770268 45 The leaders in PIC development EASE OF USE ♦ ♦ + ♦ All you need to get started with PIC Industry standard/quality board Open the box and get coding Available with C compiler or use our PicScriptto write programs using simple commands... NO ASSEMBLER, NO COMPILER, JUST WRITE AND RUN AUTOMATION SCRIPTABILITY PicDev Board with PicScript PicDev Board with C Compiler , £99.00 (plus p+p) £165.00 (plus p+p) This is a complete development suite This is a complete development suite for for the novice or non programmer. the more advanced programmer. It is shipped with: It is shipped with: . PicDev Board • PicDev Board • PicShell and PicScript software • PicShell and PicScript software • Breakout board • C compiler i • Cables . Breakout board . Example scripts . Cables . Example scripts . ICD1 Both items require Yo order* PC with serial port available Power supply adapter \vww.pagm.cQ-,uk sa 1 e Uct p agm . c o .u k Tel: -44 ( 0)1792 89192 " The Volume 2003 CD-ROM is automatically sent to you when published (February 2004) If you take out an cmnual subscription to ELEKTOR ELEC- TRONICS you may choose between two types of sub scription. www.elektor- electroitics.co.uk * PICK YOUP OWN SUBSCRIPTS TYPE AND RECEIVE THIS SURVIVAL Klf This survival kit consists of a collapsible compass with various functions, a lightweight but robust torchlight (batteries included) and a 9-piece stainless steel pair of pliers with 14 functions. © Elektor Electronics Subscription-PLUS priced at £45.50 (UK). You receive 1 1 issues (includes July August double issue) plus a copy of the Volume 2003 CD-ROM. This CD-ROM contains the complete Volume 2003 of Elektor Electronics, including diagrams, PCS layouts and an extensive search function. The normal price is £16.25 (plus P&P). However on choosing Subscription Plus the Volume 2003 CD-ROM is included in the price, and you do not pay postage. Your saving: £10.00! e Elektor Electronics annual subscription priced at £39.50 (UK). You receive 1 1 issues (includes July/August double issue). A standard annual subscription costs £39.50 in the United Kingdom: ECONOMY MAIL: £51.30 in the rest of the world; PRIORITY AIRMAIL: £52.30 in Europe and Eire, £64,00 in the Middle East. Africa. Southwest Asia, Central & South America, £66.00 in Australia. Far East & Pacific Territories; AIRFREIGHT: USS88.00 in USA & Canada only. Subscription-PLUS prices may be found on the reverse o! the Subscription Order form, and on our website. THE ELECTRONICS & COMPUTER MAGAZINE Only app cable if the rsw subscriber did not sub- scree to Elektor E ectacs \n the cast 12 months, a Offer subject to svsilat'.'iy THE ELECTRONICS & COMPUTER MAGAZINE 12. 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FMS Flight Simulator Encoder With the FMS R/C Flight Encoder described here you can polish your flying skills and gain the valuable experience you need without having to invest in a radio control or even to build a model airplane. In fact the FMS encoder will even allow you to use your own radio control to further enhance your flying ability. ELEKTOR ELECTRONICS no. 328 VOI UME 30 JANUARY 2004 CONTEMFS LED Roulette Everybody gambles sometimes, perhaps in a lottery or even in a casino. After ail, who doesn’t dream of becoming rich without having to work hard? From all at Elektor Electronics: a happy, healthy, peaceful and prosperous 2004! 64- K 80C552 Flash Board This microcontroller board is a standard 805 I -based system, with a few extras that make it suitable for use as a development system or control module for a larger system, its most important features in this regard are on-board Flash memory programming via the serial RS232 port, direct on-board program debugging and low cost. \ Construction Projects 12 Climate Logger 22 FMS Flight Simulator Encoder 28 RIAA Preamplifier with FETs 32 Multi-event Alarm Clock 40 OTL Headphone Amplifier 46 Burglar Alarm 50 Relaxation Machine 52 LED Roulette 60 64-K 80C552 Flash Board Informative Articles 36 Application Note: HV990I 56 The Sense Resistor 72 Analogue Filter Design Regulars n News The Sense Resistor Sense resistors in series with the load are central to regulating current in switch-mode power supplies* It is possible to optimise the power loss in these resistors, as we show with an example converter circuit that drives eight white LEDs from a 4.8 V battery* 67 New Products 74 Readers Corner 74 Corrections & Updates 75 Readers Services 82 Sneak Preview 82 Index of Advertisers Based on the Atm el AVR controller Flexible anci powerful ' Simple to configure * - Very compact AVR Modular Development System * C campilor supplied 1 Compatible with most douGlopmont toot? i-aystsm programmable Free Atmel debug simulator available B eiipharat drivers and libraries supplied easing range of expansion modules veb site support Check out Flexlt at www_ennovLco.uk en^ayijtd 0 ^44 (O) 1425 47SSS4 ia I a sJ-q nn Dvr. co .uk Precision measurement Embedded control Intrinsic safety Internet embedded systems US0 Interface Servicing Your Complete Prototype Needs O Prototypes at a fraction of the cos! O Tocf hg an 6 s ship in-closed O An/ contour O Ff4 I. ton. 35pm Cu 3 HCf£UiFi£ EURGCm BXHW + Tooling + Photoplots + VAT * £29. "Sbffiig jatas fn*yv&y. Pries O Industry s&ndatti quality 0 Foftow up ssiies runs 0 CAJ.i 1 CAB consulting = €49 A on l ■c tz J mtM -£>• oaoo- 3 SZ/TTp/y send 1 ywsr fifes and mdsr OfUItit WWW.PG8-P00LX ... L . Tfy oread rTTTirg S«*™ m ■ Target easily & quickly, ^ uII 'AnSI ‘C’ compiler, assemble : linker all Windows32 based. •Supports:- no & Colour LCD's, ‘oucn Panels & Keypads, y Low Power. LOW COST Source Level Debug. Driver Support with m Libraries. i Time Multitasking OS with a free run time licence. Unlimited email support. , Core up to 66 Mnz. • Extensive I/O:- Serial, ■rDA, SPI, PC, Analogue, Imers/Counters, RTC, etc Large Memory Caparity: www. cms. uk. com see our web site for full details CAMBRIDGE MICROPROCESSOR SYSTEMS LTD Unit 17-18 Zone J D' Chelmsford Rd. Ind. Es Great Dun mow, Essex CM 6 1XG Telephone: 01371 875644 email: sales@cms.uk.com for Windows fiom High performance Windows based PCB Design Capture, Simulation and Layout software at prices you'd expect from your local computer store! Ml:WS in Easy-PC 7 • Library Databook ° Step and repeat plotting 6 Swap Connection Mode • Dimensioning 8 Copy to Metafile plus much more...... ZUQx V t- $3 Yi : s* KT 13 ~ ' —r~-r ■ j. _ pen ni^ c Number One Systems rjoi N u m be r On e Systems Te^buiy^m^Gua 7 lr United Kingdom Stop press... by customer demand, now with Tsien Boardmaker 2 design import... Number One Systems delivers true 32 bit Windows software applications including features that a few short years ago would only have been available in software tools priced in the thousands! Test drive Easy-PC and Eosy-Spice for yourself and be prepared to be omozed of the super value... Call for a brochure, price list and demo CD 773662 or email sales@numberone.com (0)1684 download from VOIUME 2 2 r:- . . ■ ekEcems 1 nr-prn t jn'uts t^Scuna untr i nits amsiafoiitife l-rn &HTIWJL01 I aafc jil i&f iras t t US - fi El 1 Lfertt t W: J^rri TtoallXlKTjpT Isir: CstfUL^iIJl l Vi Cri L iirr lb ill mw ■ The second Toolbox CD-ROM again contains a vast collection of carefully selected software tools for the electronics enthusiast. £12.05 (US$ 21.25} ISBN 90-5381-171-1 In your profession or hobby, how often did you experience that your project failed to reach the target in time because essential information was missing? Toolbox 2 offers new inroads to obtain information you just can't do without. This new CD-ROM contains software tools for, and information about, microcontrollers. However, just being aware of the existence of a microcontroller is often not sufficient — available data often needs to be extended with fads and figures about the right memory devices and com- munication channels. That's why this CD-ROM gives specific attention to technical documentation [specifications, application notes, standards) about protocols (DiSEqC — Digital Satellite Equipment Control), field buses (including LON and HART), as well as modern information carriers (SmartMedia, CompactFlash, SO card, etc.) which find increasing use. The hardware side of things is not forgotten either — Toolbox 2 contains data on connec- tors, cables and adapters (audio/video, GSM, memory, networks, parallel, serial, key- board/ mouse). The CD-ROM also contains a large number of useful Internet addresses. Order now using the Order Form in the Readers Services section in this Issue Elektor Electronics (Publishing] * RQ. Box 190 ® Tunbridge Wells TN5 7WY • England* Telephone +44 (0) 1580 200 657 * Fax +44 (0) 1580 200 616 IKE EUCTSONlCi £ COMPUTER WACAZJNl 7 - —r — — ir^ See also www.elektor- electro nR$*co.uEt 1 2004 Elektor Electronics 7 QUASAR electron ics Quasar Electronics Limited PO Box 6935, Bishops Stortford, CM23 4WP Tel: 0370 246 1826 Fax: 0870 460 1045 E-mail: saIes@quasarelectronics,com Add £2.00 P&P to all UK orders. 1st Class Recorded -£4. ViSA Next day [Insured £250) - £7* Europe - £5. Rest of World -£1Q. We accept all major credit/debit cards. Make cheques/PO's | iT - ‘ ^ payable to Quasar Electronics Limited. Prices include 17.5% VAT. MAIL ORDER ONLY. Call now for our FREE CATALOGUE containing details of over 300 electronic kits, projects and modules. CREDIT CARD SALES v'Al¥' IP Al © Motor Drivers/Controllers Here are just a few of our controller and driver modules for AC, DC, unipolar/bipolar stepper motors and servo motors. See website for full details. DC Motor Speed Controller (5A/100V) Control the speed of almost any common DC motor rated up to 10QV/5A. Pulse width modulation output for maximum motor torque at all speeds. Supply: 5-15VDC. Box sup- plied. Dimensions (mm): 6GWxlGDI_x60H. Kit Order Code: 3067KT - £12.95 Assembled Order Code: AS3G67 - £19.95 NEW! PC / Standalone Unipolar Stepper Motor Driver Drives any 5, 6 or 8-lead j unipolar stepper motor it rated up to 6 Amps max. Provides speed and direc- tion control. Operates in stand-alone or PC* controlled mode. Up to six 3179 driver boards can be connected to a single parallel port. Supply: 9V DC. PCB: 80x50mm. Kit Order Code: 3179KT - £9.95 Assembled Order Code: AS31 79 - £1 6.95 PC Controlled Dual Stepper Motor Driver Independently control two unipolar stepper motors (each rated up to 3 Amps max,) using PC parallel port and soft- ware interface provided. Four digital Inputs available for monitoring external switches and other inputs. Software provides three run modes and will half-step, single-step or man- ual-step motors. Complete unit neatly housed in an extended D-shell case. All components, case, documentation and software are sup- plied (stepper motors are NOT provided). Dimensions (mm): 55Wx7QLx1 5H. Kit Order Code: 3113KT * £15,95 Assembled Order Code: AS31 1 3 * £24.95 NEW! Bi-Polar Stepper Motor Driver Drive any bi -polar stepper motor using externally sup- plied 5V levels for stepping and direction control. These usually come from software running on a computer. Supply: 8-3QV DC. PCB: 75x85mm. Kit Order Code: 3158KT - £12.95 Assembled Order Code: AS3158 - £26.95 Most items are available in kit form (KT suffix) or assembled and ready for use (AS prefix). Controllers & Loggers Here are just a few of the controller and data acquisition and control units we have. See website for full details. Suitable PSU for all units: Order Code PSU2Q3 £9.95 Rolling Code 4-Channel UHF Remote Siate-of-th e-Art. High security. 4 channels. Momentary or latching relay output. Range up to 40m. Up to 15 Tx’s 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 - £41.95 Assembled Order Code: AS3180 - £49,95 Computer Temperature Data Logger 4-channel temperature log- ger for serial port. or : F, Continuously logs up to 4 6^ separate sensors located 200m+ from board. Wide T! range of free software appli- cations for storing'using data, PCB just 38x38mm. Powered by PC. Includes one DS1820 sensor and four header cables. Kit Order Code: 3 1 45KT - £22.95 Assembled Order Code: AS3145 - £29.95 Additional DS182G Sensors -£3.95 each NEWt DTMF Telephone ReEav Swi tcher Call your phone number using a DTMF phone from anywhere in the world and remotely turn on oft any of the 4 relays as desired. User settable Security Password, Anti- Tamper, Rings to Answer, Auto Hang-up and Lockout. Includes plastic case. 130x110x30mm. Power 12VDC. Kit Order Code: 3140KT - £39.95 Assembled Order Code: AS3140 - £59,95 Serial Isolated I/O Module PC controlled 8- Re lay Board. 1 1 5/250 V relay outputs and 4 isolated digital Inputs. Useful in a variety of control and sensing applications. Uses PC serial port for programming (using our new Windows interface or batch files). Once programmed unit can operate without PC. Includes plastic case 130x100x30mm, Power 12VDC/500mA. Kit Order Code: 31G8KT - £54.95 Assembled Order Code: AS31Q8 - £64.95 Infrared RC Relay Board Individually control 12 on- board relays with included infrared remote control unit. Toggle or momentary. 15m*- range. 112x122mm. Supply: 12VDC/G.5A Kit Order Code: 3142KT - £41 ,95 Assembled Order Code: AS3142 - £59.95 PIC & ATM EL Programmers We have a wide range of low cost PIC and ATM EL Pregram m era. Complete range and documentation available from our web site. Prog ram mer Access ori e s ; 40-pin Wide ZIP socket (ZIF40W) £15.00 18V DC Power supply (PSU201) £5.95 Leads: Parallel (LEAD108) £4.95 / Serial (LEAD76) £4,95 / USB (LEADUAA) £4.95 NEW! USB 'All-Flash 1 PIC Programme^ USB PIC programmer for all ‘Flaslf devices. No external power supply making it truly portable. Supplied complete with 40-pin wf de-slot Z1F socket, box and Windows Software. Kit Order Code: 3128KT - £49,95 Assembled Order Code: AS31 28 - £54.95 Enhanced "PICALL" ISP PIC Programmer Will program virtually ALL 8 to 40 pin PICs plus a range of ATMEL AVR, SCENIX SX and E EPROM 24C de- vices, Also supports In Sys- tem Programming (ISP) for PIC and ATMEL AVRs. Free software. Blank chip auto detect for super fast bulk programming. Requires a 40-pin wide Z1F socket (not included). Kit Order Code: 3144KT - £54,95 Assembled Order Code: AS3144 - £59.95 ATMEL 89xxxx Programmer Uses serial port and any standard terminal comms program. 4 LED's display the status, ZIF sockets iBjbS not included. Supply: 16-1 8VDC. Kit Order Code: 3123KT- £29.95 Assembled Order Code: AS3123- £34.95 NEW1 USB & Serial Port PIC Programmer USB/Serial connection. Ideal for field use. Header cable for ICSP. Free Windows software. See * web site for PICs supported. ZIF u socket not inch Supply: 18VDC, Kit Order Code: 3149KT - £29.95 Assembled Order Code: AS3149 - £44.95 Secure Online Ordering Facilities Full Product Listing. Descriptions & Photos Kit Documentation & Software Downloads 8 Elektor Electronics 1 2004 BS2-SX B52E-IC BS2P/24 Parallax BASIC Stamps - still the easy way to get your project up and running! Serial Alphanumeric and Graphic Displays/ Mini-Terminals and Bezel kits Robotic models for both the beginner and the advanced hobbyist Motor Drivers DMX Protocol U /Sound Ranging Animatronics and Specialist Interface- Control Modules Quadra vox Sensory] nc Parallax j Tech -Too Is BASICMicra MP3 & Speech Systems Voice Recognition Ubicom Icq' Kib | PIC & Rom Emulators PIC BASIC Compilers Development Tools Milford Instruments Limited Tel 01977 683665, Fax 01977 681465, sales@milinst.com smart electronic solutions The most cost effective solution to PIC programming and development - Ever!! New Improved pnc BASIC ™ Integrated Development Environment Windows integrated serial bootloader software "program without a programmer!” Support for 1 2/14/1 Sbit series devices Handles 32bit signed and unsigned variables (numbers up to ± 2147483647) Specific commands for on-chip peripherals Comprehensive command set - Tighter code generation than MBASIC - More functionality than MELABS PICBASIC Pro - More flexible than ail BASIC Stamps integrates directly into Proteus VSM - allows you to build a virtual circuit and see your BASIC code run in real-time - Easy macro integration (includes Floating pointmath example) Aimed at graduates, and professionals, ail code produced is LICENCE FREE Rewritten from the ground up Best Value For Money Most powerful entry level compiler 100% MPASM™ compatibility ™ 98,ME,2000,NT & XP Windows compliant Real-Time Syntax checking Integrated PIC Programmer driver Program with one keystroke View BASIC and the resulting Assembly Supplied with book "LET PtC BASIC Unleashed” by Les Johnson PIC BASIC Smart Card Development system A nother First from Crownhill, access the world of SMART CAROS using PIC BASIC. This versatile development system provides a platform for the development of applications using SMART memory cards and SECURE memory cards. Detailed documentation describes all aspects of development using the sample cards supplied, source code and circuit diagrams are included, • Includes card Reader Writer hardware and circuit * integrated Bool loader -No iiroBrammerreniiired • Sample cards. Tocnmentallim • Fully coiiiinenlfld UGEHSEFREE Source coda T he worlds First PIC BASIC InterNet development system allowing PIC BASIC projects to communicate across the WORLD via the InterNet. Development board includes RS232, Ethernet Interface and dedicated controller, LCD, Prototype area, Power supply and full documentation. Visit WWW.plCDdSlC.org tor comprehensive details of these and other PIC BASIC products, including: Lou power > easy serial interface 2 x16 serial LCD display, supplied as a kit or ready assembled. PCB, PICmicro, LCD display, Circuit, LICENSE FREE commented source code Infra RED TX and Rx development system, with experiments and source code Ww w. labcenteno6.uk Proteus VSM Fully supported by PICBASIC Plus Full range of DEVELOPMENT boards inct Graphics LCD’s and Audio LET PIC BASIC £65.00 Proton Smart from £79.95 Proton Net £169.95 0 smart tanis in stock over NEWS Success in his Pocket! Michael Birmingham, from Calday Grange Grammar School, Wirral, attained the top mark in this year’s AQA A Level Electronics examinations and so qualified for this year’s top candidate award. This award is sponsored by European Electronique, one of the largest resellers of IT equipment in the UK and con- sisted of a Hewlett Packard IPAQ Pocket PC, Michael, who completed his other A level courses with A grades in Maths, Further Maths, Physics and General Studies, is taking a gap year with the Smallpeice TYust, This will take him to Plymouth Uni- versity for a 3 month Engineer- ing course, followed by a month’s language course in France before a 3-month work placement in Finland, probably with the Ericsson Company. When he completes his gap year, Michael will take up his place at Girton College, Cam- bridge to read Engineering. Michael is interested in com- puting, sports and socialising with friends. He says that he found the AQA Electronics course very interesting and especially enjoyed the practi- cal course work. In honour of Michael’s achievement, his school has been awarded a free one year's subscription to Eiektor Electronics magazine. About AQA AQA is one of the three unitary awarding bodies within Eng- land. The GCE A Level in Elec- tronics is a two year course and is part of Curriculum 2000. It consists of two distinct parts — the AS Level, which is the first year of the two years and the second year A2 course which, together with the AS course, forms the complete A Level award. Students would normally study this course after completing their GCSE qualifications when they are 16 years old. The whole specification assumes a systems approach to Electronics and that the candidates will undertake sig- nificant practical work. The AS Level course is split into two modules which cover the basic building blocks used in Electronics; logic gates and systems, amplifiers, input sen- sors, output devices, output drivers, astable and mono- stable circuits, counters etc. The AS Level assessment con- sists of two written examina- tions each lasting one and a half hours together with an externally moderated course- work project worth 30% of the overall marks for the award. The A2 course builds upon these basic building blocks and applies them to Electronic and Computer Control sys- tems for one module and Com- munication systems for the second. The A2 Level assess- ment has the same form as the AS assessment but is focussed on the subject content of the A2 specification. The specifi- cations for all of the AQA sub- jects can be found on the AQA web site www. aqa.org.uk European Electronique In order to promote the study of Electronics, European Elec- ironique, one of the largest resellers of IT equipment in the country,, agreed to sponsor a prize for the candidate who gained the highest marks overall in the A Level award. Tins is the second year of the award, which each year, so far has consisted of a Palm top computer. The company web site is at www eu male . com ( 0-4 ' 035 - Threatens Electrical / Electronics New Legislation The environmental support and advisory service, Envirowise, recently expressed serious con- cern over the apathy being shown by many UK electrical, electronics, telecommunica- tions and computer manufac- turers towards imp ending new EC legislation on waste electri- cal and electronics equipment and hazardous substances. Continuing failure by compa- nies to get to grips with the business actions needed to tackle the directives on WE EE (Waste Electrical and Elec- tronic Equipment) and RGHS (Restriction Of use of certain Hazardous Substances) has serious implications for the whole industry and could jeop- ardise the UK's future position in the global marketplace. Tire DTI and DEFRA support an Envirowise campaign to alert the managing directors of UK electrical and electronics companies to the problem. The campaign is also being backed by leading UK companies, including British Telecom, Fujitsu and Sony, and the elec- trical / electronics industry trade association, Intellect. Already it is estimated that the future estimated costs of the EC legislation to the UK econ- omy could be as much as £455 million a year for WEEE and some £200 million a year for RQHS legislation. This will lead to an average cost increase of 1 to 2 % for many products and as much as 3 or 4 % for some larger or more complex products. Apathy could fuel even greater cost increases and render many UK c o mp antes uncomp etit i ve . Some may even find that their products are banned from sale. Envirowise believe that much of the problem stems from the fact that companies have so far only thought of the legisla- tion as a simple environmental requirement that needn’t be Firms addressed until some ROHS substances are banned in 2006. The reality is that the legislation requires serious for- ward planning and financial, marketing and design deci- sions. and isn't something that managing directors can delay or simply gloss over. Envirowise is supporting the campaign via its website { v w .am ire wi s e . g ov, u k) , with advice through the Environ- ment and Energy Helpline [telephone 0300 585794) and through its FastTYack and D e signTYac k vis it in g s e rvice s . { 04 7007 - 1 ) 1 2004 Eiektor Electronics 11 TEST& MFASl JRFMFN Climate Logger Recording temperature and humidity Design by T. Poms http://chripo.icb.at/Rooney This electronic alternative to mechanical temperature and humidity recorders is a very compact standalone unit which draws very little current. The Dallas DS 1 6 1 6 device used comes already equipped with a temperature sensor, and besides a humidity sensor we can add a range of other sensing devices. The collected data can be transferred to a PC or notebook over an RS-232 port for analysis by user-friendly Windows software. The system can also be connected to a microcontroller board. 12 Elekior Electronics 1 2004 IE ?f ’It 1EASL !REM ENT j The climate logger operates com- pletely autonomously while it is car- rying out a ‘mission 1 (measurement sequence), and can run on battery power for a long period in this mode. The device can, for example, be left in the refrigerator or in the wine cup- board to continuously record the temperature and humidity. The Win- dows-based software running on a PC Is used not only after a mission to download and analyse the stored data, but also before a mission to configure the data logger. With the aid of the software, both the sample rate and the selection of which chan- nels are to be recorded can be con- figured. The version of the climate logger described here connects to the PC over a serial interface. The planned USB version previewed last month is still in development. CRC (cyclic redundancy check) allows errors in transmission to be detected, so that the command can be repeated If necessary. The RAM is non-volatile (NV) T which means that the memory contents are pre- served even when power is lost. Tills RAM is used to store Important parameters when the master software Is exited: these values can then be reloaded by the software when it is restarted at a later date. The following para- meters are stored by the current version of tiie software: DS1616 Intelligent 1 temperature sensors pro- duced by Dallas frequently appear in circuits in Elektor Electronics. There is a wide range of ICs offering a wide range of peripherals, so that the ideal device can easily be found to match the requirements of any particular application, A built-in memory comes in very handy for building a temperature logger. The D31616 device used here is a partic- ularly well-equipped member of this series of temperature sensors. The internal block diagram of the DS1616 is shown in Figure 1. Besides the temperature sensor and the memory the most interesting fea- ture is certainly the an alogue-to -dig- ital converter which has a resolution of 8 bits. The converter is equipped with a 3-to-l input multiplexer. It is possible to use the converter to accurately measure three external voltages in the range 0 V to 2 V, and to store them along with the internal temperature signal. The DS1616 also offers a real-time clock driven from a built-in oscillator {which requires a 32.768 kHz watch crystal). The clock is also used to drive a simple serial R3-232 interface to allow alarm times, sampling clock rates, timestamps and time delays to be retrieved from the device's mem- ory. It is also required for scanning the measurement channels and is hgure . Internal circuit of the DS 1616. needed for certain commands such as Clear Atfemory to be carried out. The D31616's built-in temperature sensor determines the operating temperature range of the climate log- ger at -^40 ~C to -3-80 Z C. The compo- nents used for the remainder of the circuit, including the humidity sens- ing circuitry, must also be specified for at least this temperature range, or the overall specific ations of the cli- mate logger will be degraded (Fig- ure 2). Memory Map The DS1616 offers 2048 bytes of memory divided into pages of 32 bytes each (Figure 3), The ETC and Control Registers and the User NV RAM areas can be written to. The use of the RTC and control registers in our climate logger application will be discussed further in the *Soft- ware ! section below. All the other locations can only be read. Each read command contains the start address from which reading is to begin, and data are then transmitted until the end of the page is reached. This means that each read command will cause a maximum of 32 bytes, plus a 2-byte CRC generated in hardware by the DS1616, to be sent to the mas- ter device (a PC in this case). The Hgure 2. Block diagram of the Ornate Logger, 13 1 2034 Elektor Electronics TBT&MfAS[JRFMr\r - The measurement channels selected for the most recently initiated sequence of mea- surements - Sample rate - Periormance -related parameters The detailed circuit diagram for the climate logger is shown in Figure 4. The serial Inter- face of the DS16I6 requires a 5 V supply but only, of course, when there is actually any communication occurring. This supply is generated using a 73L05 voltage regulator which tabes its input voltage from the PC's COM port. The two LEDs provide an indication of the status of the DS1616. The pushbutton con- nected across JP1 must be pressed for at least 0.5 s to request status information. Before a sequence of measurements (or 'mis- sion 1 ) has been initiated, the red LED (OUT- SPEC, D2) and the green LED (IMSPEC, D3) will flash together four times. If a mission has been initiated, but the first measurement has yet to be taken, the LEDs will flash four times alternately starting with the red LED, A sequence of measurements can be initiated either from the PC, or, in standalone opera- tion, by pressing the pushbutton. See also the software description below and the guide to operation at the end of this article. Tne software allows threshold values to be defined. If a measured analogue value (an external voltage or a reading from the tem- perature sensor) is above (or below) the threshold value, a bit is set in the Status 1 register. When this happens* the red LED (D2) flashes four times. If the user- defined thresh- olds are not crossed, the green LED (D3) wall flash four times. An interface is also provided to allow the data logger to be used in conjunction with a microcontroller board instead of with a PC, In contrast to the asynchronous communication used with the PC, here we use synchronous communication with the signals SCLK, 10 and RST. To switch the device from asynchro- nous mode to synchronous mode, pin 6 (COMSEL) should be tied to V cc (+5 V). Humidity Sensor Tne HSUOi capacitive humidity sensor mea- sures relative atmospheric humidity. The capacitance of the sensor, which changes in proportion to humidity is first converted into a pulse-width modulated signal, A fair amount of electronics is required to turn this signal into a voltage suitable for the AIN2 input of the DS1616. One half of a TS556 dual timer is con- nected as a free-running multivibrator, gen- erating a regular squarewave signal. Tire RO- DS'! 61 6 MEMORY MAP Address Register definition Pa ge(s) DDlXl H 003FH RTC and Control Registers 0- 1 00401 1 0G5FH User NY RAM 2 G06QH 0217H ( Reserved for Future Extensions) 3- 16* 16*- oim\ 021FH Serial Number 02 2 OH 027FH Alarm Time Stumps and Durations 17- 19 0280H 07FFH (Reserv ed for Future Extensions) 20-63 ; 1 08OGH 087FH Temperature Histogram (63 Bins of 2 Bytes Each) 64-67 0SS0H ! 08FFH ADC Channel 1 Data Histogram (64 Bins of 2 Bytes Each) 6S-71 0900 H GFFFH (Reserved for Future Extensions) 72-127 1000H 17FFH Catalog Memory (64 pages i 12S- 191 1800H ami higher (Reserved for Future Extensions) 192 +■ Fir^i 3 hues Last 5 bytES Figure 3 . D5 1 6 \ 6 memory map. combination formed by Rl, R2 and Cl sets the period at about 1 s. IC1.A triggers the second half of the timer* which operates as a mono- stable multivibrator, creating the pulse-width modulated waveform. At Its output we have a lowpass ni- ter which finally turns the PWM sig- nal into an analogue DC voltage pro- portional to the atmospheric humid- ity. Depending on the characteristics of the sensor, this voltage varies from approximately 990 mV to 1190 mV. The signal must now be processed so that it lies in the range 0 V to 2 V so that good accuracy can be obtained using the analogue Inputs of the DS1616. According to its datasheet, the sensor capacitance only varies between 161 pF and 200 pF; and the electrolytic capaci- tors used have a wide tolerance: this means that the circuit will require calibration. This facility Is provided using instrumentation amplifier IC3, which amplifies toe generated voltage by a factor of 10. Very high resistances are used here in order to keep cur- rent consumption low. The output signal isalsopassed through a high- value resistor before being taken to the analogue input of the DS1616. The voltage VCC Hl j^ is gener- ated using an LM385-2.5. This pro- duces a fixed reference from the varying battery voltage, used to sup- ply the whole humidity measure- ment circuit as rax as 1C 3* This ensures a good power supply rejec- tion ratio (PSRR) figure. A Compact Data Logger The climate logger is constructed on a single-sided printed circuit board (Figure 5). There are no wire links, and construction should not present any difficulties. The ICs should be fit- ted in sockets. Terminals are pro- vided for all the external connec- tions, including for the 9 -way sub-D socket for the RS-232 interface, and for the two batteries BT1 and BT2, BT1, which powers the humidity measurement circuit, has to supply a considerably greater current than "backup battery' BT2, which only supplies the DS1616 when it is in autonomous mode, This means that BT1 should be made up from AA or C cells in series* whereas BT2 can just be a coin cell (see also the text- box). BT2 also determines how long as the climate logger can retain its stored data and settings, while, BT1 only determines for how long humid- ity measurements can be taken. The enclosure must not only house the printed circuit board, but 14 Elektor Electronics 1 2004 ft MFASl JRFMFN also the batteries and their holders, the pushbutton, and the RS-232 socket. The humidity sensor should be soldered as close as possible to Kl. It is not recommended to mount the sensor on the side of the enclo- sure, since this will involve a greater cable length. The enclosure should not be airtight so that atmospheric humidity is present at the humidity senson Calibration Two reference capacitors {or combi* nations of capacitors) of 161 pF and 200 pF are required for alignment. The values should be checked directly by measurement. First con- nect the 161 pF capacitor to Kl, and measure the voltage at the output of the lowpass filter using a high- impedance multimeter. The offset voltage (the voltage between the input of preset PI and ground) should have the same value. The voltage at the output of IC3 should be between 2 mV and 7 mV. The voltage cannot be set to exactly zero, since we cannot do anything about the offset voltage of the operational amplifier. Now connect the second capacitor to Kl and once more mea- sure the voltage at the output of the lowpass filter. The value should be about 200 mV higher than the previ- ous reading with the smaller capaci- tor. Since we have a voltage varia- tion of about 200 mV over the humid- ity range, and a voltage Tange of 0 V to 2 V is required, the amplifier cir- cuit is configured for a non- inverting gain of 10. Preset P2 at the non- inverting input allows the gain to be trimmed. When 2.00 V is measured at the out- put of the operational amplifier, calibration has been successfully completed. Software The software runs under Windows 2000 and Windows XP; versions for Windows 95 or 98 are not currently available but may be devel- oped later (watch the authors website). The main window allows control over the main settings and shows real-time measurement results (Figure 6). The measurement chan- nels (temperature, ADCL humidity/ ADC 2 and ADC3) can be individually enabled and disabled. When the DS1616 is not on a mis- sion' , the temperature and humidity values are measured once per second (assuming the corresponding measurement channels are enabled) and the results displayed. This fea- ture is implemented using a timer whose default period is one second. However, this +U HUH +IJ KUL! Figure 4, Circuit diagram of the G innate Logger 1 2004 EEektar Electronics 15 &MFASURFMFKT QJlSmSLOSlQjaSLQA Q.QQ.Q i frTrtrtr o F'rs 1 0 0||00 00'6'UTnS r a'fODEO • ii 11 n f Ofl D5 Q OE ms O 03 Q 076-1 Figure 5. Layout and component mounting plan for the single-sided printed circuit board. timer requires CPU power to operate, which can have an impact on performance in older computers. For this reason the timer period can be set as desired under Settings/ Perfor- mance, The new value is stored in RAM so that the timer period does not need to be entered every time the software is started up. When the DS 161 6 begins a mission, only the active channels are sampled and recorded. The data logging memory or the DS1616 has a capacity of 2048 bytes. The more channels are enabled, the shorter the maximum recording time avail able. If just one channel is enabled, up to 2048 values can be recorded; with two channels enabled the maximum is 1024, If four channels are enabled, then the maximum is 512. The main window displays only the two most important values: humidity (ADC2) and temperature. The remaining values can be shown by selecting ADC Channels f Show Channels . Sample Rate 'Sample rate' specifies the time interval in min- utes between measurements. Tire registers of the DS1616 are eight bits wide, and so the maximum, value that can be set is 255 minutes. For the RTC to work correctly, and so that a series of measurements can be initiated, the sample rate must be set to a value greater than or equal to one. When the battery is changed the sample rate is reset to zero; if the RTC is set but the sample rate not set to a value of at least one. the RTC will not operate properly. Start Mission This button initiates a sequence of me a- COMPONENTS LIST Resistors: RI,R7,RI4,R15,RI8 = lOkD R2,R2! = lOOkQ R3 = 47kQ R4 - 2200 RS = 68 kO R6,RI LRI3 = IOMO R8 = 470kO R9,R! 2 - I MO RIO = 150 kO RI6.RI 7,R19,R20 = IkO PI = 250kO preset (vertical mounting) P2 — 2MQ preset (vertical mounting,! Capacitors: C I ,C2,C3 — see text C4 1 C5,C8,CJ0*C 1 1 - lOGnF C6 = 22 uF 16V radial C7 = 330nF C9 - IOuF 16V radial Semiconductors: Di - LM 3 85-2. 5 D2— LED, red, 3mm, low-current D3 — LED green, 3mm, low-current D4.D5 = 1N4I48 surements. The enabled channels and the sample rate should already have been set: incorrect settings will case a pop-up to appear. Real- time values of temperature and humidity will no longer be updated once per second, but rather at the preset sample rate. TLT2 = BC547 IC1 = TS556 IC2 - 78 LOS IC3 = MCP604 1 -1/P (Microchip) (Famell # 396-8790) IC4 = DS 1616 Miscellaneous: JP1 = pushbutton, 1 make contact Kl = 3-way pinheader Humidity sensor type HS I 101 (vAvw.humireLcom), available from Un i t ronic { www, unitronic.de) K2-K6 = 4-way pinheader BTI = 3V Lithium cel! X [ = 32.768 kHz quartz crystal BT2 = 2 UM-5 (AM- 5) or AA batteries (depending on available enclosure) 9 -way sub-D socket (female), angled pins, chassis mount ABS enclosure with battery compartment (GKW size # 3 for AA cells, e.g, RS Components # 583- 218) PCB, order code 030076- 1 (see Readers Service page) Disk, Windows software, order code 030076-1 I or Free Download Serial Number Each DS161S is factory-programmed with a unique serial number. When a save command is issued, this num- ber is stored along with the mea- sured data, so that the particular module that produced the data can be identified. 16 Eiektor Electronics 1 2004 Temperature Thresholds These threshold values set the tem- perature limits above or below which the alarm flag in the Status l register will be set, which in turn pulls the interrupt output f£J¥ low. This latter signal is available on K2 and K3 and can be used, for exam- ple, to trigger an acoustic warning signal. The ‘Clear 1 button must be pressed to reset the alarm flag. Temperature and Other Graphs This window provides information about the measured temperature val- ues (Figure 7). Sample i corre- sponds to the time given under Mis- sion started This allows the date and time of each stored sample to be determined. In order not to waste CPU time needlessly, an automatic update feature is not provided. The graph can be updated by re-opening Calculating the battery life The type CR1 620 backup battery (3 V 60 mAh) supplies only the DS 1 6 1 6 and its internal temperature sensor. The humidity measurement circuit consumes rather more current and so is supplied from two AA cells to give a reasonable battery fife. The life of the coin cell depends on the selected sample rate; in order to cal- culate the battery life, its capacity must simply be divided by the average current consumption of the circuit (I-, -). For example, with a sample period of 60 s we have: Battery life = battery capacity l avg where the average current is given by TBT&MFASURFMEKTT the window or by pressing the Update but- ton. Auto Scaling gives an overview of the series of temperature readings. The graph limits are no longer set at -40 ~C and —BO C. but are set to the lowest and highest tem- perature values stored in the data memory. The Save command stores the measured val- ues on the local hard disk, with a user- selected path. The Humidity, ADC 1 and ADC 3 plots are identical in terms of function and appearance. In future versions of the software the two spare channels will also be used. Other Windows The ADC Channels window can be called up under ADC Channels/ Show ADC Channels in the main menu. It provides up-to-date read- ings from the analogue channels. Disabled inputs are displayed in grey, as shown on the right in Figure 8. Threshold values can also be set for the analogue inputs: these operate in the same way as the temperature thresh- olds. The Alarm Settings window (Figure 9) includes the various settings relating to the RTC (real-time clock}. The RTC can be set to the PC’s system time using Set. The remaining settings can be used, for example, to implement a time switch function. An interrupt on rffi 2 is gen- erated when the RTC value agrees with the preset alarm time. RTC and alarm settings can only be changed while the DS 16 13 is not busy taking a sequence of readings. Under Settings /Performance is a facility for setting to any desired value the timer period which governs the regular reading of data from all the sensors and analogue inpurs. Tne greater this value, the greater the interval between samples, and the correspondingly smaller the amount of CPU time consumed by the software. An optimum value for the timer period can be found using the System Moni- tor (a Win XP utility) to accurately measure the CPU load and performance. PCs and lap- tops that have plenty of memory and proces- sor power should have no problem with a timer interval of one second. The functions of the System Monitor are described in more detail in the help. Uvg [ C tc" he 1 (T t. c ) ■ ioscj] where t TC is the duration of one measurement (150 ms), i TC Is the current drawn while carrying out a temperature measurement (0,5 mA), iqsc ' s the qui- escent current consumption (450 nA). and T is the sample period (60 s). The calculated battery life is approximately four years. Operation Tne climate Logger is connected to a free ser- ial port on the PC or notebook using an ordi- nary serial cable (straight-through, not a null- modem cable). The first time the logger soft- ware is run the selected COM port must be specified: this setting is stored and need not 1 2004 Elektor Electronics 17 TESTftMFASl JRFMFNT Isv _"%£TK ga-r^ ■ r - □ . _E -.ijt. I ‘ I r^LII^ L «- J ttt-K | I . L ti “ ' . tt E,TL_U j Om Til p^rr " m-71 i j kBO*ah^|i j I KK = . i : » L iT-in jc : *: ' r?s “J -. UHpirjPl -Ti> Figure 6. AJ! the important parameters are sho .vn in the main window. ' H Tn:n i*.i» ’ id 1 (? 12" 22 1 SonpiMiE* 1 * Jt3 ; i sing £ hiifltd Fb.~H-£3 CjT*rt £ Mf — ■ - jiui j ~ , r 4M3 ; tac-Him ejpp kee-vche l ■- ! = ■ ■ 1 — — s Cui F LJ.U- • : / 5 u j h -a ■- .rii'i- 75.0- CaDftrtt j i ,~i ' t 5t ■! i i . £5,3- 'a =.iE3r±B! 'rue* u:j i '~Z. □ L.J E E 7, be entered again unless the logger is con- nected to a different COM port. When first powered up a new DS1616 has its HAM filled with OxFFs. When the climate logger is connected to the PC for the first time, the RTC time and a (sensible) sample rate must be set. This must also be done Ea.a- 45.0- 4 : : - 15.0- 39.0- 25.3- 15.D' 10 0 - 5£- 3 0- -5 0- -10 G- ■15 Q- '20.13- -25.0 -iBJO- - -35.0- 1 51 73 T01 US 151 17= 221 225 251 275 0 01 325 351 OJt 401 5ZS 451 475 S'-l 525 551 575 531 £is 5 air, p! a Rgure 7 t The series of measured values (temperature, humidity, or either of the two spare inputs) can be displayed as a graph or as a table. whenever the device’s backup battery volt- age is interrupted (be,, when BT2 is changed). Until the sample rate is set, the PC will read a measured value every second, and the display will be updated every second. While the data logger is connected to the PC, the sample rate and other parameters Figure 8. 1 he three external analogue inputs are shown under ADC Charnels, SSI Sjzi" Her* : V4^=i_ T O i j D F V t - ^ 24 Mcutcx AIj jfttfhia D^. Ha-s. M i fc U3 Sec -zn&t A'sfnj Alyci ' Decf ] -1ZJXJ I Ttm 22-55:03 | Set 22 04 ■ 03 Rgure 9. Using the alarm settings the Climate Logger can be used as a time switch. can be set and adjusted as desired for the next mission. When the data logger is disconnected from the PC it retains these settings and oper- ates in standalone mode. The set- tings will only be lost if the backup battery supply to the DS1616 is interrupted. In the most recent version of the software available as we went to press (vl.23), a mission can also be initiated using the pushbutton con- nected across JPL This is done as follows. First configure the sample rate, enabled channels and so on as described under 'Software' above. Then click on ‘Enable External Start’ and clear the memory contents: the ‘Memory Cleared 5 indicator wall appear on the screen. The logger can now be disconnected from the PC and taken to the location where measurements are to be made. To initiate the mission, it is now simply necessary to press the pushbutton for at least 0,5 seconds; data record- ing will then begin. Measurements can also be initi- ated using the pushbutton while the logger is still connected to the PC. It is not necessary to shut down the program: it can remain running and will check whether a mission has been initiated. If any of the settings (enabled channels or sampling rate) is changed after ’Enable External Start 1 has been clicked, the 'Enable Exter- nal Start' feature is automatically reset. Enable External Start' should only therefore be clicked when all the needed settings have been con- figured, since it is at this point that the selected sample rate and chan- nel selections are transferred to the DS1616. If any settings are subse- quently changed on the PC t they will not be sent to the DS1616, and so the configuration of the logger will not match what is displayed on the screen. Free Downloads Windows software. File number: 030076- 1 1 PCB layout in PDF format. File number: 030076-1 .zip, wvvv/. e I e kto r- e [a-ctro n i cs , co. u k/d i df.htm . select month of publication. 18 Eleklor Electronics 1 2004 r j C rjL j |i ' j __ .. I .2525$ U .1 3 g . - -j - " T£ Based on the MSC1210 Development System In the July/ August 2003 issue we started a series of arti- cles based on the Texas Instruments MSC1210 microcon- troller. Thanks to this contemporary controller and its 24- bits A-D converter, the development system can be pro- grammed for lots of applications and measurement func- tions. Among these is a high-accuracy digital meter with no less than 5 14 digits and 8 analogue inputs. All you have to do fo build the instrument is add an LCD! We can offer the readymanufoctored, populated and calibrated board for just £ 69.00 / $ 1 12.50 (plas P&P) Because the MSC1 210 microcontroller comes in an SMD case v/ith 0.5-mm (0.02 in.) pin spacing, soldering the device properly with DIY tools is almost impossible. That's why we are offering the development board as a ready- manufactured unit only. The ready built GBDSO board costs £ 90.00 including the associated PC software and the magazine articles The GBDSO (Gameboy Digital Sampling Oscilloscope), published in Elektor Electronics October and November 2000 is still in great demand. The GBDSO is a plug-in module that turns the popular Nintendo Gameboy Classic, Colour or Advanced into a versatile dual-channel oscilloscope. An optional link to a PC even allows measured oscillograms to be viewed or stored on the PC, The GBDSO comes as a ready-built and tested PCB and may be ordered via our website: www. elek tor-eletiranhs. co. uk The ready built GBDSO board costs £ 90M including the associated PC software and the magazine articles (published in the October and November 2000 issues). Order now on www.elektar-etectronics.co.uk Elektor Electronics (Publishing) ■ P.0. Box 190 * Tunbridge Wells TN5 7WY * England. Telephone +44 (0) 1580 200 657 • Fax +44 (0) 1580 200 616 See also www.elektur- electronlcs.co.uk Pi 1 2004 Etektor Electronics 19 PC or Laptop portable measuring instruments... Resolution - 8bits Sample Rates - 1,2,5,10,20 Ms/s models £119 ex vat/pp (1 Ms/s model) Resolution Menu - 12 . 14, or ISbits Sample Rates - 5,10,25,50 Ms/s models £435 ex vat/pp (5 Ms/s model) Handyprobe HP2 - 1 Ch. s Oscilloscope s Spectrum Analyzer s Voltmeter plus! ■/ Transient Recorder S Parallel Port used R/C transmitters. If yours is not snow n. consult the owners manual or ask neb from fellow FMS users via the FMS Forum. R C generates — the more channels, the shorter the pause. The circuit The circuit diagram of the FMS Flight Simulator Encoder appears in Figure 1. You can see that it is basi- cally the Philips low pin count P87LPC767 MCU. that's doing all the work. The LPC767 is an 8 -bit 8051 based MCU with one-time program- mable (OTP) PROM and four (!) chan- nels of 8-bit analogue to digital con- verters, A programmer for the LPC76x family was described in Elektor Electronics December 2003. At power-up the encoder is in SIM mode, reading the joystick posi- tions from the four 10-kQ linear potentiometers contained in joy- sticks PI, P2, then converting this analogue information into packets of data to send to the serial port on the PC. To pro wide a means of trimming the controls, 5-kQ presets (P3-P6) have been added in series with the joysticks pots. To engage the R/C mode (which allows you to use your own R/C transmitter) you simply press down on either of the two joysticks to acti- vate an internal t actile switch. If the joysticks are not fitted, the same is achieved by pressing S2. Pulling the PL1 port line to ground causes the MCU firmware to change to the R/C encoder mode. In this mode pulses continuously sent to the MCU are converted and conveyed to the computer. The MCU waits for a pause before it samples the time delay between consecutive pulses. After the MCU detects the first pulse, it counts up in steps of 10 microseconds until it detects the next pulse. Thus for a delay of 1.5 milliseconds between pulses, the value it sends to the serial port is approximately 127 decimal or 0x7F Minor variations are not so critical since the built-in driver for FMS takes care of any calibration differ- ences. If the MCU fails to detect any more pulses it simply bails out and sends only those channels which it could count, this may be anything from a 2-channel to an 8-channel R/C pulse train. Figure 2 shows the pulses from an 8 -channel R/C. You can see that there are actually nine pulses, and that there is a delay of around 10 ms between pulse trains. It is the inverted version of these pulses which are sent to buffer tran- sistor Tl, These pulses are inverted 24 Elektor Electronics 1 2004 COMPONENTS LIST INTFRFS Resistors: Rf ,R2 = 470.Q R3.R5 = Ik Q R4 = lOQkQ R6 t R 8 - lOkQ R7 = 4kH7 P E ,P2 = mini joystick, CT5 mode! 25AI04A6QTB (order code CTS25A from wwy/. dil.nl )* P3-P6 — 5ki> preset Capacitors: CLC2 = 27pF C3 = 22 /jF !6V axial C4.CS = lOOnF C6 “ f 0//F 1 6V axial Semiconductors: Df = LED. green, 3mm D2 — LED; red. 3mm ICi = 87LPC767BN, programmed, order code 030066-41 IC2 = 7805CP Ti - BC547B T2 - BC5S7B Miscellaneous: Kl = 9-V battery with clip-on leads K2 — 9-way sub- D socket (female). PCB mount K3 — 3.5mm mono jack socket, chassis mount 5 1 = on off switch 52 — pushbutton, 1 make contact Xf - 1 1 .0952MHz quartz crystal PCB, order code 030066-1 3 wire links RS-232 cable (non- crossed) Case, e.g., Paccec WM-46 (Conrad Electronics #54 [3 03 ) " Worldwide distributor information from rrvAs-.ctSCOrp.com by Tl thus bringing them back to normal before they are sent to MCU pm 13. Output data from MCU port line PI. 6 {pin 3) is buffered by T2, with R7 providing the required level shift- ing to drive the RS232 port. Only two wires are required from your R/C radio to interface to the Figure d . Our finished and fully working prototype. Figure 4. Copper oack layout and component mounting plan of the PCB designee for the FMS Encoder (board available ready-made). 25 1 2004 Elektor Electronics GBMERAL I NTFRFST FMS encoder. Where these connections are will depend on what type of R/C yon have. A few are listed in Figure 3, You may have more information available from your radio control manual. If yon are unsure which connections to use then don't be afraid to experiment since the buffered input is quite safe. If you fail to place them the right way around the encoder will behave erratically — just swap them over and everything should be okay. The whole circuit runs off a single 9-V (6F22) battery and draws only 21 mA, most of which is consumed by the LEDs D1 and D2 which indicate SIM mode and R/C mode respectively A 7305 regulates the battery supply down to 5 V to power the MCU. At least five hours play time should be available from a standard 9-V battery Construction Construction of the FMS Flight Simulator Encoder board should be easy if you use a ready-made printed circuit board and a pro- grammed MCU supplied through the Elektor Electronics Readers Services. The respective order codes are 030066-11 and 030066-41. The MCU for this project is only available ready-pro- grammed. The author receives roy- alty payments for every copy sold hence no hex code or source code files can be supplied. The PCB (Figure 4) is spacious and single-sided. As usual, polarized components like LEDs r electrolytic capacitors, transistors and inte- grated circuits should mounted the right way around on penalty of cre- ating a hard to find circuit fault (best case) or destroying them when the power is applied (worst case). Don’t swap Ti and T2, the devices looking identical but being complementary (npn and pnp respectively). The MCU being the most expen- sive component, it really deserves to be fitted in a good quality IC socket. However, it should not be inserted in the socket before you have verified and approved the presence of the -1-5 volt supply voltage at a number of relevant points in the circuit, for example, IC1 socket pin 15, the emit- ter of T2 and the anode wires of LEDs D1 and D2. Okay so far? Then switch off and insert the MCU, observing the position of the notch on the PCB overlay. Pinheader strips beside joysticks PI and P2 are provided to connect joysticks that do not nt the board, or an old R/C of which the RF sections are faulty or even missing. Finally Users of the Encoder described in this article are encouraged to com- municate with other FMS users via the Forum which can he accessed via the FMS homepage. Happy fly- ing! }£0i6c !. Special Offers :: TEKTRONIX 2445A Just In ... H.P. c«i?ASc-.i -A'.'-'/ : V ■ -z-alZVi i £250 KfJi W 00 3 C$4525 0 -jxz Z 7r*M K ' J -• ft 25 Les-IsT mm 0 u . uczc* Zjz Tsics 25V -2 £143 __ ___ . GOULD B538Q 20WtH£ £25 ISHI 1 ™“ 11 I MAIMMAL PAHA50 H3C YF7705 . 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FA^WtU, H&J50 Q-QJ,’ 0-&M FARMELL -ZIZz O &2SA Vmm S»n*l 1 10 !7W Q-1GA FAR WELL DeM PSU XA&2T O-IEV 0-fA Tu ^ CUO LCD Etta FARMI1 \3&Z 0-3CIV: 02A .. £21 FHtmi L30-1 Q-SW' (MA ££3 Mit.j L-Auii is stsHi^e. (soteng TrasianKf 24:\ Ffoips =v 1 :::: 2^0- :v. ij -:r :-.r. FHBL1PS F • TKra f;. s Trara 244 1 1 :: i : ; ■t " vuLr ■ E '-j?r “tsc* 2£>jU!i£ Ebasr_E 1 EI75 Q - £25^ £l£-3 ESS? t275 i-v- "s^r . on I_. ' 23L T -2 7:“ 7«Ssr £125 5f Oscilloscopes Available VIU1R0H ■. : 21 , i:III t:v - K«/-i ■£- M 2SKJ ALS f« _ ESi ■ £753 ■:-“2 ■ :i 2-1 LIB =£7. H.F. ^7 A ■ V"-.: - J . s - 5:7 E»I3 ttp, seas on m&yz - ?? jwg aj an tun H_P_ aSEA SjTi* lODtl^ - sot )t£2 S« fe® f»5 Ut 1%'2HS02 Sg 6ai £4^ - . . . 7 : : -;l ■ IWlfiS PKsJlE Sg Ser= ■ DX-^r-l SZV.-z i - Lz-.~. =r : : ; r.l 7AL K31 I . - 1 1" 1 r Eg &£) aUHz^SIHz:. EfSA H-P. 2?* S A E.— F. ,n :r : ■ ’V-- £*: : : HJPCOhl Eafli 4- 'll? iV ■155)3 HP. i'7 : 4 “«acmc* >c..V€,v . .... £:i:; K P l-T-A -- l*.r (r r^-----V-r ai£3 HP. EG'E- 4 “' -iiiTiir -,zf- £1!I2 irkl>iz tfrS i ■ 2245 . .... EZilS H.P. I112A =..:?= ird:— £71/-: ilZ^s MA3B&1 zu: Ffrij ‘ : rn-c ?1EES HP. 54556 Fnc Di-rtET ILuHz QW HP. _ . £SM H.P. IEi.15 E-I j-jrra karoho 23*5 uat eEki tin? £742 Spectrum Analysers tt P. :.:EE El -j -SEE.- H7- 45E.yi I'--’- 5 r ■ "7 H.P. H P. LLEic lUHE-fJSfb 73 c/tca ILP. mSA wBi ESSU 000^21 Bit ft j. SSSEfi tifi ifcu'fl FrSot! 1 DCKHr.l =TfM fr HJ. 3E-TE4 ZKl.J-IVrfr ittl* OH 1 £tK : ei::i OSH iLF_ ^ UffAUHT R41S13 lCP24i-^5!3ir .. EATLii.JL-iL: T I M -ILE-r ■tutoa TXHfJeowsr ^ Hh ksee'vi J37C : :v— HP. lS wlfr 6557 iCKHr-SSOUKz Hf-Uli 4jVf-I i«3 * ■r:-"CV,"3 : sX^rtMEfrl 10WHJK EZrSI 27EE :- tUCu . - 44 2 Krttr U0 WHz £7 S* £743 fP TT^ r:£i!«ey & rme £2?5i LP. STStA mw : ft Artra 4394^13061^^ ? 1 1 4-S HLP. 2S77A W&M5A Stz-^DGU^ 22 L L : H_P_ 535' OA l A-rt:fc-nim []o?nah DptCG3 tKi3 DB Kill lFZlO FtftiZig FF7 __ i ■ ; T ; ; L - . H_P_ 5SJ12A PSU &2SH f 0-2A IftMnsisutiflrilc HP. S33SSO fS3 Otd CH5V B HP- FSJ G-2SF i »tt -7A5--IV C- L E 1 . . £455 £j;'I £452 H F. fciJA - -=:gn: r-- r .... . £i£f ■:-r\ r-zA 15 0-27, H F Ij-'MI “V.1.1 KSrtil* FU*T4S4 K P 14"A ' UV >> 3rn? «75 FU/lE 45 l V.V - W £4.;£ EBTHLET? : ' 2VU ~ = - — i'2JTi-3_E¥ sT =7 _ r-i-i— .rTi^ r T*:?v-i5:?r 11750 H P. -O.S” V lli^i— _ £15H RMAL Cnsttr Ej^s 1^9 2.6 GHz HP, Ciak J>re _ Oil m BKP171MI HP.XEaUfT 531234 fjxt.ir Gar; .4=3 _ T>: 52 h7 TE4TR4WGX .JEfttSIC feirST, &.r _ . H2E* HP. Efttt 2y- .tci: ‘ &R! CC - t- 7'7 1 “7 £l t'W H JS0 9uo $T4Q jonren 2010 f^on 6as ojHz-eusti . ««• — r '':v JiTiiy El'Xli.’ HP. Vi ’ 3A Pgj^s . HP. S(jh Sgsg Gssn 0 1 29&UKZ 5 5 ; 5 7 Oahu switch 543 ItH QMtt £19 Radio Communications Test Sets ; :>:l : =-_ r - +TIG ZO! 1 IflBfif tltMgiWZ^VTlT TTTTIIH- - E130I 5:-..if:T : \z-. K<> f-'I Used Equipment - GUARAHTEED. Manuals supplied. Hits is a V0TT SlilALL SAMPLE OF STOCK- SAE oi Tefepfiooe for ISfe, Pfease diedt awas^jilily btfon ordering- CAPIUAGE all units 216. VAT tote added &TofeI of Goods and Carisoe. Elektor Electronics 1 2004 Visit our website www.distel.co.uk I THE ORIGINAL SURPLUS WONDERLAND! THIS MONTH'S SELECTION FROM OUR VAST EVER CHANGING STOCKS Surplus always wanted for cash! GIANT 10" 7 SEGMENT DISPLA YS I IC’s -TRANSISTORS - DIODES OBSOLETE - SHORT SUPPLY - BULK 10,000,000 items EX STOCK F c* MAJOR SAVINGS CALL or see web site wv/w.d islel.co.uk A clx purchase grains s ^ to bring ^ Tese ©Ah i 7 ssemart d^a! cisco's to a now affotdftbte pnc&" Thq ft* charadtor eJzq eexteterto rcad- sb£y to eng dto^ees Crebbs a rcto cf sautea- Xns rdbdng &cot boards, dfcj tef docks, coun- ters, ev&nl Umars As To lints are 3 sfrn.pfs c^iiofnod'cncs d^tre and operate Tam 12 V DC, amps °,srd n _-. rarepcsi^toag a_re>_-. w;i «50 pug dreed/ into most video irearoerto afcwiig recscdon cr TV' charnels net rwfinaJy receiYsfcfe on rrvoel li/svisjcn receivers' (TsUi- B0X } -E>. Push buCDT corcrefe on £b tort penei aiew racecocri or S tel, Lnsecfe 'of! er r L-F ccfcur te&iacn chamsfe. TELEBOX hFB co^rs .Tl- a>y el Eiaisfon frequences VHF and UKF intiudr g the HYPERBAKD as used most cable TV operators. deei for desktop computer video sys- kns 5 - = (peers h petors} setes Far ccrrpfete cotcscog:/ - even rev mentors v- vtxi srxnd - an magrP 4 wsc aide ampfiar and kwv level Fi R aoo cusuiara presided $ standard. Brand new- foty garaTsed T EL E BO X ST for composite video input type meet tors £3 6.95 TELEBOX STL as S i tut fried with integral speaker £39-50 TELEBOX M & Mufcband VHF^FX^e/Hyperband bluer £89-95 Fo-r overseas PAL versons state 5,5 cr 6 mHz sound specffcaflafL >c j cab's : hipe?feand signal reception Te'sfcox V3 shoidd be ocp- nected to a cab's type service. Shipping cn sL Teiebox's, cods (B) State cf the art PAL (UK spec) UHF TV tuner module wti composite IV pp video * M EC AJM hi fi steieo sound outputs. Micro electronics ail cn on-e srrsl FCB only 73 x ito x o2 mm enable full tmvng cc-ntrd via a simple 3 wire linX to Em IBM ft hj-pe com-puier, Suppied couplete wbi simple working propram snd dbdffiieiitaiiofL PkljTbs +1Z'7 ^ + 5V CC S3 operate, brand NEW - Orfer as AfTOO. Only £39. 95 code (B) See .‘.-A-.v.dislsf. co-u k 'ds tamyOO, h tm for picture + fun detal is HARD DISK DRIVES 2Vz" - 14 ?. TOSHIBA MK1G02MAV 1 1Gb astcd 12.5 mm H) New £59.95 234" TOSH IBA V <43 13MAT 4 3Gb laptop fS^ mm H ) New £105.00 27/ TOSHIBA MK&409MAV 6 iGa laptop (12 l 7 nwH; New £98,00 27' TOSHIBA KK1814GAV 18 G6 laptop (12 mm H) Wcw£t49JS 37* convereionHlbrPcfe, GQflwimwMhGDnfieciDrc £15,15 37“ CO f.l P AQ 31 37D6-B2 1 (i 3 M) 9gb U LT/SOS13 New £1 95.00 COMPUTER MONITOR SPECIALS Legacy products High spec genuine muitysync. CGA* EGA, VGA, SVGA Mitsubishi FA341 ^TKL T4 T SVGA iMtsytK cofcxs- mcnfcr wdh fm dof pen tee snd resdLcon tf '(£4 x Jog. Avsrr STj' cr rp_"S SlOas comaxoi it s ncet ct czrroszrs &Ktod ing IBM PCs in CGA, EGA VGA £ SVGA rade5 : BBC, COMMODORE mdUdrq Afiios 1ZCC . ARCHIMEDES snd APPLE, . festrSE; Etched taspa^ fed s-.-.-Dhr.g srd LOW RADIATION f, r ?R ipeerfisden. Ftatry cLrz."‘.agd- n EXCELLEJil ::a uagdcPO Jfa vTlt ^Swtvd Base £4.75 vga^wbmpcww only £129 ( E) Tg^ Extgjn^i cabfes foredw types of cofr.pubE-f3 a’.'EiLTbl-^ - CALL Generic LOW COST SVGA Monitors We choose the make , which induties Compaq, M> jsubushi, tBM ? etc. Supplied reedy to run with si! cables. Standard RTB 90 day guarantee. _ ~ 14" £59.00 order TDS4 15" £69.00 order iG2 1 17" £79.00 order TJ66 Supplied in good used condition. Shipping code (D) VIDEO MONITORS PHILIPS HC535 (sarri st« a as CM8833) attradhaty styled 14' colour monitor with both RGB and standard cnmpositfl 15.625 Khi video inputs via 5 CART socket a.^d separate phono jades, ijTegraJ ajdb powar amp and speaker ‘cr all audio visual uses. YM3 corned direct to Amig 3 and Atari BBC computera. kfeal icr s' vi'dao monilDriftg / sacurity applcaricfts with direct connection ta most colour cameras. K'gh puaiby Vjflb many features sucb as front concealed flan conlrc!s r VCR ■DOffEOt ~~ button etc. G L L L used conettiori - fji.y lEstEd - guaranteed pi n |, , c qq a n Dimensions: Wl4‘ x H127" x 1 &>/ D. 1 1 X W5, - yu fOj PHIUP5 HCS31 Ultra corrpsct 9 cc our video momtur ^Tth stan- dard composite 15,625 Khz video input vis SCARi szc- ei. Idea 7' s 4: '■'■*: '7:.% :=-':.'s ""t 1 - z ^.-z:.. toty tested & guaranteed (posssfe minor screen bums). In sttrac- trve s|U3e biack pLsLc case meastmng WJO x H10* x 1335 D. 240 V AC maiTis poAet&L Q n [y £7g g Q (D) 37* FUJI FK-309-26 ZGrvb MFM IfF RFE 334* CONNER CP3024 20 mb IDE IfF {or equr/,) RFE 37* CONNER CP3CK4 4D mz IDl l/F(Orequ'Evj RFE 37" QUANTUM 40S ProdmfB 42mb SCSI LrT. Kuv- RFE 57' MINIS CRIB E 3425 20mb MFM 5r for ec4v.) RFE 5VF SEAGATE ST 238R 30 mb RLL LF Refjrb 57" CDC 94205-51 4Qrra HH MFM W RFE tesie-d 57 5 5 /* 6 T 5" 6’ HP 9754S &50 Mb SCSI RFE lasted HP C3010 2 Gbyte SCS! differentia! RFE tested NEC D2246 65 Mb SMD interface Mew £59.95 £59,95 £69,09 £49.09 £49.95 £69.95 £69.95 £99.00 £195.00 £99.00 £195.00 £345,00 FUJITSU M2322K 160Mb S:'.'D t F RFE tested FUJITSU M23S2K 2 Go SVD Lr RFE tested Many other floppy & H d/rVes, /D£l SCSI. ESDI e!c from stock sea website for full stock fist Shipping on sit drives is code (C) INDUSTRIAL COMPUTERS i ny £ " : e =: s zez z _ f 7 = - 1 ’4 j E S F C sy3 isti r ees _fj“3 ontv (ran) 266 w X B8 h X 272 d. Ideal for dedicated control appfi- caboris rurjilr-s DOS. Lin n>.r- even '/nrsdows l Steel case con- tains 65 to 265 V AC 50 50 ha 70 Watt PSU, a 3 set ISA passive taefcz ene and a Rocltv 31 B .PCtC4j standard, single board com- pilfef Vr7h B MByte NON VOLATILE set-d state "Disk On Chip 1 RA-S'DIiSK. Svatem cxvnpisee: Rc-zky 318 (F Cl G4) SBC ISA cam wth 46MHz AJJ 336SX CPU. 72 pin SIMM ktot with 1 6 Mbyte SIMM, AMI BIOS, battery backsd up real Lms c zou 2 x 9 pFi D 1 6uo0 eeisJ ports. EPPVtCP printer port, mini DIN iteyboard con- nectar. Hozpy peri. IDE peri fur hard drives lc to 528 MByte irt = :7y, Acjcridcc Lt-s; ariC PC ' " ■ n..j z: i \ r E,ze sb : 'c stars r cjsk on a chip" has Its c^n BIOS, end can be fz ^v-z-z formatted 5 booled. Sup-p: isd BRAND NEW fuBy tested arid guar- anteed, Pc: L . c sia see featured item on websfte. Order as QG36 100's of applications inc: firg'.va'I, routers, robotics etc Only £99.00 d TEST EQUIPMENT & SPECIAL INTEREST ITEMS thfar aaeflon are pre owned. MTTSUBUSHI FA3445ETKL 14’Trd spec SVGA mentors FARNELL Uh 60V DC @ 50 Amps, bench Power Supplies FARNELL AP3050 0-30V DC @ BO Amos, bench Siqny KINGSHILL CZ403dri 0-50V DC 2CO Amps - 1 klV to 400 kW - 400 Rz 3 p wst soutoes - ex stuck 1 3!it S23Q Type 1, Tc's.eri ring imrt d^.'-Lv 'iVayne Kgit RA200 Az7 u frequency ar.= . " IflFODEC 1U, 24 peri. RJ45 nsfA-c-ri: paraipanGte- -IH93 3COM 16570 12 Port Ethernet hub - RJ4-5 cor, rector =LD37 3COM 16671 24 Port Ethernet hub -RJ45 carrc^tz^ 3COM 167Q0 6 P&rt Ethernet hub - RJ45 connecters NEV. : JBM 53F5501 Tpkfin R ng ICS 20 port lobe modutes IBM MAU Token mg distribution panel 8228-23^50: "N A! M 501 Lew U^tedcn Osc L'ater Stiz to 33CKhz; IEEE ■ □ ALLGON 8360,1 1605-1880 MHz hyt-d was " eombinefs Trend OS A 274 Deta Analyser with G70312M) 64 ito Marconi 6310 Prograjimnaljte 2 to 22 GHz sweep generator Marconi 2022C IDKHz-IGHz RF signal generator H P 1 650 B ^ogc Analyser HP37B1A Pattern generator & HP3732A Eimr Letoctor HP6621A Dual Pr^ramn^bSe GPlB PSU 0-7 V 160 watte HP 6264 Rack mount variablo 0-20V A SOAmsterad PSU HP54121 A DC tc 22 G-z four charnel tost sc 3 HP6130A opt 020 300 MHz eu', 50 pCTLEfstor. GPiS 57 HP At T AO 8 pen WGL hWi speed drum pfctters - ' : ■ HP DRAFT MASTER 1 5 pan high speed p'ette' EGrG Brogkd^al 950 3 5C Preasicn took in amp Ksith’sy 590 CVcapadtor/ vottsge a.-'s;yser Rata! ICR40 CL3 40 c."s - nal voice recorder system f: ik era 4 5 KVA 3 ph Gn Una EJPS - Nev, irattones Emsrson AP130 2-5KVA Industrial srec.UPS Vann Tally MT645 highspeed Ir.s pc^te: Intsl SBC 488H33SE MvKbus 486 system. -Mb Ram £245 £995 £1850 £3950 £P0A £760 £2500 £43 £69 £69 £39 £PGA £45 £550 £250 £POA £4500 £1550 £3750 £POA £1800 £475 EPOA £7900 £550 £750 £1 £90 £POA £3750 £4509 £1499 £220 0 £345 rf4® °<$s' 19" RACK CABINETS Europe’s Largest Stocks of quality rack cabinets, enclosures and accessories. Over 1000 Racks from stock This month's special A 33 / 42 / 47 U- High Quality ^ All steel Rack Cabinets ,7 Made by Eurocraft Enclosure 5 _:z v: . e highest pca- sible spec, mck fEatoras ail stael constAidion Vkirii removable side, front and back doors. Freni and bade doors are hinged icr cesy access e^c a. fscfcBbfe with frve secure 5 lever banul locks. The front doer is corstructsd cf doucls_wai3ad cteel with a "designer style’ smoked aery c fror’ panel to enable states ind caters to be seen through the pansL yet remain unobtrusive. Intern ally the rack features fully slotted rein- forced vertical lining mernbe's to lake lbs heavi- est of 19" rack equipment The fAO movable ,-zrtfcal! fixing slruis (extras sva ab s) ere p-e pwched for standard J oga mrtsL A mains dis- tnbutiori panes '■torra.fy mounted to iha bottom rear, prov-J-es 6 x IEC 3 pu Euro socket and 1 i 13 amp 3 p-n switcJ";ed utility sockeL G-raral venda- tton is presided by filly louvered back door and dexite skinned top s action with lep and sice kxnrss. Tre top psr.^ may ca removed for fitting cf integral fans to l re -zre e:c. 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Because of the high input capacitance there is a Miller capaci- tance of a few nano farads, and so an input buffer in the form of source -fol- lower T1 is necessary. Here again a 2SK389 is used (one transistor per channel), which guarantees good matching between the two chan- nels. In principle any low-noise FET can be substituted. Following the SRPP stage there is an R1AA equaliser network compris- ing C3, C4, and C5, and R5, R6 and R7. The maximum deviation from the official RIAA equalisation curve is just -1,6 dB at 20 Hz and agreement is generally within about 0.3 dB. T3 to T5 form the output stage of the equaliser, with a gain of 12. The gain can be adjusted over a wide range by changing the AC feedback network formed by R10, Rll and R12. The output impedance is just a few ohms. For T3 and T4 we would ideally like to use a dual FET with a low input capacitance but with a transconductance comparable to that of the BF246B. Unfortunately such a dual device does not exist* and so we must select two suitable BF245Bs. We therefore connect the transistors as shown in Figure 3 and try to find pairs with the closest pos- sible drain currents. The lower tran- sistors of the two channels should also be as similar as possible in order to achieve good channel matching. Since a clean DC supply is essen- tial for a sensitive circuit such as this, a few words about the power supply are in order. High-frequency interference is suppressed by a mains choke and two capacitors on 30 Elektor Electronics 1 2004 &V1DE0 COMPONENTS LIST Resistors: RhR3,RI I ,RI 3,R!5,R23 = 47kQ R2,R4 t R14,RI6 = lOOfi R5.RI7 - i 2kQ 1 R6,RI8 = ikQ33 R7,RI9 - 68kQ R8,R20 - 470Q R9,R2[,R27 - tOkQ RI0.R22 = 220kQ RI2,R24 = 1 5kO R25 = 274Q R26 = 4 k 087 R28 = 22Q P 1 ,P3 — 25QQ preset F2,P4 — I kQ preset Capacitors: C I ,C9 = 27pF C2 1 C3,C6,C!0,CI I .Cl 4 = IpF MKT, lead pitch 7.5mm C4,CI 2 = 220nF C5.CI3 = 82nF C7,a5,CI7,C20 = lOOnF C8.C16 - 100/iF 40V radial 08,09 — IO/jF 63V radial C2 1 - JOQOpF 63V radial C22-C25 = 47nF ceramic, lead pitch 5 mm C26,C27 = lOOnF 250 VAC (Class X2 ) t lead pitch 1 5mm Inductors: L f = suppressor choke 2 x 27mH (Epcos # 88272 1 -K240I -N2I ) Semiconductors: Bl = B80C1500 bridge rectifier, rectangular case (80V piv, 1,5 A) Dl = LED, low current TI,T2,T6 = 2SK389-BL (Toshiba), (vw/w.reichelt.de) T3,T4,T7,T8 - BF245B (see text) T5,T9 = BC550C iCI = LM 31 7 (T 0220 case) Miscellaneous: KI-K4 — cinch socket, PCB mount (Monacor/ Monarch # T-709G) K5 — 2-way PCB terminal block, lead pitch 7.5m TR1 = mains transformer, 2 x 12V 1 .8VA (e.g. Gerth # 304.24-2] PCB, available from The PCBShop. the primary side of the small 24 V transformer. On the secondary side capacitors are connected across the diodes in the rectifier bridge, which suppress interference caused when the diodes switch. The LM317 volt- Figure 4. Printed circuit board layout. age regulator produces a stable and clean 24 V supply. Figure 4 shows the layout for the printed circuit board, which has an extensive ground plane. Unless the board is to be mounted as a whole inside the enclosure, the power sup- ply section should be cut off before populating the board. The layout ana the component arrangement are practically symmetrical, and there are two wire links, near to K2 and K4. Alignment of the circuit involves adjusting potentiometers PI and P2 so that the voltages at the source connections of T2b and T4 are each equal to U b /2. The input capacitance of the circuit is formed by capacitor Cl and the input capacitance of Tl, which, in the case of the 2SK389, is around 20 pE The optimum input capacitance depends on the type of cartridge, and will normally be found in the specifications of the system. VQ]r:2-I Internet address: www. t u b e c ad . com/ may 2 0 0 0 31 1 2004 Elektor Electronics 1 Alarm Clock In control of many daily events Design by K.-U. Mrkor A regular alarm clock, whether stuffed with electronics or of the mechanical variety, will not get you very far if you need to be reminded of several events during the day (for example, taking your medication). What you need is a multi-talent like the circuit described here. The circuit diagram of the Multi-event Alarm Clock shot™ in Figure 1 is easy to under- stand, the central parts being a contemporary combination of a microcontroller, a real-time clock and an LC display. At the heart of the circuit sits a powerful yet inexpensive and widely available 8051 -compatible 8-bit micro- controller type AT39C2G51 from AtmeL Its main features may be summarized as follows: - full 8051 software compatibility; - 2 kbytes of Flash memory; - integrated analogue comparator; - multiple outputs with LED drive capability: - static architecture (0-24 MHz) - extended supply voltage range (2.7-6 V). Quite important lor this application, the chip comes in a small enclosure with 'just 1 20 I/O pins. Port 1 and Port 3 (with the exception of the P3.6 line) provide 15 freely programmable port lines. This should be more than adequate to connect the following peripherals: an LCD to display time and menus, two pushbuttons to set the dock and the alarm times, an LED and a piezo buzzer as an acoustic alarm. To these elements should be added a real- time clock (RTC) component type DS1307 which communicates with the MCU via an 1 2 C link. Thanks to a 3- volt Lithium backup battery, the DS1307 will keep ‘ticking" in the absence of the supply voltage. Suitably pro- grammed, the chip supplies a seconds pulse at the SGW/GUT pin. - IF*. Clock reference adjustment In real life, the clock output of the DS1370 will rarely supply a pulse with a period of exactly 1,000000 seconds. This is because the quartz crystal used in the RTC clock oscilla- tor circuit is subject to a certain pro- duction tolerance. The author pur- chased and tested a number of these quartz crystals and found pulse peri- ods of up to 1.000008 seconds at the chip output. Unfortunately, what appears to be a totally harmless error in the sixth decimal position can well be the cause of serious degradation in the clock's final accu- racy, amounting to an error of four minutes per year. Although the error may be com- pensated by adjusting trimmer C5, 32 Elektor Electronics 1 2004 that really makes sense only if yon have a reliably and extremely well calibrated frequency counter boast- ing a microseconds range. Assuming you have such an instrument (or have access to it) then the probe may be connected to pin 7 of the DS1307 and the trimmer adjusted for a reading that's acceptable. Failing the above, C5 is best omitted from the circuit. Power supply The power supply for the circuit is of a less conventional design, consist- ing of a low- drop voltage regulator, IC3, with its usual satellite parts. Its function is to turn the external sup- ply voltage (from a battery or a mains adapter) into a stable 5 -V sup- ply rail for all circuit parts except the LCD backlight. Jumper JP1 ensures that the backlight current is never drawn from a battery — after all, we’re looking at something between 40 and 240 niA depending on the LCD type you decide to use. The cur- rent circuit around T2-T3-T4 (actually a current mirror) only works when a mains adapter is used to power the circuit, supplying the necessary cur- rent for the backlight lamp(s). The current consumption of the circuit with the exception of the LCD amounts to just 5 mA which may be lowered even further by a small reduction in the MCU clock fre- quency. The MCU itself does not exe- cute time-critical tasks and will hap- pily run at a clock frequency as low as 2,4576 MHz. The only conse- quence of a relatively low MCU clock frequency (determined by the quartz crystal) is a slightly sluggish menu when the clock and alarm times have to be set. Obviously the DS1307 is not affected by these changes because it employs its own timebase. Software The software for the project was written in the a C T higher language, using Keifs pVusion2 package as a development platform of which a free evaluation version may be downloaded from www.keU.com/demo/evaI .him 1 2004 EEektor Electronics GENERAUMTERET Figure 1 . The main components in the project are a microcontroller, a real-time dock chip, an LCD and two pushbuttons. The only limitations of this version are (1) non-commercial use and (2) a maximum object code size of 2 kbytes. The latter limitation is hard to object to if you realize that the size of the AT89C2051 Flash memory is also 2 kbytes! The microcontroller executable code looks after several tasks includ- ing outputting the current time, com- municating with the user via a menu structure and, last but not least, enabling the acoustic actuator when an alarm time is reached. The seconds clock pulse that’s crucial to the function of the Multi- event Alarm Clock is generated by tire DS1307 and fed to the AT89C2051 MCU by way of an I 2 C bus interface. Unlike some other 8051 derivates from Philips, the AT39C2Q51 does not have an on-chip I Z C interface, hence a few I 2 C routines had to be written based on an example supplied by Keil Access to the real-time clock is similar to reading/ writing a memory device. The only point to keep in mind is that the first eight bytes in the RTC RAM are reserved for the clock itself. The battery backup makes the remaining 56 free memory locations Ideal for the storage of alarm times. However, the DS1307 has to be initialised before it can be used as a timebase. The initialisation com- prises adjusting the clock and loading the control bytes. The memory map in Figure 2 33 . IIMIMLjMEEBESE shows the meaning and function of the indi- vidua! bits contained in the first eight control bytes. The MSB (most significant bit) in the seconds byte (CH, clock halt) is the most important in tills respect. Whenever the IC is powered up, this bit always reads 1, and the clock is not started until CH is made 0. Set- ting the OUT and SQWE bits prompts the DSl 307 to supply a rectangular signal at its OUT pin. The frequency of the output signal is determined by the RS I and RSO bits. A i- second pulse is obtained by programming die value 00b. By connecting the OUT line of the DS1307 to the INTO input of the microcontroller, a h second interrupt is generated. The relevant interrupt service routine updates the time output to the display. Next, a check is per- formed to see if the current time matches one of the alarm times stored in the DS1307 RAM area. If so, that event is signalled by three acoustic and optical signals. Bit? Bit6 Bit 5 Bit 4 Bit 3 Bit 2 Bill Bit 0 □Oh 07h 08 h 3FH .s y / CH seconds (tens) seconds seconds minutes * S / ^ f / ' J~ > 0 minutes (tens) minutes 0 12/24 10/A/P hours (tens) hours hours day date month year jJ 1 0 0 0 0 ! o day 0 0 date (tens) date ■>. "H. "S >L Sl S. -H- % 0 0 0 month (tens) month control 56 Byte RAM year (tens) year OUT 0 0 SGWE 0 0 RSI RSO Figure 2. DS i 307 memory map. Tire control program then checks if the user is pressing one of the pushbuttons to call up the menu. If so, the menu is made available, else, COMPONENTS LIST Resistors: Ri = lk£2 R2.R3 = 47kn R4 = 1 0Q R5.R6.R7 = 4kD7 R8 = 1 £15 R9 - i 00Q RIO = 220Q PI = lOkO preset P2 — 2kOS preset Capacitors: CI.C2 = 33pF C3 = 1 7 JF 63V radial C4.C6.C7.CI0 = lOOnF C5 = 25pF (trimmer) C8 = 220 LtF 1 0V radial C9= IQiiF 63V radial 1 C 1 1 = 470llF 1 6V radial ■ Semiconductors: D l = LED, red, 5mm, low current (optionally with chassis-mount holder) D2 - 1N40GI T! = BC547B T2 = BD242 T3 = 3C557C T4 = BF256C IC i = AT89C205 1 - \ 2PC, programmed, order code 020304- 41 IC2 - DSl 307 1C3 - 4805 Miscellaneous: jP I — 3 -way pinheader with jumper SI,S2 “ pushbutton, I make contact. chassis mount LCD I = LC display, 1 6 characters 1 2 lines x 8), e.g. AV0820 from Anag Vision) plus 16-way boxheader XI = 6 MHz quartz crystal (parallel resonance* X2 — 32.768 kHz quartz crystal BTi = 3V Lithium cell type CR2032 with PCB mount holder (22.75mm diamj BT2 ~ see text BZ l — 5V or 6V DC buzzer (active piezo) PCB, available from The PCB Shop Disk, microcontroller C (source) and hex files, order code 020304- 1 I or Free Download Figure 3. Copper track layout and component mounting plan of the PCB designed for the Multi-event A arm Clock. 34 Etektor Electronics 1 2004 * GBNERAUNTTFRFS the microcontroller changes to 'sleep 1 mode. In this energy-saving mode, the AT89C2G51 consumes just 1.6 mA as opposed to 7,5 mA (assuming a clock of 6 MHz). The MCU does not wake up until the next interrupt is request is received from the DS1307, when the display adjust clock enter new alarm time dear alarm time 17:45 Me RL nu C 1 k M e n u RL Clk □ □ □ □ H o u r OK s 14 + R 1 a r Pi N e w D e 1 0 m □ □ M i n : OK 12 + H o u r : @ 0 OK + m 0 0 0 14 Cl n 4 O o c k Min: @0 0 K + □ □ 0 CD 14:12 U 1 ci c k □ □ Me RL nu C 1 k □ □ fllarn New Del □ □ 1 6 Del ! 7, ft - > □ □ 17 s 45 Del 3 i 0 0 14 Cl : 12 oc.k □ □ 020334- 13 Figure 4, Operating the dock eou[d not be easier using the built-in menu. update and pushbutton check routines are run again. Construction and use The circuit is conveniently built on the s ingle - sided printed circuit board of which the lay- out is shown in Figure 3. It should be noted that a number of components are not accom- modated on the board — these include the ‘large 1 battery, BT2 (which may take the form of two Lithium cells, four Alkaline cells or a single 9-V battery), piezo buzzer BZ1, push- buttons SI and 32 and, of course, the LC dis- play, The latter is connected by way of a 16- way pinheader and two extra solder pins (A and K for the backlight). Populating the board should not cause problems as there are no unusual compo- nents to deal with or special mounting methods to observe. As a matter of course, electrolytic capacitors, transistors and inte- grated circuits must be mounted the right way around as they are polarized compo- nents. Transistor T2 and voltage regulator 103 do not need heatsinks as they pass rel- atively low currents. As illustrated in the introductory picture, the two pushbuttons are fitted directly onto the case panel, just below the display (SI to the right, S2 to the left). The alarm LED may also be mounted below the display. All user settings are guided by the in- built menu and entered using the two pushbut- tons. The menu is entered by keeping one of the pushbuttons pressed for about one sec- ond. Within the menu, the items to define invariably have two options, which are dis- played in the lower of the two display lines. The desired option is selected by pressing the pushbutton below the relevant text on the display (i,e. t left or right). The three main func- tions, clock adjust, alarm adjust and alarm clear, are shown pictorially in Figure 4. Web pointer DS 1 307 datasheet at httpi/'/pdfserv. rnaxim-ic.com/ en driPS I 3Q7,pdf Free Downloads Microcontroller C (source) and hex files. File number: 020304- I I .zip PCB layout in PDF format. File number: 020304- 1 .zip v A-AV. e I e kt o r- e Ee c t ro n i cs . c q . u k/d 1 ; d I . h tm „ select month of publication. 1 20-04 ESekior Electronics 35 APPUFfli NQ The content of this note is based on information received from manufacturers in the electrical and electronics industries or their representatives and does not imply practical experience by Elektor Electronics or its consultants. MW m D A novel LED driver By E. Haug LEDs have been around for years now but it’s only recently that things have started to get interesting with white and superbright versions appearing at reasonable cost. LEDs of course require some form of driving circuit and there is a lot of interest in more efficient or versatile techniques for driving them. This circuit isn’t fussy; it outputs a constant current suitable for high power LEDs and it doesn’t care whether the input is 12 V or 230 V! It sometimes happens that a chip manufac- turer comes up with an IC to perform a spe- cific function and later the chip is found to be useful in a different application, not antici- pated by the original designer* The HV9901 Universal Relay Driver from Supertex Inc. is just such a device* It was originally designed to provide a constant current output drive for a relay coil from a very wide range of supply voltages from 10 V up to 450 V DC without the need to alter any of the circuit compo- nents. This device offers a number of benefits both to the designers of white goods where the variety of relays used in equipment can be reduced (optimising quantity discounts) and also to the maintenance engineer who does not need to check coil ratings of a replacement relay. The HV99G1 operates at DC voltages only so for AC operation a bridge rectifier is also needed {but no reservoir capacitor is usually necessary). How come that LEDs and relays are so alike that they can both be driven by the same chip? Well both require the drive cur- rent to be as constant as possible inespec- Frgure i . The switched current source configuration. five of the level of supply voltage. In the past with low current LEDs tak- ing only a couple of milliamps the problem of driver design was not so great but with today's high power devices consuming a few hundred milliamps up to 1 A the need for efficient drivers is more acute to avoid excessive dissipation in the driver circuit. Figure 2 . Internal diagram of the HV99QL 36 Elektor Electronics 1 2004 AppueffnoNNg Figure 3, Load current waveform. MGSFET to the load and measures the load current through a sense resistor to produce a (rippled) constant current output. The oscil- lator frequency is set by the value of resis- tance connected from the RT input to ground. The ripple current Al (Figure 3) is gov- erned by the coil inductance, clock frequency i and the peak LED current I s . It is important to accurately control current through the LED because the maximum peak current of high current LEDs is only slightly more than their continuous current rating so it is important to achieve high brightness from the LED with- out over-driving it. Each time the peak value is exceeded the stress causes brightness reduc- tion. colour change and can lead to the untimely death of the LED, The ReLED driver A switched current source The step- down generator used in the HV9901 is a switched current source. Figure 1 shows the principle of the circuit. When the switch is closed current through the coil begins to rise. The rate of current rise depends on the value of supply voltage and the coil inductance. Before current in the circuit rises too much the switch is opened and the flow is inter- rupted. The ‘flywheel 1 diode allows current to continue to flow through the coil and back to the positive sup- ply but it decays almost linearly because of the energy losses through the coil and LED, Once more the switch is closed and current increases again until it is inter- rupted. This process is continually repeated so that current through the load has a ripple characteristic. The faster the switching process repeats, the smaller the peaks and troughs of the ripple will be. The HV99G1 shown in Figure 2 generates the PWM signals to switch the high volt- age input through an external power The circuit is capable of driving both relays (also electro mechanical valves and solenoids etc.) and all types of LED so the circuit was given the name ReLED (well it seemed like a good idea at the time). The circuit controls its output current by measuring peak current through the coil via a sense resistor and switching the supply on and off. This is not the conventional method of providing a con- stant current source but the circuit is very simple to use and performs reliably. The HV99G1 can accept input voltages in the range from 10 V to 450 V DC (providing that suitable MOSFETs and diodes are used) and not just ; pure r DC but also pulsed sup- {P)DR 127-1 02 (SMD) PE-i3120 02 5 WOOJS-t UQ0 1 4 1 48 Figure 4, Circuit of the ReLED driver including the mains filter. 1 2004 Elektor Electronics 37 APPLICATION NO plies like unsmoothed rectified 50 Hz mains supply. This feature allows a high currant out- put supply to be produced without the need for expensive and bulky electrolytic reservoir capacitors. The circuit in Figure 4 provides an output current of around 300 mA and is suitable to drive a blue or white 1 W Luxe on LED, Over- voltage protection and a mains filter is included on the input to the circuit to comply with EMC recommendations for any mains powered clocked circuit- Other types of LED can also be driven from this circuit providing that the value of the current sense resistors {Rl.l and R1.2) are changed if tire LED current rating is different. The current sensing resis- tor should be of a type having low parasitic inductance, connecting two identical resistors in parallel helps to reduce any inductance and also shares the energy dissipation. The coil inductance and the oscillator FWM switching frequency both play an important role in keeping the current ripple to an acceptable level. In contrast to linear current regulators the value of input voltage has only a small effect on the power dissipation in the driver (and the efficiency of the circuit). Several individual LEDs can be connected in series and driven from this circuit provided there is sufficient supply voltage available. The minim um sup- ply voltage required to drive an LED is 12 V DC or AC but with a rectified AC supply of less than around 30 V the period that the circuit cannot conduct around the zero crossing points of the rectified AC waveform is rela- tively long so the LED will noticeably flicker, A 220 uF reservoir capacitor (with an appropri- ate voltage rating) can be used to prevent this. Connections to the LED are both open and short circuit proof provided that these leads are not shorted to ground! A fast-acting fly- wheel diode suitable for the 50 KHz switch frequency must be used in the circuit other- wise there is a risk that the MOSFET will be destroyed. Component choice One area often overlooked by newcomers to PET design is the gate characteristic of the MOSFET. At first glance we notice that the input impedance is very high and mistakenly jump to the conclusion that not much energy is necessary to switch the MOSFET. This is true if the device is operated at low frequencies or DC but if we are switching the MOSFET at speed another factor is important: the gate capacitance. The maximum switching fre- quency of the MOSFET will be governed to a large extent by how fast the gate driving cir- cuit can charge and discharge this input Figure 5. Auxiliary power for additions! CMOS circuits. 4 8 HOLD. "DELAY GT CS VCC COM E» HV9901P SYNC OfO RT POL RIO 030212-15 Figure 6. Flasher circuit showing VDD and VCC finked. capacitance. Unfortunately MOSFETk with low R^gfON) k ava correspond- ingly high input capacitances so that switching power MOSFETk at speed gets more of a problem at high fre- quency and high supply voltages. When choosing the MOSFET type ids therefore important to check out the gate capacitance and not just select the device with the lowest Rds[ow)< The HV99Q1 can comfort- ably switch devices with a gate capacitance up to 500 pF and can also cope with 1 nF at a push. The suggested MOSFETs in this design can switch the LED supply at a PWM frequency of 50 kHz from mains supply voltage without the need for any heat sink. The coil specification is also important to ensure that it does not become saturated at the peak cur- rent over the complete operating temperature. A check with an oscil- loscope should indicate that the volt- age rise across the sense resistor is more or less linear. More features In addition to providing a stable LED drive current from a wide range of input voltages the circuit also has a number of other features that may be 3B Elektor Electronics 1 2004 APPUCOTiONNO VUJ VDQ IC1 VfiEF j KOL0/DEUY OT FB cs VCC COIN EM HV9901P SYNC EJiO FTT POL 12 11 10 fi a 1“- A R7 C£ 1|i \ IQk MX GND 1 Figure 7. Simple dimmer control. useful in some applications: The LED can be switched on and off by a logic signal applied to the ENI input (gal- vanically isolate this input logic sig- nal via an opt occupier). The polarity of the ENI signal can also be inverted by changing the level on the POL input. The HV9901 also con- tains an auxiliary voltage regulator that can be used to power additional circuitry. Two resistors are used to program the auxiliary voltage in the range &om 2 V to 5,5 V the maximum output current is only 1 mA but this is enough to power a couple of CMOS chips or a CMOS 555 timer or even a low power microcontroller so that many more applications can now be realised using flashing lights or timed light control etc. {Figure 5). External circuits can also be pow- ered from 9 V available from VDD, in this case the two resistors are not required and VCC is connected to VDD. The logic threshold levels of the ENI and POL inputs will also cor- respond to this supply voltage (Fig- ure 6). The circuit flashes an LED (not shown) at approximately two- second intervals. The POL input is used to invert the sense of the timer output. In a similar manner a switch- on or switch- off delay can be simply implemented with some additional logic gates. Light level detector cir- cuits or PIR movement detectors can also be powered from the HV9901. Resistors connected to the H/D input of the HV9901 are used to pro- gram the relay pull-in and holding currents when the device is used to drive a relay coil but this feature can also be used to implement a simple dimmer when an LED is used in place of the relay (Figure 7). The HV99Q1 can also be used as a step-up regulator by placing the load (e.g. a 12 V LED cluster) in series with the fly- wheel diode. In this mode the supply has a much higher ripple current. Testing times Before you try the circuit out with an expen- sive Luxeon LED it is a good idea to substi- tute a power zener diode instead of the LED. A zener diode has almost identical electrical characteristics providing you choose one with the same conduction voltage as the LED. Tne zener diode is a little more robust that the LED and any errors during testing will be far less costly. Connect a standard red LED together with a 180 Q. series resistor in paral- lel with the zener diode so that you can get a visual indication that the circuit is driving the LED with equal brightness at different input voltages. All tests must be carried out initially using a low voltage {12 V) input. If the circuit is powered from the mains it is important to be aware that the chip will have lethal voltages on Its pins and all appropriate safety guide- lines must be adhered to. Early tests using an isolated variable transformer to provide an adjustable input voltage were unsuccessful but a mains transformer with tapped secon- daries gave better results for test purposes. If the input mains filter is not fitted it is important to keep supply leads to the circuit as short as possible. On the positive side the circuit does not employ large reservoir capacitors on the high voltage side so once the ReLED is discon- nected from the mains supply any high volt- ages lurking around the circuit will be quickly discharged. £ 01 - 212 - 1 } Web Pointer HV9901 datasheet from: yyvAV.supertexxQm pdf -datasheets HV99Q I .pdf The internet site for all professionals and hobbyists actively engaged in electronics and computer technology www.elektor-electronics.co.uk 1 2004 Elektor Electronics 39 miemviDFO (I2AU7) An ‘iron-free’ valve amplifier Design by H.-J Friedli, PhD A headphone amplifier with outstanding sound quality can be built using readily available modern components. Omitting the output transformer, avoiding overall negative feedback and using good coupling capacitors guarantees a highly linear frequency characteristic, while certain construction methods yield low channel crosstalk. Measured values Supply voltage: 1 87 V THD + N: i I mW / 600 Q) 2.3 % (right channel) 1 .86 % (left channel) S/N: ( \ mW / 600 O) > 9 3 d8 > 1 00 dB A Filament supply ripple voltage: 30 mVpp Total power consumption: 17 W Valve experts know that even power valves that can deliver several hundred miliiamperes of anode current can never drive a loudspeaker with an impedance of S Q, since the internal resistance of a valve is several kiloolims. The two impedances are thus almost always matched using a transformer. In principle, there isn’t any objection to using this form of impedance conversion, but every transformer tends to degrade the sound quality. Keeping this effect to a minimum requires very careful and com- plicated coil winding techniques, good-quality trans- former iron and large core cross-sections. However, if the load impedance is not just a few ohms but instead several hundred ohms, as is the case with many types of headphones, and if in addition the required power level is not overly high, an amphher with no output transformer — sometimes referred to as an 'output trans- formerless’ (OTL) amplifier — can be a feasible option. In this case, the load is driven directly by the valve. The OTL amplifier described here is a cathode follower f 4G EJektor Electronics 1 2004 AUBIQMDFO 4 | design suitable for use with a single or dual headphone. With each head- phone element having a rated impedance of at least 300 Q. The circuit The circuit shown in Figure 1 uses the readily avail able ECC82 double triode (equivalent to the North American 12AU7) to provide amplifi- cation. In Europe, ‘special quality’ (SG) versions of this valve with bet- ter specifications and longer sen/ice life are also available under type numbers E802CC and E82CC, respectively. A preamplifier stage is necessary to generate signal amplitudes suffi- cient to adequate drive a head- phone. The triode section with base pins 1, 2 and 3 is used for this pur- pose. The input signal arrives at the circuit board via an external 50-kQ logarithmic potentiometer (PI, not shown in the schematic) that serves as a volume control, and it is directly coupled to the preamplifier stage via Cl. R1 provides tire necessary nega- tive grid bias. The gain is essentially determined by R8. while the maxi- mum input voltage is determined by R2. R9 is dimensioned such that the quiescent anode current is situated in the most linear possible portion of the characteristic curve. The inverted and amplified input signal on the anode is coupled to the grid of the second stage via C2. The cathode resistor of the second stage is split into two resistors (R5 and R6). The series resistance of R5 and R6 forms the load resistance, while the voltage division provided by the resistor pair allows the grid bias to be set to the proper level. The bias voltage is decoupled from the load and stabilised by R4 and C3 before being applied to the grid. The anode current flowing through the triode, which depends on the grid voltage and corresponding characteristic curve, generates a voltage across the combination of R5 and R6 that is exactly propor- tional to the current. This voltage is in turn fed to the headphone via coupling capacitor C4. R7 holds the output at ground potential for DC signals in order to avoid crackling noises when the headphone is plugged in. ■r200V *2CGV © Rio Rlt +20GV © +12V6 VI, V2 = ECC82 R21 R22 * | 2k2 IH 2k2 — © +200V □2Q1 55 - 11 figure I , Schematic diagram of the amplifier using two ECC82 ( I 2AU7) valves. FI K1 230 V t\j {'\ J TR1 JR2 1 00*1 AT + 200V figure 2* Two mains transformers are used to generate the high voltage. 1 2004 Etekior Electronics 41 AUBiO&MDFO COMPONENTS LIST (Amplifier) Resistors: RI,R3,RI2,RI4 - IMQ R2,RI 3 = 470Q R4,RI 5 = 82kQ R5,Ri6 = lkQ8 R6,R17 = 33GQ R7,R18 = 4k07 R8,RI9 = IOkO R9,R20 - 33kI2 RI0,Rf l,R2I,R22 = 2kQ2 Capacitors: Ci C2 s C7 f C8 = i uF 400V (MKP4 or MKS4, 250V) C3,C9 = 47[iF 63V radial €4X10 - 470liF 63V radial CSX I I — lOuF 400V radial, e.g., Panasonic ECA2GHG I OOn (FarneSi #219-9320) C6.CI 2 = 47uF 400V radial (e.g„ Conrad Electronics # 475858) Valves: VI.V2 = ECC82 or I2UA7, with Noval (9- way) socket (Chelmer Valve Corp.) Miscellaneous: JPI — 2-way PCS pinheader with jumper K1 = 2-way PCS terminal block, 5mm lead pitch K2 — 2- way PCS terminal block, 7,5mm lead pitch PCS, available from The PCBShop Figure 3* Layout of the amplifier printed circuit board. Power supply The power supply for the headphone ampli- fier is shown in Figure 2. Tire high voltage is generated using a standard mains trans- former. The winding normally intended to be used as a secondary winding is connected to the 12-V terminals of the actual mains trans- former. This results in an open- circuit voltage of around 200 VAC on the primary winding of the 'reversed' transformer, which serves as the anode supply transformer. This AC volt- age is rectified and then smoothed by C14. The DC filament voltage is rectified by D5-D3 and then smoothed by CIS. The capacitors connected in parallel with the diodes suppress high-frequency noise gener- ated by the diodes. A voltage of 12.6 V is gen- erated in a simple manner using an LM2940CT12 (for low voltage drop) with a sil- icon diode in the ground lead. LED DIO not only serves as a pilot light, but also works together with R1 and R2 to provide a minimum load and ensure that capacitor C14 is discharged, even if no load is con- nected to K3. Layout The layout of the printed circuit board for the amplifier, as shown in Fig- ure 3, is designed such that it is pos- sible to use not only 'normal' M1CS4 capacitors for Cl, C2 f C7 and C8, but also coupling capacitors with lead spacings of 15 or 22.5 mm, such as WHvIA MKP4 types. These capacitors have higher breakdown voltages and are physically larger, which makes them better for audio purposes. For the large-volume electrolytic capacitors {C6 and Cl 2), types with lead spacings of 5 or 7.6 mm can be used, or radial snap-in types with lead spacings of 10 mm. The latter type of capacitor has a larger diam- eter and thus absorbs less heat from the nearby valves. Low-inductance electrolytic capacitors designed for high-frequency switching applica- tions should preferably be used, and in any case they must be specified for operation at 105 : C . Power is supplied to the individ- ual channels via the combination of R10 and R1.1 or R21 and R22, respec- tively. These resistors dissipate 42 Elektor Electronics 1 2004 AUBIQMDFO around 0.18-0,25 W r depending on the supply voltage. Be sure to use resistors with adequate power rat* ings, There are resistors available that can dissipate 0.3-0. 4 W with the same package size (such as 1/4-W metal film resistors), and the PR01 series from BC Components can even handle 1 W. In any case, it won't do any harm to fit these four resistors well clear of the circuit board in order to improve their cooling. In the circuit board layout, atten- tion has also been given to keeping the signal paths of the two stereo channels as widely separated as possible. The connections between the ground terminals of the four anode decoupling capacitors and the common ground point are routed separately for each channel. Inci- dentally, there is one wire bridge on the amplifier board (between C5/C11 and C1/C7). The power supply circuit is housed on a second printed circuit board, to which the amplifier board can be attached in sandwich fash- ion. However, the amplifier is some- what sensitive to the stray fields emanated by the transformers, whose magnitude depends on the type of transformer used. The 50-Hz components in the frequency spec- trum (see measurement curves A and B) clearly indicate the presence of the two transformers, winch were located at distance of 20 cm. Diodes D1-D4 are 'solid’ 1N40G2 types, but there is enough room for even more robust types. Capacitors C5-C3, which have a lead spacing of 15 mm , must be X2 types. If you want to fully eliminate any ripple in the filament voltage, you can use a 15 V / 20 VA transformer for TRL As this is a slightly larger type, it will not fit on the circuit board. Although the dissipation of 1C1 will increase in this case, the specified heat sink is fully adequate. We also tried using a 15 V / 16 VA transformer, but it drew 23 VA from the mains {significantly overloaded). You are welcome to experiment with various transformers; a wide variety of results may be obtained, depend- ing on the transformer type, open- circuit voltage, loaded voltage, core size, and material. The winding ratio is always determined by the design value of the open-circuit secondary The circuit forms a power RC filter that reduces the ripple component of an unstabilised supply voltage. Naturally, this results in a voltage drop of a few volts. Here a MOSFET suit- able for use with high voltages (a BUZ4 1 A, rated at 500 V / 4.5 A) is wired as a sim- ple source follower. The gate is very slowly brought up to the desired voltage via the Rl/C I network. It takes four minutes (five RC time constants) for the output voltage to reach 99 percent of its nominal value. As the valves also take a while to warm up, this delay does not matter. The effect of using the filter can be clearly seen in Cun/e B. The voltage drop across T I Is primarily determined by the gate-source cutoff voltage and is approximately 3.5 — 4 V The gate is protected against excess voltages by Zener diode D I . C2 and C3 are necessary to eliminate the tendency of the circuit to oscillate. No circuit board layout has been designed for the filter circuit, but it can easily be built on a small piece of prototyping board. The filter dramatically reduces the amplitude of the ripple voltage. 020195 - 13 voltage. For a transformer with a nominal secondary voltage of 9 V, this can easily be 12 V To balance out the reactive power, an XI -type capacitor rated at around 150 nF / 250 V can be con- nected across the secondary wind- ing of TR2, This will cause the anode voltage to actually increase slightly, but the mains power consumption and current will decrease by around 6-7 percent. An advantage of using two trans- formers is that the high voltage is isolated from the nl ament voltage. Nevertheless, the two ground potentials must be intercon- nected, This can be done on the amplifier board and/or on the power supply board fJPl). Fitting the components to the circuit boards should not present any problems. All com- ponents are fitted on the ‘normal’ compo- nent side. Construction 43 1 2004 Elektor Electronics flIKQ&WK) The voltage regulator requires a heat sink. Its cooling tab is connected to its middle lead, which is 0,6 V above ground potential in rials circuit due to the diode. As everybody knows, the electrolytic capacitors must be fitted with the correct polarity. However, it is also necessary to observe the proper polarity when fitting the four 1-jiF capacitors. As the grid terminal is the most sensitive point in a valve circuit, it must be connected to the inner foil of the capacitor. The outer foil, which is sometimes marked by a stripe, then has a screening effect. The Cinch sockets, potentiometer, phone socket and mains switch must be wired COMPONENTS LIST (Power supply) Resistors: Rl ,R2 = lOOkil Capacitors: C1-C4 — 47nF ceramic C5-C8 = 47nF 275 VAC, Class X2, lead pitch 15mm C9 = 22G0uF 25V radial CIO, Cl I = 220nF Cl 2 = I OliF 63V radial C 1 3 — I GnF 400V lead pitch 7.5mm or ! 0mm 04 — 47uF 400V radial (BC Components # 22215266109, Farnel] # 322-7984) (BC Components # 22215266479, Farnel! # 322-8009) Panasonic ECA2GHG47G (e g,, Farnell # 319-9356) Semiconductors: D1-D4 = IN4002 D5-D8 = ! N4007 D9 = LED red, low current 1C 1 — LM2940CT-I2 with heatsink, Fischer type SKI 04 (S0.8 mm) Miscellaneous: JPI = 2-way PCB pmheader with jumper Kl ,K3 = 2-way PCB terminal block, lead pitch 7.5 mm K2 = 2- way PCB terminal block, lead pitch 5mm FI = fuse, IQOnnAT (slow), with PCB mount holder TR I = mains transformer 1 2V / I6VA (ERA BVG54-5383.GK (Conrad Electronics # 506575) TR2 = mains transformer ! 2V /I OVA (ERA BVG48-5383.0H (Conrad Electronics # 506478) PCB, available from The PCBShop externally, which leaves consider- able room for personal choice in s electing an enclosure and arranging the controls and connectors. Hie circuit board layout (Figure 3) has been kept highly symmetric with hgure 4. The power supply printed circuit board can be fitted to the amplifier board 'sandwich' fashion. 44 Elektor Electronics 1 2004 AIJDiO&VDEO Curves and sound Curve A shows the frequency spectrum of a 1 -kHz signal ( I mW into 600 12). The distortion components (right channel) amount to 2.3 percent* but this is primarily due to the second harmonic. Besides this, an enormous effect can be seen from the ripple voltage of the un stabilised anode voltage supply. To remedy this, we developed an active filter (see box) that almost fully sup- presses the iOG-Hz component and its harmonics. The results obtained using this filter can be seen in Curve B. The third curve* C, shows the distortion as a function of output power. The distortion level increases quite linearly with the output power level. The amplifier runs out of room 1 at around 5 mW T It's almost impossible to describe the performance of a piece of audio equipment using bare figures alone. The most noticeable aspect of the sound is dynamic range: what is supposed to be loud is loud, and what is supposed to be soft is soft. The sound is warm and spacious, and although it is perhaps slightly lacking in clarity of detailing at the upper edge of the fre- quency spectrum for high volume levels, this by no means reduces the enjoyment of opera voices. The sound is very pleasant and remains so during extended lis- tening. Low tones do not present any problems, and it is certainly quite enjoy- able to listen to music with strong bass components, such as rock, pop and jazz. Measurement curve B. Using a filter provides a dear benefit, with significantly reduced 1 00-Hz components. m * S — E l t - - . — - ! 8 - 23 bu “ X lOT Z-£ ’4 Z* Si ~ U Zlh Measurement curve A. Frequency spectrum without a pre-filter for the anode voltage. Measurement curve C, The distortion level increases linearly with output amplitude. regard to its visual aspect, so there is no reason not to use an enclosure design featuring a visible circuit board with its valves and other com- ponents. If you would rather conceal the circuit board but still wish to have the valves visible, you should etch the circuit board using a mirror image of the layout. In this case, the tube sockets are fitted to the copper side of the board, with all other com- ponents being mounted in the usual manner so they face downward after the board is fitted in the enclosure. All polarisations remain the same. All 230- V wiring must be made using wire with sufficiently thick insulation. It is essential to apply additional insulation to the solder points and fit an insulating sheet between the mounting panel and the undersides of the transformers. You must also provide for good ven- tilation. A double-pole on/off switch must be fitted in series with the 230- volt wiring. The transformers should be fitted in tire enclosure as far away as possible from the signal inputs. If the transformers are too close to the inputs, a typical 50 -Hz hum will be heard if the Cinch sockets are open and the volume control is turned up full. 1 2004 Elekior Electronics 45 RQJfTS (Burglar i^larm With individual sensor signalling Design by E. Martens This is a circuit of a simple but effective burglar alarm, which shows the status of each sensor with a separate LED. This allows you to see at a glance whether any doors or windows aren’t closed properly before switching the alarm on. s Main Specifications - Maximum number of sensors that can be connected: 8 - Monitoring and signalling of each sensor for activation and cable continuity - Tamper input - Panic pushbutton - Exit delay: 60 seconds - Entry delay: 60 seconds - Power supply: 230 V AC or backup battery - LEDs indicate: - alarm armed - alarm activated - tampering - backup battery active - Outputs: 2(12 Vp£ r 500 mA) - Alarm duration: 60 seconds Please note: Readers CroJis nave r c-i been tested or post-engfr^ered by :re Bektor Etectfon^cs design teboraer/. This article describes a design of a burglar alarm that can monitor up to eight sensors. The status of each individual sensor is indi- cated with an LED. This LED shows whether the sensor has been activated and whether the wiring to the sensor is in order. Obviously, this burglar alarm also has an input to : amv the alarm, a tamper input and a couple of outputs to control a siren and/or a strobe light. The alarm is also fitted with a so- called ’panic button’. Circuit description The burglar alarm is built around the ATS9C51 microcontroller from Atmel. This microcontroller provides all the func- tionality of the burglar alarm. It also takes care of {software} filtering of the signals at the inputs. Only after an input has remained unchanged for 30 milliseconds, is this new sig- nal level passed on for processing by the microcontroller program. The schematic for the burglar alarm {Figure 1) is simplicity itself and only a small number of compo- nents are required. Sensors A maximum of 8 sensors can be con- nected to the burglar alarm. These can be found along the left side of Figure 1, These sensors need to have their contacts closed when in the inactive state (i.e. Normally Closed). In addition, each sensor needs to have its tamper connection wired as well. A power supply volt- age of -i-12 V DC is available for each sensor at the corresponding wiring terminals (K3 through K10). Operation The alarm is switched on by opening key switch SI, at which point the so- called ’exit -delay 1 begins. This time delay (60 seconds) allows you to leave the protected area without triggering the alarm. The alarm is deactivated when key switch SI is closed. If a sensor contact Is opened when the alarm is armed and after the exit- delay has expired, the entry- delay {60 seconds) will begin. Under normal circumstances, the alarm will be deactivated with key switch SI during the entry-delay. In the event of a burglary, the alarm will trigger after the entry-delay has expired. The entry-delay can only be inter- rupted by switching the alarm off with key switch SI. The special ‘panic button' S2, can be used for those situations — what- ever the reason may be — that require the alarm signal to be acti- vated, The alarm signal will be acti- vated immediately, independent of £ j * r the armed or disarmed status of the ■fy burglar alarm. The alarm will be silenced after 60 seconds or after pressing the panic button again. Sabotage Tire purpose of tamper input Kll is to detect tampering attempts when the alarm is armed. Possible scenar- ios are opening of the burglar alarm enclosure, the cutting of cables, etc. The tamper input needs to be nor- mally closed (NC). A number of NC- contacts and wires can be con- nected in series (the cables to the alarm sensors, for example). Signalling Eight LEDs (D10 through D17) indi- cate the status of the corresponding 46 Elektor Electronics 1 2004 REAoasaRg its Rgure I . The alarm consists mainly of a microcontroller a number of sensor inputs and a set of indicator LEDs, sensors. When the alarm has been activated, the LED of the sensor that caused the alarm will light up, or flash in the event of a cable failure. When the alarm is armed, the LED 'alarm armed" (D13) will flash during the exit-delay* After the exit- delay, the LED will light continu- ously* D18 turns off, of course, when the alarm is disarmed. The LED ' alarm triggered 1 (D19) flashes during the entry- delay and will turn on continuously once an actual alarm has been generated. D19 turns off only when the alarm is switched off with key switch SI. When an alarm has taken place, it can be determined afterwards which sensor (or tamper input) caused the alarm to trigger. The LED ‘tamper' (D20) lights up when the tamper input (Kll) is opened. This LED will also continue to be on until the alarm is switched off* Finally, the LED "battery opera- tion" (D22) indicates that lead-acid battery BT1 has taken over the power supply for the burglar alarm. Outputs The burglar alarm is provided, from the viewpoint of reliability, with two separate outputs (K12 and K13). Both outputs are controlled by a BUZ 11 (T1 and T2) and can switch up to 500 mA at 12 V. This is more than enough for all common signal sources such as strobe lights and sirens* If more power is required or a signal source with a different voltage needs to be controlled then a 12-V relay can be connected directly to the alarm output and it in turn can then switch the signal source on and off. Power supply The circuit is provided with its own mains power supply. It follows the usual design of transformer, bridge rectifier (D1 through D4) and filter capacitor (Cl) and generates an input voltage of about 18 V for volt- age regulator IC1. With the addition of diode D5 in the ground connec- tion, the output voltage if IC1 amounts to about 12.65 V. This volt- age is subsequently reduced to about 12 V by diode D7. Voltage regulator IC2 in turn changes this 12 V into a stabilised 5 V power supply voltage. In the event that the mains voltage at K1 disappears, the 12-V lead-acid battery con- nected to K2 will immediately take over the power supply for the circuit. The battery is continually being charged via resistor R1 and diode D6 r when the mains voltage is present, D7 and D8 prevent the charging current from flowing in the wrong direction. The software that is required for the alarm is of a relatively simple design. The flow chart shown in Figure 2 illustrates this. This really shows a kind of logical summary of ail the things that have been described above. After the reset-phase of the microcon- troller, all the LEDs are switched on for a period of two seconds* This allows for a quick lamp test to check if all the LEDs are func- tional and are connected correctly. In the source code for the software, the values for the various timers can easily be adjusted to suit your own requirements. It concerns the following timers: Software 47 1 2004 Elektor Electronics EMlSSmUE Figure 2. This flowchart makes it obvious ho/, the software has been designed. timer variable default (s) panic rimer PANVAL 60 exit-delay timer UtTVAL 60 entry-delay timer 1 NIVAL 60 output X active ALXVAL 60 output Y active ALYVAl 60 incidentally, the software for the bur- glar alarm (ref. no. 020422-11) can be downloaded free of charge from the www.elektQr-ele ctron_ics.co.uk website. Construction perils It is recommended to build the bur- glar alarm into two separate enclo- sures, as illustrated in the sketch of Figure 3* The larger enclosure contains the more important part of the circuit, including the power supply and lead- acid battery, but excluding the controls and indicators. This enclo- sure needs to be mounted in a place that is relatively difficult to access. This enclosure actually has only cables going in and out of it. When building the mains power supply, keep the relevant safety require- ments in mind and provide sufficient isolation and a good strain relief (grommet) for the mains cable. The enclosure for the LEDs and switches needstobe mounted in an easily accessible place, of course. Because of the way the circuit is designed, damaging this enclosure wall have no influence on the correct operation of the burglar alarm (the key switch to operate the alarm is normally closed'. It is also recom- mended to include this enclosure in the tamper circuit. To prevent the burglar alarm from being easily circumvented without this being detected, it is necessary that the cables to the sensors are located in such a way that they are difficult to access. These cables can also be included in the tamper cir- cuit. A practical application of the tam- per circuit is shown in Figure 3. A switch (normally closed) is also included in the tamper loop. This switch needs to open in the event that the enclosure is opened or van- dalised. If not all sensor inputs are being used, the alarm contact and tamper contact of each unused sensor needs to be shorted out. Figure 3. A practical implementation of the burglar alarm separates the control and indication from the other parts. 48 EJektor Electronics 1 2004 Electronics B looks from Elektor Electronics Audio & Video 1 mm }W. \ Sn£c Build your own Audio Valve Amplifiers 1~ e cook prevss Dial [-7 : v.j ,7 5. H maktog a comeback f 15. 55. US S 31. CO Designing Audio Circuits How (Joes speedu masse* "Cii: from the record, CD, Of tesseE'r’speiSt 7 : A- sfasfcf? Hi:- ernfeavo-u rs to g we a compreteftsStfe answer E 20.75 USS42M l-.-. ... — Designing Audio Circuits £18J0VS$37M Lasers: Theory and Practice A valuable bock on Ite practical use of lasetsc £ 20.75 VSS 42.CH Build your own EieclroniG Test Instruments For good reasons (cost, chaftsoge) many researchers, t _ 1 e:i: ■/.: r.pi- r?r:er 5 ■ _ : ::e. irssl/umsrjts toa ns* £ 16.60. VSS 33.00 F r. x ?= l- hi- Electronic test instruments 1 r~ ftand&ooiE fzTscsru fec&* : c«ns 307 CIRCUITS 3D7 Circuits Summar CTrpstfs comp: y on 1997 1996 1959 £ IBM VSS 37. CO 303 Circuits Summer Circuits eompilafesi Handbook for Sound Technicians A fcSC-5c On ite Jec.-nical aspects of Sis recantiiig stodio- £20.75 USm 00 Build your own High' End Audio Equipment f: r tfios : Vj _ : can n 1 1 pay f ' ri prices fei nigh rtf atfulpntrt i £C!lL£-h Off^Ed if! This bp:? cy.tf yam own a: ::rztf E rppp t TacrtCiCSr Diclionary of Monitor Technology A : : _ :r' ri took if unE--- ;:iE~P : unv DDiumafitsa sjpTiisoftre ci c&mpiiter £25.95 US$52 QD v The PC bus , Mi , .< ¥ j i B< t - - ■ > _ The I2C Bus Til’s t-SOV dills 6jCt£T!5h£j/ viTlfi the tKhn::al spectffca- tions c-f Ihs I20fcu? £25.95 US S 52.00 PC Service and Repair This bock pjcr. in the rnlDniHSDn ymi used to bs able to deal w fli computer system faults wttsn^f they tracer. £31.15 VSS 63.00 SCSI Ttics • comas filth a CO- RQt^andvj prove n.T at:i , iuan you win! iuszn Out 1 pFPtf f“ :n a S J C 5 1 tt- tom. f 24. §5 VSS 50.03 PC Interlaces under Windows V fasure.rs.it and control bsi;'^ stanaird pirts PC Intoifa-ces can ts ut-Jd for r:n than j,et nhi pifn- 11 : rrze : e 1 . m ci = n e ' : ?y - sbek! £25.55 f/SJ5£ffi7 L. . 1 — Elektor Electronics (Publishing) P.O. Box 190 * Tunbridge Wells TN5 7WY * England. Telephone +44 (0) 1580 200 657 Fax +44 (0) 1580 200 616 vavy/, elekfor-elecfronics.co.uk A sen/o-powered pendulum Design by B. Kainka It is a generally known and accepted fact that servos used in radio- controlled models see very little or no use outside the model flying, racing or boating season. A pity, considering these devices can be used for many useful tasks... For example, a servo that’s not used anyway could be attached to a large pendulum of which the smooth and steady motion may help people relax and even fall asleep. For this (psychological) effect to be achieved the movement has to be sine- shaped like that of a real and very long pendulum. The small circuit of the Relaxation Machine you find in Figure 1 consists of two parts. A pulse generator based on a 555 sup- plies positive pulses with a length between 1 and 2 ms ('mark') and a pause of 20 ms ('space'), representing a typical servo control signal. In addition there’s a sine wave gener- ator designed to supply a very low frequency of about 0.25 Hz which corresponds to one full period in four seconds. The sinewave generator employs a phase shifting network and supplies a sinewave with very low distortion. If yon want to lengthen the period, simply increase the valne of Cl , C2 and C3 a little. The generator drives the control input of timer component IC1 via an electrolytic capacitor. Id, by the way, should be a 7555, 555C or another CMOS version of the 555. The generator drive scheme ensures that the timer k mark T duration is con- trolled, while the "space 5 length is not affected. A PCB was designed for the Relax- ation machine (see Figure 2). Like all PCB designs that appear in this mag- azine the artwork riles to enable you to make your own board may be found among this month's Free Downloads on the Publisher’s web- site at -.'AW'Aeiektcr-elecTromcs.co.uk . With the board available, the cir- cuit should be easy to build up. All you need to do is follow the parts list and the components mounting plan. There is one wire link on the board 50 Elektor Electronics 1 2004 MM Figure I . Circuit diagram of the Relaxation Machine. directions without hitting any of the stops. If the elongation (the distance the between a moving body and the point of origin) is too small or too large, you may need to experi- ment a little with the value of Rl. If you make the resistors too small (<1Q kQ) then the oscillator will no longer oscillate. Capacitor C4, too, has an effect on the amplitude. The current consumption of the circuit is of the order of 10 mA excluding the servo. The 3-way pinheader in position Ki will allow most servos to be connected up easily. If you are using a less than standard' servo, then a small adapter may be required. The connections of a couple of well-known servos are shown in Figure 3. Using our circuit, a correctly connected servo will turn slowly, describing a pure sine wave, its period being about equal to that of a pendulum with a length of four metres (I). Of course, you may also attach a smaller pendulum, a painted carton board or another ingenuous creation to the servo spin- dle, provided is not too large or heavy (because of the mechanical load on the servo). The swinging pendulum has a relaxing effect, while the sound of the servo motor at such a low speed is not unlike snoring. Warning Tills circuit should not be used on (or by) per- sons with an epileptic or narcoleptic condi- tion or subject to easy hypnosis. COMPONENTS LIST Figure 2. PCB design. Conrad Graupner Futaba Multiplex Rcbbe Microprop Sim prop JL fo JL fo — O JL JL o JL o JL O 0 [° + [° 4* O + — o o 4 , 0 + fo — \o_ JL O — + T o — o K»1 50-13 Figure 3, Servo pinouts. which should not be forgotten. The link is best made using thin isolated wire because if runs dangerously close to the pins of IC1. Positions T1 and T2 can take almost any NPN transistors with a sufficiently high gain. In most cases. this means that C suffix devices will work best , i.e., the h fe should exceed about 300. Suggested types include the BC547C, BC548C, BC549C and BG550C, Preset PI is adjusted until the servo covers the full motion in both Resistors: Rl = I SkQ R2,R3,R4 = IGQkQ R5,RB - IkQ R6 = lOkQ R7 = 220 m P I = ] OkQ preset Capacitors: CLC2 r C3 - 22uF 10V C4, C6 - 220uF iOV C5 = tOOnF Semiconductors: D I = i N4 1 48 Td T2 = BC S49C 1C I = 555C or 7355 iC MOSs Miscellaneous: Ki = 3-way pinheader 2 solder pins PCB. available from The PCBShop 51 1 2004 Elektor Electronics 6ENB3AI JlWRFS ^©Qfl0@t&<§ using LEDs instead of a ball Design by R Goossens Everybody gambles sometimes, perhaps in a lottery or even in a casino. After all, who doesn’t dream of becoming rich without having to work hard? Although you can’t win much with the LED roulette wheel described here, it does provide an excellent opportunity to practice the game of roulette at home in an honest manner. That’s because you can’t cheat with this version — the microcontroller that controls the LEDs doesn’t take bribes! The game of roulette has been known for cen- turies, and it is played all over the world. In order to make it easier to play this game at home, here we a present an electronic roulette game. This electronic version only replaces the turntable, which is the dished wheel used with a small ball to select a ran- dom number for each round of the game. You will have to make the play- ing held and the counters yourself. Roulette In the game of roulette, a random number is chosen for each round using a dished, spinning wheel within which a small ball circulates in the opposite direction. The ball ultimately lands in one of 37 com- partments (numbered 1-36 and 0), with each compartment having a colour (black, red or green). Tire play- ers can bet on the number, colour, etc, of the compartment where the ball ends up. Roulette is not played very often at home, since it requires a proper roulette wheel. Any irregularity in the construction of the wheel will distort the probabilities and thus make the game unfair. A good roulette wheel is not cheap, and it also takes up a lot of space. An elec- tronic version provides a solution to these problems: it doesn’t cost a lot and it doesn't take up much space. Implementation In this circuit, the circulation of the ball is simulated by a number of LEDs arranged in a circle. Our electronic wheel has more to offer than just a simulation of a cir- culating ball. As anyone who has ever visited a casino knows, at first 52 Elektor Electronics 1 2004 the ball rolls quite smoothly over the surface of the wheel when it is spun. But after the ball has lost speed and lilts one of the compartment walls, it starts jumping all over the place. Our wheel shows the same characteris- tics, but if you would rather have the ball exhibit a ‘wheel of fortune' type of behaviour, you can configure the circuit for this using a switch. Another nice feature of our 'wheel' is that as soon as the ball has stopped, the circuit automati- cally indicates whether the present number is higher or lower than the previous number. This means that in addition to the usual manners of playing roulette, you can also bet on whether the next number will be higher or lower than the current number. Schematic diagram Figure 1 shows the schematic dia- gram of the roulette wheel. As is common nowadays with relatively complex digital circuits, it is based on a microcontroller In this case the microcontroller is an AT89C2051 (IC1), which requires only a small number of external com- ponents. C12 and R41 generate a reset signal when the supply voltage is switched on. XI t Cl and C2 ensure that the internal oscillator of IC1 generates a 12- MHz clock signal. The user controls are provided by a regular switch and a push-button switch {32 and SI), each of which is directly connected to an I/O pin of the microcontroller The visual representation of the simulated ball is provided by 40 LEDs (D1-D40), with each LED hav- ing its own series resistor (R1-R4G). The LEDs are driven by 8-bit latches (IC2-IC6). LEDs D1-D37 are arranged in a cir- cle, and they represent the various compartments of the wheel. LED D38 indicates that the value of the most recent spin is higher than that of the previous spin. By contrast, LED D40 indicates that the value of the most recent spin is lower than that of the previous spin. LED D39 lights up as soon as the ball’ stops moving. The circuit is powered by a 9-V 1 2004 EEektor Electronics GEMERiHiMTFRFS 107 012 r > isv +SV © $1 H S3 O * O Ll 11 1' 20 © R5T IC 1 P3-Q P1.1 P3-1 PI -3 P1J2 PI -3 Pi-2 Pi .4 PJ.A PI -5 P122 Pi -6 ATS9C2051 p1 7 P3.7 ■i* XI X2 10 0? *1 + 12 P.12 13 15 15 17 15 15 Cl r i i DO HL/t 02 A EM A 0? /} mA iron 11 Ih 02 DI 4 / m. 7 Ao 6 A>4 13 AlS 14 17 f 07 IE Y 1 'i I DO t 3 ^D1 4 7 5 i_2 • / 'k~ ii 17 ^UT 13 / i ll] IhJ \D0 l 3 \D1 4 \D2 7 £ V* 13 \05 14 17 \07 15 I U IN \D0 l 3 \Ol 4 yDS 7 \2L_ a \EH 13 \D5 14 \D5 17 15 ti 1 X \D0 I 3 \Ot 4 \02 7 \03 5 SJH 13 yCS U \D6 17 \D7 IS Cl EH n r ID ^ ^ 74HCT373 IC3 Cl Vl n r ID ) ^ 74HCT373 tC4 Cl Qi n r 1 ID > ^ 74HCT373 ICS Cl Vi n r ID > V 74HCT373 ce Cl Si n r ID > ^ 033I&5-1! 74HCT373 Di Di ft + + D9 44 t>17 1 T T 0«l f T Dili □ E JhZ Di 9 12 z- as 15 Di !d 5 1c 177 15 D6 lk lie Ik lk Ik Ik Ik 11 7 7T1 5 y 1 0 -u 5 Du |3 =£ 9 12 Dl3|2i 14 Dii™^ 15 di5 S2 : ^ 15 D15S5“^ TT Ik Ik u Ilk Ik Ik Ik Ik Ik 5 ll ’-3 5 5 □20^5 rj 12 d?i Is D7i !3 E IS 023 15 024 13 — Ik It Ik n n 5 075 -» fi 2 '*■ 15 D!3jJ + 16 031 J2 ^ 15 i. 5 034 J3^r 5 0^13 x 5 0]i|3rt 12 1= 15 03Ti3i It D43?2 "*■ Ik Ik Ik lk Ik lk lk Ik + SV © Rl R£ R3 R-! R5 Rs UT PS Rf R1Q fill Rl2 R13 R14 Pits FA2 R17 Rl = FM5 &2g Pl\ P22 S?3 nil FlIz R 27 R?i- Ft 29 RjQ H31 R33 fill* R35 R35 R37 R 35 R29 B4j TT Figure S . The schematic diagram of the roulette circuit: 40 LEDs controlled by a microcontroller battery, whose voltage is reduced to 5 V by IC7 to meet the demands of the digital components. Naturally, the necessary buffer capacitors and decoupling capacitors are also pre- sent in the circuit. Resistors R42 and R43 are present because PEG and PEI are the only I/O pins of the AT89C2051 that do not have internal pull-up resistors. This allows these two ports to double as analogue inputs. However, in this circuit pull-up resistors are needed for all 53 e^aiNfTHrer OOOOQQQ, 36 0 aOOOOOOOOO £ 0000000000 . SO ' OOOOOOOO flilOXLO-Q-fi-O- 000660606 r^eiocofl flOOiSJa {3)1 03D168-1 (cj ELEKTOFl RIO [ Q A/J O l FU5 [ O [= 0 1 Ri4 [ 0 Q ] ma O l hi 2 [ Q c ormTlO 0 o" a O tC7 GiO Figure 2. I he double-sided printed circuit board holds the entire circuit except ior the 9-V battery. electronic roulette game. A double- sided printed circuit board is used here, because otherwise too many wire bridges would be needed to bits of port 1, so R42 and R43 have been added to ensure that a well-defined high' signal is also present on bits 0 and 1 when their outputs are not low. Construction Figure 2 shows the printed circuit board that has been designed for the 54 Elektor Electronics 1 2004 CWIBEIWIW COMPONENTS LIST Resistors: RI-R40 = IkQ R4I-R43 = I OkO Capacitors: C I ,C2 - 22pF C3-CJ 0 = lOOnF Cl i = IOllF 16V radial Cl 2 = luF 16V radial Semiconductors: DI.D38.D40 = LED S 3mm, green, low current 02.04,06,08,0 1 0.D 1 2 t D 1 4,0 1 6, D 1 8,020.022,024,026,028,030, 032.034,036,039 = LED, 3mm, yellow, low current 03,05,07,09,01 1,0! 3,015.0 1 7, D 1 9,02 1 ,023,025,027,029,03 1 , 033,035,037 — LEO, 3mm, red, low current 1C I = 89C205 1 - 1 2PC, programmed, order code 030168-41 IC2-1C6 = 74HCT373 IC7 = 7805CP (TO-220 case) Miscellaneous: K! = 9V battery with clip and on/off switch (optional) 51 = pushbutton with make contact 52 = on off switch XI = 1 2 MHz quartz crystal PCB, order code 030168-1 Disk, contains source and hex code flies, order code 030 1 68- 1 1 or Free Download allow the LEDs to be arranged in a nice circle. Little needs to be said about building the board. Just solder everything where it’s supposed to be and you're all set. Of course, you must pay attention to the correct polarisation of the LEDs, ICs and electrolytic capacitors. Sockets can be used for the ICs, but they are not necessary if you have a certain amount experience with soldering. If desired, all of the LEDs can be fitted on the solder side of the board, but that naturally depends on what sort of enclosure you plan to use. The switches can also be con- nected to the board using lengths of wire, so they can be fitted at the side of the enclosure if so desired. You can also fit an on/off switch at the side of the enclosure and con- nect it in series with the battery connector (Kl), Conclusion The software for the AT89C2051 was written in C and compiled using the Keil C51 com- piler, for which (as you probably know) an evaluation version is available tree of charge (http: www, keil.com/denKveval/ c51 him). As the source and hex code are available from the Elektor Electronics website under num- ber 030168-11 (and naturally on diskette as well), you can adapt the program to you; own wishes if so desired. To do this, in addition to the compiler you will need to have a certain knowledge of the C programming language and a programmer for the AT89C2051. If you have no desire to modify the pro- gram or do your own device progr ammin g, you can simply purchase a pre-programmed version from Readers Sendees (order number 030168-41). i'-isnes-' Free Downloads Microcontroller software. Fife number: 030 3 6B- J I, zip PCB layout in PDF format. File number: 030 1 68- 1, zip y.ww. e^ektor-e lectronics.co.u k : d I dl .h in „ select month of publication. 55 i 2004 Elektor Electronics GENERAllNTFRET The Sense Resistor in step-up converters By K.-J. Thiesler Sense resistors in series with the load are central to regulating current in switch-mode power supplies. It is possible to optimise the power loss in these resistors, as we show with an example converter circuit that drives eight white LEDs from a 4.8 V battery. Switch-mode regulator ICs generally include a reference voltage generator and a differen- tial amplifier This combination is used to compare the voltage dropped across an exter- nal sense resistor with the reference and then suitably drive the output stage. The voltage drop across the resistor must be of the same order of magnitude as the reference, which in modern DC-DC converters is around 1,2 V. However, particularly when high currents are involved, this can mean an unreasonably large amount of power is wasted. With the following elegant circuit we can reduce the voltage drop across the sense resistor and hence reduce the power wastage. Key points Figure 1 shows a typical switching regulator configured to drive eight white LEDs from a 4.8 V battery supply. The switching regulator has to produce a voltage U F £ D BIAS across the LEDs of nominally 4 _ 3.5 V = 14 V. The volt- age actually required in practice is not impor- tant here, since the LEDs are driven with a regulated current rather than at a regulated voltage. A DC current of nominally 40 mA should flow through each chain of LEDs. Resistor R4 serves here as the sense resis- tor: the voltage U A , which depends on the LED current, is brought to the feedback pin (pin 3) of the switching regulator IC as U FE . The output is controlled so as to make the feedback voltage 1.233 V In standard appli- cations point A is connected directly to pin 3. Then U FE = U A — R4 - I LED , and the power dissipated in R4 can be calculated as follows: — U A ■ I L £ D — R4 ■ With a feedback voltage of 1,233 V we require a sense resistor B2V55C6V2 fiATl -r 01 = z + IM-n J2 O o “ PWfMN bos 41 1V2 BZV55C24 V 2x4 wh ite LEDs Rgure 1 . Modified step-up converter. of around 30 Q. and the power dissi- pated in it will be 50 mW. The alternative circuit uses a resis- tor R2 in series with the feedback con- nection. A constant voltage source of U EiAS ” 3.000 V (generated by a MAX6063) is connected to point B via Rl. Now, in order to generate a feed- back voltage of 1.233 V, we require a much lower sense voltage at point A. Resistor R4 can be reduced signifi- cantly (to a theoretical value of 7 12), and the power dissipated in it is cor- respondingly reduced. The circuit with the auxiliary volt- age reference generator also gives us a simple way to adjust the output current. To do this we also connect up a further voltage source U AIJ j r adjustable from 0 V to 3 V, via R3. In order to calculate the resistor values, we start from the fact that a current of 45.3 u A will be flowing in Rl (39 kQ). If U ADJ is set at 1.233 V, then no current will flow in R 3 and so this path will not have any effect on the circuit: all the current flowing in Rl will flow through R2. From the graph in Figure 2 we can see that a voltage of 144 mV corresponds to a voltage U^j of 1.233 V and so R2 should have a value of 24 kfL 56 Elektor Electronics 1 2004 flEMamNTERE The LED current should be adjustable from 0 niA to 50 mA. This corresponds to a voltage across R2 from 144 mV lower to 208 mV higher than the value just considered. To achieve the latter, R3 must draw a current of 206 mV/24 kQ = 9.58uAto ground. This means R3 should be 144 kQ. In order to calculate all the values exactly we can use KirchhofPs cur- rent law, which states that the sum of the currents into a junction (here point B) is zero. Analogue or PWM? With U aj>j at 3 V the switching con- verter stops operation and its quies- cent current in this mode is 28 uA. ■ With U -jjj at 0 V the converter oper- ates at its maximum frequency and the LEDs light at full brightness. Using this analogue control signal we can obtain adjustable brightness with good EMI emissions character- istics since there are no edges of a PWM control signal to get through to the LEDs. What may be a dis ad van- tage is that the varying current through the LEDs results in a change in the emitted colour: the wave- length of the light emitted by an LED is dependent on the bias current. It is necessary to decide whether tills shift in colour will be acceptable or not in each individual application. If analogue control of the output cur- rent Is not desired, then connect U^dj directly to or simply omit the circuit involving R3 altogether. Brightness control without affect- ing the resulting colour can be achieved using PWM. To tliis end the enable pin EN of the regulator should not be connected to the battery volt- age: remove jumper J2 and instead drive EN from an external PWM signal via K7. This way it is possible not only to control the brightness from 0 % to 100 % in current mode 5 , but also to exploit the brightness-enhancing effect of using double the nominal cur- rent pulsed at a frequency of 1 kHz with a duty cycle of 10 %. Tliis gives the subjective effect often times the expected light intensity. In this case the values for Rl, R2 and R4 need to be recalculated. At such a high cur- rent the voltage drop across a white LED can rise as high as 5 V r and this should also be taken into account. See also the article ‘LED Arrays in the April 2003 issue of Elektor Electronics. The disadvantage of tliis method is of course that the LED current is pulsed and so the EMI characteris- tics are worsened. To mitigate this the LEDs should be mounted directly next to the regulator and the con- nections should be kept as short as possible. The datasheet recom- mends using a frequency of 100 Hz to 500 Hz at the enable input in PWM mode. In fact somewhat higher frequencies of 1.5 kHz to 2.5 kHz (but no higher) are more efficient. Below 100 Hz the pulses of light are visible to the eye. A PWM signal at a fre- quency of 1 kHz and an adjustable duty cycle in the range 0 % to 10 % is optimal both for the switching regu- lator and for the LEDs, Components Of course, the circuit as presented here is only a building block. Control circuitry, reverse polarity protection and overvoltage protection on the Standard Modified LED current mA 40 ^LED BEAS : ^ LEDs V 14 P LED mW 560 U FB V 1 .233 u a V 1.233 0.387 R4 (E24 series) n 30 10 P R SENSE mW si 17 P J ■ [ TT £1 i- 72 r? "J W IC 2 W 2£ W U L= S" 53 il VI n n \ J1 Li 3rf M i- o ‘1 af /; ujX Wt/i Ltl iZ s* A WW-H hgure 4. The full schematic diagram of the microcontroller board. The circuit Processor and memory Figure 4 shows the complete schematic dia- gram of the microcontroller board. The vari- ous elements that make up the circuit can be quite easily recognised. The microcontroller is a Philips 80C552 (IC4). Its most important added features com- pared with a standard 8051 microcontroller an 1 2 C interface, an 8-channel 10-bit A/D con- verter, and an extra I/O port. As usual, the lower eight bits of the address bus are multi- plexed, and they are separated from the AD signals by IG3, A 32-KB RAM (108) and a 128-KB Flash ROM (IC5) are connected to the address bus. Only 96 KB of the Flash ROM is actually used. The central address decoder is a 16V8 GAL (ICG), which generates the control signals for both memory ICs and the memory-mapped I/O. The PSEN and RD lines are used to generate output-enable signals in the address regions where these sig- nals are necessary. GAL The GAL is the central element for switching between the various oper- ating modes of the system. Several processor signals axe applied to its inputs, including PGM (which causes the GAL to switch to the pro- gramming mode when it is O') and D/R (‘0 M : normal run mode; T: debugging mode). The GAL outputs control the memory ICs and the chip- e liable signals for memory-mapped I/O. The GAL programming descrip- tion is as follows: /GE = /PSEN* /RD /CEJRAM = /JU5+/PRG-/PSEN +/WR*/RD*/ D_R*PRG + D_R * / RD * / ft R * / PS EN /CEROM = PRGVPSEN -i-/VrR^ / RD * / PRGtD_R * A 1 5 *PRG /CEIOO " /(/A11*/AI2*/A13*/A14*/A15* PRG*/P3EN) /CE IOl - A 1 5 +CE_IO 0 + /t?RG+P S EH AI6 = D_R The file upboard.pds (available on diskette or the Elektor Electronics website under order number 030042- 11) can be read using the program Pal asm, which is available on the Internet as freeware. However, if the GAL programming does not require any modifications, it can be pro- grammed directly using the JEDEC file upboard.jed. 62 Elektor Electronics 1 2004 MCE 'CONiTRfil I FR 030042 ’! <1QSLQ.Q&&.Q&Q 1 uwOTrf imre I/O All signals necessary for connecting exter- nal hardware are fed out via headers K1 and K2-, Besides the full data and address buses : they include several chip-select signals that can be used to directly drive externa! mem- ory-mapped I/O devices. Signals CEO through CE7, which correspond to addresses 0000 through 0007 r are output via address decoder IC7. If even more control signals are needed, the CE IOl signal can be used to handle the remainder of the I/O range (from 0008 to 7FFF). If a MGVX command is executed in this region, the CE IOl signal goes to 'O'. The 5-V signals from the serial port of the microcontroller are converted to genuine RS232 levels by the MAX232 (IC2), in order to allow the circuit to be connected directly to a PC. If RXD and TXD are connected as shown in the schematic diagram, it is not necessary to use a null modem cable; a regular 1:1 ser- ial cable can be used instead. The 80C552 has a full I 2 C interface that supports the complete standard in both sin- gle-master and multi-master modes. Activity on the clock line of the bus is indicated by LED DL This line is also used by the monitor program to display system status during start-up by means of blink codes. The A/D inputs (P5.Q-P5.7) are connected directly to Kl. The supply voltage for the microcontroller serves as the reference volt- age. If this is not sufficiently accurate, resis- tors Rll and R12 can be removed and an external 5-V reference voltage can be con- nected to K1.34 and K1.35, Power supply and protection A small (70 mA minimum), stabilised 5-VDC supply can be used to power the microcon- troller board. The circuit is protected against an insufficient supply voltage by IC1, This IC (a MAX691) has been specially developed for such tasks, and It generates a reset pulse immediately after power is applied. If the voltage on the microcontroller drops below 4,5 V, it is placed in the Reset state, the RAM is powered from the backup battery (if JP1 is fitted) and the RAM is put into standby mode. If the voltage drops below 4.6 V, PF0 is set to O' (the voltage level can be adjusted using R9 and R10; the threshold voltage of the PF1 input is 1.3 V). If R13 and R14 are fitted, this can be used as an early indication that the supply voltage is collapsing. Figure 5. 5MD components are used to keep the printed circuit board nicely compact. 1 2004 Elektor Electronics 63 MICROrCWROI I FR IC 1 also includes a watchdog timer, just in case the watchdog timer in the 80C552 is not sufficiently safe. The watchdog is enabled or disabled by soldering RIB or R16 in place. If you would like to know more about the MAX691, you will find its data sheet at www.maxiin-ic.com . Circuit board assembly The circuit board layout designed for this cir- cuit is shown in Figure 5, SMD components have been used to keep the circuit board very compact. This makes assembling the circuit board somewhat more difficult, but with a fine soldering tip and a steady hand, you should be able to manage it without too many difficulties. Incidentally, a bit of desol- dering braid works wonders if things occa- sionally go wrong. First fit all of the resistors to the board. The values of SMD resistors are printed on them using three or four digits. The final digit always indicates how many zeros have to be placed after the value. For instance, '333’ means *33 l followed by three zeros, which amounts to a resistance of 33 Mb However, a marking of ‘3302’ (330' and two zeros) also indicates a value of 33 Ml, A variety of options can be selected by fit- ting (M2 resistors, which are used as jumpers. (If you find it difficult to obtain such resistors, you can also use 1-12 resistors or wire bridges instead.) Tire following settings are the stan- dard values, for which the software is config- ured: Function Fitted Open Debug Run mode R! R2 Disable watchdog R6 R5 Programming mode R7 R8 Reference potential -E Rl 1 — Reference potential - R12 — 1 Low vo ! tags ’ i nte rru p i — RI3/RI4 External watchdog — RI5/RI6 When software is being developed, it is a nui- sance to have to repeatedly reset the watch- dog timer (internal or external), and this often leads to problems. Resides this, neither of the watchdogs is serviced by OS552. This means that it is better to not use the watchdog until the major portion of the software is finished. Resistors RIB and R16 are thus not fitted ini- tially. Once you have soldered all the resistors, you can fit the ceramic capacitors. Re careful not to mix up the 33-pF and 100-nF types. These SMD capacitors all look the same, since no value is printed on them. After this, fit the electrolytic capacitors in the vicinity of IC2. It hardly needs saying that it's vitally important to observe the correct Figure 6. 1 he fully assembled circuit board. polarity For rectangular elect rolytics, the positive terminal is marked by a small + sign or a thick stripe, but elect roly tics in round packages are just the opposite; they have their negative terminal on the side marked with black paint. No doubt the manufacturers did this on pur- pose to see whether you re paying attention* In any case, it keeps things interesting, because elec- trolytics fitted the wrong way round occasionally tend to explode. Next, solder the SMD ICs to the circuit board. Here you also have to pay attention to the orientation. Start by melting a small amount of solder onto a solder pad at the comer of the 1C, Using tweezers, place the IC on the board and use the soldering tip to press down the pin above the tinned solder pad. Once the IC is firmly attached, solder the pin at the opposite comer. Now check the posi- tioning of the IC, which can be altered if necessary by warming the 64 Eleklor Electronics 1 2004 MICHOCDNTO! 1 R COMPONENTS LIST Resistors; tail resistors: SMD case shape 1208) RI,R2,R5-R8 1 RI I-RI6 = 0Q (see text) R3, R4 = 3kQ3 R9 = 330 kQ RIO = !3QkQ Rl 7 = IkQ R18 = lOkn Capacitors; (all capacitors: SMD case shape 1208) CLC2 = 33pF C3-C6 - luF 16V C7-CI3 = [QOnF Semiconductors: Dl = LED, red. 3mm, high- efficiency T! = BC516 1C I = MAX 69 1 CWE (SO 1 6 case) 1C 2 - MAX232 (SO i 6 case] iC3 = 74HC573 (SO20 case) IC4 = 80C552EFA {PLCC68 case) IC5 - 29F01 0 (32-pin DIP case), < 1 20ns, programmed, order code 030042-21 IC6 = GAL 16V8DI5QR programmed, order code 030042-31 IC7 = 74HC 1 38 (SO 1 6 case) ICS = 62256 (28-pin DIP case), <120 ns Miscellaneous: XI = I 1 . 0592MHz quartz crystal B I = Lithium batter/ type CR 2032 with PCB mount holder Ki,K2 — 36-way SIL pmheader K3 — 9 -way sub-D socket (female) (not on PCB) 1C sockets for IC4, IC5, IC6, IC8 jP I — 2-way jumper PCB, order code 030042-1 Disk, project software, order code 030042-1 I of Free Download soldered pin ana shifting the IC. Once the IC is properly positioned, you can solder the remaining pins. Allow the IC to cool down after sol- dering each pair of pins, so it does not become overheated. After all of the SMD components are in place, you can ht the IC sockets and connectors to the board. Make sure that the sockets are correctly oriented, particularly the PLCC socket. There is usually a 'flat' on one of the comers. Finish the solder- ing work by fitting the transistor, the LED, the battery and the crystal. Finally, press the four ICs into their sockets. Note that before being fit- ted, the GAL (IC6) must be pro- grammed using the file upboamjed and the Flash ROM (IC5) must be programmed using the file unheard .hex. If you cannot do this yourself, you can order pre-pro- grammed versions from Readers Ser- vices (order numbers 030042-21 and 030042-31). A fully assembled version of the circuit board is shown in Figure 6. Testing the assembled circuit For testing the circuit board., you can stick a few loose pins into connector Kt for the connections or use a piece of perforated prototyping board. Mount two pin headers on the proto- typing board, each with 36 contacts. Connect pins 23 and 24 of K1 to pins 3 and 2 of a female sub-D connector, and connect ground (pin 1 of Kl) to pin S t pin 1 to pins 4 and 6, and pin 7 to pin 8. Next, connect the board to a PC using a 1:1 serial cable and start a terminal emulator program (such as HyperTerminal). Configure the serial link for 57.6 kbit/s, 8N1, no hand- shake. If you now connect a power source to the board (5 V at 70 mA minimum), the message 'Hello World’ will appear on the screen. This will be repeated if you press a key. The hie upJboard.hex pro- grammed into the Flash ROM con- tains a small application program in addition to the monitor. The only thing this program does is write 'Hello World 1 to the outside world. Congratulations - you now know that your system is alive! If the Flash ROM has not been programmed, nothing will happen. You can't program the monitor Into the Flash ROM yourself, because the board needs the monitor for pro- gramming (what a pity!}. Software The combined monitor and operating system program for the board is called OS552. It is a slightly modified version of 03535, which is used with the MSC1210 development platform. This forms part of a complete development system including a C compiler, a project manager with 'make' files and a debugger. As QS535 was developed for a different board with an 80C535 microcontroller, several small modifi- cations are necessary, among other things with regard to driving the GAL. You can use the board in three different manners, assuming you have fitted a Flash ROM containing the monitor program: 1) To program the board, run the program FiashMon on your PC. This allows you to pro- gram up to 64 KB of the Flash memory. 2) To debug a program you have written yourself, run the program SLD51 on your PC. The maximum available memory is 32 KB. 3) To run a program you have written your- self (maximum size 64 KB), first program it into the Flash memory and then reset the board. You can also run a terminal emulator program on the PC, but not FiashMon or SLD51. The board will now run your program. The monitor program, is located above the 64- KB boundary in this mode and does not affect the operation of the board. These operating modes axe described in more detail below. Simulator Software can be developed and debugged using the program SLD51. To use the board in this mode, select the proper COM port under Options/Com Settings and set the bit rate to 57,600. After the board has been switched on, it will remain in debug mode. You can use File /Open and File/Download to load a pro- gram into the RAM, where it can subse- quently be run. The program located in direc- tory sic hellowiebug can be used as an exam- ple for this purpose, FiashMon The program FiashMon from theuCSl devel- opment environment can be used to erase the Flash ROM on the board and reprogram it. To do thus, first copy the file ilasbmon.bix into the bin directory of the development environ- ment. Then start the FiashMon program. Under Options/Com Settings, set the bit rate to 57,600 and select the proper COM port. To prevent the program in the ROM from start- ing. enabled Disable Flash Autostart' in the Toolbox menu. When the board is switched on, the start- up of the regular program will be intercepted and the internal monitor program will be started instead. Now you can use Too lb ox/ Clear Flash All to erase the program in the Flash ROM (the monitor program will 65 1 2004 Elektor Electronics MICROOTNTROI I FR Summary of 8051 microcontroller boards Unlike one competitor who appears to be stuck with PICs, E/ektor Electronics has already published quite a few development board designs for microcontrollers in the 805 1 family. Here we briefly describe the most important ones: 89S8252 Flash Micro Board: a simple system for programs up to 8 KB, targeted at both experienced and novice users. Also pro- vides the basis for a programming course that explains the basics of microcontroller technology and examines several programming languages (assembler, BA5IC-52 and the Reads! I C compiler). Pub- lished in the December 2001 through June 2002 issues, with an I/O extension in January 2003. High-speed Controller Board: the DS89C420 is a super-fast 80541 derivative that can be used for processing races up to 33 MIPS. An ideal development system, with 1 6 KV of Flash program memory and in-circuit programming capabil- ity. Described in the June and September 2002 issues. XA Development Board: with a PC/ 1 04 interface for 1 6-blt microcontrollers, 64 KB of program memory and 64 KB of RAM. The XA family was presented as a 16-bit successor to the 80C32, but it essentially goes much further The XA core is considerably faster than its 8-bit predecessor. Described in the May and June 2003 issues. MSG 1 210 Development Platform: a small but powerful board built using SMD technology, which unlike the other boards described here is supplied ready-made (no soldering required!). Can handle programs up to 8 KB (8 KB development, 16 KB max in Flash), but has additional \ O and 24-bit A'D inputs. Includes a free Basic and C develop- ment environment. A digital measuring instrument using this board has already been described as an application. Published in the July August through November 2003 issues (‘Precision Measurement Cen- tral’ series). 64-K 80C552 Flash Board: a classic design for programs up to 32 KB (32 KB development, maximum 64 KB in Flash), with in-dr cult- programmable Flash memory and 32 KB of RAM. Has eight I Q-bit analogue inputs and three sets of 8 free I/O lines. Uses the same development environment software as the MSC 1210 development platform (with minor modifications). not be erased) and To olbox/D ownload to Flash to write the new program to the Flash ROM, Note that this program must contain the Instruction LILT 0>.G2 at address 0000, since otherwise it cannot be started by the monitor program. The program located in .sic Ire.-o run, which is already included in the standard firmware, can be used as an example. Monitor operation Immediately after starting up, the board enters the debugging mode and the OS 552 monitor progiam sends a command to the PC. If a program such as FlashMon is running In the PC r the PC sends back a command to the board to cause it to remain in the debugging mode. Once this has happened, the monitor waits for commands from the PC, and the LED on the board flashes regularly. If no command is sent to the board after it is switched on, the monitor checks whether a LJMP command (with destination 0x02) is present at address 0000 of the Flash ROM. This Is how the monitor recognises whether a valid program is present in the Flash Memory. The board then switches to the run mode and starts program execution at address 0000 In the Flash memory. Free Downloads Project software, including OS552 (source), 'Hello program (C source), Flash552.hex, upboard (GAL source and JEDEC files). File number: 030042- I 1 .zip. FlashMon and 5LD5 1 (in liCS I /bin.) are included in 030060-11 a,zip, see 'Precision Measurement Central 1 part 2, Sep- tember 2003), PCB layout in PDF format. Fite number: 030042- f .zip. www.efektor- e'ec:ronics.co.ijlc dj dl.htm . select month of publication 66 Elektor Electronics 1 2004 BiM2 High-Speed Radio Transceiver NEWPRODl JCTS Using surface Acoustic Wave (SAW) technology, the BiM2 Is an enhancement to Radlometrix’s renowned BiM module, and it offers all the advantages of the latter but with greatly improved receiver interference rejection together with higher data rates and greater transmit power. More- over, with its low profile of 4 mm and small footprint (23 x 33 mm), together with the low power requirement, the B1M2 is ideal for PCB installation, A major feature of the B1M2 module is the SAW- controlled IGmW FM transmitter plus front end SAW filter and full screening for EMC. The BiM2's transmit section comprises a SAW stabilised and FM modu- lated 433 92 MHz (European lie enc e - exempt fre qu ency ) oscillator feeding a 10 mW power amplifier stage. Many radio transceiver modules on the market use crystal tech- nology but SAW provides a number of significant, advan- tages. including lower cost, better data rate, low power consumption and faster power-up time. The SAW con- trolled BiM2 is the perfect choice for a wide range of bi- directional wireless connectiv- ity applications in battery- powered and hand-held equip- ment at ranges up to 200 in. The BiM2 provides data rates up to 160 kbps, features a dou- ble conversion FM superhet receiver and operates from a 3 V or 5 V supply at <20 mA. The module is verified to com- ply with both Radio standard ETSI EM 300 220-3 and EMC standard ETSI EN 301 489-3 by UKAS accredited Test Labora- tory. BiM 2 is certified by an independent Notified Body. Radio metrix Ltd. f Hartcran House* Gibbs Couch, Watford WD19 5E Z, Tel (+44) (0)20 8428 1220, fax (+44} (0)20 8428 1221, Internet: wwmradi o me trix.co m Email- inlo@rachometrix.com (037! 6+1) Catch all your Data in the Web A data logger which automati- cally uploads its measure- ments to an Internet database. The data can then he accessed and analysed with a standard web browser. Alarm condi- tions can trigger an SMS text message or an e-mail. All you need is mains or battery power and access to a tele- phone line. Getting started with the SWI 300 couldn't be easier. Simply connect the unit to a tele- phone socket, plug in the power supply and switch the unit on. Once installed the unit can be controlled entirely through your Internet browser. Simply logon to where you can set the parameters that the logger will measure, the fre- quency of the sample and the intervals between upload. The website allows a user to set alarm levels and have an auto- mated e-mail or SMS message to alert you if these levels are exceeded and you can even operate remote devices through the unit's control relay output. Each time the unit connects to the Internet it checks for new configuration settings and updates itself accordingly. With an appropriate sensor the unit can be set to measure a whole range of parameters, from temperature to humidity, voltage and current. The data is accessed securely through and can either be viewed online in graph form or exported to most popular spreadsheet programs for fur- ther analysis. The SWI 300 is available now for £349-95, which includes the first year's hosting for free. Visit or for more information. Lascar Electronics Limited, Module Hose, Whiteparish, Salisbury, Wiltshire SF5 2SJ, Tel, ( + 44) (0)1794 884567, Fax ( + 44) (0)1794 884616. Internet: www. iascar el e ctr o nies . com (C37l64-2i 1 2004 Elektor Electronics 67 NEWPRODl JCTS Min iature Web Server Compulogic have announced the release of a new miniature web server product aimed at "web enabling' existing or new systems and equipment. The PicoServ miniature web server module is an ‘Internet engine' designed to provide a browser based interface over the Internet or a LAN in a small space, at low power, at low cost and with little or no design effort. The PicoServ module takes care of all network interfacing and communications protocols, web page and file storage and provides a variety of simple interfaces to the host system or equipment. Dynamic web pages are supported through a simple HTML interface, enabling real time data to be both displayed and updated from a standard web browser. The module features a fully integrated XObaseT Ethernet Interface and both RS232 serial and 1 2 C ports for interfacing with host systems and I/O modules, PicoServ supports the following protocols: Ether- net, AKR IP ICMP TCP UDP HTTP TFTP and DHCP The TCP implementation is socket based and can support 16 s imuit an eou s c onne ci ions while the inclusion of a DHCP client simplifies module config- uration to plug and go when a DHCP server is available. Measuring only 5 Omm x 70mm (2 ’ x 2.75 r ) the PicoServ web server is available as an OEM module or can be used as a stand-alone system when housed in an optional tough aluminium enclosure. In addition, a number of stack- ing. standard intelligent inter- face modules are also available which provide ‘no develop- ment' parallel, serial, ana- logue, and digital I/O inter- faces between the server mod- ule and the outside world. Compulogic Limited, Cranfield Innovation Centre, University Way, Cranfield Technology Park, Cranfield MK43 OBT. Tel, + 44 (0) 1234 756048, fax: +44 (0) 1234 757731, E-maik en quid es @ c omp ul o gic . It d.uk Web: www.picoserv.com '• j . •_ - : SpacePort Modem Evaluation Kit The latest from low power radio expert Radio matrix is its new SpacePort modem (SPM) evaluation kit. This has been designed to test the com- pany's low-cost and highly integrated bi-directional wire- less serial interface module - the SPM. The evaluation kit makes testing in application fast, simple and accurate. The SpacePort modem is an GEL! product that can be easily incorporated Into both new and existing designs and it uses addressable data packets with error checking, packet acknowledgements and re- transmissions to achieve a reE- able and invisible wireless data link. Remote configura- tion is simple. Built for ease of use and rapid installation, the SPM has many apph cations in point to point telemetry, tele- command and tele -control to / from out st a lions or machinery, communications to and from PDAs, organisers and laptops, hand-held / portable terminals. EPOS equipment, high-end security, dataloggers, environ- mental monitoring, PLCs and alarm / exception signalling, automatic database interroga- tion. job allocation and status reporting, automatic location reporting / polling and any- where wireless RS232 daiaiinks are required. As such, it is important that the SpacePort modem be easily tested for functional integrity when in appEcation and Radio me trix s S p acePort modem evaluation kit will ensure this, adding to the ease of use and low cost of owner- ship that is the SPM’s hallmark. The new evaluation kit trans- forms the SPM into a complete radio modem and it features a 5V, 1A supply, ideal for power- ing up DTE such as barcode scanners. Test operations are made simpler still through the use of optical cues using light emitting diodes (LEDs). An on- board RS232 driver is used for direct serial port connection and a hyper terminal gives access to internal diagnostic and test modes. The hyper ter- minal also eases set-up and configuration routines. In addi- tion. users of the evaluation kit can gain access to each data / control pin for external inter- facing or testing. Radiometrix Ltd., Hartcran House, Gibbs Couch, Watford, WD19 5EZ. Tel: + 44 (0) 20 8428 1220, fax: + 44 (0) 20 8428 1221, E-mail: inf of® r a dl ometrix . c om Web: wriVWJradiometiix.com 6B Elektor Electronics 1 2004 N EWPROD IJCTS Min iature PCB-mount Transducers LEM has Introduced the HTS 10-P the smallest current transducer in its range occu- pying only 17x19x10.5 mm (L x W x H) on a printed circuit board. Using a unipolar power supply of 0 to + 5V, it allows bipolar current measurement of 10 nominal, supplying a ratiometric voltage output. Tire initial offset at no primary current (Vdd/2), as well as the gain (Vdd x 20 mV/A) at — 25~G are then directly depen- dent on the supply voltage used. With a measuring range of up to ±15Ap k! it is particu- larly suitable for detecting overloads. The size, the wide operating temperature range (-40 : C to +85C) and the unipolar power supply targets have been achieved by using an ASIC. The HTS 10-P is supplied with a tolerance of ± 12% for the ini- tial offset and ±30% for the gain at + 25 Z C. When the transducer is used with a microcontroller, these toler- ances can be improved. Other- wise. the HTS 10-P/SPl ver- sion, with tolerances upgraded to “3% and ±20% ± respectively for the initial offset and for the gain at — 25'C, is also avail- able. Tliis version also offers better thermal offset and gain drift. The performance and low cost of the HTS 10-P series make it particularly suitable for indus- trial applications (compliance to the EN 50178 standard and marked CE) such as garage door openers; electric doors, gates, shutters and awnings; electric power sears. It is also suitable for low-power, low- cost drives, where the trans- ducer can provide detection, monitoring and safety, LEM Components offers a five-year warranty for each transducer, LEM HEME Ltd, 1 Penketh Place* WestPimbo, Skeimersdaie, Lancashire WWS 9 OX, Tel: ( + 44) 1 695 72 07 77 E-Mail: kvri@lem.com Web: wwwdem.com SEEVAL® 32 Low-Cost Development Tool Microchip's new SEEVAL® 32 Serial EE PROM Designers Kit allows designers to quickly and easily develop robust serial E E P R O M -ba s e d app lie at i ons while significantly reducing system integration time and h ardw are/ software d ebua . The low-cost kit (DV243002) contains a SEEVAL 32 evalua- tion and programming board, a CD-ROM with M ic ro chip's SEEVAL 32 software and Total Endurance modelling soft- ware, a serial E EPROM sample pack containing eight devices, a user's guide, RS-232 serial cable, and a power supply. The kit provides a powerful pro- grammer/debugger tool that supports all of Microchip's Micro wire (Si. SPI™ and I2C™ compatible serial EEFROMs. It enables users to read, write or erase any byte, block, or an entire array of code. The SEE- VAL 32 Designer's Kit runs on any standard PC with Win- dows® 95/9 8/200 0/Me/XT/NT operating systems. With the Total Endurance mod- elling software, designers can quickly identify the best serial EE PROM for their application and perform trade-off analysis with voltage, temperature, write cycles and other system parameters in order to achieve the desired erase/ write endurance or product lifetime. This allows the designer to understand and predict the erase/ write endurance of the serial EEPROM. An on-line tutorial with hypertext help files is also included. Arizona Microchip Technology Ltd-, Microchip House, 505 Eksdale Road, Wlrmersh Triangle, Wokingham RG41 5TU Tel. (+44) (0)118 921 5858 Fax (+44) (0)118 921 5835 www, micro chip . com TX:- 1 2004 Elektor Electronics 69 Build your own Audio Valve Amplifiers To many people, the thermionic valve or electron tube is history. However, whether it is nostalgia, interest in the technical parame- ters, the appeal of o gleaming amplifier chassis with softly glowing valves, respect for the technical know-how of an earlier genera- tion, or perhaps the firm conviction that the sound of a volve cannot be bettered, it is a fact that the valve is making a come- back.The book contains, opart from construction projects for preamplifiers, power amplifiers, and two amplifiers for musical instru- ments, information on the operation of electron tubes, while the first chapter gives a short history of the valve. ISBN 0 905705 39 4 • 253 Pages, size 17 x 23.5 cm, softcover * RRP £15*55 ($31*00) j|jjJJjJ]|j DJj Modern High-end Valve Amplifiers based on toroidal output transformers The most remarkable features of toroidal transformers are their extremely wide frequency ranges and their very low levels of linear and nonlinear distortion. This book explains the whys and wherefores at various technical leve s, advancing from elementary concepts right up to mathematical descriptions. Schematic diagrams of valve amplifiers with output powers ranging 10 to 100 watts ore discussed extensively, with due attention given to a number of special valve amplifiers os well as the theory and practice of negative feedback. ISBN 0 905705 63 7 • 264 Pages, size 17 x 23.5 cm, hardcover * RRP £25.95 ($52.00) Order now using the Order Form in the Readers Services section in this Issue [lekior Eledronies (Publishing) • P.O, Box 190 8 Tunbridge Wells TN5 7WY 8 England, Telephone +94 (O) 1580 200 657 ■ fax +44 (0) 1580 200 616 |;~ -- | m !Hg| Hi 1 j g See also www,elektor- eletfronIcs.CQ.uk H I Evaluate for 30 days - Includes free technical support @ Research B- Space's esse of use and above all, accuracy, is why it is used by hundreds of universities and thousands of designers in the UK. US and Europe, The new ver- sion includes RF simulation and RGB export facilities. Sts the ideal electronics design toot for those who need to test their designs and know they wilt work In 'harsh environments. There are no limits is no limit on your design size or number of parts. High quality^eraphlcs ensure thai your results are easy to understand and interpret and everything can be customised to suit your needs. Spice comes with a Component library' of over 25.000 parts. You can simulate everything even dov/n to circuit temperature. Easy to use, fast and powerful export and bi ' of materials, improved schamalics with DIN and ANSI symbols, RF simulations, worst case analysis, smith and polar plots. 25.0 DO parts as standard powerful graphing and plotting - display & switch between multiple graphs easily, a new workspace" window to manage your designs and files new chooser window makes it easy to pick and place parts, combined digital arc analogue graphs, unlimited undo redo, create new mcde-s. create and edit symbols, create new PCB parts. Simulate - s'" dual parameter DC sw eep. AC sw eep, transient analysis, small signal transfer function, Fourier anah- sis. AC & DC sensitivity. Smith charts, pole zero. Monte Carlo analysis, noise, distortion operating point temperature change, and generate component faults. £194.65 (offer price) Tel: 01603 872331 jgs. Research House, Norwich Road, Eestgate, Norwich. NR10 4HA, www.spice-software.com Fax: 01603 87S010 Email info@looking.co.uk Save 15% by quoting EL79315 when ordering DrDAQ Date L< gar A low cost data logger supplied ready to use with all software and cables. It is ideal for a large variety of classroom science experiments. S f&r DrDAQ II,. J i.L i.M Output Resistance Microphone ▼ Very low cost - under £60 (excl. VAT) T Built in sensors: Temperature, Light, Sound ▼ Use DrDAQ to capture fast signals (eg sound waveforms) ▼ Outputs for control experiments ▼ Simply plug in to a PC and measure Voltage Light level Temperature External sensors (Humidity, Oxygen etc) fejdo Y [5Fti~ ' " ^ In j ADC-200 PC Based Oscilloscope PC based oscilloscopes open up many new learning opportunities in education, from looking at the waveforms of musical instruments through to measuring the speed of light. PC based oscilloscopes offer many advantages over traditional benchtop instruments such as ease of use, low cost, small size and portability. catalogue & demo ware on request For information on Pico products for education visit Tel: 01480 396395, Fax: 01480 396296, E-mail: sales@picotech.com lECTRONICSONI IN Analogue liter Design By Harry Baggen In electronics, filters are required for all sorts of applications, ranging from a simple audio circuit to the speech processor in a GSM phone. Filter theory being complex stuff for the average electronics worker and certainly no part of everyday chores, a couple of Internet addresses may come in handy if you’re suddenly faced with selecting and dimensioning a filter for an application on hand. In this month’s instalment of Electronics Online we look at a dozen or so calculation aids for analogue filters. Electronic niters represent a complex matter which is not, or not fully, mastered by many electronics enthusiasts. Wot to worry, because lots of professional engineers will also admit defeat to the niceties of modem fil- ter design. Fortunately, neither the hobbyist nor the professional worker needs to have a few dozen equations in his head — what matters is to know where the information can be found when it is needed. To help you on the way, and perhaps add a few bookmarks in your Favourites folder, we searched the Internet for software tools that considerably lighten the job of passive and active analogue filter design. Am excellent point to start from when you need filter information in the widest sense is Circuit Sage [1]. Set up a number of years ago by a bunch of IC designers, this website cov- ers a vast range of electronic designs. With each subject, the designers themselves make relevant information available, or point the way to other sources on the web. Looking under the heading 'Filter Design' the list starts with a number of calculations intended for use with the familiar Math Cad mathemat- ics program. Various types of low-pass and high-pass filters are available in passive as well as active guises. If you can not, or do not want to, work with MathCad, the second list on this web page contains addresses of alternative filter calculation programs. From the latter group we made a selection, with an eye for software that's offered free of charge. We begin with a number of calculation tools that can be run directly off the relevant website. Analog Devices on their massive website [2] offer a number of online calculation aids for active filters. The scripts allow second- order through eighth-order high-pass, low-pass and band-pass filters to be dimen- sioned, enabling you to select between filter responses like Bessel Butterworth and Chebyshev, ail with various ripple responses. A helping hand for passive filter design is offered by various tools on the Max Eroding website [3j. We found a page discussing the design of passive Butterworth filters (high- or low-pass) with up to 25 ele- S‘ Cic^ Save and Am fr roi ■ Ibiwwe Ti: T>C El *¥=£ 3, J 3 O 3 :J) !■£? .'.'nwwc 2 E 123 □ >i Q Si 3 U* H Van* JZ Rrfa *)§$ Hatscape SwtV. Filter Design and Analysis HOME -INEW ROUTINE T AND OAR OSSiOR ^^^Mot+icod Filter Software Toy T 7 ^ *5* - : • -T'T D£S3GM CE Patch iris ' j £ -‘ilkrihLlL P e ?> j c : ? i cj pNA/PA DBsiOfrl PI L D£ 51 GH TRAN SCEIVE R _ — 1 _ Circuit Soli's sal I enkey inelQNiesCMI\ DtMA iMb : : Ajrfnre F&d Spi ^Htl [BETA | - £be J_3T V"(v» jj 2 ^ zci : ^-tTcfc>* H?±. ^3 C i j V .■•.'^uj. jr,sia; C3Ey'Ar.so;_- :■:•'■ :■' ■)■■ • ± -ri 5t :^~ njr_ rt.T T 3" | jQ^ jj-ttaxh I 3, 3*fai jJ Kjiie ?.SB B HHkjh ^ 54*1*1 Hc-iK*^na*i © -S3 ^5**’ ' "■ ■ " I __; : :■ ;- «:"='i ; -= _-jt. ~ - ; , _ • ■ . ■ , ; j - ■ .r Trr* I L - “ “ * IX '. j : i J - x 3 : ;oK jvi l> - [; L* - J 'III - f - ■ .■: : • i _- ”3 □ MM Rbf TGei • : = ■=■ J| gD &%&&=***$ A i" giii ^ l HW< I U l l| BJ ■ i *. d* i f =" £:i:cj s ro>, w-c ■ Kri it'-ac-t <13 0 Q E *o*j hr— - .is-Liitjn-. MCiV'' ¥-?-^,r J: J .. i ] , j -\ stA'cji ; 3 MaJ -fi Kite ,1 Mot Jftj KsHcjdc Saatrfi S-ai.-n.: g 3 M &tU 3-ocurert E’S*!* fi 5J T 10 kOhm. I’ve used the TCL2272 series and found that the distortion of these op -amps will be rather high (> 1% at 1 kHz) when RL is smaller than 10 kOinn at an out- put swing greater than a few hundred miUiVolts. I think it’s sad that Elektor Electronics brings articles with such essential faults 1 Soeren Floug, Denmark fby email). There's no reason for sadness caused by one typo, The refer- ence to C3 in the formula on page 26 is wrong and should have been to C7 (see Corrections & Updates elsewhere in this issue . Still, the two components R@ and C7 are not related to the low -pass filter function, and no such statement is made in the article. Obviously, the low- pass filter roll-off frequency is deter- mined by R9-G7. see also the inset at the end oi the article and in particular, equation 16. The function of R19-R30, then, is to prevent audible clicks in the _ output signal when the rotary switch is operated, which is achieved by providing a DC path to ground for ail capacitors C l 1- C22 when they are not selected by S2. Alter all the output of ICi.D is at roughly half the sup- ply potential (you may have missed this point). Contrary to -//hat you seem to assume, the circuit dess not pro- vide any substantial amplifica- tion of the microphone signals. Even at extremely high volumes no more than about 8 mA of out- put current will flow not count- ing the external load), which is way below the maximum oi =50 mA specified for the op amps used Flawed Mini Project Bear Editor — your ‘SuperCap Battery' article (October 2003. Ed.) suffers from a couple of design flaws Ed like to mention. The Goldcap is discharged by R1 and R2, so a diode behind the charger circuit would, have been in order. Without such a diode, you will be unable to justify the '2-mA under no-load conditions' claim made in the article, simply because the series combination of R1 and E2 already draws more at 2.3 V An additional load is formed by the voltage regulator, because current flows into its output. To use a reverse-biased transis- tor b-e junction as a Zener diode is ludicrous for a circuit sup- posed to be reproducible — the Zener voltage will stray far too much. Also, a transistor with higher gain (C- suffix version) would help to reduce the no-load current, as it would have allowed a higher value for R3 (approx. 4.7 kQ). Diode D2 is clearly under-dimensioned. This diode can he expected to carry high currents as the full Goldcap volt- age is applied to the load by way of the coil and the diode. In this position I would have liked to see a Schott ky diode capable of pass- ing in excess of 1 A. or failing that, an 1N4O02 as the bare min- imum. The statement that the coil resistance should he under 1 o is incorrect — although it stands to reason that the con- verter efficiency drops with coil resistance. I would have like to see this mentioned. Finally, it would have been nice to see a graph with efficiency plotted against output current. Dr T, Scherer The missing diode was already noticed before we received your letter (see Corrections & Updates). It failed to show up in ihe circuit diagram because me author employs the charger and the step-up converter as separate units (as shown in the photo- graph). The ersatz Zener may look haphazard but in reality is a good choice because the only requirement for the Zener voltage is better stability than that of the battery. Also, the use of a reverse- biased transistor fits the bill of a Mini Project because most hob- byists will have a few spare tran- sistors lying around cut no Zener diodes. In our experience, the transistor- based Zener diode achieves an accuracy of about 10 A which is more than ade- quate for ihis application. A Goldcap, then, can be expected to pump a short-circuit current of up to 6 A. which defeats the use of a largish diode as yon suggest and can only be stopped by a fuse. In the unfor- tunate event of a short-circuit, we d rather see a small diode destroyed than the coil. Arguably, every project publica- tion can be optimised or extended in some respect. How- ever. a Ivlin i Project should be simple, brief and open to experi- ments. & l FOOTS Eey Counter for R/G Models November 2003, p. 56-61, 024111-1, A 4.7 kQ resistor should he inserted between pin 7 of Id and the base of T4 Without the ser.es resistor, the comparator output is short-circuited to around by way oi the base-emitter luncnoii of i4. The resulting current will however not damage trie iuC272. Electric Charge Meter November 2005, p. 2Q-B1, 030018-1. On the PCB overlay the symbols - ‘ and nss: K2 should be swapped. This error does not affect the operation of the circuit. Directional Microphone November 2003, p. 24-30, 030046-1. The equation in the article text on page 26 contains a wrong component reference and should be amended to read: R8 — d / (c - C7) USB-R3333 Interface April 3003, p. 60-65, 0200375*1. In the circuit diagram on page 62. the value ot RIC should be amended to read: 100 k£I This dees not affect the Components List or the PGB layout. Supercap Battery October 2003, p. 53-S3, 030109-1. Components TCI. R1 and R2 cause a rather too high discharge current of about 5 mA on the Goldcap battery, this can r- pre- vented by an additional diene between me Goldcap and the LM317. 74 Elektor Electronics 1 2004 RFAnTROTR\rrc Please Hole Sof:/.aJc •i?T5 nssjted @ are i.-X&T hem _:e Fr=f Dror/oatis page c i ' h z F _ : sfsTs -■< e!:- 5.~0 si ■ ‘ =s:-y~ ~ : : ; WsksSK m suppfcrf for the cowthuvc? of resists yk&hoI Internet access, £ tfSS mmnEEH S Eleklcr Eleclionics Help Disk 966022-1 Ki‘ ilndffA^sfaWi 815 14.45 Elektor Efectronics Item Tracer T 9 & 5 - 2 QD 2 036003-11 csmcls Cubase >v.-$zxs \=; e- L i:4 ■ 1 3 =|-- IS i ihrct I ” t”f “ r I f i Ss JY : r “Ij N fcj-rf ” ’.‘1 : 1 1, 2ft! Lfl: r. ■ EFmv.t- G.US PAU lE.FlGi VAOHs rr..: : r- 5 ^ i e sc>y : l - primx t~ : Prices aod ten dso^jws sipst&r cftsig* Tls pete : -aws fir if J .sf r :f:: frees .v't is” r"':- T f££Sor. Prices sr3 ileri slaurtbere ssjif- seia Ls3i3 h prcilz-is is icfs. E iG: FAST ISSUES Pii: isues. ' iii i: i i~;_ : si crCiff-s f : - WotfSHb* SListjipIsQa Semra Lb. lls ! 4. G : bti Rs-j Fll“ Pash*!/ Rill TlCEHURST Tfci THE. “5 f+44) 15E0 2G0557, In tf 44) IKS ZGQ61S- esafi h h s s .1 fH Jijda me a .< _- . i Prices ol paKflifs (except JtftfAugysi and ; - pastas far iv's iiif: if £».7a =-,; :‘: £ 5.33 ( 3 & -1 E_::t ELB.t I if - .= cvl-;? 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Csss 0331 eS -4 1 £=€205 1 -i 2 PC, prDgfsnmeo Mulli-event Alarm Clack 3 023 Z 34 ’ 1 \ Disi C Sfeju = ? h=t ffe -3 020304 - 4 1 ATB 9 C 2051 - 1 2 FC . pregrarrmsd 9'35 4-90 10-00 6-10 7 75 30-20 17 -do 17 SO 4 ' 9*0 805 4-90 6-10 16 . u 5 3.65 17.70 10.80 13.70 8.65 18.05 30.15 31.60 S.C 5 1^25 3 65 10 50 - * ■ v ■£■ # ■ - bVL iTI UL Tl i UuU FM Remote Conlrol Transmiller S Receiver B 034044-1 F €5 LEO Chrlslmas Decorallon 1020 15.05 @ 0301 5 7-1 PC 3 PS 7 LPC 76 X Programmer 7 o 5 13.35 © 030313-11 Dfe V. c rojsct EGfiiViiB Projecl Timekeeper 4 -SO 6.65 @ 020350-11 Otsit. source 4 ot^ed code fifes 4430 6 . 6-5 0203 1 FiCJ 6 F 84 - \ 0 P pJogiamm-Ed Stepper Motors Uncovered ( 2 ) 13-15 23.25 <£• E 20127-11 Dss 5 c bcctc? C 05 = ffc Universal Clock Generalor 490 6.65 @ 020355*11 Dc-L sours! cods flte Wireless RS 232 Link 4-90 S .65 @ 030204-1 PCS Mb 32ft r NQ UE MffFfl 2/7 A 2 £-70 1540 HU# w> 4 MhP — flVFIrlTIUAifl jLLfiLPv> Rev Counter for R. C Models @ 024111-1 PCS 1750 31 x 30 024 111-11 Dis-fc sons and he< code 4-90 8.65 02411 Ml 89 C 2051 - 12 PC, programmed Running Tail Display a *85 15.65 @ 020407-11 D&Sc, sam& and hes code USB Analogue Converter 4*03 8.65 @ 020374-1 KB 7-85 13 50 @ 02 D 374 -T ; C.;*l hex c od e E'.d iV ■”•;,■!$ srTAl" 490 6 65 020374-41 F.C 1 SC 7 & 5 . F^grammed 13 25 23 45 «Mr -J- v v U f 4 / £J L n £. U C/tj DDS RF Signal Generalor @ 020293-1 PCS. gefiEJfllD' 11^0 28.35 B 020259-2 PCS. codtnii 12-10 21.45 020299-41 AT 0 DSS 515 EPC. pfo^ensd Minimalist Induction-Balance Metal Oelector 30-55 54.05 ® 08 ) 230-1 PCS Xilimc PROM Programmer 8-95 15.55 @ i 1 B 109 -n Software 4-90 3.65 r*i/ J ljifriF-ALufr^f OriDC/T iLUtrj ATV Picture Generator @ Q 2 j£ 35-1 r D EX. SKJK 3 i ti i CCCf f?ies 4^*0 8.65 020295-41 AT 90 SS 515 - 3 PC, pfljgrarmsd 15*20 25.90 020295-4 2 AT 90 S 1 200 - 1 2 FC . procr DTMF Remote Telephone Switch 13-90 24.60 @ 020294 - i PCS 11-65 20 00 B 0202 24-11 0 is X. &‘C; E : : SUftAWB 4-20 8.65 020294-41 p:Cltr£ 4 A -20 P p-T-^Trr;fd LC Display v/tth 12 C Bus 14 70 2600 3 0 - 30050-2 =€3 FICProg 2003 735 130 © 2 mm-i pcb 905 16.00 S 0102 02-1 1 Of vradGA s softuiafe 4 - 9-3 S .£5 r r/s s 010252—1 PtCl 6 ' 874-23 P pn>: rsmrr^J 23 E 5 41.65 Polyphonic Doorbell @ 020354-1 1 Dssi; pr&jSd sofm''Xe 499 5 . 6.5 02035441 Pl€l 6 f£ 4 A- -10 ft pr^rsmrned 14-45 25-55 Precision Measurement Central 83006091 Ready- assemdted S ic 4 t=d bos’d 5380 112 50 Valve Preamplifier ( 1 ) @ 020383-1 PCB, ampEier bdeid 11 55 20.40 @ 020353-2 PCfi. c^A-sf Supf^N M=nd 11 40 2 * 0-23 @ 020363-3 PCS, 1 0 board 1010 17 50 Mn-RVR—ttttYifitJBnRT pfln3 1 fivrviw 1 — V U kL ,-/4 UllUu t i U U lJ Add a Sparkle @ 020293-1 1 mk. HEX snd s^rce f-:s 4-30 £.55 020293-41 Pit 1 2 G 509 A-CM SM . pfogrammetf 7-40 1310 AT 9 DS 2313 Programmer © O 3403 S -1 PCS 905 160 O Hard Disk Selector @ 034050-1 F€E 9-45 16.75 Mini Running Text Display @ 02035541 D';" scucce carfefi^ 4-90 5 55 Mini Test Chart Generator @02040241 C'.P PiC soujis csste 4-90 895 Programming Tool tor ATiinyl 5 @ D 3 OO 30-1 PC 3 7-55 13 35 @ 030030-11 Di-I- prn.E-it scaiVi-f 4-93 q 55 Quad Bridge Car Amp @ 034 O 39-1 PCS 870 IE 55 Remote Light Control vrith Dimmer @ 02033 7-1 1 EMsfc HEX s^d sot me r*s 490 £.65 02033741 ATS 9 C 205142 , prog^mn>Ed /rfftTF LSjnna 6-25 11 x 35 ” AVR TV Tennis © 0380264 3 , f =ji PCS 870 15.43 @ 035026-2 PtKNxnton* PCS 6^1 1525 @ 030826 - 1 1 Dssk. .AVR sI'.te cafe 4-90 ■3 65 03 GO 264 t AT 90 S 515 , Fxogfsmmed 15-20 26 x 5 Eiectrenic Knotted Handkerchief /- @ 020308-11 KsK PC and ccteoier stru»v^ 4-90 855 02023841 AT 90 S 2313 - 1 CFC. at^aiuiKd 1250 22 HQ Low-Cost LCD Conlroller ( 2 ) @ 020114 4 PCS £-70 ’ 5.35 © 02011441 D.f* 490 8.65 Night Light Control @ 020 115 -H D-e k. 1 >=x s/Kt source «Kfe 4 93 8 65 0201 1 541 AT&D 523 1 3 - 1 0 PC . 12*85 22 75 Universal XA Development Board @ 010103-1 FCB 13-20 23.35 @ 010103-1 f GAL ccce. tFRCV r£«: r es. XASCV 4-90 £.65 0101 03-21 EPROM 1 C a. 27 C 2 55 - 90 . pre-: : =m t aJ ID CO 17 70 010103-22 EPROM [Ct, 27 C 256 - 90 , programmed i&C D •7 70 O 1 O 103-31 GAL 16 V 8 .. progrannKd Am £.50 Kn-»iiiA - ■ JT-l/r # -■ IBh l 1 — — Countdown Timer @ 02 O 296 - 1 1 C*e>. s&inis Efd h-j ocA 4 4-90 6.65 02029541 AT 9 J- 3 1 2 CK 3 , prog^jr.isd 13-30 24.60 USB Audio Recorder @ 812013-11 DbL EFRCL' fex cods £.65 012013-21 EPROM 27 C 51 Z pnapariiKd 12-60 22.30 Valve Final Amp ( 2 ) © 02037 1 -1 Amp ■ -f toanJ - or« crid'i'.. 15 10 26.75 @ 02 OD 7 1-2 F’ci'.ErsLz^j' toL-if 1995 17.75 ri (jj JiU /iTiii/L — — — — B-Channel Disco Light Controller @ 01 O 13 M PCB 13-10 23.15 01013141 37 C 750 &: 87 C- 1 . 23-80 40.70 i 2004 EEektor Electronics 75 RFAnray^rK PCB’S AND MUCH M 0 R E r US s Pico Pic @ 01C0594 KB IB-70 33.10 © 01 CCS 9-1" D.e- sst crac^m 4-90 3.65 Single-Chip Tone Coni rot @ 020054-1 FCB 10 90 19.30 Switched* Outlet Power Bar with RS232 Control © 020298-1 F'CE 10-00 19.10 § &ZQ2&3- 1 5 U$' pfC-jMT SfffatfdZs 4=90 5.65 Temperature Indicator lor fhe PC © I IDE 5-D-: : D ic :c”: e: rji-r 4-90 £.65 G >036041 ATS9C2051 p tz&3.TWrt 1025 15.15 fit) HQ MA RON 200Q ffiiw jits in tin bn it/UJ 17 V 10 A Switch-Mode Power Supply @ 020054-3 PC 5 945 16.55 Add-on Switch imil for ft C Models @ 02fil2i5-l PCB 8-95 15.85 @ 0201 26- 11 0 i*>L h l - i source fifes 4-90 6.65 m 1 26-4 1 FiC t cC71 2-04 I SO. me ■ 2 nt nra) 1^20 25.90 AVRee Developmenl Syslem @ 02033 S-i PCB 13-20 23.35 S' 02 D 35 ' - ' 1 Q .£ v. r'tsTL *: prog rams 4-90 B.B5 Guirlar Effects Switchbox @ 020181-1 PCB 13-15 2330 Intelligent Fan Timer © 02fll?0-i1 O’i :t : ' : feci * of- a *?£ 4-50 8 65 0201 7041 j AS P4 3TW=1 12 1 . pregraatftSiJ 11-30 2c SAA3049 Repiacemeni 3.' 0200854 PCB 134)5 25 19 A 02 CC&5- 11 I i H. : f 4-50 865 020555-41 87LPE764SJ1 pccrawraj 9-90 1/55 Two-Colour Running Light T 810-3-M PC3.coi7ir-.lt/boejTJ 8-25 ■4.63 .2 010134-2 PCS. LEO t-zra UP&5 15 cJ 2 010134-11 Disk pri;^:: i:f:i'.i-T 450 3.65 010134-51 AT8SC205T-12PC. prcGnmrr-f 7-15 12.65 No, 318 FEBRUARY 2003 20 40 MHz logic Analyser © 020032-1 PCS 1 s-23’ 23.35 © 1 2 2132- 1 1 D S K Zz ~ o KD§ ram 490 5.5.5 02203 r-4 1 AT 02 5-551 5-E PC prog r^rac ^ 15-10 25.7Q Active Loudspeaker System (2) © 222054 -2 P2= 795 14.55 Autoranging Capacitance Meter s 020144-1 PC 3 7-35 135*2 @ 020144-11 Pis*, source and hat ftes 490 8.65 020144-41 PKt^84A-2ftTfp(D3a™i£d 15-26 26.90 Dimmer with 0-10 V Control Inpul @010125-1 control PCS 9- GO 17.00 3 0' 01 25-2 c'Ti.T-Ei' PCS *95 15.85 Electronic Hourglass 3 C-2C036-1 PCS 18-55 32 BE- 5 226035-1 ' 2 : - sof tv. s:e 496 6.65 022536-4 : F..3 1 6f 64- £4 P 15-20 2-5.95 Optimise pur PC Soundcard ■© 020184-11 Dfefe Excel gras dstea Mn 31 7 JANUARY 2003 490 555 fill a *J 1 i wrttfUH-ii ( £rUU «J Active Loudspeaker Syslem (1) 3 320054-1 FCB 690 1220 EEacSronic RPG Dree Roller © 0230054 FCB 10-05 17,75 @ C 2 2CC 5 -1 " Dfe sou • 1 5 c &d j f • - 4-9-3 865 02 ! •:■: 5— 41 at 93S4433-5 PC , c roe :i ~T rj 30-60 5450 fin dent Deterrent j Qiv- ■ pcs 12-05 £1.30 SMS-Controlled Mains Sockets @ 020157-1 PC 5 ?-#*? nprPMffPf? on/v? £ 1290 OSS 22 85 ffl/i y f U U K Lr E fti D C fi ^iiu£ DC! PLC @ 010113-1 FCB. tv-ra 8-40 l :: @ 010113-2 ?C3 wfnvnsl board 1 2-542 22.10 © QiQm-n D-S*'., Kjl'. SDN-.’i E"E- L SCM5TE5 LODE 4-90 a 55 01011341 AT 90555 1 5-5 PC . png rsmmed 21-20 3755 Pori Line and ADC Extension @ 020307-11 D ,e - . 8AS C O.’A- 5 1 prpfflems 496 6.65 Programmable Dial-Out Blocking Device "i O 201 K-' PCB 12-20 2155 @ 020106-11 ctEk. pn_:~L SETT.vin 4-9-3 2 55 0201 25-41 AT i 3 5205 1 -1 . pragrarrumEd 6-50 11 53 USB Audio Codoc wilh S PDIF @ 020175-1 FCB IMP 19.60 No. 315 NOVEMBER 2002 Audio Level Check for Line Inpul @ 020169-1 FC B 9-25 16.35 EPROM EmulaEor @ 024066-1 FCB 9-35 15.55 @ 024666'! ■ Q& GA.L JEDEC e: _: 4-90 555 024 066 -31 HAl 15762. prog - i : 5-00 5 5.5 LED Torch © -31 201 9-1 1 DisJ- pro : : I SdftA’sTc 4-S0 E.55 012019-41 KC1 20672-04 SM. Ffugr^wred 1040 18.40 Sland-AlDne EEDTS Pro @ 020 1251 PC3 15-35 27.15 Telephone Baby Monitor © 012016-1 PC3 1060 17.70 © 012016*" G.E 1 E-:.n= et: r~:< t iz 400 3.65 01 £01 6-4 1 AT963 1313-1 C^C. pragisrcTT&d 10-40 15 48 Vehicle Diagnostics Adapler © 020133-1 PCS 025 15.25 No 3td OCTOBER 2002 IvUt v f ¥ uU f vUCll L IUjL AT90S8535 Programmer @ 024051-1 FCB 0C5 16.05 Digital RF V/attmeter © 020026- ■ FCB 1285 22.70 © 02 CO 26-11 C'P 1 i l.'Ef COP: : 4-K 2.E5 02602041 RC1GF87fr04SP 19^50 25 22 Motorcycle Theft Alarm @ DC0193-! FOB 003 ’7.53 © 000101 -n D>1 SC-ATCt ccg’5 f >s 4-90 8.65 000191-41 FJD16FB4-04 SO 19-00 25 20 000191-42 RClGf84rD4'P 14 70 26 05 Sound Pressure Level Meter @ 620122-1 PCB IJn 111 GCPTFPJRPR 1070 2- 55 riu t JM Ofritfrlocfl £UU£ 20- Metres Band Receiver @ Q 10097-1 PCB 14-30 25 30 Capacitor ESR Tesler @ 012022-1 PCB ie 15 2 l 63’ Continuity Tester @ 020-302-1 PCS 4-60 2 10 EEDTS Pro Super Loco Decoder Upgrade 02009 4-4 1 F, C for S2 p=r ! .:cc c=c ede r 13 90 37': 020095-41 FvC for 1725 25 55 Firmware Update for EPROM EmulaEor © 024107-11 Disk hseffe 4-00 S.&5 024 1 07-? 1 A769C205 1 - 1 2F peeg r™ E-A 795 14.10 High-Speed Controller Board © 020102-1 PCB 1105 £1 15 Parallel JTAG Inlertace © 020003-1 PCS 875 15.45 No, 312 JULrtAUSUST 2002 4-Btt Decimal Display 024072-31 GAL22V i 3D-25LR ^rg^T-E j Audio Llmiler (for DUD) 003 2222 © 024074-1 FC B Distance Measurement using Infrared 13 45 Z2 EG © 020010-11 C'Ev £/•: f'- 4§0 8.85 02 OQ 10-4' s 7 L PC7S2 p roorans mso Keyboard Mnuse Changeover Switch 10-75 19.00 @ 024056-1 FOB VCP-2002 Video Copy Processor 10C0 T7.65 @ 010121-1 FOB 12-70 22 50 010121-31 EF 1/70645 LC44 . pnog ranr^d 24-00 42' 50 Products far older projects (if available) may fie found on our well site h tip: ff www. elektor-electronics. co. uk 76 Elektor Electronics 1 2004 Pizza sand th-s orde- ?c r rn io 4 (see reverse fc r conditions) Eiektor Electronics (Publishing) P.0. 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Method of payment (see reverse before ticking as appropriate) note: cheques mil made out m sterling must be increased by the equivalent of Cl 5.00 ■ □ Bank draft □ Cheque (payable to Elsktor Electronics) i , J Giro transfer _J Bank transfer _j Postal money order J VISA rrrrwp Msre^inj m Signature: SWITCH only: issue number: Expiry date: — it 1 2004 Elekior Electronics 77 ORDERING INSTRUCTIONS, P&P CHARGES Except in the USA and Canada, a It orders, except for subscriptions and past issues (for which see below), must os sent BY POST or FAX to our Tunbridge Wells address using the Order Form overleaf. Please note that we can not deaf with Fifiso^L GhUEHS, as no stock is carried at the editorial and administrative office. On-line ordering: http; w Vi W.elektor-electronics.co.uk Readers in the USA and Canada may rout are not obliged to? send orders, except for subscriptions {tor which see below), to The USA address given on the order form. Please apply to Did Colony Sound for applicable P&P charges. Please allow 4-6 weeks for delivery. Orders placed on our Tunbridge Wells office must include P&P charges (airmail — now called Priority’ — or 2nd class unless stated otherwise) as follows. Up to 500 grammes {most small parcels) UK and Eire £2 50: Europe £100; outside Europe £10-00: surface mall £5-00. Up to 1 kg (average per book): UK Eire £3-00; Europe £'5-00: outside Europe £1 4-00: surface mail £6-0 D, Up to 2kg (average per two books): UK Eire £5 00; Europe £3 00: outside Europe £18-00; surface mail £BT3Q, HOW TO PAY Unless you have an approved credit account with us. all orders must be accompanied by the full payment, including postage and packing charges as stated above. Payment may be made by cheque drawn on a London clearing bank ibut see para. 4 below), postal order. VISA. Access, MasterCard or EuroCard {when paying by credit card, the order must go the cardholder's address). Do not send cash through the mail. Cheques and postal orders should be crossed and made payable to r E!ektor Electronics (Publishing)'. Payment may also be made by direct transfer from a private or business Giro account to our Giro accounl No. 34 152 3801 by completing and sending to ihe National Giro Centre, in a National Giro postage paid envelope, a national Giro transfer deposit form. Do not send Giro transfers direct to us, as this will delay your order. If you five outside the UK. payment may also bs made by Bankers' sterling draft drawn on a London clearing bank, Eurocheque made out in pounds sterling (with holder's guarantee card number written on the back), or US or Canadian dollar cheque drawn on a US or Canadian bank. If you pay by Bankers' sterling draft, make clear to the issuing bank that your full name and address MUST be communicated to the London clearing bank. Our bankers are NAT WEST PIC, 1 SI James's Square, Wadhurst, East Sussex TN5 6BH r England Our account number is 3512 5225, Sorting Code 60-22-1 5. ISAM code : GB40 flWB K6 022 15 3512 5225 BfC code : NWBKGB2L COMPONENTS Components for presets appearing in Elektor Elecl/onios 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 D e I i ve ry A! ih o ugh every effo rt will b e m ad e to d is pate h y our ord e r w fth in 2-3 weeks from receipt of your instructions, we can not guaranies this time scale for : all orders. Returns Faulty goods or goods sent in error may he returned for replacement j or refund, but not before obtaining our consent, AH goods returned should be packed securely in a padded bag or box, enclosing a covering letter stating the dispatch note number. If the goods are relumed because of a mistake on our . part, we will refund the return postage. Damaged goods Claims for damaged goods must oe received at our Tunbridge Wells office within 10 days (UK); 14 days (Europe) or 21 days (all other co unfries). Cancelled orders All cancelled orders will be subject to a 10% handling charge : with a minimum charge of £5 00. Patents Patent protection may exist in respect of circuits devices, components, and so on, described in our books and magazines. Elektor j Electronics (Publishing) does not accept responsibility or liability for railing to identify such patent or other protection. Copyright All drawings, photographs, articles, printed circuit boards, programmed integrated circuits, diskettes and software carriers published in our books and magazines (other than in third-party advertisements) are copyright and may noi be reproduced or transmitted in any form or by any means, including photocopying and recording, in whole or in part, 'without the prior permission of Elektor Electronics (Publishing) in writing. Such written permission must also be obtained before any pari of these publications is stored In a retrieval system of any nature. Notwithstanding the above, printed-circuit boards may be produced for private and personal use without prior permission. Limitation of liability Elektor Electronics (Publishing) shall not be liable in ' contract, tort, or otherwise, for any loss or damage suffered by the purchaser whatsoever or howsoever arising oui of, or in connexion with, the supply of goods or services by Elektor Electronics i Publishing) other than to supply goods as described or, at ihe option of Elektor Electronics (Publishing)., to refund the . purchaser any money paid in respect of the goods. Law Any question relating to the supply of goods and services by Elektor j Electronics (Publishing) shall be determined in all respects by the laws of £n 9 fand - January 2004 \ .. _ Subscription rates from January 2004 issue Standard Plus I UnUed Kingdom £39.50 E45.50 a Economy Mail Rest of ihe World (excluding Europe) .£51,30 .£57.30 I Prirmly Airmail Europe & Eire- . £52.50 £58,50 Middle East, Africa, Soufiwegt Asia, Central & South America £64.00 £70.00 Australia. New Zealand, Far East & Pacific Territories £66.00 £72.00 Airfreight USA & Canada onfy .USS88.00 USS96.50 t i Payment should be mace by; * Cheque or bankers' draft in sterling drawn on a London clearing bank (except In the USA and Canada — see below); Eurocheques must have the holders guarantee card number written on the back. * US$ cheques drawn on a US or Canadian bank — only by subscribers in the USA or Canada. * Direct transfer to our bank (NAT WEST PLC. 1 St James's Square, Wadhurst, East Sussex TN5 6BH, England), Our account number is 3512 5225. Sorting Code 60-22-15. * Postal order. ; * Credit card: VISA. ACCESS. Euro MasterCard. JCB Electron or Switch, * Transfer to our Giro Account number 34 152 3801. Giro transfers should be made by completing and sending the appropriate transfer deposit form to Ihe National Giro Centre (UK) or to your national Giro Centre. Cheques and postal orders should be made payable to Elektor Electronics (Publishing). Oo not send cash through the mail. Subscription conditions The standard subscription order period is twelve months, ff a permanent change of address during the subscription period means that copies have to be despatched by a more expensive service, no exira charge win be made. Conversely, no refund will be made, nor expiry date extended, if a chance of address allows the use of a cheaper service, ■ i Student applications, which qualify' for a 20% (twenty per cent) reduction in current rates, must be supported by evidence of studentship signed by the head of the college, school or university faculty. A standard Student Subscription costs £3160, a Student Subscription-Plus costs £37.60 (UK only). I i Pi ease note that new subscriptions take about four weeks from receipt of order to become effective. ■ Cancelled subscriptions will be subject to a charge of 25 A (Twenty-five per cent) of the full subscription price or £7.50, whichever is the higher, plus the cost of any issues already dispatched. Subsclptions cannot be cancelled after they have run for six months or more, I I I I January 2004 78 Elektor Electronics 1.2004 V I CO EMitt On each ZD you v. ; a!! ariic'es pub shad in the relevant year, ind. circuit diagrams and PCB layouts, and an extensive search program. The 1997 and 1998 CD-ROMs a 5 : Abuses -'lOTvic demo -; £ E'ectrcr.bs Vtorkber: n fcr c:t: „ tsr simbafoo of sa r ectad E e-dor presets. CD (Idler 1996: Price £25.35 (USS 44.851 0 Grlricr 1997: Price £25.35 (USS 44.85} CD Ekktor 1993: Price £16.25 (USS 28.75) 0 Star 1999: Price £16.25 (USS 28.75} CO Efektor 2000: Price £16.25 (USS 28.75) CD (Wrier 2001: Price £16.25 (USS 28.75) CD (Wrier 2002: Price £16.25 (USS 2875) pP‘p( krdware i softwers 97-93 All the wiraitg entries of the Juty/August 1997 rx's-prooessoT corr-cstit :n: mere ran ICC ceabrs RRP £14.95 (USS 26.45.1 PC Softwore 98-99 rcn p r ;o r a m s COS aro Widows . RRP £12.05 (USS 21.25) MiMfer 1,2&3 VoL 1:22 Efaktor Electronics projects covering microprocessors. compete y. in texi crc-i tfagrarcs and PCS avao’s in electronic format RRP £2175 (USS 37.40) Vo •!. 2:79 rx :o p rocs as 3 r-b sees c : - stru r: on a to: eels . co ~ p a :e *\ to : 5 xt . coco 4 da r a m 3 and PC 3 iayimts * e'ecircn c format. RRP £21.15 (USS 37.40) 7ol. 3: 2o jp prefects mi text. PCE layoffs and schematics in separate files for ©fling with EAGLE 3.5 CAD software. Seeded prcjacts supp 'so won Tcrccontrol » r source code f.ies. RRP £21.15 (USS 37.40) He Asdifl CoSktiwi CD-ROM A L r :^e CD-ROM ^cr Ire :rce auG 0 (over, conta r n : r : fewer than 5 aod 0 deserts : rcrc E.eoor E eciron os macazba rear 7c .mas 1995 threjoh 1595, RRP £ 12.05 (USS 2175 (Wrier 1C d-Qlebcnk Inc if dee a rcpcitani types of 'C. eoco as NCMOS •. , CMOS ~aa r JCs, arc man;, more. De:e ad manufacturers data and sec safe circ Js. Vbib a seared rcotinas. RRP £21.15 (USS 37.40) £CD — (klric/s Caspotenf Dofcbss^ Fc or n :e ra c: , a d a fa :a r '< 5 cove if 0 g ova r 5 300 1C s . over 22,500 bipolar transistors, over 4,900 FETs, just .-■‘-sr 25. OK) d : odes. over 1 800 op: scoiders. trccsrcrc aco macs. P us 3 ca cu a- bn toe's rcr zerer a cc a seres ms s:: r a. v :; race m:. atom. vQ'tage g - bam, AM Vs. ms-sior arc irducicr vabes. RRP £ 12.95 (USS 22 . 90 ) Udder Bedrocks D^ifd Grail l i:r cry ( 1 - 2 - 3 ) On ? o!ve$ 1 Conans Op&r3G0 crc-L is complete w:r d ag^m are text. Zoom arciri: module. Fast search ia&fy. Error- t: srarc: abex seeren system Marc printed-: reult board layouts RRP £12.05 (USS 2175) 0a ifoiyiBs? A second sa'ecion ebover 380 emits compile wfth ciseram and text. RRP £12.05i USS 21.25;. Oil vdi?3| 3 A third se eci on of over 303 1 rcb is co-mpteie win d aarmm ana :ext. RRP £12.05 (USS 2L25) He Ekltfw Datcskxl Co9«fH OnVofeiae 3: Grig naS a" a urabndged datasheets, "ore than 3-00 Cs 7-:ot and 4Qx series), , : iage regulators, linear ICs m'sceilanecjs. RRP £12.05 (US$21.25) Oil Vdg3i$ 2: Datasheets of mors than 1CCO d'screle oo^p^r-scis: k^w/^r-powe r iranstslms, M,OSFETs ; thyristors, Eriacs* varactors, zener diodes, LED efisplays, etc. RRP £12,05 (USS 21.25} 0aVc^9?5s 3: Datasheets of popumr mb-rocontrc am : -e the 8651 seres F C. ST67. A - A. COP. 6! 'ACC 508 11 aivdSX. A:-so the DSP2100 series. RRP £12.05 *USS 21.25; 0a V$ha?4: U am s h ears c f ire : u er.t , u s ed m e r , cry erbsar; modules. RRP £12.05 (USS 21.251 0a V&hnse 5: M: r s -M rcrcrssrc ::.e r rc ™ :rc-::rcrc arc from 4 to 32 Ml, m 8-pin to 144 pin cases. RRP £12.05 (USS 21i5) & z* sjyit feFPGWidGBi st Iteafcs: sciutea. Free S Skjcwcn 2000-2003 This series contains hundreds of freeware and src r e,-.arc :rcca": rc am: :: e e:: j rc :s. ”:ercs: MJ s indtfoe ainfo r components, test and measurement development toots, emulation, CAD and RF sptems. Apptotrons vary from schematic capture including drgttai and analogue Emulation right up to PCB design, oomptete with calculation toots aria raxTroconfeier devek^menl toots, Dependng on their origins the programs run under Windom DOS amfor Linux. Each CD-ROM (except Vdume 2000 ) contains 0 PDF fils with s e’earove'-, lew of 0 regrams on rhe CD- ROM, ‘ v RRP £12.05 (USE 21.25) per volume Toolbox 1 eJ 2 C 1 t r :ese CD-ROMs you -: fin d 0 : ected ^ f 0 at : 1 data sh ee is ^2 app ‘ :a fb 0 note s) a rd too: 5 so frw are cct-s :e r ea •*: s per sac. s wzen worxing w th mcroccnUoi b'S RRP £12.05 (USS 21.25) per vcbme Order row using the Order Form in the Readers Services section in this issue Elekior Electronics (Publishing) * P*Q. Box 1 90 & Tunbridge Wells TN5 7WY 0 England. Telephone *44 (0) 1580 200 657 * Fax +44 (0)1580 200 616 See also www.elektor- eEectronics.co.uk NET LINKS To book your website space contact Bernard Hubbard Tel (0)1242 510760 Fax: 0044 (0)1242 226626 BETA LAYOUT vvww. p cb - pool .com Beta layout Ltd Award- winning site in both English and German offers prototype PCBs at a fraction of the cost of the usual manufacturers’ prices. BURN TECHNOLOGY LTD Distributors of a wide range of device programmers, package adapters, test and soldering equipment Order online and get free deliver/ on all orders over £30.00- COMPUCUT http 7/www. compucutte rs .com Computer Numerical Control from your home PC. Great for tricky jobs, and accurate repetitive work. We supply: - Software - Interface - Manual - Support Price £250 plus postage. CONFORD ELECTRONICS hjifn * / ! 1 t. f“ t r ? f i r nninrrta *■ .o a p a i 1 1/ Lightweight portable battery/mains audio units offering the highest technical performance. Microphone, Phantom Power and Headphone Amplifiers. Balanced unbalanced signal lines with extensive RFl protection. CROWNHILL ASSOCIATES LTD http: : t . v, w.cro v/nhi I Leo . u k tef 01353 666709 fax 01 353 666710 * Manufacturers of production quality device praog rammers * PIC Programmers ■ PIC Development tools * Manufacturers of Smart Cards * Smart Card Programmers * Design & Development Services Crowfihill Associates Limited 32 Broad Street Ely. Cambridge CB7 4 AH Tel: 01353 666709 Fax: 01353 666710 DANBURY ELECTRONICS "ftp ,v w ,v. mc-h-clemon.co.uk/tfansfoiTners.htm I Here you will find our mains and output transformers in Mike Holme s range of valve tube amplifiers sPP & SE). Also circuits, parts lists, chassis, advice. ) 0> EASYSYNC b ft p : /; v/ ww. e asysyn c.co.uk EasySync Ltd sells a wide range of single and multi- port USB to RS232/RS422 and RS435 converters at competitive prices, ELM ELECTRONICS ICS„C( Offering a variety of unique and low cost integrated circuits for the experimenter. Secure ordering via the web site with worldwide shipping. ELNEC ViV/w-sl nec.com ^ * device programmer manufacturer * selling through contracted distributors all over the world * universal and dedicated device programmers * excellent support and after sale support * free SW updates * once a months new SW release * reliable HW * three years warranty for most programmers ERVAN INTERNATIONAL Co. http : ~ ,YiY rV. erva n - i n Loo m Power Electronics and Solar Energy Design and Consultants. Also offers: Discount prices of: * Ultra Bright LEDs * PCB LED Cluster Kits ■ Laser Pointers * Solar Modules * Batteries FOREST ELECTRONIC DEVELOPMENT http:/ wvAYjOFed.co.uk FED supply PIC programmers. Sasic modules, and development software including a PEC C Compiler, Prog n Drop Visual Development and a well featured debugging environment. FUTURLEC http 7/www. firturieexo m Save up to 60% on ■ Electronic Components * Microcontrollers, PIC, Atmel * Development Boards, Programmers Huge range of products available on-line for immediate delivery, at very competitive prices. FUTURE TECHNOLOGY DEVICES fttp 7. : wmftd [chip ,co m FTDI designs and sells USB-UART and USB-EIFO interface i.e/s. Complete with PC drivers. * these devices simplify the task of designing or upgrading peripherals to USB HAMMOND ELECTRONICS http:. WWW , 'nammondmfg.com. saleserbar n ma nd -e ! ectronicsmut tef: 01256 812812. Small die-cast, plastic and metal enclosures for the hobbyist and professional. Widely available from major distributors. MQP ELECTRONICS •http:/ ww wmqpel8ctronics.cc Leaders in Device Programming Solutions, * Online shop » Low Cost Adapters for all Programmers * Single Site and Gang Programmers * Support for virtually any Programmable Device NEW WAVE CONCEPTS • id G „v.| p " r Software for hobbyists: * Livewire circuit simulation software, only £29.36 ■ PCB Wizard circuit design software, only £29.36 Available from all Maplin Electronics stores and www.m aplin.co.uk PICBASIC h ftp : !i ’’va'av. p i cbd s 1 c.co. u k * Pic basic & Pic Basic Pro * East efficient powerful compilers ■ Parallax stamp compatible code * Write in basic-compile to hex * 12c, 14c, 16c(f) and 17c pic s POND ELECTRONICS v 1 - i/i v nil nn ■ a ■ 4 i i i • ... J : ,U , |.-w [ » *■» -' ~anr PC16R7J 1 ,-L fraynr* "r.u. -i - - .■ ... me i— . . ■ ■ 9 £ $L tel +353-1-821-5060 fax +353-1-820-9384 Innovative systems for PJC development & embedded applications. ■ pFlash876 * PIC C Compilers & Programmers * MicroStack • Basic Stamp * Custom development Service QUASAR ELECTRONICS www. Q y asarEfe ctran i cs . coir Over 300 electronic kits, projects and ready buili units for hobby, education and industrial applications including PIC/ATMEL programming solutions. Online ordering facilities, Tel: -44 (0) 870 246 1826 Fax: +44 fD) 870 460 1045 Email: sales@OuasarEfectronics.com ROBOT ELECTRONICS h ft o wv i v , rot at-ei? c tro n i cs. co . u k * Ultrasonic rangefinders * Motor H- Bridge controllers * Magnetic Compasses * RC servos and controllers * PIC programmers and components * Electronic Design Development and Manufacturer to industry 80 Elekfor Electronics 1.2004 Iht World es getting onto Spicycle SPICEAGE AND SPICYCLE ii tip: ■ www-sp' i ceao e .co m Spicycle circuit design program (schematic drawing, well-featured PCB drawing. SpiceAge simulation). SuperRIter digital and analogue filter synthesis and optimisation. Download a free working evaluation and enjoy software renowned for Its high quality at prices that make it seem like Christmas all year round. Make contact with Those Engineers (020 8906 0155), real engineers, who will understand your needs. TECHNOBOTS http^temtechnobots.eo.uk Welcome to Technobots - the one stop shop especially for die remote operated robot builder, S radio control and engineering hobbyist. TELNET http: //www.te In et.u k co m The site shows graphically Telnets wide range of quality second -user test and measurement equipment including oscilloscopes and spectrum analysers. ULTRALEDS h rip it / www. u lira 1 eds . co.uk tel: 0871 7110413 Large range of low cost Ultra bright leds and Led related lighting products. Major credit cards taken online with same day depatch. USB INSTRUMENTS http://wv/w.usb-i ostium e n ts.com USB Instruments specialises In PC based instru m e n tati on prod ucts and software such as Oscilloscopes. Data Loggers, Logic Anaiaysers which interlace to your PC via USB, VIEWCOM http :■ www.vi e wco m .19 .co. u k tel: 020 8471 9338 fax: 020 8552 0946 • Mail Order supplier of: • Integrated Circuits and Components. * Kit and parts for Elektor projects, * Transistors. FETs f Capacitors, Resistors, Crystals, etc and hard to find devices. Viewcom Electronics, 77 Upperton Road West, Piaistow,. London E13 9LT 1 2C-Q4 | f l i I l I I t I I I I 1 I I I I I * l 1 I I I f I I I PROMOTE YOUR WEBSITE HERE Elektor Electronics have a feature to help customers to promote their v,eb>hes. Net Links - a permanent feature of the magazine where you will be able to highlight your she on a regular basis. * For \u>i £120 + VAT (£10 90 per issue for eleven issues) Elektor will publish your company name, a 25-\vord description and y our v. ebsite address. * For £300 - VAT for the y ear cL2 7 .2 _ per issue for eleven issues l we will publish the above plus run a 3cm deep full colour screen shot from your site. Places are limited and spaces will go on a strictly first come, first served basis, please tax back vour order todav! r m- I wish to promote my company, please book my space: * Text insertion only for £120 + VAT * Text and photo for £300 + VAT NAME: .ORGANISATION: JOB TITLE:., ADDRESS: * ! . TEL: i PLEASE COMPLETE COLTON BELOW AND FAX BACK TO 00-44- 1 0 1 1 242 226626 | COMPAN Y NAME [ WEB ADDRESS...., [ 25-WORD DESCRIPTION 1 \ I i .. . I I * - - | I * — - - - - - i I ELECTRONIC ENTHUSIASTS Only one magazine tests its projects and circuits in its own lab beforepublication - ELEKTOR ELECTRONICS THE ELECTRONICS & COMPUTER MAGAZINE Contact: Worldwide Subscription Service Ltd, Unit 4 Gibbs Reed Farm, Pashley Road, Ticehurst TN5 7HE Telephone: (+44) (0) 1S80 200657 Fax: (+44) (0) 1580 200616 Or visit our Website: www.elektor-electronics.co.uk 81 Elektor Electronics SNEAK PRIVFW Next month in Elector Electronics Start Developing with CPLDS This article kicks off a short series covering professional applica- tions of CPLDs Complex Programmable Logic Devices). In true Elektor style we start with a hands-on example: a digital rev counter based on a G?LD type 7128s from Altera. iAccess Intelligent Access Control System Using I -Button devices from Dallas as the key com- ponents (pun intended) we developed an access system to help you protect your home. The system allows two entrances to be separately protected. In addition to a door opener driver there are also a couple of relay outputs. The system is controlled using an LC display or a remote PC (connected up via RS232). Trie serial link also allows the access sequence to be given a certain protocol. Simple 12 -to -2 30V Power Inverter Tnis tried and tested, short-cir- cuit proof inverter employs a dead normal toroidal mains transformer and offers a lot of power given i:s low complexity and minimum component use. Also... PIC Based Digital Alarm Clock. SMD Valenrine Heart. Bascom AVR. To u ch- Control! e d Swit ch . Battery Polarity Protection. RESERVE YOUR COPY NOW! Tfee February 2004 issue goes on sale on Friday 23 January 2004 (UK distribution only). UK subscribers will receive the magazine a few days before this date Airicle titles and magazine contents subject to change. NEWSAGENTS ORDER FORM SHOP SAVE / HOME DELIVERY Please save / deliver one copy of Elektor Electronics magazine for me each month Name: Address: Post code: Telephone: Date: Signature: Please cut out or photocopy this form, com- plete details and hand to your newsagent. Elektor Electronics is published on the third Friday of each month, except in July. Distribution S.G.R. by Seymour (NS). Index of Advertisers Autotnx .............. .... Mww.zmif 2 xsdE. coin .64 Bets Layout. Net Links A\w*v.pcB~p3nLcQfn 6* 80 Tv Teriv.c zti LID. Net Links .20 CHS .iV//V/.C#7JS.i,VCOjT7 . .6 Gomcwcut, Net Links .... ....... Avy.vy.cainpuiutidtsxom .30 ConfbRi Etectrories, Net Links . . ww.£0:r[Qtfefec :: uk .................. -SO CmSdewood 21 GfGvmM Net Links wvv* row l CO. W 10. SO Dir. bury ............... ...... .siv-iV. rx-.i. cennm.CQ.uk ................. .80 Display BectoM&cs jvw^sfci.eo.w 27 Easy$yn& Net l Ms ............... .ww bss) syrc.co.L < .80 ELM Electronics Net Links, .......... BO Bnec, Net Links . Wiv.e ; r,$c.cc ! n .SO Bmmi .............. ..... .6 Ef van, Net Links — i SO FdiesL Net Links ^mfomfeot K .................. .80 Future, Net Links ................. jAWAJinuKec.com _ .30 Future Technology Devices, Net Links . , jwAYM&cti&corn ..... ,30 HanvrcxH) Electronics, Net Links ...... .mvxhsmtTxndnigxQm ...... ....... .30 Kb ZV. wM&xomk- dxcEd ................. .20 OP .ivv/iY. itp 10l.com ,20 Kit Bafiio Company JicmstG'ATs.ssLEo .:.' ■ ■ rst x: ...21 Matrix tfuitimetiia Ltd „ . jo vw ;> 'sif^m&imsci's-coxr: ....... .21 MifOflf Instruments — .i vhta: m r ; sLd£mnnxo.Lk ............. .9 MOP Efecfrontcs, Net Links .......... \m.mpqsiecirjsn ss.coT: BO Net Links M. 81 New Wave Concepts. 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Net links .......... :awa: ash-miR; m&ts. com .81 View cornu Net Links . .f9xo.uk — 81 ADVERTISING SPACE for the issue ci ITFeteBry 2004 may be reserved not Eater than 21 January 2004 with Beklor Oectronlcs (Publishing) Advertisement Office - 3 Crescent Terrace - Che tier ham GL50 3?E - England - Telephone 01242 510 750 - Fax 01242 223 626 - e-mail: ■ cat ■ to whom a correspondence: copy instructions ami artwork should be addressed. 82 Elektor Electronics 1 2004 • .r TM The universal U/O solution DataStation's 16 configurable channels provide 391 different I/O configurations and >500 samples per second, allowing it to adapt to virtually any application. 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