+ WHAT Free Audio Measuring Software 0BD2 Simulator -wheels car electronics Programmable DIY RFID ✓ home-brew tags ✓ wireless electricity www.elektor.com InterSceptre Extension Board one opens doors (and ports) for you ikroEl w'l'ltt'l ® m i tin POWER CHING POWER SUPPLY USB PROG :» nit in }2A\t> gcjhthast yfWfl4 a^to^ SERIAL LCD n ii 1 1 1 PORT EXPANDER EasyAVR™6 microcontrollers using a PC CW*TSP?3T»!*TiiT?iTMf>T*Tl^TTif?T«TT5ir>Ta«Ti?! ^ TgniiHiun ^ *ii T iiMiii {^i^A*ii : « tiltu includes an on-board programmer providing an interface for programming sim . 1 JLj J. jl (controller using eric 2x16 LCD with AVR® compilers AVRprog™ programmer nicati to easily simulate the operation of the ta m EXPERIENCE THE EASE OF CREATING YOUR OWN ELECTRONIC DEVICE WITH THE EaSyflUR™6 GET IT NOW www.mikroe.com The RS EDP. No other platform can make your concepts fly quicker. EMBEDDED DEVELOPMENT PLATFORM rswww.com/edp 08457 201201 T&M is everywhere If you look at a thousand electronic cir- cuits, which is time consuming but pain- less by browsing, say, ten volumes of Elektor, it's not too difficult to pinpoint an aspect of test and measurement in at least five hundred. In some cases, it's there right in front of you: the audio amplifier requiring an ammeter to set up the quiescent current in the final stage; the latest microcontroller board with 12-bit ADC channels to hook up sensors (which are ‘totally' measurement); or the linear power supply with its current sensing resistors somewhere telling the control circuit when to shut down the output voltage. ]n other cases, you have to think harder to identify the "T&M 11 factor in a circuit or publication, and you might be inclined to say “none in this one" with some confidence. But do not forget your intui- tion as a powerful instrument for lots of measurements of the unscientific type. Personally I can never resist gauging the temperature a power transistor ora volt- age regulator is running on its heatsink, simply by first sniffing the air above the heatsink and then — just maybe — touch- ing the surface with my finger. No Ptioo probes or IR gun thermometer required — anything running above 40 celcius or so is ever so easy to spot. Another meas- urement completed to prevent trouble arising — coarse but okay. In this edition of Elektor T&M is all over the place — in OBD, too. Your car Is constantly measuring a hundred or so parameters to check for faults and if one occurs, flags an error code for reading out through the OBD interface. If you're an astute Elektor reader then surely you'll want to use the Elektor OBD analyser for that purpose — after all, you don't want to be taken for a ride by joe from the garage down the block. With this month's OBD Mini Simulator (page 18) it's not necessary anymore to plug into a lot of cars with the Engine Failure light on T just to convince yourself that your OBD analyser is working properly, or indeed to learn to work with It, Safety is not just in numbers but in measurement results too, jan Buiting, Editor 6 Colophon Who's who at Elektor magazine, 8 Elektor Foundation Awards 2010 10 News & New Products A monthly roundup of all the latest in electronics land, 16 Energy from the Internet, Water and ICs We discovered some unexpected sources of electrical energy you, too, might want to tap into to help save the planet. iS OBD2 Mini Simulator A chicken and egg problem ended; this simulator will tell for sure if your OBD analyser is working properly — with no car around. 24 Wireless Electricity meets RFID An end to the myth held up by professionals saying you can't make your own RFID readers, personalized tags, or an RFID system to transfer energy. 32 High Speed Flash Trigger Here's how the Elektor ATIVhS board takes control of ultra-fast photo flashing for events requiring high time resolution, 36 DMx512 Control Interface Based on a Cypress PSoC powerhouse this DMX512 controller has a mass of functionality and a sleek user interface, too, 43 Two USB scopes and one not so USB USB oscilloscopes are all the rage. This month E-LABs examined three instruments, one low cost, one high end, and one with no USB and no PC connected — yes. it's stand alone! 46 Audio teamwork E-LABs were called in to provide assistance with distortion measurements on a few high-spec audio amplifiers. Some quirky results! 48 Measuring for Free Why buy expensive test equipment if 4 □6-2 mo elektor CONTENTS Volume 36 June 2010 no. 402 18 OBD2 Mini Simulator OBD testing on a real vehicle can be a little uncomfortable especially if you don't have the option of working in a garage. The MiniSim simulates the signals that you would normally expect to encounter when you plug an OBD analyser Into your vehicle's OBD2 connector. This allows you to carryout testing and de- velopment of a new anatyser design from the comfort of your own lab bench. 24 Wireless Electricity meets RFID RHD tags based on the EM4102 chip are cheap, even in small quantities, and readily available. In this project we use a small printed circuit board with the EM4095 reader 1 C mounted on it, which allows you to transfer the data from the RFID tag to an ATM18 test board. The reader board can also be used to make an RFID reader using an ATtiny23i3. 36 DMX512 Control Interface The DMX512 protocol is a professional standard for controlling lighting equi- pment, However, truly general-purpose DMX driver interfaces are far from cheap. This circuit provides a wide variety of outputs and is based on a Cypress PSoC device that supports visual configuration. This makes it very easy to gene- rate the desired setup for lighting systems. # 4 . | 48 Measuring for Free Most of you will be aware that an oscilloscope and a function generator are required for in-depth Investigation of electronics circuits. However, using a PC and some free software you can have this functionality for low frequency measurements, without having to buy Teal 1 test equipment. your PC, a good soundcard and some free software are just fine for many measurements in the audio frequency range? 52 LiPo AutoBalancer Here we get to grips with 25 . 3s and 4s Lithium Polymer battery packs and the need to balance their charging process. 58 Intersceptre opens doors (and ports!) for you Fast, convenient prototyping of sophisticated microcontroller applications becomes a reality with this multi-platform extension board. 64 Starry Night 1 his unique celestial slide show displays the major constellations using an MSP430 microcontroller. Fully configurable and expandable it’s sure to be a talking point. 68 Alternative HiFi Power Supplies Here we examine if those dirt cheap switch-mode power supplies from China etc. are any good for serious audio applications. 71 My Friend the Accelerometer Stick an accelerometer device onto a loudspeaker cone, add a suitable preampiifierand you have a tool of the trade for advanced acoustic measurements, Ed Simon explains. 74 Design Tip: Mini dice A PIC and a few LEDs make a dice circuit that does really well in terms of randomness, 76 Hexadoku Our monthly puzzle with an electronics touch. 77 Retronics: elektermmaf (1978) Regular feature on electronics 'odd & ancient*. Series Editor: Jan Suiting 84 Coming Attractions Next month in Elektor magazine elektor 06-2010 5 elektor international media bv Elektor International iMedia provides a multimedia and interactive platform lor everyone interested in electronics. From professionals passionate about their work to enthusiasts with professional ambitions. From beginner to diehard, from student to lecturer. Information, education, inspiration and entertainment. Analogue and digital; practical and theoretical; software and hardware. Programmable DIY RFID ✓ home-brew tags ✓ wireless electricity 4 InterSceptre Extension Board opens doors (and ports) for you ■fe ill ANALOGUE • DIGITAL » MICROCONTROLLERS & EMBEDDED AUDIO • TEST & MEASUREMENT * M ~ j Volume ],G, Number 402, June 2010 ISSN 175,7-0875 Elektor aims at inspiring people to master dec ironies at any personal level by presenting construction projects and spotting developments in electronics and information technology. Elektor international Media, Reg us Brentford, 1000 Great West Road, Brentford TW8 gHH. England. Tel. (+44) 208 2614509, fax 1 . (+44) 20S 261 4447 www.elektor.com The magazine is available from newsagents, bookshops and electronics retail outlets, or on subscription. Elektor is published 11 times a year with a double issue for July & August, Elektor is also published in French, Spanish, American English. German and Dutch, Together with franchised editions the magazine is on circulation in more than 50 countries. Wlsse Hettinga (w.liettinga - elektor.n!) Jan Suiting (ed it oi^Pele ktor.com J Harry Sagged. Thijs Beckers, Eduardo Corral, Ernst Krempelsauer, |ens Nickel. Clemens Valens. Antoine Aulhier (Head), Ton Giesberts, Luc Lemmens, Daniel Rodrigues, Jan Visser, Christian Vossen Hedwig Hennekens (secretariat s elektor.nl) Giel Dels, Mart Schroijen Paul Snakkers Carlo van Nrstelrooy Elek tor 1 n tern atrona I Media , Regus Brentford, 1000 Great West Road, Brentford TW8 gHH. Eng kind. Tel. (+44)208 261 45 og, fax: (+44) 208 261 4447 I n te rnet : www. e I ek to r. co mf subs 6 06-2010 elektor DVD Masterclass High-End Valve Amplifiers Specifically for audio designers, audiophiles, DIY enthusiasts etc. Masterclass PTTwTO BONUS: 25 Elektor publication about valves elektor In this Masterclass Menno van der Veen will examine the predictability and perceptibility of the specifications of valve amplifiers. Covered are models that allow the characteristics of valve amplifiers to be explored up to the limits of the audible domain from 20 Hz to 20 kHz. This then leads to the minimum stability requirements that the amplifier has to satisfy. The coupling between output valves and output transformer are also modeled. Including: *3,5 hours of Video materia f * PowerPoint presentation (74 slides) * Scanned overhead sheets (22 sheets) * AES Publications mentioned during the Masterclass Contents: Part 1 Preamplifiers Equivalent schematics t limits in the frequency. Part 2 Power amplifiers Modeling of class A to 8, interaction of the specifications forOut- putTransformers (OPTs)and frequency range and damping factor. Part 3 Negative feedback How negative feedback can be done right, remarkable experi- ments in the project. Pa rt 4 Ou tpu t transformers Limitations and possibilities of the output transformer. ISBN 978-0-905705-86-6 - £24.90 * US 540,20 Further information and ordering at www.elektor.com/shop Em a ih s u bscriptions 'Telektor.co n l Rates and terms are given on the Subscription Order Form. Elektor international Media b,v. P. O. Bom n N L- 6114 - ZC S uste re n T he Net h erland 5 Telephone: (+31)464389444, Fax: (+31) 46 4370161 DUiiribuiion: Seymour. 2 East Poultry Street, London ECiA. England Telephone: +4 4 207 4294073 Advertising: Huson International Media, Cambridge House, Gog more Lane, Chertsey. Surrey KTi6gAP, England. Telephone: 144^32 564999. Fax: +44 1932 5.64998 Ema i I: r.dga rfthuson media .com Internet: vwvw.husonmedia.com Advertising rates and terms available on request. 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 ,n our bonks and magazines (other than third-party advertisements) are copyright Elektor International Media b,v. and may not be reproduced or transmit- ted in any form or by any means, including photocopying, scan- ning an recording, in whole or in part without prior written per- 1 1 1 ission I rom t he Publi sher, Such writ ten perm iss ion must jl so 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, [he Publisher does not accept responsibility for failing to identify such patent! s) or other protection. The submission of designs or articles implies permission to the Publisher to alter the text and design, and to use the contents in oilier Elektor International Media publications and activities. The Publisher cannot guaran- tee to return any material submitted to them. Prices and descriptions of publication-related items subject to change. Eirors and omissions excluded, slcklor International Mtdi.l b,v. inng Printed in the Netherlands elektor 06-2010 7 ©ELEKTOR Truly unique: the Eiektor Foundation Awards 2010 Eiektor handed out the first Eiektor Foundation Awards last year. In a simple and straightforward event, we highlighted the activi- ties of a number of people and companies. People who carry their passion for electronics further than most and who give it special form in rescue operations, stimulating education and learning, and sustainable projects, to mention a few examples. The awards cer- emony honours the more than 250,000 readers and sponsors in the many countries where Eiektor is active. Although no monetary prize is associated with the awards, the Foundation and the awards are open to electronics com- panies that wish to spon- sor a category or wish to assist a winner with money, good advice, products or services. The directors of the Eiektor Foundation and Elektor s international editorial staff collaborate closely in the selection and nomination process and granting of the awards. For instance, the first round of the selection process is based in part on suggestions from Eiektor readers. This year the selection categories for the Eiektor Awards are 'unique design' (an electronics project with a unique design or approach), ‘unique learning' (which encom- passes unique study projects, courses of study or teachers), and 'unique & sustainable 1 (how electronics helps improve our world). E L E K T 0 R F 0 U N D A T 1 0 N Eiektor Foundation If you have any ideas or suggestions regarding people or organisa- tions that in your view deserve an Eiektor Award in 2010, please send a short e-mail message to Award201 0@elektor.com. Naturally, you may also send a message to the Editor at editor@efektorxom. If you wish to sponsor an Eiektor Award or assist a winner in his or her good work, please contact Sponsor Manager Don Akkermans by e-mail at don.akkermans@elektorfoundation.org. The road to India, Turkey and South Africa For several years now, we have been receiving requests to initi- ate activities In India. With the signing of a contract with the firm Esskay in Mumbai, we have now taken the first step towards launch- ing Eiektor activities in India. During the coming months we will work on developing a website, publications and products. We are fully confident that these products will appear on the market before the end of the year. If you wish to stay on top of developments and have a front-row seat, please let us know at Elektorindia@esskay.in. Naturally, this also applies to companies inside or outside India. We also expect to commence Eiektor activities in Turkey In the near future. There's a whole lot going on in this enormous country, and we hope to foster a new generation of electronics enthusiasts there with our Eiektor products. The same applies to South Africa, With India is coming to Eiektor — Eiektor is coming to India India, South Africa and Turkey, Eiektor will then be active in fourteen countries, including Germany, the Netherlands, England, France. Spain, Portugal, Brazil, Italy, Sweden, and the United States. Lust for (Eiektor) Lifve! The third edition of the Eiektor Live! event will be held in the Neth- erlands on 20 November 20 1 0. The venue is the former Philips exhi- bition hall Evoluon in Eindhoven. In this fantastic building, which resembles a giant UFO on the ground, you can look forward to a day jam-packed with demos, workshops and hands-on sessions dealing with everything related to the subject of electronics. This year Eiektor Live! features a very interesting morning seminar pro- gramme. Seminar participants will receive three hours of instruc- tion on specific hardware, development boards or a particular tech- nology, So far we have (provisionally) lined up NXP, Matrix Multi- media, Muvfum, Altium Transfer and elQuip as seminar presenters. There is a fee for participation, and participants may take home the lesson material (hardware, software, etc.). After three hours, you'll be your own expert! It*s all happening @Elektor Wisse Hettinga 8 06-2010 eiektor THE ORIGINAL SIMCE: 994 PCB-RQDL Beta LAYOUT Specialising in Prototype PCBs Hi*- Hi*'- HI*' Free Laser Stencil with all Prototype PCB orders 1 WD prototype service — i ~ * — 4 Chemical Tin Finish (no extra cost) , A £'$ CZ) Free Phone UK 0800 389 8560 5. simply send your layout tiles and order ONLINE PCB-POOLCQM * sales@pcb-pool.com jF«e ^ I C.-.I JTS-27J-X 0 Em T PC* FtB-KShUG Don P just Pest it... Analyse fPi Special Offer prices for limited period or white stocks test? piak electronic design ltd The Famous Atlas LCR f Model LCR40 Passive component analyse:. Identify inductors, capacitors and resistors Auto frequency selection,. Removable probes Optional SMD Tweezers, Crocs and Clutch Grabbers Supplied with battery and universal hook probes. Aulc^Ranges: luH - lOH 1 pF - IQ.OQQuF t Ohm - 2M Nominal Accuracy; Resislar.ee 1 % Inductance 1 5% Capacitance 1.5% Test frequencies; 1kHz, 1 5kHz and 200kHz Dimensions; 103x70x20mm Aftes SCR * Modal SCR100 Connect Triacs or Thyristors any way round Auto part+pinoul Identification Check gate "OOuA to 100mA Measures gate voltage drop. Regulated loadtesi conditions Atlas ESR - Model ESR6Q Capacitance and ESR 1 Capacitance 1 uF to 22.000 uF ESR 0.01 oh ms to 20 ohms Gold pissed croc A Was ESR PLUS - ESR7Q Audible a lens* ESR 0.01 ohms to 40 ohms. Capaciianoe measurement. Alia s DC A ■ Model DCA55 The famous Peak Alias! Now with premium probes Connect any way rounti to identify semiconductor type, pinout and lots of parameters Tr.UIMSl'JJS QaiungiDns MOSFETa D-i^dcs LEDs and rftore £55.00 Identity network r^abting lype Identify many fault types. Tesls sockets and cables Complete wilh all this ftggggl {£60. 00+ VAT] Atlas Star Pack (LCR/DCA) EErcaM Includes the Allas LCR, Atlas OCA and a premium padded cany ease. spare battery Peak Electronic Design Ltd, West Road House, West Road UK Please add L2.75 pSp per order Buxton, Derbyshire. SK 17 6HF Prices include UK VAT. lel 01296 70012 www.peakeiecxo.uk &Bles@peakelec.co.uk See website for overseas prices P www.picotethxom/scGpelOOS E HIGHEST PERFORMANCE PC OSCILLOSCOPE 350 MHz BANDWIDTH 5 GS/s SAMPLING UP TO 1 GS MEMORY 4 Channel oscilloscope with spectrum analyzer Built-in arbitrary waveform generator CAN bus decoding Advanced triggering Mask limit testing Full math and measurement functions High Speed USB connection Easy-to-use software SDK for major third party applications Five-year warranty All included, from only £2995 elektor 06-2010 9 NEWS & NEW PRODUCTS Link cellphones and PDAs compatibles with USB memory devices Mobidapter, newly intro- duced by Saelig Company, fnc,, is a USB memory stick reader which plugs directly into the SD memory slot on mobile/cell phones, smart phones and PDAs, permitting — for the first time - reliable, rapid transfer of files from USB sources. Just insert Mobi- dapter to a phone’s SD slot, connect it to a USB memory device, and — in an instant — textiles, images, PowerPoint files, can bee-mailed. Now files can be transferred anywhere, without a PC, in all oper- ating systems since no drivers are required. USB memory sticks have become the de facto way to carry and transfer data, but until now it has been impossible to connect them to mobile phones and PDAs, Mobidapter works with any make of mobile/cell phone, SmartPhone or PDA that features an exter- nal SD socket. It can also be used with mini-50 sockets using simple adapter. Both SD and SDHC hosts are supported. In effect, Mobidapter becomes a standard USB host connector, interfacing with USB memory devices to a maximum 32 CB. IVlobidapter can be used with many other devices, such as TVs, PDAs, GPS devices and Digital Picture Frames. It is now possible to transfer data such as pictures, MP3 files, Microsoft Office applications, or any type of file from a standard USB memory stick to and from a mobile device. Last minute data sent from head office while you are In the field, but no Internet access? No problem! Download it via your cellphone to a memory stick (and hence your laptop) using Mobidapter, Mobidapter is compatible with virtually all of the latest phones with an external SD memory slot and all standard USB memory sticks. Power is provided from the host device so no batteries are needed. Applications include: instant transfer of images, music and data between phones, PDAs, MP3/4 players from any location; data back- ups; work files, etc. Mobidapter is available now from $59.00 each directly from Saelig Company Inc., Pitts - ford NY. In the UK, please contact IGStore, www. sa elig.com www. ela ndigital sy ste msxo m/ a dapt er/ mobi d a pter. p h p www. i osto r e, co, u k (T 0026 G-XII) IMext-generation multi-standard video decoder solution for HDTV set-top boxes Fujitsu Microelectronics Europe recently launched its next-generation high-defini- tion (HD) multi-standard video decoder solution. The MB86H61 complies with the Digital Video Broadcasting (DVB) and China Audio and Video Coding (AVS) Standards. The decoder chip is capable of decoding MPEG-2, H.264/AVC, AVS and VC-1 com- pressed video up to HD resolution. It com- bines a fast ARM 1 1 76JZF-S™ CPU with more than 475 DMIPS with all the features required by next-generation HDTV receiv- ers including advanced security for support- ing CI-Plus and the latest embedded Condi- tional Access (CA) systems. This cost-effective, low power and highly integrated System on-Chip (SoC) incorpo- rates all the necessary processing functions for digital video, digital audio, powerful on- screen graphics and a variety of connectiv- ity options for set-top boxes (STB), personal video recorders (PVR) and in-car TV receiv- ers, With the included stand-by controller, it adheres to The European Code of Conduct on Energy Efficiency and enables customers to realise STBs with extremely low power consumption. The integrated PHYs for SATA and two USB ports allow for cost-effective product designs. Additional system benefits Include support for low-cost, high-speed DDR2 and NAND flash technologies. A significant part of this new HDTV video decoder solution is the comprehensive STB application software including drivers, mid- dleware and a customisable user Interface. The software package Includes ports for various third party software IPs for digital TV functions such as MHEC-5, DVB Tele- text/Subtitles and Cl-Plus. With its appli- cation teams located in Europe, China and Japan, Fujitsu Microelectronics is capable of providing excellent local support to Its cus- tomers helping them to design their next- generation digital TV products. The DVB digital broadcasting standard is used in Europe, Russia, the Middle East, and by some broadcast systems in China that broadcast in standard definition (SD) and high -definition using the MPEG-2 and H.264 video compression formats. The AVS specification provides one of the most comprehensive standardisation solu- tions for the Chinese digital video and audio industry because it addresses system level content transport, video/audio coding for- mats and media copyright management. It also provides video coding efficiency that is two-to-three times more efficient than MPEG-2 (and equivalent to H.264), http://emeaTujitsu.com/microelectronics (100266-XV) Compact base station analyzer to provide coverage up to 6 GHz Anritsu Company introduces the Cell Master MTS21 3E, the most compact handheld base station analyzer to provide frequency tover- 10 06-2010 elektOr NEWS & NEW PRODUCTS age up to 6 GHz. Combining excellent noise and RF performance, and 1 0 MHz demodu- lation bandwidth in a compact, lightweight design, the MT8213E is ideal for cell site technicians who need to accurately and quickly test and verify the performance of installed 2G/3G/4G networks, including LTE, G5M/EDGE, W-tDMA/HSDPA, WiMAX, and CDMA/EV-DO. The Cell Master MT8213E continues the tradition of Anritsu's “E hl platform, a new generation of handheld field instruments that features integrated functionality in a robust, lightweight, field-proven design that provides all the tools necessary to deploy, maintain, and troubleshoot today's most demanding wireless equipment and networks. The Cell Master MT82 1 3E inte- grates a 6-GHz two-port cable and antenna analyzer and 6-GHz spectrum analyzer, as well as a power meter, interference ana- lyzer, channel scanner, and Tl, El, and 11/ T3 backhaul analyzers. Field technicians can conduct a full suite of measurements with the Cell Master MT8213E. Among the cable and antenna tests that can be made are RL, VSWR, Cable Loss, distance-to-fault (DTF), phase, and power. Sweep speed Is typically 1 msec / data point. When in spectrum analyzer mode, users can measure occupied bandwidth, channel power, ACPR, and carrier-to-lnterference ratio (C/I). Cell Master MTS213E can also provide spectrograms, signal strength, RSSI, and signal ID. The analyzer has dynamic range of >95 d8 in 1 0 Hz RBW, DANL of - 1 52 dBm in 1 0 Hz RBW, and phase noise of -1 00 d Be/ Hz max @ 10 kHz offset at 1 GHz. The analyzer's day light viewable 8.4-inch touchscreen allows users to display results in single- or dual-mode for more thorough analysis capability. It has two USB ports that provide the convenience of exporting measurement data to a flash drive while a power sensor is connected to the analyzer. As with all Anritsu handheld analyzers, the Cell Master MT82 1 BE has been designed to withstand the rigors of the field environ- ment and is extremely lightweight, weigh- ing only 8.2 lbs. Cell Master MT821 3E is compatible with Anritsu's Master Software Tools (MSI). A powerful PC software post-processing tool designed to enhance the productivity of technicians, MST allows acquired data to be easily transferred to a computer for report generation, data analysis, and testing auto- mation. Measurements can be saved as .DAT and are compatible with HHST. www.anritsu.com (100266-XVI) Smart contact lens with embedded wireless sensor helps glaucoma diagnosis treatment 5T Microelectronics has announced that it will develop and supply a wireless MEMS sen- sor that acts as a transducer, antenna and mechanical support for additional read-out electronics in a breakthrough platform developed by Swiss company Sen si mod AG. This solution will enable better man- agement of glaucoma patients via earlier diagnosis and treat- ment that is optimally tailored to the individual patient. Known as the SENSIMED Trig- gerfish®, the solution is based on a 'smart 1 contact lens that uses a tiny embedded strain gauge to monitor the curvature of the eye over a period of, typically, 24 hours, providing valuable disease management data that is not currently obtainable using conventional ophthalmic equipment, GlautomaB, the second most common cause of blindness around the world, is an irre- versible progressive disease of the optic nerve that can eventually lead to blindness. Although it cannot be cured, its progress can be controlled once it is diagnosed and treated properly. The standard test is the measurement of intraocular pressure (IOP), using an instrument known as a tonometer, during periodic visits to an ophthalmolo- gist. However, the tonometer may fail to detect an elevated IOP, especially in glaucoma patients, because the pressure varies during the day and often peaks during sleep or outside of office hours. As a result, the disease is often diagnosed only after significant damage to the optic nerve has already occurred, and the disease keeps progressing in many patients due to inadequate treatment. Sensimed ’s ingenious solution is a two-part system comprising the smart contact lens and a small receiver worn around the patient's neck. In addition to the strain gauge the lens contains an antenna, a tiny dedicated processing circuit and an RF transmit- ter to communicate the measurements to the receiver. The lens is powered via the received radio waves and does not need to be connected to a battery. The embedded components are positioned in the lens in such a way that they do not interfere with the patient s vision. The lens is fitted by the ophthalmologist and when the patient returns the next day the ophthalmologist removes the lens and receiver, obtaining a complete record of IOP changes over the preceding 24 hours, ST engineers are now working with Sensimed to translate this breakthrough technol- ogy Into a reliable commercial MEMS product ready for mass production. ST expects the development of the MEMS sensor to be completed in Q2 201 0 and manufacturing to start in Q3 2010, with availability outside trials to doctors and patients subject to regulatory approvals, Sensimed and 5T anticipate progressively rolling out the prod- uct country-by-country across Europe beginning in Q3 and entering the US market by the end of 2011. www.st.com (ioo266-Xlii) elektor 06-2010 NEWS & NEW PRODUCTS Pico’s new 12 GHz TDR/ TDT sampling oscilloscope The Pi coScope 921 1 ATDR/TDT Sampling Oscil- loscope is a new instrument specially designed for time-domain reflectometry (TDR) and time- domain transmission (TDT)* It provides a low- cost method of analysing cables, con nectors, circuit boards and 1C packages. The PicoScope 921 1 A works by stimulating the device under test using its two independently programmable, 1 QO-ps (typical) rise-time step generators. It then uses its 12 GHz sampling inputs to build up a picture from a sequence of reflected or transmitted pulses* The results can be displayed as volts, ohms or reflection coef- ficient against time or dista nce. As well as TDR/TDT analysis, the Pico- Scope 921 1 A can also be used for mask limit testing of a wide range of communi- cations standards including SONET/SDH, Fibre Channel, Ethernet, InfiniBand 2. SC and 5,0G, XAUI, ITU C.703, ANSI T1/102, Rapid 10 1.25G and 3.125C, C. 984.2, PCI Express 2.5C and 5.0G, and Serial ATA 1 .5G and 3.0G. Over 150 industry-standard masks are included. The instrument has three trigger inputs — a DC to 1 GHz direct trigger, a 1 to 1 0 GHz prescaled trigger and a 1 2 .3 Mbps to 2. 7 G bps clock-recovery trig- ger— as well as a 1 0 Gbps pattern sync trig- ger for averaging eye diagrams* Unlike traditional, bulky bench-top instru- ments that contain a PC and a display, the PicoScope 921 1 A takes very little space on your workbench* If you Ye working at a cus- tomer's premises, the only extra equipment you need to carry is a laptop and a mains adapter. The analyser connects to any Win- dows XP or Vista computer with a USB 2.0 port, and an Ethernet port is provided for remote operation over a network. There are no extra software modules to buy. The PicoScope 921 1 A is on safe now, priced at £7,495. The price includes all necessary calibrated cables, filters, power splitters and adaptors. www.picotech.com (100266-XVII) Extruded aluminium Eurocard cases Vero Technologies has introduced three styles of extruded aluminium instrument cases, designed to accept three quarter and full width Eurocard RGBs. Circuit boards are mounted horizontally into multi-posi- tion internal slots in the body of the case, which has a black anodised finish for good resistance to wear and tear and improved heat dissipation. The smaller three quarter width E003 range is 40 mm in height and will accept a 75 mm wide PCB into four RGB slot positions; the larger E005 and E006 are 61 mm high and will take standard 1 00 mm wide Eurocards into eight PCB slot posi- tions. The external surface of the enclosure incorporates a series of ribbed fins to aid heat dissipation and T slots are provided on both sides and the base to enable the units to be securely attached to other equipment if required. For enhanced access, the E006 full width units have a removable aluminium top cover; all sizes are supplied with two flat aluminium end panels* Each of the three families Is available in lengths of 100, 125, 165, 200, 225 and 285 mm as standard; other lengths are available to order. Alternative finishes to the standard black anodised can be speci- fied and all sizes can be factory machined with holes, slots, cut-outs and apertures in the body and end panel to meet specific customer requirements and an option neo- prene gasket sealing kit gives protection to IP65 if required. www. verotl.com ( 1 0 026 6 -X I ) PowerBurst® PC5 ultracapacitor Tecate's PowerBurst Type PCS ultracapa- citor is engineered to provide extended power availability during dips, sags, and outages in the main power sources as well as to relieve batteries of burst power func- tions. The RoHS-compliant part's flat pris- matic cell design notably incorporates stain- less steel, hermetically sealed cells. Due to this unique construction, it boasts an extre- mely low profile (5*1 mm max*) making it an excellent choice for space constrained applications* The low ESR (Equivalent Series Resistance) PC 5 ultracapacitor is capable of accepting charges at the Identical rate of discharge, and features accessible termi- nals and an electrostatic storage capability to facilitate over 500,000 duty cycles and a 1 0 -year life capability. Tecate’s PowerBurst Type PCS ultracapaci- tor is commonly specified for employment in a broad range of applications including providing, holding up, or bridging power until the back-up power source 'kicks in' when the primary power source fails. Its back-up power capabilities make it well suited for soft shutdown, last gasp’ notifi- cation, battery swaps, and memory reten- tion. In addition, the PC5 is used in tan- dem with batteries or other power sources where batteries alone do not meet perfor- mance objectives. The small form factor part is highly appropriate in military and consumer electronics, wireless transmis- sion, medical devices, automatic meter readers (AMRs), solid state drives (SSDs), smart grids, RAID (Redundant Array of independent Disks) controllers, handheld GPS devices, and remote sensors. Its utili- zation often enables designers to downsize the primary system batteries. The radial-leaded ultracapacitor has a small 14 mm (L) x 23*6 mm (W) X 4.8 mm (W) footprint, and very low, 5.1 mm profile. Standard parts feature a voltage of 2*5 VDC capacitance of 4*0F, and an extended temperature range of from -40 degrees to +70 degrees C Capacitance tolerance is ± 20 %* www. te ca te g ran p . co m (10 0266-X I V ) 12 06-2010 elektor NEWS & NEW PRODUCTS VeeaP VttW.uW Kit 1 VoiceCP voice recognition development tools TIGAL recently launched their VoiceGP family of products under Its VeeaR brand of voice and speech recognition products. The VoiceGP family includes all the hard- ware and software required for easy and cost effective development and implemen- tation of speech synthesis and multi-lan- guage speaker independent and speaker dependent speech recognition capabilities to virtually any application. The product family consists of the VoiceCP Module and two Development Kits with bundled Devel- opment Software. The VoiceGP Module is based on Sensory's RSC-4128 mixed signal processor. Its small size of 42mm x 72mm and two 2 8- pin con- nectors with 2.54 mm pin spacing make it breadboard friendly and suitable for pro- totype boards. The module is capable of running the latest Sensory FluentChip™ core technology libraries which enable speaker dependent recognition in any language, speaker independent recog- nition (US/UK English, German, French, \ Italian, Spanish (Latin American), Japa- nese and Korean), Speech, DTFM Synthesis, Speaker Verification, and Record and Play. The module has 51 2 K8 of Code/Const Flash, 51 2 KB of Serial Data Flash, 128 KB External RAM, and enables full access to the I/O pins of the R5C-4X processor It also features an expansion bus that allows fast 5PI interface to MMC cards, 5 dedicated chip select out- puts, 2 memory enable outputs and an 8-blt wide read-write memory bus. The VoiceGP Development Kit includes the VoiceGP module and a Development Board that can be powered via USB, batter- ies or an external power supply. It also has an on-board USB / Serial adapter and pro- grammer, on-board microphone, selectable audio output (PWM or DAC with on-board amplifier), 4 push-button inputs and 4 LED outputs for demos and fast prototypes, Elnec: new extremely fast BeeProg2 Universal Programmer Elnec, manufacturer of Europe's leading Device Programmers, has recently released a new 48-pln universal programmer which currently supports more than 52,000 devices. Since programming times are faster than ever before, this new product will appeal not only to the community of hardware developers, but also to small and medium sized manufacturers. The BeeProg2 is an enhanced version of the popular BeeProg+ universal programmer (in daily use at ElektorLabs). The company 1 p s target was to optimize this product for fast programming of high density memories which has been achieved through the use of a much more powerful FPGA based core inside the programmer. The BeeProg2 is able to program NAND and NOR Flash memories up to 70% faster than its predecessor. The programmer is a perfect solution for both developers and manufacturers who pro- gram devices in higher quantities. It reliably programs a wide range of programmable chips in the ZIF socket (more than 800 models of socket converters are available) as well as through the ISP connector. Efnec’s programmer software allows up to eight BeeProg2 programmers or its predecessors ( Bee Prog+/ Bee Prog) to be connected and operated from one PC making for a very flexible production solution. Furthermore, as a whole it works as a concurrent multiprogramming system. As a result, each program- mer can work independently and when necessary, program different types of chip. This solution saves user s time and also funds needed for staff and hardware. The BeeProg2 is not only a programmer, but also a tester of TTL/CMOS logic ICs and memories, fn addition, the programmer performs device insertion tests (wrong or backward position) and contact checks (poor contact pin-to-socket) before it programs each device. These capabilities, supported by overcurrent protection and signature- byte check, minimize the possibility of chip damage due to operator error. As mentioned earlier, the programming speed increase for serial and parallel NAND and NOR Flash memories means, in absolute numbers, that the BeeBrog2 can program and verify a 64 Mbit NOR Flash in less than 1 3s a nd program and verify NAND Flash of the same size in less than 123s. The BeeProg 2’ s programming times a re comparable to competing programmers claiming to offer ‘ ultra-fast programming speed" and costing up to 50% more. Elnec continues its tradition of manufacturing high quality products and provides a unique worldwide 3 year warranty with this programmer. Updates to the program- mer software, including new device sup- port, are available from the Elnec website free of charge, Elnec focuses on providing flexible support and releases new soft- ware for 48-pln programmers on average every two working days. www.efnec.com (100346-!) and an SD/SDHC/MMC compatible socket for extended storage. The bundled development software consists of an Inte- grated Development Environment, a tool chain with VeeSee C language code trans- lator, VeeSee integrated C pre-processor, resource compiler and linker and VeeLoader code down loader / flash programmer. Sen- sory’s FluentChip™ Technology Library (build tools and documentation) and Senso- ry’s QuickSynthesis4 p1 software for speech and audio compression are also included. The kit is also optionally available with a user license for Sensory's Quick T2Sl rvi software that allows quick development of Speaker Independent vocabularies from text-based input in multiple languages. The VoiceGP Development Kits are shipped with the VoiceCP Module, VoiceGP Dev- Board, Software CD and a USB Cable. The VoiceGP Module is also available separately. All products are available directly from TIGAL or your local distributor. The VoiceGP DK, VoiceGP DK-T2SI and VoiceGP Module are priced at £149, £299 and £45 respec- tively, with discounts available at higher volumes. All software tools (except QT2SI), documentation and demo videos are avail- able online as a free download, www.veear.eu www.tigal.com 13 elektor 06-2010 NEWS & NEW PRODUCTS New custom front panel service Having pioneered the facility for engineers to pur- chase RGBs online (pob-pool.com), Beta LAYOUT has announced the introduction of a new online FRONT PANEL service. This new service enables users to configure their own Front Panel designs and place an order directly online. As well as providing a professional “free -to -down load” Design Software, numer- ous machining options, material thickness, fonts, colours, & finishes are available. The free, easy-to-use, Design Software simplifies the configuration and ordering of custom Front Panels. You can choose from many standardised construction units (e.g. ventilators, sub connectors) which are available in the software’s library. The software even calculates the price of the finished Front Panels for you. Once your Front-Panel design is complete, an order can be placed directly through the software itself. Alternatively DXF files from any CAD program can be converted and processed for a small surcharge. Separate printing Si inscription files are required for this option. Various Front Panel materials can he selected from a wide range of natural or coloured anodized aluminium and plastic (acrylic). Material thickness from 1.5mm to 3mm can be selected. The minimum dimensions possible are 30mm x 30mm, up to a maximum of 300mm x460mm. High precision CNC machining, such as drilling (with and without threads), countersunk drills, flat milling and cut-outs are ail possible. Ultra-modern mill- ing and drilling machines are used to complete the manufacturing process. The inscrip- tion of Front Panels with text, logos, images, scalings etc, is achieved using engraving methods and/or high-resolution digital printing. The maximum order quantity is 50 pieces; lead-times are available from 3 to 8 working days. www.panel-pool.com (100346-11!) Vinculum-ll VNC2 evaluation modules Future Technology Devices International (FTD1) have launched a range of VNC2 evaluation modules (V2DIP-x), a VNC2 evaluation kit (V2-EVAL) and a VNC2 debug module. These modules are designed to help designers quickly develop embed- ded USB 2.0 Host/Slave designs based on FTDFs recently announced Vinculum VNC2 devices. VNC2 is a user programmable dual USB 2.0 Host/Slave intelligent SOC control- ler featuring a customised 1 6-blt MGU core, 256 KByte e- Flash program memory and 1 6 KByte of SRAM data memory. VNC2, and its associated modules, are aimed at designers wishing to add USB connectiv- ity while implementing their own custom application firmware. The V2-EVAL evaluation kit is a complete prototyping platform for VNC2 and con- sists of a main development board which can takes a 32, 48 or 64 pin daughter board to suit the VNC2 package selected. Two USB type TV connectors and a USB type 'B 1 connector provide interfacing, con- figuration and silicon level debug of the VNC2 application. A debug interface pro- vides access through the USB interface to a comprehensive range of firmware debug features using the royalty-free Vin- culum software development toolchain and Integrated Design Environment (IDE), The board provides I/O headers for all sup- ported interfaces such as UART, FIFO, SP1 and GPIO. In addition, user configurable LEDs and switches are provided. The V2DIP-X family is a range of compact VNC2 based USB Host/ Slave evaluation modules designed to fit into either a 0.6” or 0,8" standard DIP socket, allowing quick and easy connection to a development board or end product. Single (V2DIP1 ) or dual (V2DIP2) USB type TV connector ver- sions are available for all 3 package sizes. VNC2 I/O pins are available via the DIP head- ers. In addition, a 6 pin header is provided to connect to the VNC2 Debug Module. The VNC2 Debug Module, when used in conjunction with the Vinculum software development tool suite, provides full VN02 silicon level debug. Connection to a host PC is provided via a USB type ‘B 1 con- nector (and standard USB cable), while a 6 pin, 2 mm socket provides an interface to any of the V2D1P-X evaluation modules. Pricing for the modules, based on single unit quantities, are as follows: V2DIP1-48 $21.50, V2DIP2-48 $25.24, VNC2 DEBUG MODULE $16.83, 2-EVAL $79.00, V2-EVAL- EXT48 $13.71 daughter board for use with V2-EVAL. www.ftdichip.com (T00346-IV) 14 06-2010 elektor QUASAR electronics me ffecfrOrtfc KH SUncs 1PP3 r lease vise our online snop now tor details of over 500 kits, projects, modules end publications. Discounts for bulk quantities. Quasar Electronics Limited PO Box 6935, Bishops Stortford CM23 4WP, United Kingdom Tel: 01279 467799 Fax: 01279 267799 E-mail: sales@quasarelectronics.com Web: www.quasarelectronicsxom Postage & Packing Options (Up to 0 5Kg gross weight) UK Standard 3-7 Day Delivery - £4 95 UK Mainland Next Day Delivery - £9.95, Europe (EU) * £8 95. Rest of World - £12 95 (up to 0.5Kg) lOrtfer online for reduced price UK Postage! We accept all major credit/debit cards. Make cheque s/PO's payable to Quasar Electronics, Prices include 15.0% VAT* hlAmm* _ .a. II M. - 1 . a . -* W JPAA a. + a. Credit Card j - Motor Drivers/C ont rollers ■ Controllers & Loggers Here are just a few of our controller and Here are just a few of the controller and driver modules for AC, DC, Unipolar/Bipolar data acquisition and control units we have, stepper motors and servo motors. See See website for full details. Suitable PSU website for full range and details* for all units: Order Code PSU445 £7,95 Computer Controlled / Standalone Unipo- lar Stepper Motor Driver Drives any 5-35 Vdc 5. 6 or 8-lead unipolar stepper motor rated up to 6 Amps. Provides speed and direc- tion control. Operates in stand-alone or PC- controlled mode for CNC use. Connect up to six 3179 driver boards to a single parallel port. Board supply: 9Vdc. PCB: 80x5Qmm. Kit Order Code: 3179KT - £15.95 Assembled Order Code: AS3179 - £22.95 Computer Controlled Bi-Polar Stepper Motor Driver Drive any 5-50 Vdc, 5 Amp bi-pol a r stepper motor us- ing externally supplied 5V levels for STEP and DI- RECTION control. Opto- isolated inputs make it ideal for CNC applica- tions using a PC running suitable software. Board supply: 8-30Vdc, PCB: 75x85mm, Kit Order Code. 3158KT - £23.95 Assembled Order Code: AS3158 - £33,95 Bi-Directional DC Motor Controller (v2) Controls the speed of most common DC motors (rated up to 32 Vdc, 10A) in both the forward and re- verse direction. The range of control is from fully OFF to fully ON in both directions. The direction and speed are controlled using a single potentiometer. Screw terminal block for connections. Kit Order Code: 3166v2KT - £22.95 Assembled Order Code: AS3166v2 - £32,95 DC Motor Speed Controller (100V/7.5A) Control the speed of almost any common DC motor rated up to 100V/7,5A. Pulse width modulation output for maximum motor torque at all speeds. Supply: 5-15Vdc. Box supplied. Dimensions (mm): 60Wx100Lx60H. Kit Order Code: 3067KT - £17.95 Assembled Order Code: AS3Q67 - £24,95 Most items are available in kit form (KT suffix) or assembled and ready for use (AS prefix). 8-Ch Serial Isolated I/O Relay Module Computer controlled 8- channel relay board. 5A mains rated relay outputs. 4 isolated digital inputs. Useful ^_ l in a variety of control and ^ sensing applications. Con- trolled via serial port for programming (using our new Windows interface, terminal emula- tor or batch files). Includes ptaslic case 130x100x30mm. Power Supply: 12Vdc/500mA. Kit Order Code: 31G8KT - £64.95 Assembled Order Code: AS3108 - £79.95 Computer Temperature Data Logger 4 -channel temperature log- ger for serial port. Q C or °F. Continuously logs up to 4 separate sensors located 200m+ from board. Wide range ot tree software applications for stor- ing/using data. PCB just 45x45mm. Powered by PC. Includes one DS1820 sensor, Kit Order Code: 3145KT - £19,95 Assembled Order Code: AS3145 - £26*95 Additional DS182Q Sensors - £3.95 each Rolling Code 4-Channel IJHF Remote State-of-the-Art, High security. 4 channels. Momentary or latching relay output. Range up to 40m, Up to 15 Txs can be learnt by one Rx (kit in- cludes one Tx but more avail- able separately). 4 indicator LED 's. Rx: PCB 77x85mm. 12Vdc/6mA (standby). Two and Ten channel versions also available. Kit Order Code: 3180KT - £49,95 Assembled Order Code: AS3180 - £59.95 DTMF Telephone Relay Switcher Call your phone num- ber using a DTMF phone from anywhere in the world and re- motely turn onv'off any of the 4 relays as de- sired, User settable Security Password. Anti- Tamper, Rings to Answer, Auto Hang-up and Lockout, Includes plastic case Not BT ap- proved. 130x110x30mm Power: 12 Vdc. Kit Order Code: 3140KT - £74.95 Assembled Order Code: AS3140 - £89,95 Infrared RC Relay Board Individually control 12 on- board relays with included infrared remote control unit. Toggle or momentary, 15m+ range. 112x122mm, Supply: 12Vdc/0.5A Kit Order Code: 3142KT - £59.95 Assembled Order Code: AS3142 ■ £69.95 New! 4-Channel Serial! Port Temperature Monitor & Controller Relay Board 4 channel computer serial port temperature monitor and relay con- troller with four inputs for Dallas DS18S20 or DS18B2Q digital ther- mometer sensors (£3.95 each). Four 5A rated relay channels provide output control. Relays are independent of sensor channels, allowing flexibility to setup the linkage in any way you choose. Commands for reading temperature and relay control sent via the RS232 interface using simple text strings Control using a simple terminal / comms program (Windows HyperTerminal) or our free Windows application software. Kit Order Code: 3190KT - £69.95 PIC & ATMEL Programmers We have a wide range of low cost PIC and ATMEL Programmers, Complete range and documentation available from our web site. Programmer Accessories: 40-pin Wide ZIF socket (ZIF40W) £14.95 18Vdc Power supply (PSU120) £19.95 Leads: Serial (L0C441) £3.95 I USB (L0C644) £2.95 USB & Serial Port PIC Programmer USB/Seriaf connection Header cable for ICSP Free Windows XP software. Wide range of supported PlCs - see website for complete listing. ZIF Socket/USB lead not included Supply: 16-1 8Vdc. Kit Order Code: 3149EKT - £49.95 Assembled Order Code: AS3149E - £59,95 USB 'All-Flash 1 PIC Programmer USB PIC programmer for all ’Flash’ devices. No external power supply making it truly portable. Supplied with box and Windows Software. ZIF Socket and USB lead not included, Assembled Order Code: AS3128 - £49,95 See website for full range of PIC & ATMEL Programmers and development tools. asare/ectronics. com Secure Online Ordering Facilities * Full Product Listing, Descriptions & Photos * Kit Documentation & Software Downloads INFO & MARKET Energy from the internet, Water and SCs By Wisse Hettinga (Elektor Editorial) Let's make one thing clear: Elektor plays a minor and very modest role in the area of energy supply and sustainability. In fact, in our several decades of existence we have made a sizeable contribution to C0 2 emissions with our collection of test equipment and soldering irons* How can we make up for this? Just because we play a minor role doesn't mean that we don’t have an opinion on the subject of energy or sustainability. As always, if you Ye part of the problem you're also part of the solution. Here we present a small sampling of topics that we regard as ‘typical Elektor 1 , Bloom Box: fact or fiction? This development nearly escaped our notice. Fortunately* several prominent figures have devoted their attention to this company and engineered an enormous publicity campaign* Colin Powell (f/ie Colin Powell) is a member of the company’s Board of Directors, and the official launch of the power unit had a lot in common with an Apple product announcement. Even Arnold Schwarzenegger found time to attend the event and give it a bit of muscle. The people at Bloom Energy HI certainly know how to attract atten- to older techniques. The only advantages seem to be the decentralized structure and low conduction losses (accounting for a few percent). Basically the same applies to bio gas powering, but the efficiency of the SOFC (Bloom Box) could be a little higher than that of a conventional bio gas plant of equal size (larger biogas platforms are more efficient). I believe the solution employing much smaller block- type power stations is considerably smarter and more efficient because: - Better C0 2 balance by using the waste heat, with an overall efficiency 94% (which is obviously not the cose with Bloom box): - Smaller, decentralized units (flexible, safe supply, existing funding model); - Proven , durable and cost effective technology , Received and acknowledged: thanks Ernst! Bloomen tion, but their efforts have also drawn some critical comments* According to the company* the Bloom Box is a fuel cell developed on the basis of sand. 1 can almost hear whole populations thinking “well, there's certainly no shortage of sand rt , but this sand doesn't simply start generating energy by itself. The official designation is ‘solid oxide fuel cell v The sand is formed into tiles which are fired in an oven* a coating and an electrode are applied to each side, and there you have it: a compact fuel cell Elektor's German editor Ernst Krempelsauer is an expert on fuel cell technology, and he sent us the following comments: Note to Bloom box: in theory, the solid oxide fuel cell (SOFC) can achieve a system efficiency of 55-66%, which is in the range of the most up to date conventional power plants using gas turbines (60%), So when operating with natu- ral gas * there is no progress with regard to the C0 2 balance compared i6 The Pringles battery container You can find a very special type of energy source in virtually every house. Let's call it the ‘Pringles battery'. It's usually located in the pantry, and it slowly accumulates energy in the form of countless discarded batteries* Curious as ever, Elektor drew up a list of simple questions about this type of battery, such as: How many batter- ies are there in a typical Pringles can? How much do they weigh? Whafs the composition of the contents? How can we find out how much energy is contained in a typical Pringles battery? The results are: 25 A A cells, 1 4 AAA cells* two 9-V bat- teries, three heavy-duty 1 ,5-V cells, 14 button cells* and another 25 leaky batteries In all of the previously men- tioned shapes and sizes. 06-2010 elektor INFO&MARKE The proportion of leaky batteries reveals that what we have here is a Pringles battery that has been in service for at least one yean What is more surprising is that quite a bit of energy can still be obtained from the batteries that aren't leaking. Batteries are apparently ide- ally suited for use in 'second life' applications, such as energy-effi- cient LED lamps, clocks, small electronic circuits, and (ultimately) the Pringles battery itself. Instant electricity - just add water The Keshe saga continues \ 2 l During the past 30 years, this man has devoted himself to the realisation of his dream; generating energy from nothing. His name is Mehran Keshe, and he is on the verge of making his dream come true, Elektor has had regular contact with this remarkable person in recent years. Of course, it's easy to consign these developments to the realm of myth, but at the same time we have an obligation to report on these developments. We like to see things from the latter perspective. His first demonstration, three years ago, took place in a hotel on the Antwerp Ring Road. Inside a cofa bottle he reproduced what occurs constantly in the universe, and the result was a small voltage. Over the years since then he has further refined his technology, but the question remains: when is proof really proof? We asked him to prove that he could make a LED fight up, and in November 2009 he phoned to report that the LED was shining. He also said that the LED contin- ued to emit light for several weeks, even though we expected it to stop after a few minutes. Naturally, we wanted to see this for our- selves, and a few weeks ago we again invited Mr Keshe to present a demonstration, this time in our lab. Afterward we were not quite sure what to think. We saw what happened and we saw the result, but we were unable to explain it. With his cells connected in sim- ple series and parallel circuits, he managed to generate significant voltages and currents. What we saw, as always with demonstrations by Mr Keshe, was to a certain extent improvised, l-lis demo mode! was a compartmented plastic storage tray, such as we use to hold screws and components. There were two metal electrodes in the tray, like those we know from our electrolysis experiments, with the difference that one of these electrodes had been specially treated. He simply added tap water, and - wonder of wonders - this arrangement produced enough voltage and current to power a computer fan. This con- tinued for a bit less than two hours, after which the fan stopped turning, A deposit had formed around the wires in the plastic tray, and he said that this prevented the further generation of electric- ity, According to Keshe, this deposit consisted of CO^, and this was confirmed by reports he sent later. Instant electricity - just add water! This seems to be the gist of the story. We were already imagining a pocket torch that you could fill with water instead of inserting batteries, so you would have a torch that could in principle produce light indefinitely. A few weeks later we received an e-mail message with a photo: the flashlight actually worked! Tech the future What role does technofogy play in solving major issues related to energy and sustainability? The answer is that technology plays a double role: as a cause and as a solution. Everyone who has a basic understanding of Ohm's law knows that using electricity to move yourself around is the worst of all possible options and that our elec- tricity distribution network is simply not able to meet the increas- ing demand for electrical energy - but what can meet this demand? How can technology help us resolve these issues? r i m > I’Fir'i f C*'tl #si« ^EO T -' fail 1 rv riw* i ^ f ’ 1 Tft-i >4h*!3« th**. ~ ' I an ww * r* hdUfT. Hid >fW >JI r l«i J > W! (*■ « 1 Nn ** i In any case, information plays a key role here. Providing information on the latest developments, mentioning solutions, asking questions and thinking laterally: all of this is necessary, and this is a typical job for Elektor. To give this process a boost, we are also collaborating with the Techthefuture.com website. ( 100122 - 1 ) Internet Links [ 1 ] www.blQomenergy.com [2 j http://keshetechnologies.com elektor 06-2010 V AUTOMOTIVE- El. EC IRON ICS OBD2 Mini Simulator Virtual car supports PWM/ISO/KWP2000 By Folker Stange and Erwin Reuss (Germany) Designers working with the OBD vehicle diagnostic port have a problem when it comes to equipment testing. A full sized car parked next to your bench may technically be a good solution but in most cases just isn’t not possible. You don’t need to resort to expensive professional equipment to do the job. The MiniSim OBD simulator device described here is a low-cost and efficient unit which simulates communication from a vehicle’s OBD port and can communicate using four of the most popular OBD protocols. This is a very useful tool for anyone thinking about developing OBD hardware or software or even just for test purposes. The MiniSim simulates the signals that you OBD2 connector. This allows you to carry lab bench. Testing on a real vehicle can be a would normally expect to encounter when out testing and development of a new ana- little uncomfortable especially if you don’t you plug an OBD analyser into your vehicle’s lyser design from the comfort of your own have the option of working in a garage. Even 18 06-2010 elektor AUTOMOTIVE-ELECTRONICS OBD2 Standard QBQ604 ■ i s Figure 1 * The circuit consists of a microcontroller with firmware, MOSFETs and comparators to perform the necessary voltage level- shifting (5 V/1 2 V), The pots allow control of the simulated vehicle speed and engine rpm. then you wifi most likely need to test an GBD analyser on several different makes of cars to ensure compatibility with every protocol. The need for a convenient, bench top GBD2 simulator gave rise to the design of this unit. It can send out pre-programmed sensor values and indicate a MIL condition. It also supplies freeze frame data and a selecta- ble number of trouble (error) codes. This simulator supplies a Vehicle Identification Number (VIN) as 'AGV-MINhSIM VI .0* in the appropriate format. The simulator has been designed to make a useful and versatile tool whilst keeping the design simple and using minimum hard- ware. The QBD2 simulator supports four of the most popular GBD protocols. The CAN - bus protocol however would require a much greater hardware investment and has not been implemented. Specifications - Four predefined protocols; - KWP2000 Fast Init KWP2000 Slow Init (5 -Baud Init) - ISOgi4i-2 -PWMJ-1850 * Protocol selection using OIL switches * Four predefined error codes * Up to 15 configurable error codes Circuit and function The microcontroller used in the simula- tor circuit (Figure 1 } is the popular Atme) Mega 8 clocked at 6 MHz, a standard 10-pin header can be fitted to the board to allow * Sensor dat a for speed and rev count adjustable by potentiometer 4 MIL generation by pushbutton • 'Connect' and active l MIL“ Indicators * Freeze frames store sensor data when MIL is generated • Several assembly options dektor 06-2010 19 AUTOMOTIVE-ELECTRONICS Table i. Protocol selection using Si Protokoll Si-i Si-2 KWP2000 Fastlnit Off Off KWP2000 5- Baud tnlt On Off 1S09141-2 1 Off On PWMJ-1850 | On On in-circuit device programming. The periph- eral hardware takes care of the communica- tion interface signal levels and is controlled by the microcontroller appropriate to the protocol selected. The 1 0-pin SIL resistor network contains five independent resistors so it does not matter which way round it is fitted. A 78L05 voltage regulator is sufficient to handle the circuit's power requirements. The use of MOSFETs as signal drivers simplifies the circuit and gives clean, fast edges to the transmitted data. Received data from the OBD connector is ro uted to comparators (IC5.A a nd IC5.B) and converted to TTL levels to ensure compati- bility with the controller I/O. LED D1 ('con- nect’) indicates successful connection to an OBD analyser (or scanning tool). LED D2 is the MIL (Malfunction Indicator Lamp) which indicates that a fault has been detected. With a press of pushbutton TA2 'DTC the settings of the 'VELO' and *RPM h potentiom- eters are stored In a freeze-frame data file in just the same way that a snapshot of sensor readings would be stored in an engine's ECU whenever a fault is detected. Each trouble code therefore has its own 'environment' COMPONENT UST Resistors RKR2 - Ikil R3 = 2,2 kO R4 = I.SkO RN 1 , RN2 = 5-way 51 L 1 Okll resistor array, 1 0- pirt (SIL 1 0-5, see text) PI ,P2 = 1 QQkQ trimpot with spindle, vertical mounting or P5,P6 = 1 0OkH trimpot with spindle, horizon- tal mounting (see text) Capacitors C5.C6 = 22pF C2.X4.C7 " lOGnF Cl - 47pF 25V Semiconductors TT -B5250 T2.T3 ** BS170 id =78105 IC3 = ATMegaS-l 6 PU, programmed ' ) fC5 LM393 D1 ,D2 “ LED, 3 mm D3 “ 1N4004 Miscellaneous Q1 = 6MHz quartz crystal BUI = low voltage DC adapter sockeL. PCB mount TA1 ,TA2 = miniature pushbutton, 1 pole, PCB mount BU2 « OBD socket PCB * # 080804-1 (contained in kit) Kit of parts with PCB and all components, or- der code 080804-71 (see Elektor Shop sec- tion, or www.elektor.com/080804. Project software and PCB design: free download from www.efektor.corn/080804 Figure 2. The PCB does not use any 5MD devices. The smaller user-interface section can be separated from the main part of the PCB and linked via a ribbon cable. of sensor read i ngs which wou Id normally be used by a technician to give additional infor- mation about the conditions which existed when the fault occurred. VELO or velocity is the vehicle speed in km/h or mph. The type of protocol used is selected via the two -pole Dl P- Switch 5 1 (see Ta bl e 1 ) . After power-up the controller reads the posi- tion of switch SI . To change protocols after power-up, select the required protocol on SI and then perform a reset. The reason- ing behind this is that a real vehicle does not normally have the option to change its OBD2 protocol. From the analyse! ’s point of view a change of protocol will always be preceded by loss of power as the scan tool is unplugged from one vehicle and plugged in to another. The simulator requires a sup- ply from a mains adapter in the range of 1 2 to 15 V. This voltage is linked to pin 1 6 of the OBD2 connector, A diagnostic scan tool connected here will usually draw its supply from this pin. Be aware that the protection diode D3 introduces a 0.6 V voltage drop between the mains adapter supply and the voltage at pin 16. This can be reduced by substituting a Schottky diode for D3. Construction With no SMD devices in sight the board (Figure 2) is relatively easy to populate. Start with the smallest components: resis- tors, protection diodes and then both ICs. Sockets can be used for the ICs but are not strictly necessary. Next fit the decou- pling capacitors and the loading capaci- tors around the crystal and then the crystal itself followed by the resistor network. Next is the transistors, voltage regulator and if required, the programming connector pin header. The PCB layout can accommodate either vertical standing or horizontal lying pots. The upright positions are identified as PI and P2 whilst the horizontal positions are identified as P5 and P6. The DIP switch 51 is available in two variants: switchable from the side or from above. The OBD connector can be fitted horizon- tally or vertically but first it must be manu- ally assembled. Fit contacts in positions 2, 4, 5, 7, 10 and 16 then secure them with the blue plastic packing strips pushed up 20 06-2010 elektor AUTOMOTIVE-ELECTRONICS from the solder-end of the connector. These help prevent the contacts from being forced beck as the connector is used, More details together with some illustrations of the connector assembly can be found on the project site Ml, Once the connector is assembled mount it to the PCS with screws before carefully soldering the connections to the PCB pads. Figure 3 shows a sample PCB fitted with a horizontally mounted OBD connector, side-action DIP switch and pre- sets fitted with actuating spindles. To Increase the versatility of the device the PCB Is designed so that it can be sep- arated into two (with the help of a fine- toothed saw). The two PCB parts can now be linked using a length of 10- way flatca- ble (10 to 20 cm long) between positions SV1 and SV3, This gives you the option to mount the OBD port connector away from the user-interface section of the PCB, Fig- ure 4 shows one example of how this can be done. It can also be easily fitted into an enclosure or integrated into some form of presentation panel. Power to the circuit! Once you are sure all the components have been fitted correctly the simulator board can be powered-up. Use a standard 12 V mains adapter, connect the OBD analyser unit and check that the supply rails voltage lies in the region of 12 to 14 V, The microcontroller is supplied pre-pro- grammed so that one of four protocols can be selected by the switch setting of SI (see Table 1), With both switches of SI in the ‘off position the KWP2G00fast protocol will be selected. At power-up both LEDs light briefly. An OBD2 analyser device can now be connected to the unit. For OBD analys- ers with a PC connection (such as the Ana- lyser-IMG with Bluetooth) now Is the time to start any diagnostic software on the PC, MoDiag PI is a good example of this type of program. With everything functioning cor- rectly so far use the Connect via KWP20O0 command and receive data. Select the page showing sensor data and observe the received values. The two potentiometers allow control of vehicle velocity (VELO) and engine speed (RPM). The moDiag program Whv so many protocols? The OBD2 interface has undergone continued refinement and development since its in- troduction In The United States in 1 996, The first protocol used VPWM with a communi- cation transfer rate of 1 0.400 Baud and 8 V signal levels. In 1997 Ford introduced a PWM protocol in petrol -engine vehicles. This uses a faster communication rate of 41*600 baud and requires a relatively higher performance hardware interface. Because of the faster data rate some manufacturers of OBD diagnostic equipment have tended to overlook support for it in their diagnostic tools. Communication set up with this standard is also a bit tricky and data transfer prone to interference. It was not Jong before manufacturers started to replace it by the CAN bus protocol (particularly Fold). In 2000 the ISQ9141 -2 protocol was introduced Europe wide. It is closely related to the KWP2000 Slow Protocol {Key -Word-Pro- tocol), It has a data format very similar to RS-232 standard with a data rate of 1 0,400 Baud and a signal level corresponding to the vehicle battery voltage of 1 2 V, Even today vehicles such as the Toyota Ayga Citroen Cl and Peugeot 107 which share a common mechanical platform use this ISQ914 1 -2 Protocol, The more recent CAN bus is a ver sat lie protocol de- signed to provide fast, secure communications and command pathways between subsys- tems throughout a vehicle. Its versatility means that an interface is more sophisticated and therefore more expensive than most of the other protocols. Figure 3. A completed sample PCB with a horizontally mounted OBD connector and side-activated DIP switches. Figure 4. Sample board showing a vertically mounted OBD connector and separated user-interface section. elektor 06-2010 21 AUTO MOTIVE- ELECTRON ICS Overview of the programmed PIDs 020Cxx Engine Speed (RPM) (aktudler Model: 01 00 PIDs supported 01 .,20 010 3 DTC Count, MIL lamp, monitor s up port/s tat us 0101 Fuel system status 0104 Calculated Load Value 0105 Engine Coolant Temp. 010A Fuel Pressure 0108 Intake MAP 01 0C Engine Speed (RPM) (POTI) 01 CD Vehicle Speed (VELO) (POTI) 01 OF Intake Air Temp, 01 10 Mass airflow (MAP) 01 1 1 Absolute Throttle position sensor 0113 Location of Oxygen Sensors 01 14 Bank #1 - Q2 sensor#! 01 1C OBD requirements level Mode 2 - Freeze Frames: 020Gxx PIDs supported 01 . 20 O202xx PTC that caused freeze frame 0204xx Calculated Load Value 0205xx Engine Coolant Temp. can use this data to produce a simulated acceleration measurement. One fea ture of the Min 1 Sim Is that it can on iy initiate a MIL after a Connect. Once Connect POTI -Wert) (J20Dxx Vehicle Speed (VELQ) (aktueller PCm-Wert) xx * Frame Mummer (wird jedoch ignoriert, a lie Frames identisch) Die Freeze Frames werden nur fur den ersten Fehlercode gespeichert. Mode 3 - DTC: 03 Read Error codes Mode 4 - Clear DTC: 04 Gear Errorcodes Mode 9’ VIN: 0900 PIDs supported 01 ..20 0901 Frame count for PI D 02 0902 VIN TAGV-MINI-SIM V 1 ,0" is successful the MIL button can be pressed which lights the LED and stores the current values of VELO and RPM into the freeze- frame store where they can be later read. The stored trouble codes can also be erased providing the analyser device is capable of this action. The MIL LED will then turn off. Requesting VID in Mode 9 will cause the MlniSim to send the VIN which in this case will always be: ACV-MINI-S1M VI .0. Software and configuration The Firmware is written in Assembler and the resultant Hexcode file is available for free download Ml. Included in the download is the configuration file MiniSimConflg, The pre-programmed MiniSim controller can implement four protocols (see table) and four trouble codes. In addition it is pos- sible to configure an additional 1 1 trouble codes by means of the OBD2 interface ML To make use of them it is necessary for the ana- lyser device to be using either the AGV or DXM chipset, the configuration commands are integrated into the chips. A very simple tool to use here is the Analyser-NG Ml with Bluetooth interface Ml. Now start the config- uration program MiniSimConfig, The Ana- lyser-NG must first be connected via Blue- tooth to the notebook and also plugged in to the OBD port of the MiniSim. The Bluetooth COM port can be setup in the Config program, even though it has most probably already been configured during correct installation of the device. After suc- cessfully connecting a total of 1 5 trouble codes can now Individually be selected, set up and activated. The EXIT button stores the current configuration into the control- ler's non-volatile EEPROM, Lastly, note that the positions of SI are only read at switch- on, any change of SI will not be recognised until the unit undergoes a reset. (080804) [ 1 1 vvww . el e k to r. c o m / 0808 04 |2] www.modiag.de [3] www.obd-diag.com 1 4 j www. e I e k to r. co m / 090451 1 5 1 www. e I e k tor. co m / 0 909 1 8 moPMj T. C£E ■ £ m &> ErtujlUr 1# liApgliifi Hi v.*-™ mr-riM 05 □wb- Q] r — — 1 E tip* L#rcn t pJ:!*-. > 30 EOKiEirtpd • ■ Lrwt'Fw. dl Figure 5. The moDiag program running on a PC is useful to display the simulated values. 22 06-2010 elektor M INBm XGioirUVv' gGS AVft S-Bit Main- PCB Board, hi' XGS Gamepad Controller. / t325 + Page Printed Manual: —jfkAtmel AVR ISP MKI 1 Programmer * Power Supply & A/V Cable, ^ PC Serial Port to XGS Converter PHPC DVD-ROM. ( 1 GB Micro SP Card + Adapter/ . Bonus: eBooks on Hardware, ' Game Co ns o I e pes i g n , an d More ! The MOST CD WPLET! ATm(i MEGA AVH D f, v K»t AVAJLftBi.f WWW. elektor. com Schaeffer FRONT PANELS & HOUSINGS Cost-effective single units and small production runs Customized front panels can be designed effortlessly with the Front Panel Designer. The Front Panel Designer is available free on the Internet or on CD. New Version 4.0 with new features, for example free contours for Linux, Windows and Mac OS X ► automatic price calculation - delivery in 5-8 days - 24 -Hour-Service if required r — ^ ■ r r rrrr Sample price; 34.93t plus VAT ' shipping Schaeffer AG ■ Nahmitzef Damm 32 ■ D-122 7- Benin ■ Tel +4g (0)30 8 05 86 95 -C Fax +49 (0 ! 30 3053695-33 ■ Web infa^sehaeffer-ag.de - '.v w w. sdiEieffer-ag , cfe Get off the grid with a do-it-yourself system that can produce up to a maximum of 30 watts of dean, green electrical energy! Once assembled you will have a panel that produces a substantial amount (6 volts) of electrical power. The energy produced per square foot is comparable to commercially available solar panels. Daisy-chain multiple units together for higher voltage/current/power output! Dimensions - 77 ° " 1 5.8 x 0.375 in {60.45 x 40, 1 2 x 0.95 cmj. videos show you how to property handle and solder the delicate cells and their wiring interconnections* — P/FMl+A www.paraltax.com . "Pa roltoxlnc " on Twitter, Facet ook, and You Tube nsiuDe Milford Instruments www.mitinst.com Spinvent www. sp in ve n t co. uk elektor 06-2010 33 Do-it-yourself wireless RFID sensor systems By Martin Ossmann (Germany) In this article we describe a do-it-yourself RFID reader as well as a way of making your own RFID tags. What’s more, we show how to make RFID tags that include a transducer, opening up the possibility of making RFID sensors. The tiny sensor module operates without an internal power source and delivers its readings to the RFID reader for further processing. RFID tags based on the EM4102 chip are cheap, even in small quantities, and readily available. In a recent issue of Eiektor we pub- lished a design fora reader for these tags! H. In this project we use a small printed circuit board with the EM4095 reader 1C mounted on it, which allows us to transfer the data from the RFID tag to an ATM 18 test board. The reader board is available with the SMD components already mounted. It can also be used to make an RFID reader using an ATtiny2313. Suitable freely-usa- ble routines for reading the data from the EM41 02 are included in the software down- load that accompanies this article. The more interesting part of this project; however. Is where we show you how to build your own RFID tags, adapted to whatever application you have in mind. We then go on to look at how to build sensors into these tags, and communicate sensor data to the reader device. These sensors are electrically iso- lated and can move freely in space. Energy transfer The EM41022 RFID tag 1C receives energy from the reader by inductive coupling at a frequency of 125 kHz. The author's thought was that if this device can do it, there is no reason why we should not make our own RFID tags. Furthermore, the data rate offered by the EM41 02 is not very high, and In particular should be well within the capa- bilities of a simple microcontroller. The circuit shown in Figure 1 was used to determine how much energy is available from the receiver coib The RFID reader was fitted with the recommended coil (L-750 pH, 85 turns of 0,25 mm diameter / AWG #30 enamelled copper wire, coil 24 06-2010 eiektor INSTRUMENTATION diameter 50 mm). For the receiver coil (LI ) we used a 95-turn coil with an inductance of 1 mH ( tuned for resonance at 1 25 kHz with Cl. Transmit and receive coifs were mounted one above the other, parallel to one anotherand 20 mm apart. Current and voltage were measured as the resistance R was adjusted. The left-hand graph in Fig- ure 2 shows the measured voltage as a func- tion of current, while the graph on the right shows the transmitted power. Curves are shown for the cases where the tuning capac- Itorvalueis 200 pF too great and 200 pFtoo small, to illustrate the effect of below-opti- mal tuning. From the graphs it appears that at a voltage of 3 V it is possible to transfer a couple of tens of milliwatts of power. An ATtlny microcontroller draws about 2 mA at an operating voltage of 3 V and a dock frequency of 1 MHz; at 1 25 kHz the current drawn is less than 0.1 niA, So it seems that there will be no difficulty finding enough power to operate the microcontroller. The E1V14I02 RFID 1C communicates its ID by modulating the load on the reader. Each bit transferred takes 64 cycles of the 1 25 kHz carrier, giving a gross data rate of 1953,125 bits per second. A complete packet can be transferred in 32.768 ms. It is possible to use the 1 25 kHz signal as a clock for the RFID controller. This automat- ically ensures that the bit dock is synchro- nous with that in the reader, and current consumption at this clock rate is, as we saw above, very low. However, it also means that the CPU will have only 64 dock cycles to cal- culate the next bit to be transmitted: for this reason we program the CPU (the ATtiny 1 3) in assembler, RFID? DIY Fig ure 3 shows the complete circuit dia- gram of our DIY RFID tag. The microcon- troller is provided with a dock from the res- onant circuit formed by LI and Cl. Simul- taneously, the diode bridge rectifies the 1 25 kHz AC signal and supplies the CPU with power. T1 allows the resonant circuit to be loaded, and it is through modulating this load that the microcontroller can transmit data. However, the signal level must not be dvced excessively, or else the clock to the _ - _ " os t ■ Features RFID reader: * standard microcontroller (ATtiny23i3) * works with EM41 02 -compatible RFID tags * output over RS232 interface DIY and sensor RFID tags: *. standard microcontroller (AT tiny 13) * EM4102 compatible * analogue and digital inputs lor sensors - status and readings transmitted via RFID ID ■ separate adaptor board fur programming and debugging We have developed a printed circuit board for the circuit in the Elektor labs (Figure 4), The coil is wired in parallel with Cl, and so connection points are provided adjacent to it. A suitable reader is available in the form Open source software collection; ♦ REID reader firmware * DIY RFID tag firmware for: - standard RFIO tag (fixed ID) - RFID tag with alternating ID - RflD tag with swftchable ID - RFID tag with configurable ID - RFID tag with Lwc analogue inputs - RFID tag with temperature sensor Availability: Kit available from Elektor Shop including read- er module, printed circuit boards and ready- programmed microcontroller: see par ts lists. of the SMD board mentioned above MI using the EM4095, although that project did not use the BASCOM library used in the ATM 18 system to drive the 1C, As in one of the author’s previous projects PI, special EM4095 Board Figure 1 . Circuit to measure the power transferred to receiver coil by the RFID reader. Figure 2. Results of the energy transfer tests; voltages, currents and power. n 2 5 INSTRUMENTATION Figure 3. Circuit of the DIY RFID tag using an ATtiny 13, Fisting 1, Manchester decoding if ( PIND t 4 ) { inBit=l ; } if ( inBit==QldBit } { Duration +-1 ; } else { if (Durations 12 ) { PutlnFifo (OldBit) ; } if (Duration>=4 ) { PutlnFifo (OldBit ) ; } Durational ; 01dBit“inBit ; } software was written for the reader in C (using WinAVR/CCC), The circuit of the reader in Figure 5 is very simple and can easily be built using perfo- rated prototyping board. But to make things even easier, Elektor labs have designed a printed circuit board (Figure 6). The EM4095 board Is connected at K3 (Figure 7). The coil connected to ANTI and ANT2 on this board should have an inductance of 750 pH, This is not critical, however, as the EM4Q95 reg- ulates the frequency using an internal PLL: otherwise the frequency would not match optimally with the RFID transponder, whose frequency is fixed at 1 25 kHz. Resistors R1 =lkil R2 * 4 . 7 k£ > R3 = 33GQ Capacitors Cl - 1 ,7nF (see text) C2 = I OuF 25V C3 = 1 0Opi F 25 V Inductor LI = ImH (see text) The data bits from the RFID tag are demod- ulated by the EM4Q95 HI and passed on to the microcontroller in the form of a Man- chester-coded stream. The first job of the microcontroller is to extract the bits. This is done in an interrupt service routine which is triggered 8 MHz/ 2 56 = 31250 times per second. A data bit is thus exactly 1 6 inter- rupt periods long (see Figure 8), The code snippet shown in Listing 1 decodes the Manchester-coded stream. The code measures for how long the logic level on port pin D.4 remains steady: the varia- ble Duration is incremented as long as inBit is equal to OldBit. When the level changes, Figure 4. Printed circuit board for building the RFID tag. one or two new half-bits have been received with value equal to OldBit, Depending on the measured duration, either one or two half-bits are stored in a FIFO queue for later processing using PutlnFifo(OldBit), The decoding routine itself takes half- bits from the FIFO queue. The first task is to recognise the start of a data packet: to do this the software moves the half-bits along a shift register until the synchroni- sation sequence is found. Subsequent data bits are then decoded and output over the R5232 port (19200 baud, SN1 format). While these are being output new half-bits may arrive and wait in the FIFO queue until the main program is able to process them: this ensures no bits are lost. The RFID reader can be used to read any standard RFID tags compatible with the EM41 02 HI. Coifs For both the RFID readers and for the tags it is simplest to wind the coils yourself as suitable ready-made coils are practically unobtainable at least in very small quanti- ties, The job can be done without an induct- ance meter. Application note AN41 1 by EM Microelectronic, called ‘RFID made easy 1 15], gives a helpful formula for calculating the inductance of an air-cored coil of this type: COMPONENT LIST: diy rfid Semiconductors D1-D4= BAT43 IC1 = ATTinyl 3-2QPU, programmed, Elekto* # 100051-41 1 Miscellaneous K 1 = 6-way right-angled pinheader PCB# 100051-1 * 26 06-2010 elektor INSTRUMENTATION RSI A. +5V O C_> 5J > IC1 PA2,'RESET PDO (RxD) PD1 (TxD) PD2 (INTO) PD3(IMT1| pQ 4 (Tt»ATtiry2^13 POSjTIJ PD6 (ICP) |SCK) PB7 {MISOJ P06 (M05I) P05 PB4 (OCI) PBJ PB2 19 SCK , 18 MESO j 17 MOSI (AIN1 J FBI — (AINOJPBC — £ 2 < K Q Z to l/l XI H H SMhz T GMD Cl I 00 n MESO 1 SCK 3 RST 5 16 J5 14 13 D2 1N4Q07 K5 J a3 -O' 2 C2 K 1 o a o o O Oi +5V J 4 M05I GND GNO mu 25 V GND 100051 - 13 Figure 5- Circuit diagram of the RFID reader using an ATtiny2313. The EM4095 board is connected atl<3. RFID Reader Miscellaneous K 1 = 6-pin (2x3) pinheader K2 “ 9-way sub-D socket, right-angled pins, PCB mount K3 - 5-way SIL socket K4= 5-way SIL socket, right-angled pins K5 =■ DC adapter socket, PCB mount, for plug diam. 2.1 mm where d is the diameter of the wire, D the diameter of the coil and N the number of turns. The author has made a number of experi- mental coils and measured their induct- ance. Table 1 shows the resuits, and indi- cates that the values obtained using the formula typically differ from the measured values by up to around ten per cent, which in practice is dose enough. The induct- ance values in the table can also be used as a starting point for your own designs. RFID software The home-made RFID transponder is now programmed so that it behaves just tike a normal RFID tag. The dock rate is 1 25 kHz and a half-bit lasts 32 clock cycles, and it is therefore out of the question to carry out complex calculations between bits. How- ever, we do have the opportunity to use the PWM facility of TimerO. We configure the timer always to count to 64 (by setting OCROA to 64-1 = 63) and set the PWM value to 50 per cent (by set- ting OCROB to 32). The PWM generator for TimerO can be arranged to generate either a low-to-high transition when the counter reaches 32 or a high -to -low tran- sition: see Figure 8 where the timer value is shown below and the Manchester-coded data stream above. We can therefore gen- erate either a zero bit or a one bit in accord- ance with the Manchester code, simply by COMPONENT LIST (PCB ft 100051-3) Resistors R1.R2.R3- Ikil R4-2.2kn Capacitors C1.C3 = lOOnF C2 ° 100pF 25V C4 = lOpF 25 V Semiconductors D1 = LED, 3mm, red D2 = 1M4G07 IC1 = ATTlny23 1 3-20 PU, programmed, Ele- ktor# 10005 1-42 IC2 = 78L05 XI = 8MHz ceramic resonator T1 = BS170 Inductor 11=1 mH (see text) RFID module #080910-91 (SMD stuffed EM4095 board) PCB ft 100051-3* Kit of parts, order code 100051-71. Con- tains RFID module # 0809 10-91, PCBs # 1 0005 14,-2 und -3 and programmed microcontrollers # 100051-41 and -42, see Elektor Shop section or www.elektor. com/ 100051 ) Project software and board layout PDF files: free downloads from www.elektor, com/100051 Figure 6 . The printed circuit board designed for the reader. elektor 06-2010 27 INSTRUMENTATION Figure ?. Lab prototype of the reader. The receiver coil is connected to the EM4095 board. Figure 8* Manchester coding. changing a bit in the PWM generator regis- ters* This all happens in an interrupt service routine (Listing 2). Register IntBit contains the data bit that is to be transmitted, and IntMail is set to 1 to acknowledge that the bit has been accepted. The main program is then only responsible for marshalling the data bits along with their accompanying check bits. To ensure that the system works as reliably as possible with an unstable supply voltage. the brown out detection threshold is set to 1 .8 V and the watchdog is enabled. Data packet and payload A complete data packet is formed as shown in Table 2. The packet commences with nine ones. This preamble cannot occur elsewhere in the packet and can therefore be used to recog- nise its start. The data bits proper, or 'pay- load', starts after the preamble. The payload consists often groups of four bits, or nibbles* The first two nibbles form the customer ID. Eight data nibbles follow. After each nib- ble a 'row' parity bit for that nibble is sent. After ten such nibbles a row of 'column' parity bits is sent, followed by a zero. So In total a packet consists of 9 + 10 r (4+1)+4+1 = 64 bits. Each bit lasts for 64 of the 125 kHz clock cycles, and so the bit rate is 1 935.1 25 bits per second and a complete packet takes 32.768 ms to transmit. To use this protocol for an RFID sensor we have eight data nibbles and two ID nibbles at our disposal, making a total of ten hex- adecimal digits or 40 bits. This is enough to transmit a good deal of Information, although if you wish to extend the proto- col this project gives you everything you need. RFID tag construction and extensions Figure 9 shows a prototype of the DIY RFID tag using the printed circuit board in Fig- ure 4 (which corresponds to the circuit dia- g ram of Fig ure 3)* To make it easier to a dj ust the resonant circuit the capacitor and coil can be attached via a plug and socket. It is then possible to experiment with vari- ous coils: experience shows that in prac- tice the best range is achieved when using a capacitor value about ten percent higher in value than theoretical calculations would indicate. Since the RFID software has been written specially for this project and is available as Figure 9* Populated DIY RFID tag board. Sensors can be connected to the header. 28 06-2010 elektor INSTRUMENTATION 8x 1 M rrrm © lllllll I I Cl 100n 11 12 13 16 © DO PL D1 IC1 CP D2 07 03 07 CM o 5 ™C165 DG DS n? pc 10 15 K1 O O Q O VCC PB 2 PBO PB4 GND 100051 -17 Figure 1 L Connecting a DS1 820 temperature sensor to K1 on the DIY RFID tag board. Figure 1 0. This expansion circuit allows the connection of up to eight switches to the RFID tag. a source code download at |G), it is of course possible to modify the programs to equip your DIY RFID tags with novel functions. Header K1 on the printed circuit board can be used to connect switches, potentiome- ters and other sensors, which can then be interrogated wirelessly by the reader. This opens up the possibility of taking sensor readings from rotating or otherwise moving parts, as well as providing galvanic isolation in high-voltage environments. Sensors can be suspended in fluids, with their readings safely brought back to dry land. Range tests indicate that when using a coil with a diameter of 50 mm a gap between reader and tag of 60 mm can easily be bridged. Below we give a few examples of the kind of novel applications that can be realised using RFID sensor tags. These examples are supported by code in the software collection (downloadable at l 5 !}, where the README text gives an overview of the individual programs and correspond- ing required settings. Dynamic ID and status requests For our first example we consider an RFID tag programmed so as to switch between two ID codes. This idea can be used as a starting point to make RFID keys that can open more than one lock. changed at the press of a button. The corre- sponding program is included in the down- load accompanying this article. The switch is connected between port pin B.4 (pin 3 of the ATtinyl 3) and ground. Sometimes a large number of digital inputs will need to be sampled. Since we are using a microcontroller in our tag, there is a wide range of options available to achieve this. We must always keep current consumption in mind since all our energy is ultimately option is to use a shift register to perform parallebto-serial conversion. Figure 10 shows a circuit that can be connected to K 1 on the RFID board. RFID with two ADCs The ATtinyl 3 has two analogue-to-dig- ital converters, which makes it possible to build RFID tags that can measure a voltage wirelessly. The software package Includes a version of the code that performs conver- sions on two analogue inputs and returns derived from the transmit coil, A simple +5V +5V The first version uses a switch to select between the two codes. This gives two pos- sibilities; remotely determining the position Figure 12 . Circuit of adaptorfor programming and debugging the ATtinyl 3 of a switch, or maki ng a tag whose ID can be microcontroller* elektor 06-2010 29 INSTRUMENTATION COMPONENT LIST: Programmer / Debug Adapter Capacitors Cl = 1 OOnF Semiconductors [Cl = ATTinyl 3-20PU (for programming / debugging) Miscellaneous K1 = 6-pin (2x3) pinheader K2 = 5-pin right-angled pinheader K3 = 6-pin right-angled pinheader PCB# 1Q005D2 Internet links [1] ATM 18 = RFID Savvy, Elektorjune 2009 www. e le k to r, com / 08 09 1 0 [2| Experimental RFID Reader, Elektor September 2006 www. e I e k to r T co m / 0 60 2 2 1 [3] FM4095 RFID reader 1C www.em microelectronic .com/ webfi I es/product/rfid/ an /an404,pdf [4j FM4 102 datasheet www.emmicroelectronic.com/ webfiles/product/ifid/ds/eni4 1 02_ ds.pdf Figure 1 3. Component mounting plan for the adaptor board. [5] 'RFID made easy' www.emmicroelec trank .com / webfiles/product/rfid/an/an41 1 ..pdf [6] Etektor project page for this article www.elektor.com/ 1 0005 1 [7] RFID principles of operation www.em microelectronic .co m/ web- files/ product /rfid/an/ wireless.pdf the values via the ID code to the reader. The reference voltage used is the supply volt- age to the ATtinyl 3, which has both advan- tages and disadvantages: for example, if it is desired to read the position of two poten- tiometers, these can simply he connected across the supply to the ATtinyl 3 with the wiper taken to the analogue input. The result is that the conversion result is inde- pendent of supply voltage as the meas- ured voltage rises and falls proportionally with the supply: a so-called ‘ratiometric* conversion. Two accelerations can be measured using a type MMA7260 sensor, which provides ratiometric voltage outputs. In other cases a Zener diode or small 3.3 V regulator should be used to provide a supply to both micro- controller and sensor. When measuring absolute voltages there is always the problem that the supply to our RFID tag, and hence the reference voltage, depend on the distance to the reader. One option is to use a low-power reference such as the LM385 to provide a known voltage (such as 2.5 V) to one ADC channel, and use this to measure the supply voltage. The sec- ond channel can then be calibrated and a precise measurement can then be made, RFID temperature sensor Our final example illustrates the connec- tion of a Dallas/Maxim D51S20 tempera- ture sensor using its one-wire interface. This interface is easy to implement in software, although it is rather slow. The microcontrol- ler in the RFID tag must stop responding to the reader while it is talking to the DS1 820 temperature sensor. This is not a problem for the reader, which is simply forced to wait a little longer for the packet preamble. After the communication with the sensor 1C is complete the tempera- ture value is converted to a decimal value, which is then formatted into the ID code. Hence the RFID sensor provides the temper- ature value almost as ‘plain text'. Figure 1 1 shows how the DS1 820 is connected to the RFID board. In principle the software can be adapted to handle several temperature sen- sors or other one-wire ICs. 4 A * 4 * j Figure 14. The adaptor board can be connected directly to the reader board using its header for testing purposes. 30 06-2010 elektor INSTRUMENTATION RFID sensor debugging The examples we have discussed above show how Et is possible to build an RFID tag yourself. When developing your own appli- cations testing and debugging must always be kept In mind. The simplest approach is to use the ISP interface. However, this has the disadvantage that the microcontrol- ler in the tag will not have enough energy available from the coil to allow program- ming, and for this reason the adaptor dr- Table i. Inductance of circular air-cored coils D/mm d/mm H L/llH (calculated) L/uH (measured) 50 0.25 100 | 1050 1000 50 1 0,25 75 608 577 50 0.25 40 1 84 170 15 [ 0.12 150 1143 1000 25 [ 0,12 100 529 470 25 .0.12 [ 80 346 310 JS 1 0 L12 L 75 306 273 23 J 0.12 80 313 275 20 1 0,12 too 405 360 30 [ Q.12 50 175 P 160 100 0,25 65 1047 1130 D = coil diameter d - wire diameter N = number of turns Listing 2, Interr upt service routine for encoding using PWM , org 3 ; TIMOOV; sbi PORTE, 0 ; in SREGsave , SREG ; cbi PORTS, 0 and! IntBit,! ; brne DOone ; DOzero : out TCCROA, PWMmodel ,- ldi IntMail , 1 ; out SREG, SREGsave ; reti DOone : out TCCRQA, PWMmodeO ; ldi IntMail, 1 ; out SREG, SREGsave ; reti timer 0 overflow jumps here f lag start of interrupt, routine save status end of test pulse test that bit and go to DOzero or DOone clear OCQB on compare match, set QCOB at TOP flag as fetched restore status set QCOB on compare match, dlear OCOB at TOP flag as fetched restore status cuit shown in Figure 12 was developed. The ATtinyl 3, which contains the RFID and sensor software, can be programmed over its ISP interface (l<1 on the adaptor board in Figure 1 3 ), and the same sensors can be connected to K3 on this board as to K1 on the RFID board. Header socket K2 on the adaptor is connected to K4 on the reader board, and the reader then supplies the ATttnyl 3 with its 125 kHz clock and proc- esses the data stream output by it on port pin B.1, This arrangement makes it easy to test new RFID sensor software. (100051) Table 2. Data format used by EM4102 RFID tag 1 C preamble 11111 1 1 1 1 customer id 0 0 0 0 0 1 1 1 1 0 dataO 0 0 0 1 1 data! 0 0 1 0 0 data2 0 0 1 1 0 data3 [ 0 1 0 0 1 data4 0 1 0 1 0 data 5 j 1 0 1 1 0 0 da ta6 0 1 1 t 1 data7 1 0 0 0 1 columnparity 0 1 1 0 0 elektor 06-2010 3 ^ MICROCONTROLLERS High Speed Flash Trigger By Burk hard Kalnlta and Wolfgang Rudolph (Germany) Photography and electronics make good companions. If you want to photograph fast events with high time resolution, you can’t manage without a sophisticated flash controller. Photos of moving objects, such a droplet falling into water, are especially popular. Photos of falling water drops require precise control of the time when the photo is taken. If you want to control a flash unit, you first need a suitable event and then a time delay. Experiments with interrupting a light beam proved that this approach Is difficult, which ted us to the idea of using an acoustic signal to trigger the flash. A piezoelectric transducer can be used as the microphone, either immersed in the water (in a watertight package) or attached to the bottom of a flexible container. The control tasks are handled by the ATM 18 board, equipped with an ATmegaSS microcon- troller and Basccm control software. You have the choice of triggering a single flash or a series of three flashes. A simple strobo- scope mode, which generates a continuous +5V +5V F igure 1 . Flash trigger circuit with a piezoelectric transducer for sensing sound waves or vibrations. Figure 2 . An LDR can also be connected to act as a supplementary light sensor. 3 2 06-2010 elektor MICROCONTROLLERS series of flashes with adjustable flash rate, also allows the circuit to be used for other applications. These light effects can be put to good use not only for photography, but also for entirely different purposes such as scientific or engineering experiments and light shows. Mini circuit As you can see from Figure T, port CO (PCO pin) of the ATM 1 8 provides the control sig- nal for an LED and a thyristor* For your initial experiments, you can use a 1-watt power LED (such as a Luxeon Lumiled) as a flash source. The necessary energy comes from a 1 000-pF electrolytic capacitor charged via R5. The transistor (a BC337) has a high pulse current rating (800 mA maximum) and can easily drive the LED. With a value of 1 00 Q for R1 , it takes approximately 1 00 ms to fully charge the capacitor* A faster flash rate can also be used, at the cost of reduced bright- ness. An LED Hash has the advantage that a separate power supply is not necessary, and in particular that a it does not require a high voltage. * Photo flash control using acoustic or light signals ‘ Controls a flash LED and/or conventional flash unit (using either a thyristor ora tr lac) * Adjustable trigger delay {too ms max.) * Selectable single-flash and triple-flash modes * St ro b oscop e m o cl e - Circuit and firmware suitable for use with ATMtS and MinimodiS ■ Bascom software with source code (open source for DIV modifications) Figure 3. The expansion circuitry built on a piece of prototyping board. delay or flash rate (in flash mode or strobo- scope mode, respectively), and the piezo- electric acoustic transducer is connected to the AD7 input* The circuit is also suita- ble for connection to the Minimod 18 (see Table 2)* In addition to the LED stage, the PCO signal Is connected to the gate of a thyristor via R4 so that it can be used to trigger a ‘real* flash unit. This also works with older-model flash units that operate with a high trigger voltage. Modern units operate with a lower trigger voltage, although the specifications vary considerably from one unit to the next* Before connecting a flash unit to the circuit, you should examine its specifications care- fully* The thyristor used here must have a sufficiently high working voltage and a low trigger current (less than 1 0 mA). The read- ily available TfC1Q6D, for example, has a 400 V blocking voltage and requires a trig- ger current of only 0.2 mA* If you use a triac, you can also switch a negative voltage on the trigger input of the flash unit. In our pro- totype circuit we used a 2N6073 triac (400 V rating), which can also be triggered with a 470-Q gate resistor because It requires a trigger current of only 5 mA. In addition to the circuit diagram, Table 1 lists the signals used by the control circuit. Potentiometer PI is connected to A/D con- verter input AD6 in order to set the time M P ATM18 signal connections Signal (on ATM 1 8 Board) PBQ PB1 PC4 PCO AD6 AD7 +5 V (K4) CND (K3) connected to Button SI (ATM 18 board KS. pin 1) Button S2 (ATM! 8 board K8, pin 2) Button S3 (ATM 18 board KS, pin 3) R3 and R4 (flash control circuit) PI (flash control circuit) Piezoelectric transducer (flash control circuit) H b V (Hash control circuit) Ground (Hash control circuit) Table a. Minimod signal connections Signal (pin) (Mcnimod 1 S, connector K 1 ) con nected to PG4 (pin 7) ___ Button 51 (external: see Minimod 1 8 inset) PCO (pin 5) R3 and R4 (flash control circuit) ADC6 (pin 3) PI (flash control circuit) ADC7 (pin 4) Piezoelectric transducer (flash control circuit) +5 V(pin 2) +5 V (flash control circuit) CND (pins 9 & 1 0) Ground (flash control circuit) efektor 06-2010 33 MICROCONTROLLERS Software and operation The basic functions of the software (see Listing) are selected and executed using pushbuttons 51 -S3. A long press' on but- ton SI selects the Strobo (stroboscope) sub- routine, which generates a continuous series of flashes with an adjustable flash rate. The value of the 'Time 1 potentiometer as meas- ured using the AD6 input is divided by 1 0 to produce a time delay with a maximum value of approximately 100 ms. Button S2 selects the Trigger 1 subroutine. The A/D converter delivers a 10-bit output with a maximum value of 1023, The pro- gram runs in a loop for detecting an acoustic pulse signal The voltage on the AD7 input is 2.5 V in the quiescent state, which yields an output value of 512. The program sub- tracts 512 from the output value and takes the absolute value of the result, so it doesn't matter whether the pulse is positive or neg- ative. The program exits the loop when an acoustic pulse greater than 350 is measured. This is followed by the flash delay and then the actual flash pulse, with a pulse width of 1 ms. After the trigger is armed by briefly pressing S2. the program can in principle wait in the polling loop indefinitely until the desired event occurs. You can exit this loop at any time by pressing 51 , which puts the circuit back into stroboscope mode. Button S3 selects the Trigger3 subroutine. It differs from the Triggerl subroutine in that it generates a series of three flashes, it’s best to try out the circuit first with a few ‘dry run' experiments, which means with- out water. Place your ‘experimental setup' ( ATJV1 1 S board and connected circuitry) on a table in darkened room, and put a roll of solder on top of the piezoelectric transducer to ensure good acoustic coupling with the table. Then you can trigger a flash of light (after the set time delay) by dropping some- thing on the table, such as a roll of electri- cian’s tape. The roll will appear to be float- ing above the table when the flash is trig- gered, since it rebounds a short distance above the table after the impact. You can play around with the delay time to vary the apparent floating height. Experiments Once you start experimenting with this device, it's usually hard to stop. In some sit- Listing ' ATMl 8 /Minimodl 8 Flash Trigger and St robe light $regfile = "m 88 def.dat" $crystal = 16000000 Dim De laytime As Kord Dim Trigger As Integer Declare Sub Strobo Declare Sub Triggerl Declare Sub Trigger3 Con fig Adc = Single , Prescaler =64 , Reference = Avcc Config Lcdpin = Pin , Db4 = Portd.4 , DbS = Portd.5 , Db6 = Portd.6 , Db7 - Portd.7 , E = Porte. 1 P Rs = Porte. 2 Config Led = 16 * 2 Ddrc.3 = 1 'R/W LCD = 0 51 Alias Pinb, 0 52 Alias Pinb . 1 53 Alias Pine . 4 Outl Alias Porte. 0 Ddrc.O = 1 Forth . O = 1 Forth, 1 = 1 Porte. 4 = 1 Initlcd CIS Locate 1 , l Led "Mini mod" Do Locate 2 x l De laytime = Get adc { 6 ) Delaytime = Delaytime / 10 'O...102 ms Led Str (delay time) + 11 ms " Waitms 200 If SI = 0 Then Strobo If S2 = 0 Then Triggerl If S3 = 0 Then Trigger 3 Loop Sub Strobo Do Figure 4, The power and signal leadsof the flash trigger circuitry are wired to a socket header (2x5), which can connected directly to K1 of the MimmodlS. 34 06-2010 elektor ' 0 ... 102 ms MICROCONTROLLERS Del ay time = Get add (6) Del ay time = Del ay time / 10 Out! = 1 Waitms 1 Outl = 0 Waitms Del ay time Loop Until SI = 1 End Sub Sub Triggerl Delaytime = Getadc(6) Del ay time - Del ay time / 10 Do Trigger - Getadc (7 ) Trigger - Trigger - 512 Trigger = Abs (trigger) If SI = 0 Then Trigger = 200 Loop Until Trigger > 50 Waitms Del ay time Outl = l Waitms l Outl = 0 End Sub Sub Triggers Delay time - Getadc {6} Delaytime = Delaytime / 10 Do Trigger = Getadc {7} Trigger = Trigger - 512 Trigger = Abs (trigger) If SI = 0 Then Trigger = 200 Loop Until Trigger > 50 Waitms Delaytime Outl = 1 Waitms 1 Outl = 0 Waitms Delay time Outl = 1 Waitms 1 Outl = 0 Waitms Del ay time Outl = 1 Waitms 1 Outl = o End Sub % 0 . # * 102 ms 'End by SI ' 0 . . . 102 ms ' End by Si nimod18 The circuit and software are designed such that they can be used with the AT MIS board (AT mega 38 MCU) or the Mf.mm.odl 8 (ATmega328 MCU). All neces- sary signals are available on pin header K1 of the Mint mod 1 8, while with the ATM 1 S board they are available around the mi- crocontroller (see Tables 1 and 2), How- ever, there are a few minor differences. The MlnimodlS has an LCD module, and it would be shame not to use it. Accord- ingly, the Bascom software writes the delay time setting to the display. Note that the R/W pin of the display module is connected to PC3, which the Bascom software does not service automatically. The software must pull this output to ground. The ATM 1 8 does not have a dis- play module, so the display driver simply operates In a vacuum without causing any detrimental side effects. With the ATIVil 8 board, the three push- buttons SI -S3 are connected to the mi- crocontroller by wire jumpers. The Mini- mod 1 8 already has two buttons on the PCB, and the flash trigger software uses them as $1 and S2. If it is also desired to have S3 available, an external pushbut- ton can be connected to PC4. Figure 5. Here the signal points on the ATM! 8 board have been wired to a 2x5 pin header that mates with the socket header of the flash trigger circuit. uations, it may be useful to trigger the flash with a light sensor. Among other options, you can use an LDR for this purpose. With the implementation shown in Fig- ure 2, the trigger circuit responds to posi- tive or negative light pulses in the same way as it responds to an acoustic signal, with the further advantage that laborious adjust- ment of the operating point is not neces- sary. Here the operating point is set auto- matically thanks to the use of AC coupling with a capacitor. The trigger circuit responds to a reduction in the amount of light falling on the sensor (such as interrupting the light beam) or an increase in brightness. With this circuit fitted near an outside win- dow, you can automatically snap a mug shot of any would-be burglar who explores around the window with a pocket torch. (ioocng-1) elektor 06-2010 35 By Markus Wagener (Germany) The DMX512 protocol is a professional standard for controlling lighting equipment, However, truly general-purpose DMX drivei interfaces are far from cheap. This circuit provides a wide variety of outputs and is based on a PSoC device that supports visual configuration. This makes it very easy to generate the desired setup. Regardless of whether you're putting on a private party or organising a major festive event, you need the right lighting as weti as the right sound to set the right mood. The DMX512 protocol has become established among professionals as the standard for controlling all types of lighting devices. It is based on a RS48S bus with peri- odic transmission of control bytes for up to 51 2 channels VU 2 l Even a large number of devices can be controlled using a single cable. The operator interface for this system can be a light mixing board, but a more economical solution is an inexpensive DMX USB interface (such as the Elektor design PI; see Figure 1 ) in combination with the free DMXControl PC program Hi, These undeniable advantages convinced the author that what he needed for controlling DfY lighting systems was a truly inexpensive control interface that could be operated via DMX51 2. Unfortunately, most of the available units that he found provided only 5-V outputs without PWM capability. The author regarded this as Far from ade- quate, especially considering that he also has devices that require a 10-V control signal. A few floating switch outputs would also be nice, along with an output for driving a DC motor (with clockwise and anti-clockwise rotation). The icing on the cake would be a fan control function. The author quickly decided to develop his own design for a circuit meeting these specifications. Naturally, a general-purpose control interface of this sort requires flexible configuration and programming capability, but this should be fast and simple and should be possi- ble without elaborate additional hardware. Accordingly, the author decided to buifd the control interface around a Cypress PSoC micro- controller, which can be programmed visually using the free PSoC Designer program. As the development environment already con- tains many ready-made and tested modules (including a DMX512 receiver), putting together a suitable program is truly child's play. The inexpensive JVliniProg USB programmer l 5 1 can be used to download the firmware to the PSoC 1C. A kit containing the programmer, a test boa rd , a USB cable a nd soft wa re Is ava i table from various distributors including Farnell, for around £1 5 / € 20 [ 6 |, Figure 2 shows the schematic diagram. The supply voltage at X2 may be provided by a DC supply or an AC supply. The allowable Input voltage range is 1 3-1 8 V DC or 9-1 2 V AC. The two supply voltages needed by the circuitry (5 V and 1 0 V) are generated by a pair of LM317 adjustable voltage regulators. If necessary, the volt- age on the higher-voltage supply rail (1 0 V with the present design) can be adjusted by altering the values of resistors R1 1 and R 12. This could for example be necessary iFyou need to connect a device with a 12 A/ control input. The input connector for the DMX signal (usually a 3-way or 5-way I 3& 06-2010 elektor * Versatile output configuration * Visual microcontroller configuration ■ Free development environment ■ DMX 512 input * DMX512 output (feedth rough or repeater) * DMX status LED * 4-section DIP switch for configuration settings * Temperature sensor for fan control ■ Supply voltage range 13-18 V (DC) or g-12 V(AC) Outputs: * 1 fan (motor) drive * 1 DC motor drive with bidirectional rotation * 5 configurable outputs (with separate status LED for each channel): Open collector (with pull-up to 5 V or 10 V) - switch pulse or PWM mode Hi-wide switch (10 V) - switch, pulse, PWM, or analogue (0-10 V) mode - 6 floating switch outputs (solid-state relay) male XLR connector) is wired to K1 6. One of the main advantages of the DMX standard is that multiple devices can be connected in series in a daisy-chain configuration. For this reason, the received signal is output on connector K1 7, to which a female XLR connector can be attached. Note that the pin numbering on the PCB matches the pin designations of the XLR connectors. The interface is implemented as a repeater to ensure that the DMX signal is transmitted with the highest possible reliability. This has the advantage that both ends of the cable are terminated according to spec, and it also means that the signal is regenerated when it passes through this stage. This allows more devices to he connected and enables longer transmis- sion distances. If you wish to omit this feature, you can simply use wire jumpers to route the DMX signals from the input connector to the output connector. In this case, components R59, R60 and IC4 should be omitted. Five configurable outputs (K3-K7) are available on the PCB. Each output has a status LED for visual monitoring. As you can see from Figure 3, the following configurations are possible depending on how you fit the jumpers at locations A to E: open-collector switch with pull-up to V (A and D) open-collector switch with pull-up to + 1 0 V (B and D) high-side switch from +10 Vto GND (Cand E) Alt outputs can be driven in PWM mode as required, which makes dimming effects and much more possible. Naturally, resistors {such a series resistors for LEDs or current limiting) can be used in place of the jumpers. To allow the control interface to be used for the greatest possible variety of applications, six floating outputs are available (EFF 1 - EFF 6 on K10-K15). These outputs are driven by ASSR-41 28-002 solid-state relays. Their advantages relative to mechanical relays are shorter switching times (cycle rate > 100 Hz) and wear-free opera- tion, The maximum load current per channel is 1 00 mA, which is more than adequate for control tasks. Output K 8 Is provided for driving a DC motor. The options here are motor off. clockwise rotation, and anti clockwise rotation. To ensure that both directions are not accidentally selected at the same time (which would cause a short circuit), the signals for the two rotation directions are interlocked via T 8 . The motor is powered from the 1 0- V supply rail. The maximum allowable load current is 500 mA. A voltage divider consisting of resistor R7 and PTC thermistor R 8 provides a temperature-dependent voltage. With the aid of the A / C converter integrated in the PSoC 1C, this voltage can be used as a control signal for driving a fan. The circuit includes a separate LED as a status indicator for this. However, in the example program described below the fan is controlled by the states of the switch outputs enabled by the DMX control signal. The fan connected to K9 is powered from the unregulated supply voltage (approximately 12 V). Figure 1 . The Elektor DMX USB interface adapter (with the circuitry contained in the XLR connector) and the free DMXControl software transform an ordinary PC into a light mixing board 1*1. If at some later date you want to use speed-controlled fan drive in your system, you may encounter problems with the pin assign- ments, depending on the specific configuration. For this reason, pins 3 and 41 of the PSoC 1C are connected together so the drive signal can come from either of these pins. It is imperative to ensure that only one of these pins is configured as an output at any given time. Tine four DIP configuration switches can be used for various pur- poses, such as setting the DMX address or switching between dif- ferent software configurations. Last but not least, a DMX status LED (D 1 2} indicates whether data is being received. f" ji 1 J 1 1 jj I W C T| I I Our example project is designed to receive data on ten DMX chan- nels. The channel assignments are shown in Table 1 . The configura- tion switches are not used in this example. You can download the ready-made project Hies from the Elektor website PL To help you elektor 06-2010 37 AUDIO & VIDE i ) IC13.A 4 10 V + ^tC Wi-. © ® — GsZH Liflll 30 - It Figure 2. The user-configurable outputs are described in the text. Connector K1 is the programming port for the PSoC 1C. 38 06-2010 eiektor Figure 3. Outputs K3-K7 can be configured in various ways using wire jumpers at locations A, B t C, D and E* The schematic diagram details show outputs configured as open -co [lector switches with pul] -up to 5 V or 1 0 V and as a high-side switch. understand how everything fits together and enable you to develop your own software, the development process for this example is described below step by step. You will need the PSoC Designer 5.0 Service Pack 6 development environment and PSoC Programmer 3,1 0 (or a later version). Both programs can be downloaded free of charge from the Cypress web- site is|. After installing the two software packages, launch PSoC Designer. Then choose ‘New Project' on the menu bar. select 'System-level Project 5 * enter a project name (in this case "DMXI’}, and confirm with H OKC An empty design window will appear, A list of predefined mod- ules arranged in function groups appears at the left edge of the window. Now you can simply drag and drop the necessary modules to the design window* as described below. Select 'Valuators' and then Interface"* For each of the DMX channels to be received, drag a 'Discrete 5 module to the design window and define the module name (Wto"V9’)* Under Interfaces 5 * select "Communication" -* "I2C\ Drag a slave to the design window. Define the module designa- tion (’ll C), This module is necessary for debugging* Under Interfaces 5 , select "Communication 1 ’DMX512T Drag a receiver to the design window. Define the module desig- nation (DMX 1 Specify the module properties (starting slot: 97; number of slots: 1 0). See Figure 4. Under "Inputs’ , select ‘Digital Input’ ’Banked Input 5 * Drag an 5 Interna I Pul I Down 5 module to the design window. Define the module designation (‘ADR’)* Specify the number of bits (4). This module can later be used for address or configuration settings. Under 'Outputs’* select ’PWM' -+ ' Variable Duty Cycle’. Drag five ' Vdd. 1 0 mA High Side' modules to the design win- dow. Define the module designations (PWMO 5 to ■RWhM')* ini- tial state (Off), and frequency (8000 Hz)* Under ‘Outputs 5 , select ‘Digital Output’ DC Switch’* Drag six ’Vdd, 1 0 mA High Side 5 modules to the design window. Define the module designations (’EFF1 1 to ‘EFF 6 ’) and the initial state (Off). These output modules drive the six solid-state relays. Under ’Outputs', select 'Digital Output 5 - ’DC Switch’, Drag two 'Vdd!, 10 mA High Side' modules to the design win- dow for the motor driver. Define the module designations ("MOT l ’ and 'MOT2 5 ) and the initial state (Off)* Under 'Outputs’, select "Digital Output’ ‘DC Switch'. Drag one H Vdd, 10 mA High Side’ module to the design window. Define the module designation ( 5 FAN_DRIVE 5 ) and the Initial state (Off). Under ’Outputs', select 'Display’ - 'LED’ - 'SingleColorV Add two ’On/Off with blink’ modules to the design. Define the module designations (’TEMPTED' and ‘DMX.LED'), BlinkRate (2), CurrenlMode (Sourcing), and initial state (Off), After all the modules have been placed, the design window should look like Figure 5. Figure 4, The PSoC Designer package includes ready-made DMX receiver components, and the channel bytes can be stored in variables. elektor 06-2010 39 VO VI V2 T W FWMQ PWM1 PWHZ V* PMC PWM< Figure 5, All necessary modules arranged in the design window. Pf terilyt pcflder tncodii IftruFer Function - PWMO ihOnPWV!0= 'M’HHMjSl 0-255 PWM 0-1 00% 97-101 For general- purpose outputs PWMO to 0-63 64-127 102 128-191 192-255 0-127 103 128-255 0-127 104 128-255 0-127 105 128-255 0-99 106 100-199 200-255 Outputs EFF1, EFF2, and EFF3 Off Output EFF1 On Output EFE2 On Output SFF3 On Output EFF4 Off Output EFF4 On Output EFF5 Off Output EFF5 On Output EFF 6 Off Output EFF 6 On DC motor Off DC motor runs clockwise DC motor runs anti-clockwise t\ 0 Figure 6. Transfer functions can be defined to determine how the DMX input channels affect the outputs. The next task is to process the values stored in the valuators by the DMX signal and drive the outputs accordingly. For this pur- pose, P5oC Designer provides various transfer functions that can be accessed via the context-sensitive menu of the output module concerned. Figure 7. The DMX Status LED should blink when no data is being received. The two transfer functions used in this example program are: PriorityEncoderfor all outputs control by the DMX signal; TableLookup for driving the LEDs. Let’s start by defining the transfer function for the PWM outputs. To do this, open the context-sensitive menu of the appropriate out- put (by right-clicking the symbol) and select 'Transfer Function... -> PriorityEncoderL You can enter a condition in the first column of the subsequent dia- log (see Figure 6). As the output value Is calculated unconditionally in this simple example, simply enter '1 ' here. In the second column, you enter the formula for calculating the out- put value. Here the DMX value with a range of 0 to 255 must be con- verted into a PWM duty factor of 0% to 1 00%. The corresponding formula is: V0 *1 00/255. Enter the same formula (adapted appropriately for VI to V4) in the cells for the transfer functions of outputs PWMO to PWM4. Next you have to define the transfer function for outputs EFF1 to EFF3. In our example, a single DMX channel (102) is used to drive all of these outputs (see the table of DMX channel assignments). Using the appropriate PriorityEncoder dialog, the DMX value range (0-255) is mapped onto the three digital outputs: 40 06-2010 elektor User Pin Assignment EFF 1 EFF 2 EFF 3 if V 5 < 64 then EFF 1 = 0 if V 5< 128 then EFF 1 = 1 if 1 then EFF 1 = 0 if V 5<12 8 then EFF 2 = 0 if V 5<192 then EFF 2 = 1 if 1 then EFF 2 = 0 if V 5 <192 then EFF 3 = 0 if i then EFF 3 = 1 You may have noticed that the above expressions are sometimes contradictory. This Is no problem because the higher-level expres- sion takes priority in each case. This elegantly simple notation saves quite a few V symbols. @0 Dreg and Drap Drivers onto Pins Id Aswgn. r^i_o,T TUPPED ffjtjsiwz ^ _0_l WTI mot; N.^3 PrtJJ fti FpUJ} Port_S_J Pw1J_T fHfl1_DW3i7 ICKIUP* tpm 5«CJ| 4«tf| SPJ51 TPJI] * P^i| *«ri 1-5 IM^JI t*M l l 1}SW NP3(T1 'ira« is nm I7PJPJ iinR 1*n|l] MP1I7] H F1I3 IJP11N 1*VM CYiCLEMI SSOP «^cc *aP3ri| hHP5t,0| C'^l *1 KP1 *0^01 »6«*1 51 ir p using Assembly, C and Flowcode I fdn i <70 1 € 50 discoun i / ' ^LleMo'coroldirtance, earning In this course you will learn how to program an embedded microcontroller. We will start with the absolute basics and we will go into a lot of detail. You cannot learn about software without understanding the hardware so we will also take a close look at the components and schematics. At the end of the course you will be able to design your own embedded applications and write the appropriate software for it. VA® Contents: Background Digital Ports Serial Communication (RS232) Analog Signals Pulse Width Modulation Timers/Cou liters / 1 nterrupts Memory LCD Display PC Communication SP3 Communication USB Communication Configuration (Fuses) Answers to the assignments Appendix @cr [ p.1* 1 Your course package: * Courseware Ring Binder (747 pages) * CD-ROM including software and example files * Application Board * Support at Elektor Forum * Elektor Certificate Price: £395.00 / S645.O0 / €445,00 Please note: to be able to follow this course^ E- blocks hardware is required which you may already have (in part). All relevant products are available individually but also as a set at a discounted price. Please check www, elektor. com/ distance I earning for further information. ■f ■ toi \ * \0 e I e k AC A D E V * \ ~ i c- A h'M 4- jpgs the sc hoot of eledronics \ Further information and ordering at www.elektor.com/distancelearning MEASUREMENT SOFTWARE Measuring for Free By Harry Baggen {Elektor Netherlands Editorial) Anyone who works with electronics on a regular basis needs at least some minimum of test equipment to carry out measurements on electronic circuits or equipment. A multimeter forms the basis of this, but a scope and function generator are also required if a more in-depth i*tu* Til mull fflIQ t yj |Sj-plmg M.-'f Hart#; Jin. C: an T lints Mil Hi^AiriWA JOI 0 M Sll tJ.4Uri.INI] lol .* Tii hi - T-r r f '-\r - * ... A / ' ! _ Vfl l -JF ; | GhkftJUi* 1 * " Hi Q.-iLi I Vp» '*4 |g nUfe ; hUidlVidhai ■ nMn [ lb 1 I l'*'r2Ury< - IDT7HJ <"»»* ' i IBMf c ePHu ai7hf .7666 v f^ >** Hi -V* • Jift O lm ‘•"ijgF Vk « M.tn, ft : f“D«. L DQwwd 'igif‘1 lft ?. r dE Ifl, IP >:t£ *+c» cm i-m[ imC L£ll!l£T C*“* SfeiE^ J. «* s* I«t S3 ItUs KaX Fi m at. ' A «* £ - tion to a normal scope display you can also change, using a tabbed page, to X-Y display for Lissajous figures. Furthermore there is a tab which shows an FFT window, so that you can also do a Fourier analysis on the meas- ured input signal. The next tab reveals a two-channel function generator, which can, for the most part, also be set using rotary buttons. For the signal shapes you have the choice of sine, triangle, square, sawtooth and white noise, A sweep between two fre- quencies is also possible. In the final tabbed page we find the settings for the sound card (such as sampling frequency) and a recorder where the measured signal can be stored as a .wav file. Very handy! Visual Analyzer PI is a program with Italian workmanship and has a remarkably large number of options. By default there appear two large windows on the screen: one func- tions as a two-channel oscilloscope and the other window simultaneously shows an FFT analysis of the measured signals. Both the scope and FFT analyser react very quickly and they are therefore very nice to work with. There are countless settings and as a consequence it is sometimes hard to locate the desired option. In addition you can also display the phase characteristic in a separate window and you can also call up a window' with a frequency counter. There is, of course, also a comprehensive signal generator which can generate various waveforms and also offers a sweep function. Other features are the option to calculate THD automatically [1j Audio Analyser: http://softsolutions.sedtJtec.de/audio- analyser, php [2] BIP Oscilloscope: www.electronics-lab.com/downloads/ pc/002/index.html [3] Audio Sweepgen: www.satsignal.eu/software/audjo. html#SweepGen [4] BIP Sine Wave Generator: www.electronics-lab.com/d0wnloads/ pc/OO S/index, him I and to make LCR- measurements with the aid of some additional hardware (the sche- matic is avai [able from the authors 1 website). Unfortunately the design is a little cluttered and the program does not always stick with the standard Windows conventions, but if you can live with that then this program offers a superb number of features. (100175-I) [ 5 1 Multisine: imp:// sof tsofutions.sediHer.de/rnuF tisine.php f G] Sigjenny VO. 989: www.n ate hxo,uk/down load s/Sigjen- ny/ Sigjenny.htm I [7] Audio Test Bench: www.higherfi.com/software htm 1 8 1 Soundcard Scope: www.zeitnitz.de/Christian/scope_en [9| Visual Analyzer www . si I fa n u m sof t . org / p rod 0 1 . h tm & Literature elektor 06-2010 51 BATTERIES LiPo Auto Balancer 'L Most people are aware of lithium rechargeable batteries: they are lightweight and can supply lots of power. They also have a bit of a reputation for being sensitive to abuse and have been known to burst into flames. Nevertheless LiPos are becoming the cell of choice for a growing range of mobile applications. What exactly are 2S t 3s and 4s battery packs and why do they need balancing anyway? Read on, we will shed some light on the subject* By Dr* Thomas Scherer (Germany) As an ideal rechargeable battery LiPos tick more boxes than most other types of cell* They are light in weight, offer high energy density, low self discharge and have the ability to be recharged relatively quickly. On the downside these cells are rather intoler- ant to careless charging indeed the charging technique is almost a science in itself. Any consumer product boasting ‘Lithium powered’ is sure to come with its own dedicated charger with spe- cial charge and monitoring cir- cuitry* This is designed to pre- vent the two destructive processes of LiPo batteries, namely deep-discharge and more seriously overcharging or cel! short-circuit. The last condition is particularly dangerous, lithium is highly reactive; if this does occur, better have a bucket of sand handy! LiPo cells Lithium Polymer (LiPo) rechargeable batter- ies have In recent years been embraced by the mode! building community. Their light weight and high discharge current capabil- ity make them an Ideal power source for air- borne electric model applications. Recent price falls have also made them more attrac- tive. LiPos from recognised manufacturers such as Kokam or Ansmann retail at around £28 per 4000 mAh cell* in comparison cells from China are currently selling on eBay at around £5 per ceil, A quick search of il !ipo 5s" on eBay will give you a bet- ter idea of today’s going rate* A battery pack described as 5s has five ceils connected in series. The battery's capacity (C) is given in mAh, A 4000 mAh battery stores enough energy to supply 4 amps continuously for one hour. A 4 Ah battery with five cells is therefore described as LiPo 5s 4000, Another impor- adjustable balancing of 2s- 5s Lithium batteries 52 06-2010 elektor BATTERIES tant property is the battery's maximum permissible discharge current. When the author originally bought batteries for this project the Chinese versions had inferior dis- charge rate of 1 S C compared to 30 C from the recognised suppliers. The most recent offerings from China however maintain their low price but have a much improved spec, equivalent to the recognised brands. A battery rated as 30 C can safely discharge 30 times its hourly rate; in this case 1 20 A in two minutes. Even with the 1 5 C rating of the cells used by the author (Figure 1 ), 60 A is quite impressive and more than sufficient for this application. These batteries were originally purchased from the Far East over a year ago to power a homebrew electric cycle project. To date they have been subject to more than 100 partial charging cycles with- out any problem. With a combined voltage of 37 V the two battery packs have prob- ably never delivered any more than 10 A maximum. In hindsight the outlay of around £40 for these batteries has represented very good value. A tricky balancing act Charging a LiPo cell is not especially difficult; just supply a constant current in the range of 0.5 to 1 C and wait until the cell voltage reaches 4.1 to 4.2 V. Fora single cell this is quite straightforward but when several cells are wired in series to form a battery pack, slight variations in each of the cells proper- ties create problems over time as the pack undergoes many discharge/charge cycles. These discrepancies will cause a cell to age prematurely and eventually die if no steps are taken to balance them out. This prob- lem does not occur with MiCd or lead-acid batteries. LiPo cells in a battery pack are not com- pletely identical. Each has a slightly larger or smaller capacity than the next. Take a sim- ple case with two cells wired in series, the one with the smaller capacity becomes fully charged before its partner, if charging con- tinues until its partner is fully charged the tower capacity cell will receive a slight over- charge. During discharge the lower capac- ity cell runs out of charge first so its poten- Figure 1 . The power source for the authors electric bike. Two series-wired 5s LiPos from China built into a small aluminium case with a thermal fuse. Features * * Fully automatic balancing * • Two LED indicators per cell * * Voltage range 6 to 32 V (6 to 44 V using an LM^Sn) * ♦ Selectable LiPo pack size from zs to 5s using jumpers * * Lead -acid cells from 3s to 5s can be balanced * • Balance can be performed on two LiPo packs (up to 3s each) * - 200 mA balancing current (expandable) * • Balancing of cells with 2 Ah to 10 Ah capacity (expandable) * * 2.5 mA quiescent current with 5s and 1 mA with zs packs Charge + Figure 2. A power opamp and three resistors is all it takes to perfectly balance two cells. elektor 06-2010 53 BATTERIES 090*76 ■ ti tial falls. In time and with more charge/dis- charge cycles the differences between the cells becomes magnified and the successive overcharging and deep discharging leads to damage to the lower capacity cell. The solution to the problem in principle is fairly simple: cell potential is a good indica- tor of the amount of charge in the cell t we therefore only need to make certain that each cell in the pack has exactly the same voltage to ensure that it is balanced. Balancing methods The brute force approach is (after every two charge cycles) to discharge each cell until its potential falls to a defined volt- age level. All the cells will then be at the same voltage with any accumulated offsets reduced to zero. The disadvantage of this method is that the energy discharged dur- ing this procedure has simply been dissi- pated and lost. The cells must be charged again before use. Laptop battery packs usually contain battery management hardware within the battery housing. Here a microcontroller monitors the voltage of each cell and diverts charging current around weaker cells to ensure that the entire pack achieves a full charge* Even more complex are the chargers which can return surplus energy so that when the cells are being balanced as little energy as possible is wasted. From the point of view of energy conservation this solution is opti- mal but the additional hardware is quite complex. f igure 3. More cells = more opamps and more resistors* More current = Class B Darlington transistor output stage. More convenience = LEDs indicate current flow. We can surely do better than the crude first method and the more complex meth- ods are really not universal enough. There is an alternative; a super-simple method How it works Connect the balancing connector of the LiPo pack to connector K1 of the balancer, lumpers JP2 to jP5 are used to set up the balancer for the number of cells (2 to 5) to be balanced. The jumpers marked JPx- T con- nect the battery voltage to the circuit while jumpers jPx-2 connect the battery to the voltage reference chain. Two jumpers are necessary for 25 to 45 packs, but 55 packs require just one jumper. A fully charged five cell LiPo battery pack will have a voltage of up to 21 V(4.2 V/ cell). The voltage taps are produced by a chain of close tolerance resisters R! to R5 connect- ed across the battery voltage. Each opamp compares the actual cell voltage with the reference voltage tap. When the cell voltage is different from the tap voltage the opamp switches one ot the Darlington transistors to either charge the cell (when its celt potential 54 06-2010 elektor BATTERIES Figure 4. The components are well spread out, COMPONENTS LIST Resistors R1-R5” 10kQ0*1% R6-R9 - I.SkQ R10-R13 = 1,2Q R14— R1 7 = 10 Rl8-8.2kn Capacitors C 1 -C4 - 1 0n F, lead pitch 5mm C5.C6 = 1 QOnF lead pitch 5mm Semiconductors D1-D4 = LED, green, low current, 5mm D5-D8 = LED, yellow, low current, 5mm D9 = LED, red, low current, 5 mm DI0-D17 - 1M4148 T1-T4 - TIP 1 20 T5-T8 * TIPI 25 IC1 = LM324. LM348N (see text) Miscellaneous K1 = 6 -ptn 5IL pin header, lead pitch 0.1 in, (2.54mm) JP2- 1 -JP4-2 " 4-pin double row pinbeader, lead pitch 0,1 in, (2,54mm) JP5 = 2-pin pinheader, lead pitch 0, 1 in, (2.54mm) 14-way 1C socket for IC1 ) 0 pcs heatsink isolation set for TO 220 style transistor Aluminium bracket or heatsink PCB ff 090476 which performs the delicate balancing act automatically with relatively low energy losses.,. An auto balancer The operating principle of this method using two cells is shown in Figure 2. A potential divider formed by R 1 and R2 produces a voltage at its centre point of exactly half the combined volt- ages of the upper and lower cell. The (power) opamp drives current via the current limit resistor R3 to the centre con- nection of the two batteries. When the u pper ceil has a higher voltage than the lower cell, current flows into the lower cell until both are is too low) or discharge it (when the cell po- tential is too high). The result is that all the cells attain the same voltage level As long as the balancing current is >20 mA the corresponding LED will light up. The out- put stage can pass a maximum balancing at exactly the same potential and balance is achieved. No set-up or calculations are nec- essary except to fix the value of R3 to give a balancing current somewhere in the region from 0.02 to 0.1 C. What if you have more than two cells? Sim- ple, just add more opamps. A quad opamp will be sufficient to balance packs with up to five cells. Standard opamps cannot handle the required balancing current so a class B current of 250 mA, Output current limiting can be described by looking at the configu- ration around 1C 7 A for example. Depending on the state of charge D1 or D5 will be lit by current through R6. The voltage across the conducting LED will be around 1 ,8 V. Sub- tracting the forward conduction voltage of the diode (DIO or D1 1 ) and the base emitter transistor stage is added to boost current. Low-priced power Darlingtons (T1 to TS) are a good choice to hefp keep costs down. Fig- ure 3 shows the complete circuit diagram of the balancer in regular use by the author. It can balance two to five cell bat- tery packs. The forward volt- age drop across each LED lim- its the transistor base voltage. Together with the emitter resis- tor this gives an output current limit of approximately 200 to 250 mA, This is suitable for cells with a capacity in the range of 2 to 10 Ah. With the addition of extra heat-sinking the balanc- ing current can be increased by using lower value resistors RIO to R1 7. The unit will then drop of the Darlington (about 1.0 to 1.1 V) leaves 0.2 to 0.3 V drop across the 1 £1 emit- ter resistor which effectively limits the cur- rent to around 250 mA. Fully automatic balancing elektor 06-2010 55 BATTERIES Figure 5, The completed PCS. A length of aluminium angle provides sufficient heat sinking for balancing the 4 Ah celts. achieve balance more quickly shown by the LED indicators. The heat sink only requires a limited thermal capacity. The use of jump- ers allows the unit to be configured to bal- ance packs from 2S up to 55. Construction and test The finished PCB (Figure 4) shows that the components are well spaced out on the board and no SMD packages are used. Con- struction should therefore be fairly easy even for those who admit to being a little ham-fisted. As can be seen from Figure 5 a length of aluminium right-angle profile is fit- ted on the board to act as a heat sink for the output transistors and in most cases this will suffice. The transistors can also be mounted standing up at right-angles to the PCB giv- ing space for a larger heat-sink. Mounting holes for such a heat sink are provided on the PCB. It is important to ensure that the tran- sistors are electrically isolated from the heat sink by using mica (or similar} insu- lators together with insulating bushes on the mounting bolts. A small amount of heat-sink compound under the transistors assists heat transfer. Once construction is complete a continuity tester can be used to check that all 10 transistors are insulated from one another. After the insulation test and a final visual check of the component placement fit a sin- gle jumper to JP5 (5s) leaving all the other jumper positions free. Adjust the output voltage of a bench power supply to approx- imately 1 0 V and connect it to the two out- ermost pins of connector K1 (observing cor- rect polarity}. LED D9 should now light and just a few millramps will be drawn from the supply. If everything is in order increase the supply to 20 V. D9 should now burn more brightly and using a multimeter you can check that voltage levels on pins 2, 3, 4 and 5 of l< 1 a re 4 t 8 T 12 and 16V respective ly (i.e. fifths of the total supply voltage). Using a bench supply with current limit capabil- ity set the maximum current to 0.5 A and short together any two adjacent pins on K1 . A maximum balancing current of approxi- mately 200 m A now flows from the supply. Once the circuit has been tested it can be connected to the battery pack balancing connector. Don't forget to fit the correct jumper corresponding to the battery pack: for a 3S pack for example make sure that jumpers are only fitted to positions JP3-1 and JP3-2. The auto balancer should be left connected to the battery until all the LEDs (except D9) have gone out. It Is not strictly necessary to balance the LiPo pack at every charge. The author’s routine is to balance them after every tenth charge cycle. His installation consists of two 55 packs connected in series so first each pack is individually balanced. The balancer can now be jumpered into 25 balancing mode and the dual battery pack reconnected with its positive lead connected to pin 3 on K1 , the negative lead to pin 1 and the battery series connection to pin 2. This final bal- ancing stage can only be completed if an LM348 is fitted in position IC1 in the circuit, this iC is rated up to 44 V. The alternative LM324 is suitable for voltages up to 32 V maximum which is sufficient for 2 x 4s (and of course 1 x 5s). (090476) Literature ‘Super Lithium Batteries'. Elektor April 2005, www.elekto r.com / 040 1 G8 56 06-2010 elektor Messe Milne hen International get the whole picture 24th International Trade Fair New Munich Trade Fair Centre 09-12 November 2010 www.electromca.de/en electronica 2010 components 1 systems 1 applications SCEPTRE InterSceptre opens doors (and ports!) for you By Clemens Valens {Elektor France) A few months ago, we introduced Sceptre, a fast prototyping system fitted with a 32-bit microcontroller. Even on its own, this little board will let you produce some great results, but if we add an extension board to make it easier to access all its peripherals, the Sceptre platform becomes downright powerful. What’s more, if you fit this extension board into a suitable case, you’ll be able right from the start to develop a prototype that you can use ‘properly’ in a installation, with no trailing wires or bits of sticky tape holding everything together. Now that’s what you call fast, convenient prototyping! So there we have the broad specifications for EnterSceptre, the Scep- tre Ml extension board with multiple interfaces. And even though the development of InterSceptre was inspired by the Sceptre, the board can be used with any other micracontrolEer, provided it is fit- ted to a board that' I fit into the space reserved for the Sceptre, Enter- Sceptre operates from 3.3 V and 5 V, so it's perfectly suited to Pits, AVRs, and other popular micros. So what has InterSceptre got to offer? Well quite a Jot, actually (Fig- ure 1 ): two R5-232 ports, two R5-485 ports (or one RS-422 port), a DMX512 port, a MIDI input/output, an I^C port, an 5PI (or PS/2) port, space for a WIZnet Internet module, four analogue outputs (DAQ, analogue inputs (ADC), digital 3/Os (logic, PWM), four LEDs, a JTAG connector, a holder for a button cell, a small prototyping space, exten- sion connectors, and a 5 V power supply. All this on a PCB that fits exactly into an attractive, Italian-designed case meas- uring IS x 20 x 5.4 cm. Before you rush off to the Elektor online shop to order this extraordi- nary board, do just be aware that you can't use a El of these facilities at the same time. Even though the Sceptre offers lots of peripherals, it only has fifty pins, which means that certain functions are obliged to share pins. Nevertheless. we've done everything we can to make InterSceptre as flexible as possible, in any case, there are very few applications that would require everything to be used at once. Detailed description Let's taf SD 3 pi 2u y « 7 PO 2/ / 46 6 ”L3" sesei y 47 5- ■'w'" _ pi 7u y 43 4 pd .20 y 45 A V pb i 9 y 44 3 M PI ■- y .: : , -Pr XI y 12 14 J2 pi . 20 y 41 13 . . r j n 17 y 40 12 po i6 y 39 if V" pfi! y 3$ ttl pi 3 y 37 9 P0.iv / 36 3 pi . 22 y 35 7 V po ij y 34 5 po i 2 y 33 6 Po.n y 32 4 pi . 23 y 31 3 u po it y 30 3 Li po.i y 29 t po t y 56 vbat y Level sh UEor It, 5 V 24: 3V3 +3V3 +5V © © lo 2 ol *21 2 JPG K19 541 £2-6 LJ \POjJ_ 11 Lflvol ffltifior t-!;SV 24: 1VJ R15 H i&flp J - 6 o o6’2oio elektnr Figure 2 . Complete circuit diagram for interSeeptre, A bit big, because of the many components, but nothing very complicated. SCEPTRE vcc 1C017J ■ M eiektor 06-2010 61 SCEPTRE plexer. In this way, InterSceptre has four analogue outputs, aval [able on the 2 5- way sub-D connector K22. The gain of the output stages is adjustable (a bit too much, really, for reasons of simplicity) and they are powered from 5 V, at all times, which means a 33 V system can produce (nearly) 5 V analogue sig- nals. The gain is adjusted using 25-turn presets, if unity gain is all you need, you can omit these and connect the inverting inputs directly to the outputs. This will save you a bit of money. The (de)multiplexer IC6 in fact contains two multiplexers so, as we don’t like wasting precious resources, the unused multiplexer is accessible on an 8-way terminal strip, which lets you connect this multiplexer to the DAC output or one of the Sceptre's analogue inputs — or both, PC and GPfO The Sceptre has two l 3 C ports, one of which is readily accessible without disturbing the other Functionstoo much. This is the port we've connected to a 6-pin RJ1 1 connector via a voltage booster. In this way, it is possible to connect a 3.3 V l * 2 C peripheral (for example a N unchuck controller for the Nintendo WII games console) to an InterSceptre running at 5 V (or 3.3 V); it also works the other way round. The very handy Pocket terminal that goes with the running- in bench described in PI runs on 5 V t so it can be used with the Scep- tre running on 3.3 V. The Pocket terminal offers an LCD display, five push-buttons, and a rotary encoder, driven via PC, The voltage booster used comes from a Philips (or NXP) application note l 4 J. It’s both simple and ingenious, as it’s bidirectional. For example, let's take the SDA sig- nal (P03) and assume that the power rail is 3,3 V while the output voltage is 5 V (so all the jumpers are in positrons 1 and 2). If SDA (in output mode) on the source of FET Q 3 is at 0 V, Q3 conducts andi hence the output (drain) is also at OV. If SDA as at 3.3 V, Q3 is turned off and the output Is at 5 V thanks to pull-up resistor R21 * The other way round, when SDA is in input mode, it’s a bit more ingenious. If the drain is at 0 V. the spurious diode in Q3 conducts and takes Q3 source, and hence SDA, towards 0 V, This causes V gi to rise, the FET starts to conduct, and SDA goes to 0 V. If the drain is at 5 V, pull-up resistor R34 ensures that the SDA input sees a level of 33 V. The l 2 C port is also connected to a Microchip port expansion 1C, This 1C is compatible with 3.3 V and 5 V, so no voltage boosters are needed. It offers 16 programmable I/Os with interrupts and lots of other possibilities too. As it’s an PC port device (it is also available In an SPI version), it requires a programmable address. This is obtained using three switches, even though an PC address consists of seven bits. The chip itself adds the missing four MSBs, hence its address is OOlOxxx, where xxx represents the position of the three switches (0x20 to 0x27 in hex). The chip’s port A is accessible on the 25-way sub-D connector: port B is connected to 9-way terminal strip K23. JTAG, LEDs, and other connectors The JTAG connector is wired to the standard defined by and for ARM, i.e, 20 contacts with (optional) pull-up resistors. To put the Sceptre into jTAG mode, jumper JP7 must be set and the board rebooted. Four LEDs (to be fitted at 90 q underneath the Sceptre, otherwise they can't be seen) share a number of the jTAG port's signals, if this causes difficulties with JTAG communication, don't be afraid to remove them. 25-way $ub-D connector K22 gives access to a selection of the microcontroller's various ports. So we find the PWM outputs, cer- tain analogue inputs, the analogue outputs, a number of interrupts, and some basic I/Os. Each of the signals is protected by a smafl cur- rent- 1 Smiting resistor. This protection is rudimentary, so be careful all the same, and don’t hot (drs)connect equipment. The 34-way extension terminal strip K20 gives access to the micro- controller’s other signals. Here, there's no protection at all, so you need to take great care. This terminal strip is opposite a little area with mounting holes where you can fit a few components to create an interface you need, A row of holes each side of the microcontrol- ler board gives you direct access to all the processor’s signals. Power supply and battery During application development, the Sceptre will be connected to a computer via a USB cable connected either directly to the Sceptre, or via the InterSceptre. In this situation, the USB port can provide all the power. For applications where no USB connection is possible or necessary, or if more power is needed than can he supplied by a USB port, a 5 V supply is avail- able via the InterSceptre, We have made provision for two possible regulator types (a 7805 or a fow-voltage-drop 1 1 1 7-style), which, for some unknown reason, do not have the same pin-outs. So take care how you fit the regulator! The on-board supply takes priority over the 5 V from the USB ports by way of diode D4, making the regulator output voltage around 03 V higher than the USB port voltage. The other diodes (D2, D5, and the other D2 in the Sceptre) take care of the rest. One impor- tant detail not to be overlooked: when fed from a USB port, the InterSceptre’s 5 V rail isn't in fact quite 5 V, but more like 4.7 V. When self-powered, however, the 5 V rail really is 5 V, The InterSceptre operating voltage V cc is selected by means of JP2. As already mentioned above, the InterSceptre itself does not pro- duce the 33 V, it comes from the Sceptre, If you are not using a Sceptre, you'll have to make provision for a 33 V rail if you need one. One minor drawback with the Sceptre is the absence of the battery voltage on the extension connectors — but it does have its own bat- tery. If you use a different microcontroller board without its own battery, a button cell holder is available on the InterSceptre. Atten- tion! If you connect the Sceptre battery to the InterSceptre, don’t fit a battery in the BAT1 holder as well! Vou can connect a switch to JP9 to let you turn off the Sceptre power. This can be handy where the Sceptre is being powered from a bat- tery. Don't forget to link the Sceptre switch contacts to the Inter- Sceptre ones, which are just underneath. open-source and hardware 62 d6-20to elektor SCEPTRE NQISN3 BfH/ 1 ■ L; j „ j, . Sc; ■*■1. ■ * v? '• ■iEiyfc - , 2 . 1B| .i- ! • t aS « Cc eft fcetceeXtetcGi I * Figu re 3 * Co m bi nation of Sceptre + I nterSceptre + W 128 1 2 M] . And finally*.. interSceptre uses only non-SMD components (except for the USB connector) and so is easy to wire up. No need to fit the parts you don’t need — particularly the connectors, which can be quite expensive. The InterSceptre PCB has been designed to fit into a case which, in addition to providing protection, also lets you use the unit directly within a final application without its looking like a bodge. The case we’ve chosen is a Teko 935.5 (white) or 935.9 (black), which comprises two plastic shells (handy for the Sceptre’s Blue- tooth) and two aluminium front panels held in place by the shells. The shells fix together using a pair of screws. The example in our prototype was kindly provided to us free of charge by Okatron [e], the French distributor for Teko. Like the Sceptre, InterSceptre is also an open-source, open hardware project. So on i 7 l you can find the Eagle files for the circuit diagram and PCB, the components list and a few bits of software fortesting and using InterSceptre, (100174-!) Internet links 1 1 ] www.etektor.com/090559 [2j vvwvAelektor.com/0906n7 I3j www. el ektor.com /OS 02 5 3 [4] ics,nxp.com/siipport/documents/6nterface/pdf/an97055.pdf [5] www.teko.it/en/prodotti/famlglia/FP/serie/30 [6] www.okatron.fr 1 7 ] www. e I ekto r, co m / 1 0 0 1 7 4 elektor 06-2010 63 LEDs Starry Night By Lars Lotzenburger (Texas Instruments Germany) Armed with a handful of LEDs a few driver chips and a microcontroller you can recreate a little bit of the Cosmos to hang on your wall at home. This unique celestial slide show displays the major constellations and is sure to be a talking point. The software can be easily altered to cater for system expansion. The author built this originally to hang in his niece' s bedroom, ft gives a pleasant back- ground glow and gently cycles through depictions of some of the major constella- tions. Using 32 LEDs the controller shows up to eight different constellations and Is pre- programmed with the Big Dipper, Orion, the Dolphin, the Swan and Cassiopeia all of which can be seen from the northern hemisphere (see picture). Other constel- lations can also be programmed. The LEDs are fitted into a display panel, and in order to keep it to a manageable size the constellations are shown one afterthe other using some of the same LEDs to represent differ- ent stars in different constel- lations. A microcontroller adjusts the brightness of the LEDs to present a sort of celestial slide show with all LEDs reverting to a background level of brightness before the next constellation is highlighted. Any LEDs not used for a particular constellation are shown as dim ’back- ground' stars. The Hardware The design is flexible and the hard- ware described here can drive up to 48 LEDs so that many other constella- tions can be implemented. The software in its present build supports the depiction of up to eight different constellations. The LEDs are fixed in holes drilled in the chip board (or MDF) panel. For more details see 'Construction’, The author has developed a simple low-cost electronic circuit; a microcontroller controls the brightness of individual LEDs connected to a multi-channel LED driver (the TLC5943 from Texas Instruments). The MSP43GF20 1 2 microcontroller was chosen for this job; it is one of the smallest members of the well known MSP430 family. LED drivers The LEDs are driven by three TLC5943 [1)16 channel LED driver chips as shown in the cir- cuit in Figure 1 . Each output pin provides a constant current sink function so this means that all the LEDs must be wired with their anodes connected to the positive supply and their cathodes connected to output pins of the TLC5943s. A global maximum current for each of the 16 LEDs is set by a single reference resis- tor connected to the J REF pin. This maxi- mum value is divided into 128 steps by a 7-bit internal brightness control register (see block diagram in Figure 2). A value of 1 27 corresponds to the maximum current defined by the resistor connected to IREF. The resistance value used in this application gives a maximum of 30 mA per LED (values up to 50 mA can be defined). Each channel has a 16-bit wide grayscale register which allows 65536 levels of bright- ness to be set for each LED individually (this fine resolution is useful to give smooth tran- sitions because the eye is particularly good at detecting slight changes of brightness). The 'focal’ brightness of each LED is control- led by a Pulse Width Modulated (PWM) output signal which is generated in the driver chip using the greys- cale input clock GSCLK supplied by the microcontroller. The internal logic generates indi- vidual PWM signals for each LED with an on/ off ratio defined by the value stored in the corresponding grayscale register. One PWM period consists of 65536 GSCLK periods and the number of GSCLK peri- ods that the LED is on dur- ing this time corresponds to the value in the greyscale register. The simplest way to implement the PWM waveform to control the LEDs would be to switch all LEDs on at the same time and then counting GSCLK periods turn each one off at a time when the count equals the value in the LED’s grayscale register. The on/ off switching rate must however be greater than approximately 70 Hz otherwise a flicker is noticeable. Using this simple method would require a GSCLK of around 5 MHz to avoid flickering, A better technique employed by the TLC5943 Is to divide the complete PWM period into 128 equal periods (each period consisting of 51 2 GSCLK periods). The on period for each LED is then ’spread" over the 1 28 peri- 64 06-2010 elektor 11 Figure 1 . The three LED driver chips are daisy chained. The data paths are linked in series while control signals are paralleled. ods (see Figure 3). This effectively increases the LED switching frequency and is known as 'Enhanced Spectrum PWM" (esPWM). Communication The Grayscale LED values and the global brightness control value are sent to the LED driver chip over a serial interface which uses pins SIN, 5QUT and 5CLIG The voltage level on the MODE pin 6 (or BCSEL on the data sheet) determines if the serial data Is either greyscale data (MODEHow) or global brightness control data (MODE=High). A ris- ing edge on the XLAT pin transfers the serial data (greyscale or brightness) into interme- diate latches. The microcontroller software also makes use of the BLANK pin by pulling it high to turn off all the LEDs, An important feature of the TLC5943 is the possibility to expand the system by con- necting additional TLt 5943s in a daisy chain configuration. The 50UT signal from the first chip in the chain is connected to the 51 N of next chip. Other signals such as the clock and control signals are connected in paral- lel with the corresponding dock and control pins of the other chips in the chain. To send a data word or byte to a particular driver chip it is inserted in the correct position in the serial data stream along with data for cuTo out i Quin out is 000895-13 Figure 2. Block diagram of the LED driver. Maximum LED current is defined by an external reference resistor. A 7-bit brightness control register can further reduce LED brightness. elektor 0G-2010 65 Software M odd in The software can be adapted to meet your requirements. Changing the following #defines in the source code will alter the program's behaviour; #define Default Description IDLEJTME 2 The period in seconds when no constellation is depicted (All stars are background) FADBNJTME 5 The constellation fade-in time SIGISMTME 3 The period in seconds when the constellation is displayed at maximum brightness FADEOUT_T)ME 5 The constellation fade-out time (must be the same as FADEIN_TIME) BRIGHT.BACKGROUND 250 Background brightness of the LEDs (No constel- lation displayed) RRIGHT_5IGN 10000 Maximum brightness of the constellation LEDs (1 to 65535) TLC5943_CNT 3 The number of TLC5943 chips in the system And finally each LED must be assigned to one or more constellation(s), The LEDs are num- bered from 0 to NUM^LEDS - 1 (1 6 x TLC5943 _CNT * 1 ), Where the LED number is assigned from: NumLED = NumTLC5943 x 16 + NumPm NumTLC5943 is the number of driver chips where 0 represents the last in the chain from the controller's viewpoint. The LEDslnSigns[ ; field indicates which constellation the LED is used in. The field contains as many unsigned char dements, as there are LEDs. Now a bit position is assigned to each constellation (according to 1 . 2. 4. 8, 1 6 to 1 28). When a LED is used in one or more con- stellations. the respective bits are set in the associated field elements. The Signsf ] field defines how often and in what sequence the constellations are displayed. When the last constellation display is finished the controller goes into sleep mode until the next reset. the other drivers and clocked through until it is latched into the driver's registers. Additional LEDs can be wired in series at the output pins to produce more light. Addi- tional information can be found in the data sheet [1], Constant Current Driver OIWOFF Tmiocj in ES-PWM (i.AMK G 5 CLK 1 -Vr -\V- i * a 5 l 2 in li i i d 16383 18 385 16,387 35.767 32.76* 33,77 1 <3,151 «.153<9 155 65, CtW 65026 65536 16 382 16.38* 16386 32.76632.766 32,770 «.tSOI9 1524?.1&4 65.02366.025 65.633 66,536 jum . . juuui . . juinium . , jmsm . . jjiniiM . . jwm . . . juuuui VuflOQPlmT. - ri'l OF* otmi tih ........ 1GSMTA ■ MOfiJ OFF QVTn OH 10-SCW'A W!Fli lit P»rkKl 2nd rT _ 33*id iird Fierlgd AnruQd PtrlDd “Vr 63th, 65tH Klh 9716 1J71I, .™ h -„ |D _ ,, 1PBflrtd PerlDd Period Prnad Period Pb-jhkI ‘T- . L r- (ij -*■ — T-fSCLK-’d 7TJ *i — ^ -fr- Cf F OUTn On IG5DATA . OOJfif OM OWTTni □H iGSCWTft ■ HH*i] OFF OUTn Cm IGSEkATA - g&ini U ■j ■»- T . - ' 1 Hfr- T - GStlH ■ IS u — l l Aulc firpMl li nutted T - G5C4.K i 1 d - 1 — — —T-OSCudii 7 U TJ T , (SSCut . is — — 16 U 1J f ■ OStL* . ifl- — Sr — i i .2 T • <150 * , IB • t .4 > H U Figure 3. The value in the greyscale register (CSDATA) defines the on/ off ratio of the PWM signal for each LED, Unlike standard PWM the on time is spread over the PWM period to reduce LED flicker. Controller and power supply The LED drivers were discussed in some detail butthe microcontroller need only be a general purpose device. Its most important task is to implement a bidirectional serial communication interface (SPI). It needs both a timer and the capability to generate a sufficiently high frequency G5CLK signal required by theTLC5943. In the interests of economy the controller should be as small as possible with the least number of unused pins. The MSP430F2Q12 from Texas Instru- ments fits the bill admirably; it has a 2 kB Flash and 1 28 Byte of RAM on board [2]. Running at 1 G MHz the controller consumes around 4 mA, The US! (Universal Synchronous interface) uses the SPI protocol which is also supported by the TLC5943, TheGSCLK clock is provided from a GPIO pin of the MSP430F2O1 2 where it is derived from the controllers 1 6 MHz sys- tem clock. A DCO (Digitally Controlled Oscil- lator) in the microcontroller is software pro- grammable and generates the system dock, an external crystal is not necessary. The circuit runs at 3.3 V produced by a LDO LP2985A-33 [3] regulator from the 5 V to 8 V input voltage. The input voltage upper limit is governed by the maximum power dissipation P m allowable in the LDO pack- age. At 25 °C this is given as approximately 0,58 W, The maximum current I, n drawn by the MSP430 microcontroller and the three TLC5943 LED drivers (excluding LED cur- rent) is approximately 1 24 mA, This gives a maximum voltage drop across the regula- tor of around 4.7 V. The LEDs draw current directly from the input supply and are not always on so power dissipation in the driver chip output stage is low. As a rough guide for white LEDs with a forward voltage drop of 3.5 V and a current of 30 mA we can say that the ideal supply voltage for the circuit is 5 V. These calculations are only valid if single LEDs are used as output loads but for appli- cations using two or more In series it will be necessary to recalculate the supply voltage. The Software Software for this project is written in C and was developed using the embedded work- bench Kickstart from IAR systems. This 66 06-2010 elektor complete development environment is free to use and can be downloaded from the Tl home page [4] amongst others. This version allows a code size limit of 4 KB but is more than enough for this application. The individual hardware components are initialised in the Main function of the code. The internal oscillator of the M5P430 runs at its maximum dock rate of 16 MHz. Once the CPIOs have been defined and the USI has been configured for SPI mode the glo- bal brightness value is sent to the bright- ness control register in each TLC5943 (the value of 1 27 used in the example software is the maximum). As already mentioned the CSCLK signal is derived from the microcontroller's system clock, the routine to configure this can be found in the Main function. The M$P43G T s 1 6-bit timer is used to gen- erate the clock which transfers data to and from the LED drivers. The routine to cal- culate new LED brightness values is called every time the 1 6-bit timer overflows at the beginning of every PWM period i.e. after 65536 CSCLK periods or 4 ms approx- imately. The resulting interrupt causes the M5P43G to calculate new brightness values for each LED and send them to the TLC5943. When all the data has been sent a pulse on the XL AT input latches the data into the TLC5943*s registers. Storage of all the greyscale values for the LEDs requires 48 1 6-bit words. In order not to use up the precious RAM resources the software makes use of the fact that these values are stored in TLC5943 In serial form. The latest greyscale values are read back into the microcontroller using the serial interface; the next value is calculated and then sent back to the display drivers. In our case the calculation is quite simple; if an LED is part of a constellation the new value will be increased or decreased by a certain amount depending on whether the constel- lation is being faded in or out. The constellation display is a cyclic 'State- Machine’ with four states: 1 . Background: All LEDs have equal back- ground brightness. This is the transition phase between constellation depictions. Duration: 2 seconds. Construction First off work out which constellations you wish to represent, the software can display up to eight different constellations. To get the exact positions of each star in a constel- lation it is necessary to find an image file and transfer the coordinates of the stars onto the display panel. The Internet is a good source of information here. Any LED can be used in any of the constellations (the software supports this). Each constellation tan be rotated and scaled to make optimum use of the LEDs, Once the positions are marked on the panel the holes can be drilled. To reduce the risk of splintering, place a piece of tape over the drill position and drill from the front of the panel. The drill size depends on the size of LED used. Once all the holes have been drilled use a larger drill with diameter equal to or slightly greater than the LED's shoulder to make a counterbore from the back of the panel Do not go all the way through, the depth of coun- terbore governs how far the LED protrudes from the front of the panel. Once all the LED mounting holes have been drilled the outline shape of the panel can be decided and the panel trimmed accordingly. Finish off with a coat of paint. Fix each LED in position with a drop of wood glue or hot glue. Wiring to the LEDs is not critical you can either connect the anodes of all the LEDs together and run a common wire back to the positive supply connection or run individual wires from the anode of each LED to the positive supply, When using the first option it is best not to have just one wire, this can give rise to flickering LEDs because current to all the switched LEDs passes through a single wire. The cathode of each LED can now be wired to output pins of the TLC5943 driver chips. Which LED is connected to which driver pin is not cri tical because the LED allocation for the constellations is taken care of in software. Finally fix the PCB to the back of the panel. 2, Fade in: Increase the brightness of the main stars in the displayed constella- tion. Duration: 5 seconds, 3, Constellation; The LEDs depicting the constellation stars are at full brightness. Duration: 3 seconds. 4, Fade out: Reduce the brightness of the main stars In the displayed constellation back to the background level. Duration: 5 seconds. The software for this project can be freely downloaded from the Elektor site [5], The program example depicts the constellations of Orion, Cassiopeia, The Swan, the Big Dip- per and the Dolphin. The C source code can be ed ited for exa mple constants given in the #define section such as background bright- ness level, maximum brightness of the con- stellation stars, display time of the constella- tions and the fade in/out time are just some of the simpler changes that can be made. More suggestions can be found under the "Software Modding’ heading. Once the dis- play is finished you can attach it to a wall and now you won't need to wait for a cool clear night to do a spot of star gazing, sit back in the warm and enjoy your own per- sonal starry slide show. (080895-I) Internet Links [1 1 http://focus.ti.com/docs/pFod/folders/ print/tlc5943.html [2] http://foais.ti.com/docs/prod/folders/ pnnt/msp430f201 2.html 1 3 1 http://focus.ti, com/docs/prod/folders/ print/lp29S5a-33.html [4] http://focus.ti.com/docs/toolsw/folders/ print/iar-kickstart.html [5] www.elektor.com/08089S elektor 06-2010 67 SWITCH-MODE AUDIO POWER SUPPLIES Alternative HiFi Power Supplies Is a standard SMPSU suitable ications? By Ton Giesberts (Elektor Labs) & Thijs Beckers (Elektor Netherlands Editorial), based on an idea by Dr, Thomas Scherer (Germany) Why couldn’t you just connect two standard switch-mode power supplies in series to create a symmetrical power supply for a power amplifier? What are the pitfalls and what do you need to look out for? And... is the quality acceptable? Every (power) amplifier obviously needs a power supply. Up to now one would normally use a toroidal transformer with a bridge recti- tier and a pair of heavy-duty electrolytic capacitors. Building your own switch-mode power supply is something few people would attempt at home. But iron is expensive and buying a toroidal trans- former could easily cost you over £30. And that is before you've added several decent smoothing capacitors... Proportions Switch-mode power supplies are usually available with certain fixed output voltages and the trick is then to find a type that can deliver sufficient current to drive a 4 or 8 £2 loudspeaker up to the supply voltage rail. If we assume a load of 8 Q this means that with a volt- age of 24 V (a standard output with such power supplies) the power supply should be able to provide at least 3 A. Saving iron We thought there had to be some other way. We had previously seen news items and datasheets on industrial switch-mode power supplies, but it wasn't clear how easy it was to incorporate them in our own circuits. The output voltage is usually fixed (often there were models with 1 2, 24 and 48 V outputs) and with just a single output. But why not combine two power supplies to create a sym- metrical one? The ridiculously low cost of these power supplies made it worth- while to give it a try. So at the end of March we had four power supplies waiting for us in the test and measurement department ofourlab. In practice, and especially with the output stage used here, we can assume there is a ‘voltage drop' of about 3 V that occurs because the driver transistors cannot drive the output transistors up to the power rails. In this case a 2.6 A power supply should suffice. We ordered four power supplies from the manufacturer Mean Well HI: two of S-60-24 and two of LP5-75-24 so we could create two symmetrical power supplies for comparison. Industrial power supplies are often placed into ‘power series': The 5-60-24 tested by us comes from a series that are rated at 60 watts. In this series we find models with different output voltages and currents that all pro- duce the same power output of 60 W, The LPS-75-24 comes from a 75 W series and is a bit more powerful. 68 06-2010 elektor SWITCH-MODE AUDIO POWER SUPPLIES Test setup To test the industrial switch-mode power supplies we connected up an ICBT power amplifier from the June 1995 issue. The operat- ing voltage of this amplifier should really be 43 V, but the only part that had to be modified for use with the lower output voltage of the combined industrial power supplies was the power-up delay. This is set (via R35 in the original circuit diagram) to a 30 VAC volt- age. If the Common of the power-up delay is connected directly to the common of the circuit and the positive side of Cl 3 Is connected directly to the supply voltage, the amplifier will also turn on with a lower supply voltage. The only part that doesn't function properly is the turning off of the relay when the supply is turned off, but this has no effect on the testing of the power supplies, so this doesn't matter. We had a number of heavy-duty power resistors available to use as load for the power amplifier. In practice Since most amplifiers, just as the ICBT power amplifier, require a symmetrical power supply, we require two (single-output) mod- ules. These are connected in series, where the junction becomes the Common and the remaining positive and negative outputs become the supply voltages. The modules that we tested have a floating out- put. This means that there is no reference to a common Earth (US: Ground) so there won't be any unintended shorts. When we chose our power supplies we assumed that they could be overloaded somewhat before their output voltage would drop. In the first test we loaded the S-60-24 with a nominal power resis- tor (24 V across 8 Q results in 72 W!). In this test It appeared that the voltage began to drop when more than 3 A was required (22 V across 7 Q, which is still quite good). So far this power supply looks good for use in this application. In the original circuit of the IGBT power amplifier there are two 10,000 pF electrolytic capacitors on board, which decouple the sup- ply voltage dose to the power transistors as well as possible. When the amplifier was driven at full power at low frequencies around 20 Hz the power supplies weren't able to keep the large electro- lytes fully charged, which caused a large and irregular ripple to appear on the supply lines. The peak current that the electrolytics required from the power supply was simply so large that it triggered the protection circuit of the modules. When these electrolytics were left out It resulted in an increase in distortion from the amplifier. A compromise was found where the electrolytics were replaced with 1 000 p F types. The distortion at 1 W/8 £2 a nd a bandwidth of 80 kHz then became slightly higher (0.042 % instead of 0.032 %). During a standard distortion measurement with a bandwidth of 80 kHz, it was immediately noticeable that it returned a much higher value than when a normal power supply was used. The orig- inal IGBT power amplifier had a distortion figure of only 0.002 % when it was powered by a normal mains transformer, bridge recti- fier and smoothing electrolytics. An FFT analysis of the spectrum of the output signal quickly confirmed the differences. In Figure 1 you can see the complete spectrum up to 1 30 kHz. What stands out most are the frequency components above 20 kHz. These mostly Figure 1 . FFT of the output of the IGBT power amp when an S-60- 24 is used as a power supply. The biggest interference peaks are still more than 70 dB below the test signal and are far outside the audio band. originate from the power supply. They are, however, far outside the audio band. According to the datasheet of the power supply the S-6G series switches at 77 kHz, which can be dearly seen from the FFT measurement. At higher audio power these frequency components become slightly less prominent and the harmonics of the audio signal take the upper hand. All components are at least 70 dB below the fundamental fre- quency (which was suppressed to achieve a lower noise floor in the FFT). This corresponds to less than 0.1 pW! Figure 2 shows an enlargement of part of the spectrum. From here you can see that the two series connected power supplies don't have exactly the same switching frequency. It is not quite clear what the cause is of the two more distant components at 69 and 93 kHz, but we do know that they also originate from the power supplies. Under normal circumstances most power is required at lower fre- quencies. It is therefore interesting to find out how hard the ampli- fier can be driven at 20 Hz. For the S-60 the maximum output power Figure 2, When we zoom in on the switching frequency we see several strange peaks from the S-60-24. dektor 06-2010 69 SWITCH-MODE AUDIO POWER SUPPLIES ■7! 7 ~ -Hi ID? — -as im| -9? w? E -10? 733 -lGJ 64 d S 1!2 547 r -nr A -127 ?&t -132 !73 ■ 13 ? 09 ■ 14 ’ 39 ? ■ 14fi 993 .Ml 60k 6?k S& 00 k B2k 66k !ftk 96k KOi' M- Figure 3, The FFT for the L PS-7 5-24 looks a lot tidier. There is Figure 4, When we zoom in on the switching frequency we see that virtually no interference from the residual switching frequency the LPS-75 has ‘exemplary 1 behaviour. (88 dB below the reference signal). at 20 Hz was 30 W into 8 H, 39 W into 6 £2, 42 W into 5 Q and 44 W into 4 Q (THD+N = 0,1 %). At 1 kHz the maximum output power was 57 W into 4 £2 (54 W at 1 00 Hz). The lower the load impedance becomes, the more the output voltage of the power supply drops during the peak of the signal. It is clear that the power supply has reached its limits here. Comparisons To get an idea if the spectrum we measured was typical of this type of power supply we also tested two modules from a different series, made by Mean Well. These were taken from the open series (no shielding), which could supply slightly more current: the LPS-75-24. This type was specified to deliver 3.2 A. We also tested this power supply with a ‘normal’ resistor. The LPS- 75-24 only started struggling (falling output voltage) when more than 4 A was demanded, which is 25 % above the value speci- fied. With this type we could therefore use slightly lower load impedances. The complete spectrum of the amplifier when used with this power supply (again, two modules were connected in series to create a symmetrical power supply) can be seen in Figure 3* It is noticea- ble that there is a much cleaner spectrum directly above the audio band (20 kHz and higher). In Figure 4 you can see an enlargement of the frequencies around the switching frequency. The spectrum here contains fewer components (and with a smaller amplitude) than the S-60 version. Improvements? The peak to peak ripple at the output of the 5-60 power supply turned out to be slightly more than was stated in the datasheet, about 200 mV instead of 1 50 mV (ignoring any spikes). The first thing that came to mind when we wanted to improve on the results was to use a pair of chokes in series with the supply lines. Chokes of 64 pH/3 A appeared to make very little difference in the FFT analy- sis and seemed to have an adverse effect on the distortion figures; these clearly became higher. Extra electrolytics also made things slightly worse, so there didn’t appear to be a 'quick fix* to improve on the specifications. This doesn’t mean that these types of power supply are unsuitable for audio applications. Despite the fact that the distortion in the fre- quency band up to 80 kHz is greater than when an 'analogue 1 sup- ply is used, the effect of the noise from the switching frequency is negligibly (inaudthly) small as far as we Ye concerned. We 1 re talking about 1 00 nanowatts at 77 kHz ... From the measurements it appears that the L PS-75-24 works better than the S-60-24, It could be that the board layout of the modules is a reason for the difference between the two types. In the 5-60 series the mains side is right next to the low-voltage output. In the LPS- 75 series these connections are on opposite sides of a long, narrow board, which gives them an optimal separation. The shielding in the S-60 appears to have very little influence, although it is of course safer. However, on the 5-60 the AC powerline connection and the low-voltage connection are on the same screw terminal block. On the LPS-75 half of the board is at AC live potential. On the downside, the connections on the LPS-75 series are on separate JST connec- tors, for which you have to find the appropriate plugs. The biggest 'problem’ with this type of module is that they have been designed with DC loads in mind. In a power amplifier the aver- age current of a sine-wave over half a wave is about one third of the peak current (as long as the amplifier isn't over-driven). Con- sidering the average power, one module for half of the power sup- ply for the ICBT power amplifier with a 4 £2 load could be rated for half the power (between 30 to 40 W), as long as the power supply is able to deliver a peak current 3 times the average. This is some- thing that the modules we tested couldn't do. The solution is to choose higher rated power supplies or ones that have been specially designed for audio use and that can supply higher peak currents (such as the SAPS-400 Rf). At the end of the day, the tested power supplies weren’t totally Ideal, but they were inexpensive. The cost of the modules we tested was about £20 each. Try building a traditional power supply for this, with a transformer and large electrolytics! (090941) Internet Links [ 1 j www, meanwell.com [2jwww.elektor.com/07O688 70 06-2010 elektor EXPERIMENTAL ACOUSTICS By Ed Simon {USA} One of the tools of the acoustics trade* Is the and one of those tools you can’t live without once with the relevant technology using low-cost components and DIY methods, we also get < building a shaker table from an old woofer. As you may know a change in distance per unit of time is velocity, and a change in velocity per unit of time is acceleration, Digikey's catalog listed a single axis model part #MSP1 001 that costs less than $50,00. It is a small ceramic package with three leads, and designed to be glued onto a test surface unlike the more general purpose units that can be screwed on. The unit arrived with a small calibration slip that said it produced 9.3 mV per C (that“s Gravity not grams!). The manufacturer's website showed a typical preamp circuit to boost this to a more convenient level. The preamp My take on this circuit is shown in Figure 1 . Effectively the gain of the original circuit was modified so that my sensor produced either 0.1 V/G or 1 .0 V/C. You could also change the second op-amp circuit into an integrator if you wanted a velocity output. In my parts collection there was a miniature 4-pin Lemo connector set, so it got used for the input connector. BMC connectors are com- mon in test gear so that became the output connector. It was easy to make a small PC card for this circuit with two outputs, one 0. 1 V per G and the other 1 V per G. A jumper cable from the card to the BMC connector allows for either to be used. It has stayed at 1 V/C as nothing so far has been above 1 G« A small wall wart style 1 2 volt AC plug-in transformer seemed fine for the power supply. Figure 2 shows the preamplifier with the parts mounted on a circuit board and the connectors installed. Applying the sensor The sensor was epoxied to a small piece of wood to allow It to be screwed firmly to the device under test. I wanted a good solid hard- wood, so a flitch of ebony from the scrap bin seemed to be perfect. Of course hickory, ash, or even hard maple would be good choices. I then placed a small test loudspeaker on my bench with three sorbothane feet under it. After trying a few mounting methods for the sensor on a stick, double stick tape won! ft seemed to give the same results as screws or clamps. I mounted the sensor to the top (shortest side), side and back of the case. Moving the sensor around gave pretty much the same curves. The minimum reading or back- ground vibration level seemed to be about 5 or 6 milli-Gs, The results for four of the loudspeaker tests are shown in Figure 3. IflOp Figure 1 . The preamplifier is designed to convert the accelerometer output into a signal with a 1 V/G or a 0, 1 V/G gradient. Figure 2. Assembled preamplifier in its case. Note the on-board rectifier and symmetrical supply section. elektor 06-2010 71 Figure 3* Frequency response measurements* 2 -way 1 " thick walnut bookshelf loudspeaker, top dead center blue Same loudspeaker long side centered light blue Same loudspeaker long side center of rear edge green Back yellow Figure 4, Use this homebrew shaker table to reveal some unexpected weaknesses of electronic components. This showed that the case was solid with no spikes revealing cabi- net buzzes. The crossover frequency was clearly evident. I won- dered If l was seeing case vibrations or the energy response of the loudspeaker. c Figure 5. Biasing circuit for capacitors under test on the shaker table. The complementary piece of equi pment for the accelerometer is the gizmo to move or shake things and then measure their response. 1 had a nice good condition JBL 2206 1 2 " woofer that mishandling tore a large hole in the cone. Before reconing the loudspeaker it seemed reasonable to try It out as a shaker table* I cut off most of the cone, removed the dust cap and placed a 1 / 8 " (3 mm) piece of ply wood across the voice coll. Placing the accelerometer on the table showed this made a reasona- bly nice shaker table. It subjected the parts in audio gear (capacitors and resistors) to between 0.2 and 0.5 Gs depending on frequency. You could use a feedback system to make it more linear if you had a need. 1 used Moyen loudspeaker cement to mount an assortment of capac- itors and the accelerometer to the platform (Figure 4} 1 allowed this to dry overnight, I then used a 9-volt battery and a 10 kn 1/4 watt metal film resistor to bias the devices under test. The 'interface* cir- cuit diagram is given in Figure 5* This was fed through another film capacitor to my Audio Precision test set. A Crown IVTA2400 amplifier was used to power the former JBL 2206 shaker table. The test system moved things more than you should get just from sound pressure, A transformer in a power supply produced 0.2 Cs right were it was mounted but this should be less at the actual circuit card. Your music system will have a gain of 20-odd dB in just the power amplifier. Some preamps add another 70 dB or even more! So if the test shows 500 microvolts at 0.5 Gs that could be 158 millivolts to your speakers at 5 milll-Cs! The results were quit interesting. Figure 6 shows the results from two different mounting methods on two types of capacitors and the test leads shorted. Large liquid filled capacitors were often less sensitive to vibration than other types* On rectangular capacitors the wide side was more sensitive than the narrow side* Round capacitors were not better than rectangular ones. Miniature capacitors did not do as well as the larger version. Of course capacitors also have other differences besides vibra- tion sensitivity* So this is certainly a design consideration but not the only one. 72 06-2010 elektor K - RIMENTAL ACOUSTIC Figure 6. Capacitors on the shaker table. Sideways Panasonic 1 uF 1 00V ECQE Series Metalized Polyester Film Rectangular Case Light Blue Nichicon 1 OuF 25V VR Series Aluminum Electrolytic Miniature Radial Case Yellow Shorted Test Leads PC Mounting Green Blue Red In short use as few motion sensitive parts as possible. Mount your capacitors so that the narrowest side is on axis with the most induced vibration. In active loudspeakers or just crossovers you might want to decouple the circuit. Mechanically isolate or physi- cally separate the power transformer. Finally don't use parts with high sensitivity in low level parts of a circuit. (080879 Python Programming and GUIs Get started quickly and proceed rapidly This book is aimed at people who want to interface PCs with hardware projects using graphic user interfaces. Desktop and web based applications are covered. The programming language used is Python, an object-oriented scripting language; a higher level language than, say, C. Obviously having fewer lines of code will be quicker to write but also fewer lines of code means fewer opportunities to make mistakes. Code will be more readable, and easier to modify at a later date. You can concentrate on the overall operation of the system you are making. This abstraction also applies when writing graphic user-interfaces. Writing low level code for graphics and mouse clicks and the like is something that you do not have to do. In Python all this is wrapped up in relatively simple functions. The book guides you through starting with Linux by way of a free downloadable, live bootable distribution that can be ported around different computers without requiring hard drive installation. Practical demonstration circuits and downloadable, full software examples are presented that can be t he basis for further projects. 224 pages * ISBN 978-0-905705-87-3 £29.50 - US $47.60 Elektor Reg us Brentford 1 000 Great West Road Brentford TW8 9HH United Kingdom Tel. +44 20 8261 4509 Further information and ordering at www.elektor.com/shop elektor 06-2010 73 DESIGN TIP Mini dice By Petrus Bitbyter (The Netherlands) There have been countless designs for electronic dice over the years, each attempting to outsmart the others. What's special about this mini dice is the minimal number of components needed; one chip, one capacitor, one pushbutton and seven LEDs. To keep everything small the author used SMD parts and a miniature circuit board for the prototype. Should you want to make it smaller still, then you could make an even tinier circuit board using smaller LEDs, But if you can't even see these so-called sprinkles then you may also use through -hole par ts and a small piece of prototyping board. All the work in this circuit is done with the PJC10F200. one of the smallest microcontrollers known to mankind. Nothing appears to happen when the circuit is first switched on, but after a button push the first number appears. With each subsequent push the dice closes its eyes (so It can think} and generates the next number There has to be some time between two consecutive button pushes. If the button is pushed too soon the dice will not react. When the but- ton is held too long, the dice will react when the button is released instead of when it is was first pushed. The software is relatively straightforward. Using the built-in timer a clock of about 1 kHz is generated. The exact frequency is not terribly important, as long as It is stable. The clock drives a software coun- ter which continuously counts from 1 to 6 and then wraps around. At the end of each clock period the software checks whether the pushbutton is pressed. If this is the case, the counter value at that instant is stored, and will be used as the next number. At the same time all the LEDs are turned off and two software timers are started. The first timer determines how long the LEDs remain off. When this timer expires the new number is displayed. The second timer deter- mines the length of time before a new button push is accepted. As long as this timer Is still counting it will not react to any new button pushes. If the button is still (or again) closed when the timer expires, then the release of the button is considered the command to pro- duce a new number. bti vdd (01 GPO Cl si GP3/MCIR CPI PIC1DF2000T GP2JTQCLK 4V5 1 0On £ f 1 1 J" 090242-11 — ft-i 01 02 M — M- 03 tt DA M □5 D6 D7 D 3 J [D 2 j (D7) (D5 □ij [04 The supply voltage for the dice has to be somewhere between 3.5 and 5 V. You could use three AA alkalines or a 5-V power supply with a series diode. A little experimenting may be required because the light output is strongly dependent on the characteristics of the LEDs used. The drive to the LEDs is multiplexed and they are therefore not continuously on. The current is limited by the microcontroller. This reduces the number of components but does make the circuit more sensitive to changes in the power supply voltage. (090242) The source code and hex files for this project are available at www.elektorcom/090242. The PCB layout in Lagfe format can also be downloaded from there. Prototype & small series PCB specialists PCB proto STANDARD pool TECH pool IMS pool On demand all options up to 16 Call us: 020 8816 7005 Email: euro@euroclrcults.com See us five at National Electronics Week — NEC booth dedicated prototype service widest choice 1 * 100 pm technology metal -backed ALL SERVICES Instant online pricing Instant online ordering Low pooling prices Deliveries from 2 days No tooling charges Stencil service www.eurocircuits.com 74 06-2010 elektor TO DISCOVER. 000 Uektor Buselb ^3 letthe •r* 1JILJ* nm rum I EUCN T^CiiU TO DISCOVER ATWlTi Logic I |Uly Fii '*£ SCEPTRE RULE! l.rttrn-camP^ 1 -■ __ MODULO d A J2-Wt*NM7 (pit (imtoLWi"' 1 * iyiLr* + |lnu* op a t-Wp The upgraded Elektor-PLUS subscription! o All 1 1 issues including the Summer Circuits edition o Included in your PLUS subscription: Annual DVD 2010 o 20% cheaper than normal retail price o Welcome gift worth £25 O Up to 40% discount on selected Elektor products O Elektor is delivered to your doorstep every month O Read your copy before everyone else O NEW: On your personalized Elektor PLUS website, you have permanent access to the three latest issues of the magazine in PDF format, as well as to a fast Elektor search engine! NEW: exclusive access ^,. e |ektor-plus.com. When taking out an Elektor PLUS subscription you get exclusive access to www.efektor-plus.com where the three latest editions of Elektor magazine are available in the form of pdf files (i.e. the current issue and the two pre- ceding ones). With a simple click you download the complete issue (front to back]) or any single article. www.elektor-plus.com also sup- plies the most extensive Elektor search engine found on the web. However the upgraded PLUS subscription offers many more interesting extras like free E-books and supplementary articles. www.elektor.com/subs * Tel. +44 (0) 20 8261 4509 Or use the subscription order form near the end of the magazine. Hexadoku Summer is upon us and you should admit to having a bunch of outdoor activities to attend to besides working on your electronics projects and sending them to Elektor for publication. But surely there's an hour or two left to solve this month's Hexadoku! Send the hexadecimal numbers in the grey boxes to us and you automatically enter the prize draw for four Elektor Shop vouchers* Have fun! The instructions for this puzzle are straightforward. Fully geared to electronics fans and programmers, the Hexadoku puzzle employs the hexadecimal range 0 through F, In the diagram composed of 16x16 boxes, enter numbers such that all hexadecimal numbers 0 through F (that 5 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. Correct entries received enter a draw for a main prize and three lesser prizes. All you need to do Is send us the numbers in the grey boxes. Solve Hexadoku and win! Correct solutions received from the entire Elektor readership automati- cally enter a prize draw for one Elektor Shop voucher worth £ 80,00 and three Elektor Shop Vouchers worth £ 40.00 each, which should encourage all Elektor readers to participate. Participate! Before July 1 , 2010, send your solution (the numbers in the grey boxes) by email, fax or post to Elektor Hexadoku - 1 000, Great West Road - Brentford TW 8 9HH United Kingdom* Fax (+44) 208 2614447 Email: hexadoku@elektorxom Prize winners The solution of the April 2010 Hexadoku is: DFB12. The £80.00 voucher has been awarded to: Gerhard Dum (Austria), The £40.00 vouchers have been awarded to: Mark A, Saywell (UK). Anton Ioffe! d (USA) and Gabi & Thomas Riester (Germany), Congratulations everyone! 7 4 8 3 6 9 8 C 2 9 0 0 C 5 1 0 1 B E_ C 7 9" A F 3 F C 5 6 1 2 F 0 A 4 9 B 5 3 A 6 9 3 B 1 7 8 E 2 4 7 4 6 B A 3 C 9 D A D C E 9 2 2 1 3 4 F 6 D 3 E 8 F B C 4 A 7 6 6 8 3 D 7 0 F 4 9 5 6 1 0 E 9 E 2 F 8 4 7 F 5 C A 7 6 ' 3 4 8 (El con» 5 8 B E D A 9 C 4 7 2 6 IF 3 0 1 1 2 C 6 4 7 E 8 3 0 D F 5 B A 9 A 9 4 3 F 6 B 0 C 1 5 8 E D 7 2 7 F 0 D_ 1 3 _5_ 2 E J3_ 9 A 6 _C_ 4 8 0 5 F C E 2 4 A 6 9 1 3 B ( 8 D 7 4 6 9 ' 7 0 8 3 B 2 A C D 1 E F 5 2 B 8 1 9 D C F 0 5 7 E 3 A 6 4 E D 3 A_ 7 5 _1_ A B _8_ F _4_ _9_ 2 _ _C_ 0 B E 7 5 2 0 F 1 8 D 6 C A j 9 3 A D 3 1 9 C 4 A 1 E 7 F B 2 8 : 0 5 6 8 C 6 2 3 9 D 5 A 4 0 1 7 F E B F 0 A 4 6 B 8 7 9 _E_ 3 _5_ [D 1 _2_ _C_ 9 1 5 B A C 0 3 F 6 E 7 2 4 8 D 3 4 2 8 5 E 7 9 D C A ' B 0 6 1 F C 7 E 0 8 F 6 D 1 2 4 9 A 5 B 3 6 A D F B 1 2 4 5 3 8 0 C 7 9 E The competition is not open to employees of Elektor Intern a tic rid I Media, its business partners and/or associated publishing houses. 06-2010 elektor RETRONICS elekterminal (1978) By Antoni Gendrau (Spain) Many moons ago P computers were unsophisticated — they had very poor graphic screens, and text screens were even worse. In the earfy 1 980s I owned a Super- board II computer. It was based on a Rockwell 6502 microprocessor, and the text screen had a 'superb' 30x30 characters resolution. As an aside, this computer featured a Microsoft BA5IC interpreter (in only 8 Kbytes of ROM), that was probably written by Bill Cates himself. I used it fora while for programming, gaming and typewriting, but soon realized that 30 characters per line wasn't enough for some jobs on hand. When I was thinking how to improve my text screen, I suddenly remembered I had a copy Elektoris December 1978 edition, with an article about a project called elekterminal (s/c) — a 'dumb' ASCII VDU provided with a serial interface and capable of displaying 16 lines x 64 characters. The whopping 64 characters per fine for the first time allowed me to write real lines of text and to understand program code more easily. Furthermore, the serial port enabled me to leave the computer in my lab and access it from any room in my home thanks to the elekterminal. All quite essential — because my Superboard had put on weight due to several 'improvements' and expansion cards added overtime. When J decided to build the elekterminal, I was faced with three major problems; the components, the printed circuit board and an outlandish device called PROM. J barely had heard of programma- ble devices before! Firstly I tried to find all the necessary components, and surprisingly, I was successful in local shops. At that time electronics retail out- lets were numerous, although with hindsight the number of devices stocked was limited. Secondly, the PCB, With my budget best described as 'really small’, and Elektor kind enough to print the PCB copper track layout in the article, I decided to make the board myself, using the traditional method, i.e, photocopying the Elektor page containing the PCB design onto a piece of transparent film, then applying the f Im over a piece of photosensitive board and finally exposing the solder side of the circuit board to about 45 seconds worth if of UV light from the sun. Lastly I etched away the unwanted copper using hydrochloric add and hydrogen peroxide. The result: a perfect single sided PCB. And finally, the PROM. The device is used to assist the CRTC chip in deciding which ASCII characters are used to erase the screen (CLS), go one line down (LF), and many other special functions. Sadly 1 didn't have a PROM programmer, and the formidable task of pro- gramming 1,024 bits of data manually (and without errors) looked like an impossible mission. What to do? Mulling over the problem, 1 realised that the first half of the memory space was blank, and in the second half only 34 characters (136 bits) had to be programmed. Now the problem was down to the timing. To program a bit, a very short pulse must be supplied to a PROM pin. I tried with a pushbut- ton, pressing it as fast as 1 could, and.., it worked! The assembly of the PCB was easy, as well as putting all the items In a suitable case while making sure the result would look accepta- ble, as shown In the picture. Usually, the first time power up of a homebrew circuit is a thrill, but I was not less excited when I carried my elekterminal from the attic for examination and to write this piece for the Retronics series. I powered up, and Eureka! The familiar screen full of gobbledygook appeared again. Nope, elekterminal has no provision to erase the screen RAM at power up! Oh dear, my version of the power sup- ply had two 7805 regulators connected in parallel — definitely not something I would do today! Inspired by Elektoris December 2009 edition on home automation standards, and using AC power line signalling I managed to connect equipment to the elekterminal without a long RS-232 cable. I was able to communicate at 1 200 baud with a simple circuit. The Idea is to modulate a fixed frequency for 1 , and nothing for 0. At the far side, a filter tuned to the frequency transmitted recovers the logic 1 's. Today 1 am working on designs to automate my home using the elekterminal as a portable programming unit — giving it a second lease of life. (100117) 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.com elektor 06-2010 77 ELEKTOR SHOWCASE To book your showcase space contact Huson International Media Tel. 0044 (0) 1932 564999 ASTROBE V3.0 www.astrobe.com Windows Development System for LPC2000 microcontrollers. • Develop high-and low-level software without C or assembler • Generate fast 32-bit native ARM code • No special programming hardware required • Personal. Standard and Professional Editions ATOMIC PROGRAMMING LTD www.atomicprogrammingxoni * AP-1 14 ISP/JTAG Programming System * JTAG Programming and Testing * Boundary Scan Testing * Universal In-System Programming * EEPRGM and SPI Flash Out-of-Circuit Programming * Generic GDB Proxy Server * Jennie JW51 48 ZigBee Development Applications * Training Platform available AVIT RESEARCH www.avitresearch.comk USB has never been so simple... with our USB to Microcontroller Interface cable. 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' Hi + ltl + M fa a, - a fa 1 aa-aa- aa-aa aa-aa- - *- **■■* -fa aa-aa aa aa-aa B+a+a+B+fa fa fa + ■ + + 1-M M M ■ a fa fa fa a p. p p bb r P(tH fa -i JtMftM M ‘■J tfa.fafa a 1 a as a a- a a- a- a a fa i fa S fa pbpbpbprp-p----»p-F'«--*-- J | SHOP BOOKS, CD-ROMs, DVDs, KITS & MODULES A laser alarm, USB teasing mouse, soundswitch and much more 50 PfC Microcontroller projects This book contains 50 fun and exciting projects for PIC microcontrollers such as a laser alarm. USB teasing mouse, eggtimer, youth repellent, soundswitch , capacitive liquid level gauge, finger in the water” sensor, guarding a room using a camera, mains tight dimmer (1 1 0-240 volts), talking microcontroller and much more. Several different techniques are discussed such as relay, alter- nating current control including mains, I2C, SPI, RS232, USB, pulse width modulation, rotary encoder, interrupts, infrared, analog-digital conversion (and the other way around), 7-segment display and even CAN bus. Three PIC microcontrollers are used in this book, the 1 6f877A, 1 Sf4455 and 1 8f4685, It is also discussed how you can migrate your project from one microcontroller to another - T 5 types are supported - including two example projects. 440 page* * ISBN 978 “0-905705-88 0 * £36.00 ■ US $58,10 Several case studies included PIC Cookbook for Virtual Instrumentation The software simulation of gauges, con- trol-knobs, meters and indicators which behave just like real hardware components on a PCs screen is known as virtual instru- mentation. !n this book, the Delphi pro- gram is used to create these mimics and PIC based external sensors are connected via a USB/RS232 converter communication link to a PC. Case studies of virtual instruments are detailed including a compass, an oscillo- scope, a digital and analogue thermometer and virtual displays for cars and aircraft. 264 pages * ISBN 978 0-905705-84 2 £29,50 ■ US$47.60 Home electric power Your own Eco-Electrical Home Power System This book provides the semi-technical, power-conscious homeowner a place to begin in the quest for home electric power. Both the essential principles and detailed information on how to build or maintain a home electric system off the utility grid are presented in an easy-going style. This booklet wi 1 1 help you to safegua rd or de- velop your own homeelectridtysupply.lt containsstep-by-step calculations, practi- cal details, examples and much more, 75 pages - ISBN 978-0-905705-82-8 tt6,50 * US S26.70 V \ So Prices and item descriptions subjectto change, E. & O.E 06-2010 elektor Learn more about C# programming and .NET C# 2008 and .NET programming This book is aimed at Engineers and Scien- tists who want to [earn about the .N ET en- vironment and C# programming or who have an interest in interfacing hardware to a PC. The book covers the Visual Studio 20QS development environment , the .N ET framework and C# programming language from data types and program flow to more advanced concepts including object ori- ented programming. 24(1 pages * 15BN978 0-90S705-81 1 £29.50 * USS47.60 COMPLETE PR ACT It AL MEASUREMENT SYSTEMS USING A PC ■ = ■ . MM m £• M Him tout Circuit design and programming Complete practical measure- ment systems using a PC This book covers both hardware and soft- ware aspects of designing typical embed- ded systems based on personal computers running the Windows operating system. Ifs use of modern techniques in detailed, numerous examples has been designed to show dearly how straightforward it can be to create the interfaces between digital and analog electronics, programming and Web-design. Readersare encouraged by examples to program with ease; the book pro vides dea r g u idellnes a s to the appropri- ate programming techniques "on the fly". 292 pages * ISBN 978 0-90 57 05-79-8 £28.50 • US 546.0(1 r* pulton Get started quickly and proceed rapidly Python Programming and GUIs This book is aimed at people who want to interface PCs with hardware projects using graphic user interfaces. Desktop and web based applications are covered. The pro- gramming language used is Python, an ob- ject- oriented scripting language; a higher level language than, say, C. Obviously hav- ing fewer lines of code will be quicker to write but also fewer lines of code means fewer opportunities to make mistakes. Code will be more readable, and easier to modify at a later date. You can concentrate on the overall operation of the system you are making. This abstraction also applies when writing graphic user-interfaces. Wri- ting low level code for graphics and mouse clicks and the tike Is something that you do not have to do. In Python all this is wrapped up in relatively simple functions. The book guides you through starting with Linux by way of a free downloadable, live bootable distribution that can be ported around dif- f e re nt com p u ters wi th o ut req u i ri ng h a rd drive Installation. 224 pages * fSBN978-0-9057G5-87-3 £29.50 * US 547.60 l V More information on the Elektor Website: www.elektor.com Elektor Regus Brentford 1 000 Great West Road Brentford TW8 9HH United Kingdom Tel.: +44 20 8261 4509 Fax: +44 20 8261 4447 Email: sales@elektor.com L j A whole year of Elektor magazine onto a single disk dvd Elektor 2009 This DVD-ROM contains all editorial arti- cles published in Volume 2009 of the Eng- lish, American, Spanish, Dutch, French and German editions of Elektor. Using the supplied Adobe Reader program, articles are presented in the same layout as origi- nally found in the magazine. An extensive search machine is available to locate key- words in any article. With this DVD you can also produce hard copy of PCB layouts at printer resolution, adapt PCB layouts using your favourite graphics program, zoom in / out on selected PCB areas and export circuit diagrams and illustrations to other progra ms. \SBU 978 - 90 - 5381 - 251 -8 £17.50 * US 528.30 1 1 0 issues, more than 2, 1 00 articles dvd Elektor This DVD-ROM contains the full range of 1 990-1999 volumes (all 110 issues) of Elektor Electronics magazine (PDF). The more than 2.1 00 separate articles have been classified chronologically by their dates of publication (month/year), but are also listed alphabetically by topic, A comprehensive index enables you to search the entire DVD, ISBN 978 -0-905705-76-7 £69.00 * US Si 1130 V elektor 06-2010 Si See the light on So ltd State Lighting dsPIC Control SHOP BOOKS, CD-ROMs, DVDs. KITS & MODULES ED Toolbox (May 2010) This DVD-ROM contains carefully-sorted comprehensive technical documentation about and around LEDs. Forstandard mod- els, and for a selection of LED modules, this Toolbox gathers together data sheets from all the manufacturers, application notes, design guides, white papers and so on. It of- fers several hundred drivers for powering and controlling LEDs in different configura- tions, along with ready-to-use modules (power supply units, DMX controllers, dim- mers)- In addition to optical systems, light detectors, hardware, etc,, this DVD also ad- dresses the main shortcoming of power This control board has been designed for incorporation into typical industrial elec- tronicsapplications like controlling mo- tors or adjustment of static up- or down -converters Jhe objectives were to obtain a board with a large number of pul- sewidth modulation (PWM) generators, which enables us to control several mo- tors and static converters at the same time. The cost of the control board nee- ded to be as low as possible too. In addi- tion, it must be possible to construct the board using a soldering Iron, without re- quiring use of a reflow oven. LEDs; heating. This DVD contains more than 1 00 articles on the subject of LEDs. PCS r populated and tested ISBN 973-90-5381-245-7 £28.50 * US $46.00 Elektor’s Components Database 5 (May 2010) cd ECD 5 The program package consists of eight data- banks covering ICs, germanium and silicon transistors, FETs, diodes, thyristors, triacs and optocou pie rs . A fu rthe r el even applica- tions cover the calculation of, for example. LED series droppers, zener diode series resis- tors, voltage regulators and AM Vs. A colour band decoder Is included for determining resistor and inductor values. ECD 5 gives in- stant access to data on more than 69,000 to m pon ents. A! I data banka ppl icati o ns are fully interactive, allowing the user to add, edit and complete component data, ISBN 978-90-5381-159-7 £24.90 * US $40.20 The CQ ? Meter published in our January 2008 edition continues to operate very well, so why bother to do a new design? The answer is both simple and obvious. In the previous article, we mentioned that too high a concentration of C0 2 negatively affects the ability to concentra- te. And in which daily activity does the abi- lity to concentrate play an important role? Exactly! While driving a car (excluding con- vertibles). We therefore developed a C0 2 meter that is suitable forin-car use. Kit of ports, including sensor and LCD ( excl. enclosure ) (April 2010) A power supply with adjustable output voltage and current limiting is part of the basic equipment of every electronics lab. However, the increased complexity of a switch-mode design scares away many potential builders, even though it actually isn’t all that com plicated if you use a sui- table combination of well-known techno- logies. This circuit is suitable for build i ng a single ordual power supply. PCS and of/ components, /ess power transformer Ari f 090786-71 - £64.00 * US SI 03 JO (March 2010) This open-source & open-hardware pro ject aims to be more than just a little board with a big microcontroller and a few use- ful peripherals — it seeks to be a fast pro- totyping system. To justify this title, in addition to a very useful little board, we also need user-friendly development tools and libraries that allow fast Implementa- tion of the board's peripherals. Ambitio- us? Maybe, but nothing should deter you from becoming Master of Embedded Sys- tems Universe with the help of the Eiektor Sceptre. PCB, populated and tested, lest software loaded (excluding Bluetooth module) 82 Prices and item descriptions subject to change, E. & O.E 06-2010 eiektor r A s 3 ]une201Q(No.4G2) £ US 5 0B02 Mini Simulator Virtual car sup ports PWM(i5G|KWP2Q00 080804-71 ,„, Kit of parts 84.G0.....1 35,50 Wireless Electricity meets RFID 1 00051-7 1 .... Kit of parts, containing 3 PCBs {RFID Tag, debugger and reader}, 2 programmed micro- controllers and 080910-91 module www.elektor.com InterSceptre opens doors (and portsl) for you 1 001 74-71 .... Kit of parts, contains PCB and components www.elektor.com May 2010 (No, 401) dsPlC Control Board 090073-91 .... PCB, populated and tested 140,00 225.90 Cloud Altitude Meter 090329-91 .... Popu I ated PCB in en closure {see poll) www. elektor.com In -vehicle C0 2 Meter 1 00020-71 .... Kit of parts 1 3 7. 00. .,.,2 2 1,20 1 00020-72 .... Enclosure 19,00. 30.70 VisiOLED 081141-1 Printed circuit board....... ,. 13,30 21,50 April 2010 (No, 400) UnfLab 090786-1 Printed circuit board 16.00 *.25,90 090786-71 .,... PCS and all components, less power transformer 64.00 103.30 Smallis Beautify i:Minimod18 090773-41 .... Programmed controller with Bootloader pre-programmed.. 2 1.80 35,20 090773-91 ,.„ PCB, populated and tested with Bootloader pre -p rogra mm ed ..* 5 6, 00 „ . ... ,9 0.40 Bluetooth for OBD-2 090918-71 .... PCB with SMDs fitted, BTM222 Bluetooth module..,,. 26,70 43, 1 0 Fun with Fireflies 100014-1 ...... Printed circuit board juiLiuii.aiui (■■■■■riiiiiii>ririiriiri-H>HP4' a 11.00 17.80 100014-41 .... Programmed controller .. a ■ m ■ ■ j ■ ■ ■ iij ■ bo b a ■ b ra fl'Bi a ra bibb m bi ■ f m r + i r l 11^ 00 ..17.80 Beep, beep... Sesame 08 1 1 43-41 .... Programmed controller, 1 5.50 25,00 5 V Power Controller 090719-1 Printed circuit board 8.90 1 4.40 March 2010 (No. 399) Reign with the Sceptre 090559-91 ,.., PCB, populated and tested, test software loaded (ext I ud i ng Bi u e tooth mod ule ) — 89.00,, Modulo D 090563-71 „..PCB, SMD-populated.and all other components 69.90... ,,143.60 ,.112,80 ■I ►H It* P + a «■ 17.80 28,80 124,00 200.00 ITlFTlITlf + OtiF ■ 1 B I 1 Ft! FI 1 P M S9.00 143.60 February 20 10 (No, 398) Battery Checker 071131 -41 .... ATmega32-1 6PU, programmed 071 131-71 Kit of parts, excl. enclosure ... Winamp Controller 090531-71 .... Kit of parts The ATM1 8 Radio Computer 090740-71 .... PCB with Si4734/35 radio 1C ready mounted and tested 27. 50.,, 44.40 January 2010 (No. 397) USB Magic Eye 0907 88-1 Pri nted ci rcu it bo ard BFBBTIBMFi- fe + 4 14 P P + 1 + + P # + ■■■■■ P ■ P ■■■■■■ ® ■■■ ■ 9,90. ,16.00 090788-41 ATtiny231 3-20PU. programmed 9,90 16,00 MfAC for Home Automation 090278-91 Populated PCB in enclosure ..... 1 54,00 248.40 Dimmer with a Micro 0903 1 5-41 .... PIO 2F629A, programmed 7.60... 1 2,30 2 o o CO 4 5 r 1 ‘ O □ “8 08 5 1 2 3 4 5 PICCookbot )k for Virtual Instrument at [on ISBN 978-Q-9Q57G5-84-2*.** £29*50 US$47.60 Python Programming and GUIs ISBN 978-0-905705-87-3 .... £29.50 US S47.60 Complete practical measurement using jpc ISBN 978-0-905705-79-8.... £28.50 US S46.00 C# 2008 and .NET programming ISBN 978-0-905705-81 -1 .... £29,50 US S47.60 PIC Microcontrollers ISBN 978-0-905705-70-5..,. £32.00 US $51 .70 Masterclass dvd High-End Valve Amplifiers ISBN 978-0-905705-86-6.... £24.90.... US$40.20 DVD Elektor 2009 ISBN 978-90-5381-251-8.... £17.50 US $28.30 DVD Eleictor 1990 through 1999 ISBN 978-0-905705-76-7,... £69,00 ...US$1 1 1 .30 DVD LED Toolbox ISBN 978-90-5381 -245-7.... £28.50 US $46.00 ISBN 978-90-5381-1 59-7..., £24.90 US $40.20 UnlLab Art. #090786-71 £64.00 US$103.30 Modulo D Art. # 090563-71 £69.90 ...US $112.80 Reign with the Sceptre Art. #090559-91 £89.00 ...US $1 43.60 Bluetooth for OBD-2 Art. # 090918-71 £26.70 US S43.1 0 SDR Preselector Art. #09061 5-71 £47.00 US$75.90/ www.elektor.com/shop or use the Order Form near the end of the magazine! ektor Elektor Regus Brentford 1000 Great West Road Brentford TWS 9HH * United Kingdom Tel +44 20 8261 4509 Fax +44 20 82614447 Email: sa!es@elektor*com S3 elektor 06-2010 Do not miss Elektor*s best selling issue of the year — get your copy in time Slimmer Circuits 2010 - Mega compilation of circuits, ideas and tips Summer Circuits 1 , Elector's extra-thick July & August double edition is the established Numbers source of inspiration for all electronics enthusiasts, Elektor's editors and lab staff have again compiled a massive coflection of small circuits, new 1 C apps, software and project development tips and ideas covering the whole gamut of electronics. From the contents Slope meter LED tester Sweep generator Bicycle rear light Cheap channel zapper FM test generator Guitarcompressor Lithium battery charger Magnet train Capacitor tester Voltage guard 3D pyramid with USB Cable tester Water alarm Magnetotester Extra in the Summer Circuits 2010 edition: DSP General Coverage Receiver A small general coverage receiver with lots of features was developed based on the SI4735 DSP chip. The radio has a two-line LCD and covers the long, medium and short wave bands, as well as VHF FM stereo with an RDS readout included. There’s also automatic preselector tuning, switchable AM bandwidth and precision signal strength metering in dBpV. The first part of this awesome project appears In the Summer Circuits 2010 edition. A; tide titles ami magazine confers subject to change; please check the Magazine tab an www.eMfurcofn Elcktor UK/Emapean edition on sate {line 24, 2010 Elektoi USA edition: published June ij, :oio, cii V v EMw C<«ij Jer ref I- Kph-llffe MtP inn TVy-tica iJu-xh *"□!&!□ ftfc Aft PhO"! , .1# r ■ ; 3 *h itrt V*rtu*i (Vnri r 5*nr niin-jEr e™ i> ' ■« C ?rn|Khnrn; P«Ki,h 4 il»r Eirb^r p-_'. - iihi =■.“.■■■ jijektor 1 — “ ■ a j ^ □ ill Lrrj*ii .1^ *■- rt aI in )i. | 4C:'4 | l it r J in STD. . r Pr Dramming Eml: edd fd PltMitjacDnirallths “-ji o Kit of part! ElektortVh* o irrajEr v i ., \m **!► vii-b-t*. Lb uC r - f i- - 1 ' H %- "n (liii^rjin. nuiff'U •■iid li-fi Hau io^it * J b !. > >: !•- !• t w 1 k fLA tUr tPfiCi TDki (i"np« I^S'O! ‘ fri w fedCHC ■ alPuin Prn.y«3TTirnLnf[ inri cut. ! MlrALL i Onitrt fi umhw nr . Zi •stsiUM 84 06-2010 elektor Description Price eadi Qty. Total Order Code 50 PIC Microcontroller projects rulffl £36.oo Python Programming and GUIs £29.50 DVD Masterclass High-End Valve Amplifiers £24.90 DVD Elektor 2009 £17.50 PIC Cookbook for Virtual Instrumentation £29.50 Sub -to to/ Prices and item descriptions subject to change. Th e p u bl ish ers re se rve th e right to ch a n ge prices P8tP without prior notification. Prices and Item descriptions shown here supersede those in previous issues. E. & O.E. Totat paid METHOD OF PAYMENT (see reverse before ticking as appropriate) Bank transfer | Cheque (UK- re si dent customers ONLY) | | Giro transfer □ visa □ Expiry date: Verification code: Please send this order form to (see reverse for conditions) Elektor Regus Brentford 1 000 Great West Road Brentford TWS 9HH Nam ? 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Orders placed on our Brentford office must include P&P charges (Priority or Standard] as follows: Europe: £6.00 (Standard) or £7,00 (Priority) Outside Europe: E9.00 (Standard) or£l 1 ,00 (Priority) HOW TO 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. 4027021 1 held by Elektor International Media BVwith The Royal Bank of Scotland, London. IBAN: CB96 ABNA 4050 3040 2702 11* 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 International Media BV* 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 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 guaran- tee this time scale for all orders. 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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 cus- tomers 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 International Media BV, 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 permanent 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. 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January 2010 Order custom-designed boards from the Elektor PCB Service The advantages at a glance • Professional quality PCBs. • No film charges or start-up charges. • No minimum order quantity or charge for this service * Available to private and commercial customers * Design check applied to all entries. We'll let you know within 4 hours! * Two PCBs supplied - three produced. n the third board is also okay, you receive it as well - Quick, cheap and secure www.elektorpcbservice.com Index of Advertisers Astfobe. Showcase www.astfQbQ.com — « «-*♦ * APD Shaw: www.apdanglia.ofg.uk Atomic Pros'?.? ? Ltd Showcase . mm 3 tomicpfogfamming.com. . Beta Layout Showcase . www.pcP ‘pool, com By Vac. Show :.is- CEDA. Showcase . . mviY.tiyvac.com . » r t * r * - * www.ceda.in, Designer Syi's-s Showcase www.Pesignersystems. co.uk , . Easysync S! - : a case ■ ^ www.ea5ysync.co.uk . Electronic i 22' l Eirtec. Showcase Euro Circuits www. electronics, cte. en mvw.elnec.com ■ b ■ + First Techno c ] . Transfer Ltd, Showcase . . wwwJttco.uk . FlexiPanei Lie Showcase ... - www.flexipanet.con7 * Ha meg Showcase . . www.hameg.com HexWax Ltd. Showcase www.hexwax.com. . . 79 - - ■! r tJ , , .78 Avil Reses'C' wcase www.avMresearcti.C8.UK . . . . 7B ♦ ,9> 78 Black Robe :■ S^uwcase , www.bfackrobotics.CQm 78 7S *■ !■ - "• »■ ■ <■ I I » ■ ■ r i i i + I ! I 78 Dectbit Co Ltd Showcase * , ♦ . . www.OocM.com ....... . . ♦ . . , , 78 .78 78 57 .. . .78 ........ www.emfctrcuits.com 74 .78 ....... 78 Future Techno! og . Devices, Showcase www.ftPtcfiip.com 2. 79 ■i’ b ■ ■ HI' ■ ■ * * « .78 79 Labcentec www.labcmtor.com - ■ B8 MfkroEleKtronika. . . . * mnvjwkwe.com . 2 MOP Electronics, Showcase . - . , www.mqp.com . , , . - 79 Nujve Networks Www.xgamestetion. com . 23 Parallax + »■+•=» . , , . WWW. para flax, com - ► * - - 23 Peak Electronic Design www.peakeloc. comk. 9 Pico. . - www.picotech.wm/SC0pB200a ♦ ♦ . - 9 Quasar Electronics - vmw.quasarelectroniCS.com t5 Robot Electronics Showcase www.foPoi~elecirorncs.co.uk .79 Robotiq, Showcase www.robotiQ.co.uk . . 79 ■ f i + r § - ■« * ■ [l RS Components ... T . www. rswww.com /ebp . ■ ■■■■■ # 3 , - Ht- - ■ J W Schaeffer AG www.scbAGffer-tiQ.dE 23 Showcase ....... t . . . . ■ ■ * + . -* , + ■ ■ 78, 79 USB instruments. Showcase wwwMsb-instfments. com * . . 79 Virtins Technology, Showcase . . www. virttos. com. . ... . 79 Advertising space for the issue 19 August 2010 may be reserved not later than 20 July 2010 with Huson International Media - Cambridge House - Gogmore Lane - Chertsey, Surrey KT16 9AP - England - Telephone 01932 564 999 - Fax 01932 564 998 - e-mail: ros.elgar@husonmedia.com to whom all correspondence, copy instructions and artwork should be addressed. elektor 06-2010 87 CHECK All Components Placed - CHECK All Connections Routed - CHECK Power Planes Generated - CHECK No Design Rule Violations - CHECK Design with Confidence: The latest version of the Proteus PCB Design Software provides a multi stage Pre-Production Check which will detect and prevent a variety of common mistakes prior to your boards being sent for manufacture. Board Autoplacement & Gateswap Optimiser. Direct CADCAM, ODB++, IDF & PDF Output. Integrated 3D Viewer with 3DS and DXF export Mixed Mode SPICE Simulation Engine. Co-Simulation of PIC, AVR, 8051 and ARM7. Direct Technical Support at no additional cost. Hardware Accelerated Performance. Unique Thru-View™ Board Transparency. Over 35k Schematic & PCB library parts. Integrated Shape Based Auto-router. Flexible Design Rule Management. Polygonal and Split Power Plane Support All levels of the Proteus Design Suite include a world class, fully integrated shape-based autorouter at no additional cost - prices start from just £150 exc. VAT & delivery Electronics Labcenter Electronics Ltd. 53-55 Main Street, Grassington, North Yorks, BD23 5AA. Registered in England 4692454 Tel: +44 (0)1756 753440, Email: info@labcenter.com nil - - £ j| l "1 kJ ■ June 2010 + WHAT Free Audio Measuring Software DIY RFID ✓ home-brew tags ✓ wireless electricity + DMX51 2 Int www.elektor.com InterSceptre Extension Board opens doors (and ports) for you 9 R.26 06 770260 46115