu SM 1-mM ciituiltfJwhM 1 ? hxmMnA mtKlftPfct «■ •HWRvl 9/2007 - elektor electronics 75 INFOTAINMENT PUZZLE Hexadoku Puzzle with an electronic touch Phew, have you fully recovered from that horrid Alphanumski puzzle from the Summer Circuits edition? Good, as this month it's back to a more leisurely pace with a regular Hexadoku waiting to be solved. The prizes are well worth your effort: an E-blocks Starter Kit Professional and three Elektor SHOP vouchers. Participate! Please send your solution (the numbers in the grey boxes) by email to: editor@elektor.com Subject: hexadoku 09-2007. Alternatively, by fax or post to: Elektor Electronics Hexadoku Regus Brentford 1 000 Great West Road Brentford TW8 9HH United Kingdom. Fax (+44) 208 2614447 The closing date is 1 October 2007. The competition is not open to employees of Segment b.v., its business partners and/or associated publishing houses. The instructions for this puzzle are straightforward. In the di- agram composed of 1 6 x 1 6 boxes, enter numbers such that all hexadecimal numbers 0 through F (that's 0-9 and A-F) occur once only in each row, once in each column and in each of the 4x4 boxes (marked by the thicker black lines). A number of clues are given in the puzzle and these determine the start situation. All correct entries received for each month's puzzle go into a draw for a main prize and three lesser prizes. All you need to do is send us the numbers in the grey boxes. The puzzle is also available as a free download from our website Prize winners The solution of the April 2007 Hexadoku is: 1 B456. The E-blocks Starter Kit Professional goes to: Michael Murphy (IRL). An Elektor SHOP voucher worth £35.00 goes to: Knud Dahl Christensen (DK), John Stevens (UK), and Tony Jacques (UK). Congratulations everybody! 0 3 5 A E 1 2 D F 1 2 D 7 4 9 7 A E 0 6 D 4 8 1 C 2 3 E 5 7 C A 6 F 4 E 8 2 0 E C D 1 F 9 2 A 6 8 A E 4 D 5 F 9 C 9 6 8 B C 5 0 4 D E 5 F 7 3 E 5 C 7 F 4 0 2 B 0 8 1 2 D 3 B A D 7 6 E F 4 5 6 8 E 3 B F 6 E C 2 0 4 7 5 D 4 8 9 5 D A 1 (c) PZZL.com Solve Hexadoku and win! Correct solutions received enter a prize draw for an E-blocks Starter Kit Professional worth £248.55 and three Elektor Electronics SHOP Vouchers worth £35.00 each. We believe these prizes should encourage all our readers to participate! 76 elektor electronics - 9/2007 RETRONICS INFOTAINMENT Philips '60'- series NORbits (1968) Arthur Pistorius It must have been 1980 when a Philips employee handed me a plastic bag filled with bulky, black, red and blue "ICs" and the message: "see if these are any use to you". The lot came with a manual that unfortunately had to be returned to the library. To a budding electronics enthusi- ast, this was a once in a lifetime opportunity to get started with digital electronics. The Internet has little information on these parts. However, Elektor's Retron- ics page is a fine place to repro- duce some user experience with a number of components from this series. As it turned out I had been given one of the earliest forms of inte- grated digital circuits housed in large (1 by 2 inch), 17-pin DIL cases, developed by Philips in the 1960s. Inside the modules is a small PCB containing some tran- sistors and resistors. The docu- mentation confirms that these building blocks belong to the RTL family of logic circuits. The black cases contain two or four NOR gates (2.NOR60 or 4.NOR60) and may be considered the basic 'bricks'. In RTL technology, NOR gates can be made from a single transistor and two or more base resistors, or by paralleling multi- ple transistors, each with its own base resistor. NORbits were pro- duced using the first principle, with the inherent disadvantage of limiting the drive units (DU) of successive gates. The transistors, by the way, are npn types. The modules were specified for either a 1 2 V or a 24 V supply. The red cases (TU60) contain a monostable multivibrator and might be described as a precur- sor of the legendary 555. Two types of amplifier are available to drive other circuits like small motors or relays: the 2.IA60, a blue module containing two in- verting amplifiers; and the PA60, a single power amp in a dual blue case with a heatsink, capa- ble of supplying up to 1 amp or so. The documentation also men- railway crossings with light sig- nals, and to make a train wait for a predetermined period in a station. These days the same train is controlled by EEDTs on a much larger track layout. How- ever, for old time's sake, an au- tomatic shuttle built from NOR- bits still operates on a side track, electrically separated from the main system, with train detec- tion implemented using reed contacts. The wait times at the end stations are generated us- ing TU60s with a standard flip- flip added for the train reversal. The high supply voltage makes the system immune to noise. The photo puts the size of the circuit (without the PWM speed control) in a wholly new perspective. One carriage almost disappears be- hind it! It's corny but a lot has changed in 40 years... ( 075079 - 1 ) Reference Control system design manual for 60-series NORbits (1968), Philips. 240 pages. ISBN 9399 263 016 01. tions a green case containing a few input filters (2.SF60) for use in combination with sensors like reed contacts (I VSR; iron vane switched reed). The component was not available however. The collection also include a number of 'chassis' having fast- on connectors at the top side. The type UMC60 (Universal Mounting Chassis) has room for six standard enclosures. Electri- cal connections between the long connecting pins could be made using wire wrapping but plain soldering also worked fine. The 60-series NORbits were typ- ically used in machine control systems, suggest ing an analogy with more contempo- rary PLCs. In my attic, an experimental system wa available in the form of a model train 'doing the rounds' on a track. Commercial model train controls were (and still are) expensive, so the first circuits were designed for Retronics is a monthly column covering vintage electronics including legendary Elektor designs. Contributions, suggestions and requests are welcomed; please send an email to editor@elektor-electronics.co.uk, subject: Retronics EE. 9/2007 - elektor electronics 77 ELEKTOR SHOWCASE To book your showcase space contact Huson International Media Tel. 0044 (0) 1 932 564999 ATC SEMITEC LTD www.atcsemitec.co.uk Thermal and current-sensitive components for temperature control and circuit protection; • NTC Thermistors • Current Diodes • Thermostats • Re-settable Fuses • Thermal Fuses • Temperature Sensors Call today for free samples and pricing Tel: 01 606 871 680 Fax: 01 606 872938 AVIT RESEARCH www.avitresearch.co.uk USB has never been so simple... with our USB to Microcontroller Interface cable. Appears just like a serial port to both PC and Microcontroller, for really easy USB connection to your projects, or replacement of existing RS232 interfaces. See our webpage for more details. From £15.00. 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For just £220 + VAT (£20 per issue for eleven issues) Elektor will publish your company name, website address and a 30-word description For £330 + VAT for the year (£30 per issue for eleven issues) we will publish the above plus run a 3cm deep full colour image - e.g. a product shot, a screen shot from your site, a company logo - your choice Places are limited and spaces will go on a strictly first come, first served basis. So-please fax back your order today! _ n I wish to promote my company, please book my space: • Text insertion only for £220 + VAT • Text and photo for £330 + VAT NAME: ORGANISATION: JOB TITLE: ADDRESS: TEL: PLEASE COMPLETE COUPON BELOW AND FAX BACK TO 00-44-(0)1932 564998 COMPANY NAME WEB ADDRESS 30- WORD DESCRIPTION 9/2007 - elektor electronics 79 HANDS-ON MICROCONTROLLERS Automating the R8C Starter Kit Ludwig Libertin D1 1N4148 IC1 SI BT1 5 1- y-fr O-h i — C11 Cl 78L05A ■> ♦ lOOn lOOn C2 lOOn 2 RXD 3 TXD 8 5 GND - 4> & 5 6 R3 T2 § 100k I BC557 T1 &[C) BC547 R2 unj XI iHi 12MHz C3 22p C4 22p 1 D2 RESET R6 C9 lOOn 1 D3 '5 MODE CIO lOOn IC2 R5 L_J IC2.B IC2 = 4011 R8C/13 R7 8 _ 9_ io_ 11 1 2_ 13_ 14 15_ 16 O RXD1 TXD1 O O CNVSS AN6 o- O RESET AN5 o- O XOUT AN4 a O VSS MODE 0- O XIN AN3 a O VCC AN2 a o P17 AN1 0- o P16 AN0 o- o P15 a o P14 P30 0- o P13 a -o P12 P31 o o P11 0- o P10 P32 a o P45 P33 a 32 _ 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 R5F21134 R8 & 6 ” ^^>4 if READY RIO no R9 R14 1N4148 IC2.C <3^ D7 & STOP C5 1 p R11 C6 1 ^x R12 IC2.A Iz & R15 IC2.D L-l R13 D6 11 1N4148 C8 1 p & 12 13 I C7 1 [X 060169-11 We described the £10 ‘Tom Thumb’ R8C microcontroller starter kit in the February 2006 issue of Elektor Elec- tronics. A disadvantage of this mini- mal system, in the author’s opinion, is that the programming procedure entails considerable manual inter- vention: ‘press Reset’, ‘press Mode’, ‘release Reset’, ‘release Mode’ and so on, involving both the PC and the microcontroller. It might also be pos- sible for contact bounce to cause a button press to be registered several times: reason enough for the author to automate the process by souping up the system with a couple of extra components. A low-cost CMOS quad NAND IC, type 4011, is used. The gates are configured to produce delays using RC networks. When power is applied the outputs of all the gates will be high and so the ‘Stop’ LED D7, connected to the output of IC2.C, lights. Approximately half a second later the output of IC2.B goes low and the ‘Mode’ LED D3 lights: this corresponds to the imaginary pressing of the ‘Mode’ button. Another half sec- ond later the output of IC2.A also goes low, lighting the ‘Reset’ LED D2 to in- dicate that an imaginary ‘Reset’ button has been pressed. Another half second passes and then the output of IC2.D goes low. This pulls down the input to IC2.A, extinguish- ing the ‘Reset’ LED. This corresponds to releasing the Reset button. Finally, a further half second later, the output of IC2.C goes low, extinguish- ing the ‘Stop’ LED. The inputs to IC2. B are pulled low via D4, and so the ‘Mode’ LED also goes out; the ‘Ready’ LED D5 also lights. The ‘Mode’ but- ton has in effect been released and we are ready to go. When the ‘Ready’ LED lights the Flash programming process can be started from the connected PC. When program- ming is complete power to the circuit can be switched off and the microcon- troller removed. To simplify things further the author has designed a small printed circuit board for the R8C microcontroller with a form factor compatible with a 32-pin DIL IC. If the circuit described here is built using a commercially- available zero insertion force socket, reprogramming and testing are made much easier. ( 060169 - 1 ) 80 elektor electronics - 9/2007 lektor Order now using the Order Form in the Readers Services section in this issue. CD-ROM BESTSELLERS EW Ethernet Toolbox This CD-ROM contains all essential information regarding Ethernet inter- faces! To help you learn about the Ethernet interfaces, we have compiled a collection of all articles on this topic that have appeared in Elektor Electronics and complemen- ted them with additional documen- tation and links to introductory articles on Ethernet interfaces. It includes a collection of data sheets for dedicated Ethernet interface ICs from many different manufacturers. The CD-ROM provides a wealth of information about connectors and components for the physical layer (PHY) and specific software tools for use with the Ethernet (Software). ISBN 978-90-5381-214-3 I £18.90 (US$ 37.90) Elektor 2006 This CD-ROM contains all editorial articles published in Elektor Electronics Volume 2006. Using the supplied Acrobat Reader program, arti- cles are presented in the same layout as originally found in the magazine. All free, printed, supplements our readers got last year, like the Visual Basic, C and i-TRIXX booklets are also contained on the CD. The Elektor Volume 2006 CD-ROM has a rather different look and feel than previous editions. It’s gone through a makeover in more than one way! ISBN 978-90-5381-207-5 I £16.90 (US$ 33.80) Home Automation This CD-ROM provides an overview of what manufactu- rers offer today in the field of Home Networking, both wired and wireless. The CD-ROM contains specifications, stan- dards and protocols of commer- cially available bus and network systems. For developers, there are datasheets of specific com- ponents and various items with application data. End-users and hobbyists will find ready-made applications that can be used immediately. ISBN 978-90-5381-195-5 I £13.90 (US$ 27.80) Elektor Electronics (Publishing) Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Telephone +44 208 261 4509 Fax +44 208 261 4447 Email: sales@elektor-electronics.co.uk home AUTOto^i (ON C % "oOMOTiaUE domotica □OP/lOtiK More information on www.elektor-electronics.co.uk 304 Circuits ISBN 978-0-905705-34-7 366 pages £13.45 (US$ 27.00) 305 Circuits ISBN 978-0-905705-36-1 369 pages £15.55 (US$ 31.00) 307 Circuits ISBN 978-0-905705-62-0 342 pages £1 8.20 (US$ 37.00) 309 cmcuirs Complete your 30x circuits series now! The 30x series of Summer Circuit compilation books have been best- sellers for many years. You can use these books not only for building the circuits described, but also as a treasure trove of ideas or circuit adaptions for your own experiments. Many readers have found in these books that new approach, new concept, or new circuit they were looking for. 308 Circuits 309 Circuits ISBN 978-0-905705-66-8 ISBN 978-0-905705-69-9 367 pages 432 pages £1 9.25 (US$ 38.50) £1 9.95 (US$ 39.95) BESTSELLING BO 1 j 309 Circuits ISBN 978-0-905705-69-9 £19.95 (US$ 39.95) Visual Basic for Electronics Engineering Applications ISBN 978-0-905705-68-2 £29.00 (US$ 58.00) 3 ^ Microcontroller Basics ^ ISBN 978-0-905705-67-5 £19.50 (US$ 39.00) 4 ) PC-Interfaces under Windows ISBN 978-0-905705-65-1 £27.25 (US$ 54.50) ^ Modern High-end Valve Amplifiers ISBN 978-0-905705-63-7 £27.25 (US$ 54.50) More bestsellers on www.elektoi^electronics.co.uk lektor Order now using the Order Form in the Readers Services section in this issue. Order o www.elektor-el Digital Inspector (September 2007) Kit, incl. PCB, controller, display, case and all parts 060092-71 £ 77.60 / US$ 155.20 Software Defined Radio (May 2007) Ready-populated and tested board 070039-91 £ 72.45 / US$ 126.50 Stand-Alone OBD2 Analyser (June 2007) Kit of parts, incl. case, cable, front panel foil and mounting materials 070038-72 £ 51 .70 / US$ 97.50 Speedmaster (May 2007) The circuit voted winner of the R8C Design Competition! Ready-populated and tested board (excl. R8C module) 070021-91 £ 51 .70 / US$ 97.45 No. 369 SEPTEMBER 2007 £ $ Tilt Gamepad 070233-41 Programmed controller ATMega8-16PI 6.20 12.35 070233-81 Software on CD-ROM 5.20 10.40 070233-91 Printed circuit board with sensor fitted 18.90 37.80 Digital Inspector 060092-1 Printed circuit board www.thepcbshop.com 060092-41 Programmed controller PIC1 8F4580-I/P 13.10 26.20 060092-71 Kit of parts PCB, controller, case and all parts 77.60 155.20 060092-81 Software on CD-ROM 5.20 10.40 No. 367/368 JULY/AUGUST 2007 Dual Battery 070343-1 PCB, bare 5.20 9.75 Fast Charger for NiMH Batteries 070213-1 PCB, bare www.thepcbshop.com Lithium Charger 070273-1 PCB, bare 8.90 12.95 Low2 Cost USB Demo Board 060342-81 CD-ROM, project software 5.20 9.75 060342-41 PIC18F4550, programmed 15.15 28.50 LPC 900 Programmer 070084-1 PCB, bare 6.90 12.95 MotoBox 070129-1 PCB, bare www.thepcbshop.com 070129-41 PIC1 6F628-04/R programmed 14.80 27.95 Propeller Prototyping Board for BoeBot 070275-1 PCB, bare 11.00 20.75 Satnav for Robots 070350-81 CD-ROM, project software 5.20 9.75 070350-41 ATmega32, programmed 16.50 31.15 Serial Interface for the Propeller 070276-1 PCB, bare www.thepcbshop.com Stereo Robot Ears 060040-1 PCB, bare www.thepcbshop.com 060040-81 CD-ROM, project software 5.20 9.75 060040-41 PIC16F88, programmed 10.00 18.85 No. 366 JUNE 2007 2.4 GHz WiFi Spectrum Analyser 070040-1 PCB, bare 8.25 15.50 070040-1 1 CD-ROM, Linux & Windows software 5.20 9.75 Coil Clinic 060195-1 PCB, bare 7.60 14.25 060195-11 CD-ROM, project software 5.20 9.75 060195-41 Atmega48-20PU, programmed 5.20 9.75 Linux Oscilloscope 060241-11 CD-ROM, project software 5.20 9.75 060241 -W Program listing free download Stand-Alone OBD2 Analyser 070038-72 Kit of parts, incl. case, cable, front panel foil and mounting materials 51.70 97.50 070038-21 Online simulator examples free download 070038-W1 Manual free download Whistles from on high 060044-1 PCBs, bare; set for TX and RX 12.00 22.75 060044-11 CD-ROM, project software 5.20 9.75 060044-41 ATtinyl 5PC, programmed 10.00 18.75 No. 365 MAY 2007 Software Defined Radio 070039-91 Ready-populated and tested board 72.45 126.50 070039-11 CD-ROM, project software 5.20 9.75 Thank your for Flying USB FliteSim 060378-1 PCB, bare ' www.thepcbshop.com 060378-41 PIC1 8F2550I/SR programmed 15.50 29.25 Universal JTAG Adaptor 060287-1 PCB, bare, with programmed microcontroller 11.00 20.75 060287-41 EP900LC only, programmed P&P only P&P only Magnetometer 050276-1 PCB, bare www.thepcbshop.com Speedmaster 070021-91 Ready-populated and tested board (excl. R8C module) 51.70 97.45 Seismograph 060307-1 PCB, bare www.thepcbshop.com 060307-11 CD-ROM, project software 5.20 9.75 060307-41 ATTiny45, programmed 10.35 19.50 nline at ectronics.co.uk Due to practical constraints, final illustrations and specifications may differ from published designs. Prices subject to change. See www.elektor-electronics.co.uk for up to date information. Wireless USB in miniature (March 2007) iDwarf -1 68 Transmitter module (built & tested) 050402-91 £ 25.40 / US$ 50.80 Elektor Electronics Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel.: +44 (0) 208 261 4509 Fax: +44 (0) 208 261 4447 Email: sales@elektor-electronics.co.uk Kits & Modules g-Force on LEDs (April 2007) PCB set, bare, incl. 2 MMA7260 sensors, BDM cable parts 060297-71 iDwarf Node Board (built & tested) 050402-91 £ 18.10 /US$ 36.20 £ 10.50 /US$ 21.00 USB Stick with ARM and RS232 (November 2006) iDwarf Hub Board (built & tested) 050402-93 £18.10 /US$36.20 Assembled and tested board 060006-91 £ 79.90 / $ 1 49.95 ATtiny as RDS Signal Generator 060253-41 Attiny2313-20, programmed 4.20 7.80 No. 364 APRIL 2007 Battery Charge-n-Check 050073-1 PCB, bare, main board 10.30 19.50 050073-2 PCB, bare, display board 10.30 19.50 050073-1 1 CD-ROM, project software 5.20 9.75 050073-41 ST7FMC2S4, programmed 16.90 31.85 g-Force on LEDs 060297-71 PCB set, incl. 2 MMA7260 sensors, BDM cable parts 10.50 21.00 060297-1 1 CD-ROM, project software 5.20 9.75 Programmer for Freescale 68HC(9)08 060263-1 PCB, bare www.thepcbshop.com A Simple Mains Inverter 060171-1 PCB, bare www.thepcbshop.com Very Simple Clock 060350-1 PCB, bare www.thepcbshop.com E-blocks Light Chaser Squared 075032-1 PCB, bare www.thepcbshop.com No. 363 MARCH 2007 AVR drives USB 060276-1 PCB, bare 10.60 21.20 060276-1 1 CD-ROM, project software incl. source code 5.20 9.75 060276-41 ATmega32-16PC, programmed 9.50 19.00 Wireless USB in Miniature 050402-1 PCB, bare, iDwarf prototyping board 8.70 17.40 050402-91 iDwarf -1 68 Transmitter module (built & tested) 25.40 50.80 050402-92 iDwarf Node Board (built & tested) 18.10 36.20 050402-93 iDwarf Hub Board (built & tested) 18.10 36.20 Mobile Phone LCD for PC 060184-1 PCB, bare www.thepcbshop.com 0601 84-1 1 CD-ROM, project software 5.20 9.75 060184-41 ATmega16-16PC, programmed 8.95 16.85 Scale Deposit Fighter 070001-1 PCB, bare' www.thepcbshop.com 1 No. 362 FEBRUARY 2007 £ $ ... 3, 2, 1 Takeoff! 050238-1 Transmitter PCB, bare www.thepcbshop.com 050238-2 Receiver PCB, bare www.thepcbshop.com MP3 Preamp 060237-1 PCB, bare www.thepcbshop.com A Telling Way of Telling the Time 050311-1 PCB, bare www.thepcbshop.com 050311-31 CPLD, programmed 35.50 66.95 FPGA Course (9) 060025-9-11 CD-ROM, course software incl. source code 5.20 9.75 Explorer-16 Value Pack 060280-91 Four components packaged together in a single box 127.60 255.20 No. 361 JANUARY 2007 Sputnik Time Machine 050018-1 PCB www.thepcbshop.com 050018-11 CD-ROM, project software (incl. source code) 5.20 9.75 050018-41 AT89C2051 , programmed 3.60 7.20 Very Simple Clock 060350-1 PCB www.thepcbshop.com 060350-1 1 CD-ROM, project software (incl. source code) 5.20 9.75 060350-41 PIC1 6F628-20, programmed 5.80 11.60 FPGA Course (8) 060025-8-1 Software (incl. source code) 5.20 9.75 No. 360 DECEMBER 2006 Shortwave Capture 03041 7-1 PCB, bare (receiver board) www.thepcbshop.com 03041 7-2 PCB, bare (control & display boards) www.thepcbshop.com 030417-41 AT90S8515-8PC, programmed 12.10 24.20 Products for older projects (if available) may be found on our website www.elektor-electronics.co.uk home construction = fun and added value SNEAK PREVIEW GPS Tracking Aid It's a reality to owners of expensive BMW and Mercedes cars, and a dream to the rest of us poor souls: to know the exact whereabouts of the prize vehicle when you're not driving it! The dream now comes true: send your 'wheels' an SMS message prompting it to text back its whereabouts on the globe by means of GPS coordinates! The Elektor GPS Tracking Aid is based on a Wavecom modem handling the GSM/SMS comms, and a Trimble Copernicus module for the GPS satellite reception. All you have to do is program the board using your PC and then install it in your car in tamperproof fashion. That's right, no soldering — the unit comes ready-assembled through the Ele- ktor SHOP! (we're sorry this article could not be included in the September 2007 issue as planned) Clean Audio Power No audio equipment achieves optimum sonic performance if it isn't powered from a clean supply voltage. In the PSU, due at- tention should be paid not just to its current capacity (specially for audio power amps), but also to the degree it's capable of suppressing mains-borne noise, horrid spikes and other interference (common-mode or not) mainly from dimmers, cheapo power tools and power line signalling devices. This article delves deep into the theoretical and practical aspects of what should be essentially included in any PSU for audio equipment: a noise suppressor with a properly designed filter response to eradi- cate all that noise polluting the mains and interfering with the audio signal. Apart from presenting 'must-know' information for audio purists, the article also goes practical by explaining how to design and build such a filter, as well as adapt it to your personal requirements. INFO & MARKET Hybrid Audio Power Amplifier This project combines valve and transistor technology in one design of an audio amplifier that's easily reproducible as well as inexpensive. Output power is rated at 100 watts from transistors type 2SC5200 in a quasi-complementary configuration, while ECC83 (1 2AX7) and ECC88 valves in the prestage and driver stages add not just a nostalgic look & feel to the ampli- fier, but also what many call the 'warm sound from valves'. RESERVE YOUR COPY NOW! The October 2007 issue goes on sale on Thursday 27 September 2007 (UK distribution only). UK mainland subscribers will receive the magazine between 22 and 25 September 2007. Article titles and magazine contents subject to change, please check www.elektorcom. NEWSAGENTS ORDER FORM SHOP SAVE / HOME DELIVERY Please save / deliver one copy of Elektor Electronics magazine for me each month Name: Address: Post code: Telephone: Date: Signature: lectronics Please cut out or photocopy this form, complete details and hand to your newsagent. Elektor Electronics is published on the third Thursday of each month, except in July. Distribution S.O.R. by Seymour (NS). w.elektor.com www.elektor.com www.elektor.com www.elektor.com www.elektor. Elektor Electronics 33 the web All magazine articles back to volume 2000 are available online in pdf format. The article summary and parts list (if applicable) can be instantly viewed to help you positively identify an article. Article related items are also shown, including software down- loads, circuit boards, programmed ICs and corrections and updates if applicable. Complete magazine issues may also be downloaded. In the Elektor Electronics Shop you'll find all other products sold by the publishers, like CD-ROMs, kits and books. A powerful search function allows you to search for items and references across the entire website. Also on the Elektor Electronics website: • Electronics news and Elektor announcements • Readers Forum • PCB, software and e-magazine downloads • Surveys and polls • FAQ, Author Guidelines and Contact 84 elektor electronics - 9/2007 Description Price each Qty. Total Order Code 309 Circuits £ 19.95 Formula Flowcode Buggy 85.00 CD-ROM Ethernet Toolbox fTjjH £ 18.90 CD-ROM Elektor 2006 £ 16.90 Visual Basic for Electronics Engineering Applications £ 29.00 Prices and item descriptions subject to change. The publishers reserve the right to change prices without prior notification. Prices and item descriptions shown here supersede those in previous issues. E. & O.E. Sub-total P&P Total paid Name Address + Post code Tel. Email Date - - 2007 Signature EL09 Yes, I am taking out an annual subscription to Elektor Electronics and receive a free 1GB MP3 player. I would like: |71 Standard Subscription (11 issues) Subscription-Plus (11 issues plus the Elektor Volume 2007 CD-ROM) * Offer available to Subscribers who have not held a subscription to Elektor Electronics during the last 12 months. Offer subject to availability. See reverse for rates and conditions. Name Address + Post code Tel. Email Date - - 2007 Signature * cross out what is not applicable EL09 METHOD OF PAYMENT (see reverse before ticking as appropriate) □ □ □ □ Bank transfer Cheque (UK-resident customers ONLY) Giro transfer AiatfBfCant Expiry date: Verification code: Please send this order form to* (see reverse for conditions) Elektor Electronics (Publishing) Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel.: +44 208 261 4509 Fax: +44 208 261 4447 www.elektor-electronics.co.uk. sales@elektor-electronics.co.uk *USA and Canada residents may (but are not obliged to) use $ prices, and send the order form to: Old Colony Sound Lab P.0. 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Please apply to Old Colony Sound for applicable P&P charges. Please allow 4-6 weeks for delivery. Orders placed on our Brentford office must include P&P charges (Priority or Standard) as follows: Europe: £6.00 (Standard) or £7.00 (Prio- rity) Outside Europe: £9.00 (Standard) or £11.00 (Priority) HOWTO PAY All orders must be accompanied by the full payment, including postage and packing charges as stated above or advised by Customer Services staff. Bank transfer into account no. 40209520 held by Elektor Electronics with ABN-AMRO Bank, London. IBAN: GB35 ABNA 4050 3040 2095 20. BIC: ABNAGB2L. Currency: sterling (UKP). Please ensure your full name and address gets communicated to us. Cheque sent by post, made payable to Elektor Electronics. We can only accept sterling cheques and bank drafts from UK-resident customers or subscribers. We regret that no cheques can be accepted from customers or subscribers in any other country. Giro transfer into account no. 34-152-3801, held by Elektor Electronics. Please do not send giro transfer/deposit forms directly to us, but instead use the National Giro postage paid envelope and send it to your National Giro Centre. Credit card VISA and MasterCard can be processed by mail, email, web, fax and telephone. Online ordering through our website is SSL-protected for your security. COMPONENTS Components for projects appearing in Elektor Electronics are usually available from certain advertisers in this magazine. If difficulties in the supply of components are envisaged, a source will normally be advised in the article. Note, however, that the source(s) given is (are) not exclusive. TERMS OF BUSINESS Delivery Although every effort will be made to dispatch your order within 2-3 weeks from receipt of your instructions, we can not guarantee this time scale for all orders. Returns Faulty goods or goods sent in error may be returned for replacement or refund, but not before obtaining our consent. All goods returned should be packed securely in a padded bag or box, enclosing a covering letter stating the dispatch note number. If the goods are returned because of a mistake on our part, we will refund the return postage. Damaged goods Claims for damaged goods must be received at our Brentford office within 10-days (UK); 14-days (Europe) or 21 -days (all other countries). Cancelled orders All cancelled orders will be subject to a 10% handling charge with a minimum charge of £5.00. Patents Patent protection may exist in respect of circuits, devices, components, and so on, described in our books and magazines. Elektor Electronics does not accept responsibility or liability for failing to identify such patent or other protection. Copyright All drawings, photographs, articles, printed circuit boards, programmed integrated circuits, diskettes and software carriers published in our books and magazines (other than in third-party advertisements) are copyright and may not be reproduced or transmitted in any form or by any means, including photocopying and recording, in whole or in part, without the prior permission of Elektor Electronics in writing. Such written permission must also be obtained before any part of these publications is stored in a retrieval system of any nature. Notwithstanding the above, printed-circuit boards may be produced for private and personal use without prior permission. Limitation of liability Elektor Electronics shall not be liable in contract, tort, or otherwise, for any loss or damage suffered by the purchaser whatsoever or howsoever arising out of, or in connexion with, the supply of goods or services by Elektor Electronics other than to supply goods as described or, at the option of Elektor Electronics, to refund the purchaser any money paid in respect of the goods. Law Any question relating to the supply of goods and services by Elektor Electronics shall be determined in all respects by the laws of England. September 2007 SUBSCRIPTION RATES FOR ANNUAL SUBSCRIPTION Standard Plus United Kingdom £41 .90 £48.80 Surface Mail Rest of the World £54.50 £61.40 USA & Canada US$ 95.50 US$106.50 Airmail Rest of the World £68.90 £75.80 USA & Canada US$120.00 US$131.00 HOWTO PAY Bank transfer into account no. 40209520 held by Elektor Electronics, with ABN-AMRO Bank, London. IBAN: GB35 ABNA 4050 3040 2095 20. BIC: ABNAGB2L. Currency: sterling (UKP). Please ensure your full name and address gets communicated to us. Cheque sent by post, made payable to Elektor Electronics. We can only accept sterling cheques and bank drafts from UK-resident customers or subscribers. We regret that no cheques can be accepted from customers or subscribers in any other country. Giro transfer into account no. 34-152-3801, held by Elektor Electronics Please do not send giro transfer/deposit forms directly to us, but instead use the National Giro postage paid envelope and send it to your National Giro Centre. Credit card VISA and MasterCard can be processed by mail, email, web, fax and telephone. Online ordering through our website is SSL- protected for your security. SUBSCRIPTION CONDITIONS The standard subscription order period is twelve months. If a perma- nent change of address during the subscription period means that copies have to be despatched by a more expensive service, no extra charge will be made. Conversely, no refund will be made, nor expiry date extended, if a change of address allows the use of a cheaper service. Student applications, which qualify for a 20% (twenty per cent) reduction in current rates, must be supported by evidence of student- ship signed by the head of the college, school or university faculty. A standard Student Subscription costs £33.50, a Student Subscription- Plus costs £40.40 (UK only). Please note that new subscriptions take about four weeks from receipt of order to become effective. Cancelled subscriptions will be subject to a charge of 25% (twenty- five per cent) of the full subscription price or £7.50, whichever is the higher, plus the cost of any issues already dispatched. Subsciptions cannot be cancelled after they have run for six months or more. January 2007 £ lectomcs 309 Circuits The present tenth edition of the popular ‘30x Circuits’ series of books once again contains a comprehensive variety of circuits, sub-circuits, tips and tricks and design ideas for electronics. These 309 Circuits offer a representative indication of present-day electronics. ISBN 978-0-905705-69-9 Approx. 432 pages £19.95 / US$ 39.95 Complete your 30 x circuits series now! Regular £ 30x series’ enthusiasts will no doubt know what to expect: 309 Circuits contains many fully elaborated electronics projects. In addition, there are numerous ideas, each of which with a potential for use in your own research, projects and applications. Among many other inspiring topics, the following categories are well presented in this book: test & measurement, RF (radio), computers and peripherals, audio & video, hobby and modelling, microcontrollers, home & garden, power supplies & battery chargers, etcetera. Order now using the Order Form in the Readers Services section in this issue. Elektor Electronics (Publishing) Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel. +44 208 261 4509 See also www.elektor-electronics.co.uk Index of Advertisers Antex Electronics Ltd www.antex.co.uk. 41 ATC Semitec Ltd, Showcase www.atcsemitec.co.uk 78 Avit Research, Showcase www.avitresearch.co.uk 78 Beijing Draco www.ezpcb.com 53 Beta Layout, Showcase www.pcb-pool.com 53, 78 Bitscope Designs www.bitscope.com 3 Byvac Electronics, Showcase www.byvac.co.uk 78 Decibit Co. Ltd, Showcase www.decibit.com 78 EasyDAQ, Showcase www.easydaq.biz 78 Easysync, Showcase www.easysync.co.uk 78 Elnec, Showcase www.elnec.com 78 Eurocircuits www.eurocircuits.com 6 First Technology Transfer Ltd, Showcase . www.ftt.co.uk 71, 78 FlexiPanel Ltd, Showcase www.flexipanel.com 78 Future Technology Devices, Showcase . . . www.ftdichip.com 78 Futurlec, Showcase www.futurlec.com 78 Jaycar Electronics www.jaycarelectronics.co.uk 2 JB Systems, Showcase www.modetron.com 78 Labcenter www.iabcenter.com 88 Lektronix www.lektronix.net 7 London Electronics College, Showcase . . www.lec.org.uk 78 Marchand Electronics Inc, Showcase .... www.marchandelec.com 78 Mikro Elektronika www.mikroe.com 31 MQP Electronics, Showcase www.mqp.com 79 New Wave Concepts, Showcase www.new-wave-concepts.com 79 Newbury Electronics www.newburyelectronics.co.uk 75 Number One Systems www.numberone.com 53 Nurve Networks www.xgamestation.com 71 Paltronix www.paltronix.com 45 Peak Electronic Design www.peakelec.co.uk 13 Pico www.picotech.com 57 Quasar Electronics www.quasarelectronics.com 61 Robot Electronics, Showcase www.robot-electronics.co.uk 79 Scantool www.ElmScan5.com/elektor 6 Showcase 78, 79 SourceBoost Technologies, Showcase . . . www.sourceboost.com 79 Tsien (UK) Ltd, Showcase www.componentbin.com 71, 79 TTE Systems www.tte-systems.com 11 Ultraleds, Showcase www.ultraleds.co.uk 79 University of Derby www.derby.ac.uk/adt 57 USB Instruments, Showcase www.usb-instruments.com 79 Virtins Technology, Showcase www.virtins.com 79 Advertising space for the issue of 22 October 2007 may be reserved not later than 25 September 2007 with Fluson International Media - Cambridge House - Gogmore Lane - Chertsey, Surrey KT 1 6 9AP - England - Telephone 01 932 564 999 - Fax 01 932 564998 - e-mail: aerrvb@husonmedia.com to whom all correspondence, copy instructions and artwork should be addressed. 9/2007 - elektor eledronics 87 v . '^ T V h. J_ , Y Sr L>*J #r ■» „■ M r j •■ *** ■< _r- p — ^ ^ f' ■ ■* i\J; f adfar "ic-r ■- w *»r Viri L mTi r .^S', + * _ IXIEW IIM DESIGIM SUITE 7: IXIEW: Redesigned User Interface includes modeless selection, modeless wiring and intuitive operation to maximise speed and ease of use. IXIEW: Design Explorer provides easy navigation, design inspection tools and cross-probing support to R prove quality assurance and assist with fault ding. IXIEW: 3D Visualisation Engine provides the means to preview boards in the context of a mechanical design prior to physical prototyping. IXIEW: Simulation Advisor includes reporting on simulation problems with links to detailed troubleshooting information where appropriate. IXIEW: Trace capability within both MCU and peripheral models provides detailed information on system operation which allows for faster debugging of both hardware and software problems. IXIEW: Hundreds of new device models including PIC24, LPC2000, network controllers and general purpose electronic components. Electronic Design From Concept To Completion Labcenter Electronics Limited Registered in England 4692454 Electronics E-mail: infii@ > labcenter.coiii Tel: +44 (O) 1 756 753440 Fax: +44 (O] 1 756 75E857 Registered Address: 53-55 IVIain Street, Grassington, IXIorth Yorks, UK, BDE3 5AA