i j f i T yi 1 | | I ilt: 1 Mm TEm 1 L • 4 w r'} 1 * ^ ijtgy (ji" 9 A The leaders in PIC development All you need to get started with PIC lnH " ctr v/ standard/quality board upen the box and get coding Available with C compiler or_ use our PicScriptto write programs using i ft. «- NO ASSEMBLER, NO COMPILER, JUST WRITE AND RUN SCRIPTARIUTY PicDev Board with PicScript £99.00 (plus p+p) This is a complete development suite for the novice or non programmer. It is shipped with: . PicDev Board . PicShell and PicScript software . Breakout board . Cables . Example scripts Both items require i o order* • PC with serial port available * Po we r supply adapt er ww wypa g nr co.uk PicDev Board with C Compiler £165.00 {plus p+p) This is a complete development suite for the more advanced programmer, ft is shipped with: • PicDev Board . PicSheli and PicScript software C compiler . Breakout board • Cables . Example scripts ICD1 saIesgpagmxo.uk Tel: -44 (0)1^92 S91927 DrDAQ Output r*f OrOiO Temperature External sensors: Humidity Temperatun 02 In Air Reed Switci under £60 • Low cost • Built in sensSrs for light, temperature and sound (level and waveforms) • Use DrDAQ to capture fast signals • Outputs for control experiments • Supplied with both PicoScope (oscilloscope) and PicoLog (data logging) software For more information on DrDAQ, please visit: 1 www.picotech.com/drdaq110 Scope and spectrum analyser functions A fraction of the costpf benchtop scope Save multiple setup^ for ease of use... Save, print and e-mail your traces ^ FREE technical support for life \ FREE software and upgrades t Automated measurements l Itfrfua/ Instrument For more information on our scopes, please visit: § www. picotech .com/scope230 E-mail: saIes@picotech.com Tel: 01480 396395 Fax: 01480 396296 II | A l^T /Research www. a vitresearch.co.uk TO MARKTHE LAUNCH OFTHE 1 2 C BUS TOOL WE HAVE AN EXCLUSIVE OFFER TO READERS OF ELEKTOR EC' or SMSib Monfejring up To 400kHz * wy/w. a vit rese arch.co.u kc'e ! e ktc r. ti tm : r costs Be+Tor 1 i,r°- c^^rr-g AVIT Research also supply: l 2 C Bus Monitor * Aliev, s ur PC lo n o: no- -he AC V 3 si ar traism U end isdev d Et.c ii . - Tr ■ ,±- I - Seisd or optional USB connection 5 : < S' - ! 3 3v cprrqjglsbte : v ' no pcv, er supp ■ required Easy to lt5s Hypef-Temkreal imerface- “t- Frtere Message address colours ACKs MACKs L'SSEjr S : 5vfi L jTf-jr .rr ;1 WititfEHS Scfhvsra- DeveSopet'-s Kftmdi&eu Prssve erf the 1*0 6 us X&03 £ ifv 00 USB to TTL Cable - c :-n.neci > l level drcu :ry *o . - _ E 5 ■ ■ ' H~r Er: " _-EE -C-r^S- SuC'PF&d .'.'U: F£. C: r"!£--fA.-j= 35 a sfeijJ deVlCe f4 for cqRnecZjng iT^ocori±no^iSi and legacy serial devices to yoyr F ” _ SB port RS232 to TTL Cable - Connec: TTL lei. ei Ire. ir v 10 RS232 * interface ffseffStjZ pen to TTL serai wim ens amp^catte www.avitresearch.co.uk info@avitre5earch.c0.uk I . -f44 (0)S70 741 3536 free-pcb-software.com Swordfish* PS40f-' 10 Ha nd HtW USB Oscilloscope ~i ~ : -Ji: Ac- - e : _ r: ; .-*i !-» -? =±12 . ■ iee-=L _ _ — fen ala r-.is k 3 ■■-e=.er= 1 -- ? si - :; e i TU , nLtrv:-a-riL PSttHiQ 'hP_r±i = rv£j£±l±-* fr-±=L^.- ipf'.-® pfCii . _ :z *r^±i an :< _hl! — inl-r ever- 5 — i l s~ -A i — 7 -* 73 = instruments t« o iT-i« :j .“---Eii a wr.u ; -..-j. jrz=>is ar bk «£*« w tt$±rK. ?s*ini0 7 a a =i±±a me* susswc* mo tti *' J ULP - J . m - RJM Tti Sn , jyEid YT)S4ati CLLi ulewi 5= p-mv ta t_ J ±± n ±=,--± A!v_ i " '4 i ;--T— 'T -3j»i CE r: L~.i tprrri ;n : i-t -aa - irr^rt SAordftsfi* PS4QB10 Feaiufesr + Shipping Et VAT Str:-Gra> ' 0S1M1Z CjbI Cnannel Os-UU escape, 5=gFT3l S MuiU- Function InsUumen-. “Stingray' 051(412 Features Technic I Infcr^isj.on r-ZZ =E=±_-2l tl — “11 — J ^ -- .-■ ± J v “». e>ii=l i » j t aKut - cr-n C7 1 Sal® Information AS? -f^n. - rn n V ••■■= i±= .11 Sie-ii-e: iieer. 6 Q= u <_ Tr - 3!4j 413 flisi fee :1*I41?-5I10 i. ■“■ L : E' S §CCE'f 2 *--= Cl _ t I , t-1 ■ H-B i±i rl r K. L - . l D.; Chi — r- iLr-.it-: EM ~ : :t~ - en:~ II i ■.- _■ iar. ti_t t:T =i ~ . i ■ - r. :r cr i-tij ;-n =i ri: r { rtprt t. -’ t JH S* A*S rY St^ia] G-tr-CjA<*. J Ertan .=1 T. ^ .cr ^ j ±i ■ . , i.i .:= ±;t - &: iLiir-l -7 £;i: — - : ■ r. : : : — i i ~i: m . — :hi t-'il-: n!?ii. at t-~i f ‘ f Ft nfi-ri .“7= T-:rT , :r? - -- r I-t— : F=^: Tf- . , r ; l;n fKf tic- ai; ■■ 5 :-—e e ss - i-i-irT: 7 . 1 . cc-i F:pS*P5 V Handyscope HS3 2 cm Resolution Menu - 12, 14 or 16bits Sample Rates - 5,10,25,50.100 Ms/s models / Oscilloscope / Spectrum Analyzer / Voltmeter plus! / Transient Recorder / Arbitrary Waveform Gen. / Two hi-z probes 1:1-1:10 / USB 1.1 or 2.0 / Windows OS- all iTp Ltd 28 Stephenson Road, Industrial Estate, St Ives. Cambs. Pe27 3WJ Telephone: 01480 300695 Fax: 01480 461654 info@itp10t.com www.itp101.com www.tiepie.com 4 elector clKtTc^ia - 12/2CD4 - » Components From the mass of emails we get with comment on the component selection in our published circuits we can only con- clude that mony of you think along with us. In many cases, the components referred to ore no longer available from local retailers [if they still exist). Both in the industry and the retail trade, the distribution of electronic parts has changed radically over the past few years. Apart from lots of standard parts Elektor also employs {relative} newcomers to the market. We do this whenever we feel a nev/ part repress nts a better solution to a problem than one that's been around for some time,, or, indeed, can be classified as an old-timer . After oil, our readers are interested in better solutions while at the same time learning about tne latest developments. On the down siae, components may not be available locally anymore os on-offs. These days, people con buy nearly everything on the Internet, All known electronics mail order campon ies and distrib- utors can be reached via the web and in general supply at very short notice. Looking at Lhe trends on the web, it appears that new on-line electronics shops pop up every day. Likewise, you can now watch all the leading semicon- ductor manufacturers set up on-line shops with a direct supply line right down to individual customers. Nov/ isr/l that shopping paradise for electronic parts? Not so, apparently. We receive lots of complaints about minimum order quantities and shipping charges. The (after 1 find a bit surprising considering the cost of fuel and parking tickets if you use your car to get to a retail store. On the other hand, I too have to admit to hesitation if I really would like to order something but the small print says £3.50 far postage and packing. However, such doubts are not rational. If you drink a pint in the pub, surely you do not spoil the fun by thinking that the same amount of money could have bought you five times os much conned beer at the supermarket? Tne moral of my story: we have to live with the constraints imposed by the changed distribution of electronic compo- nents. However, [ am convincea mai we now have access to far more and more modern parts thon in the past. Make clever use of if and do not be put on by the changed price structure. Karel Wolraven, Head of Design Department f3lektor L. ~ E lectronics Volume 30 h Number 338. December 2004 ISSN 0268/45 ! 9 Ekktm Electronics aims at inspiring people to master elec- tronics at any personal level by presenting construction proj- ects and spotting developments in electronics and informa- tion technology. E^ist s profiled and pubisfi ed by BeiOfx Ekctranks RO. Box 190, V/efe TN5 7WX fegand TeL; f+44) (G)f 5SO 2130657, fejc, (-1-44) (0) f 5BQ 20061 6, -J,;, The s avs iabfe from bookshops and eJerirortecs out* ^ cr o' ^tecTTpobn EMlst fedTDfXS h II bres a y=ar Wth ontjjb kq ^ fry- ^ ty ft Afjgjst Under itse t^siar 3d ■ the ni^zaie is gwo ptJJjgjptf n G&m&i 2nd Dusdi , Tqpeiher v*sEh fraftd&saii ecg&jra ihe magazine is on i _ inrerc L"z- 50 cournies international Editor >'sz ■ c---:e z _ - Editor: jl ~-tng zz J _- ' - - v ~. ■ - ;z International editond stiff; H-ry Bagger Qavxi Dsamert. F^G&^mfori Ems. ■ r e— -e ■' Qu- 3 = ederz _ z - Design staff; K&id fpd of tfesjgi). Ion G issbe i F^if Gbosssis. — - t=nrr^4 - Editorial isecretariat: - -sc.-. f — £ ■ - e-\ezz -:i , ” : r--_ Graphic design DTP: 5_ — - Giei Dob Managing Director Publisher: Rez >-.■+=— CirtuUtion Cnfriml: r^-T Zzi- z^*- ■ ■ *_ r , V Subscriptions ■ Verfe 5 j!s. - r* z r 5f s ltd. _ — ; - Gi&s Read Farm, Ftehtey Roe : — TN5 THE B^ird- ■^^^(>44)0)1.5^1100657. Fac (+44) (D)J 53021)06 Ems '■■'■££ ~ jj fetes and terns arc the Sutecnpticai Order Perm Head Office !:-E^TkErit b.v. PO, Bex 75 NL-6i9QzAB Ee^c The Neihafends L£: : - -Z-ZZ+™ r z- G - ! - Dirtribuiion: Sewr-c^r “ E.ev- F 2«.C fVg^pn UK Advertising " f — EZ“ 3 C'EZZE - : "fences 1" "t _ ^e" GLEy V?E, z r ~:E'c { +44) (0) 1 242 Si 0760, fee (+44) (0) 1 7+2 226626 t-TlcJ L-' ..“1 E‘J 1 _-Z ' v 13 _ ■ Ih-z'LI -.r E"7 IE-— ^ Z. z zz+ or. Internationa] AdvenisiTig ' Ie-Zz--- :■ ■ , •; ■ E3 Z ■ -1 - - zE3 I “ _3 iz“ £ = ,- +-ides ■: t I'-JJL-" ■ ■' l -' _ .e~e"£ e:el zz:; te- e e,e EE 1 z z- - "ez-EEi Cop/nght, Modes The uu^ tss£TS)cd h its ma^zsie hr dsjfnesSc us «!#y. JJ phcsagraiJs, wept bOKtJ 6 t7^s; d teu5e, CD-PO' F zzz.rZrz lZz. rsE s-q criiuc: rz=ii t?± ~ zz n arcoefead rrgpsba fa t te r t h gr dird-paT/ fTieiis>=re OAT>wr b.v. aid rray nci re rqrojljtzri cr ~m 3^ ibrm or !?>’ =ry wem S^riigan oabadii^ srvvhofe or in oar* wlhbUt pricr pernieacn6t+n the Stgfi ^ H n3£f> ptrrraEsoi rrest Eho oe ct-eirad wy parr ofdis ^itjorai & a. d 3^ fs^ye. NftWt pro^zrerk majr esgt si losses of o evks. asc described tn zti t rrag=ak'£. Thr RjUaijer bos roc *br fd&h' fn kS&tifsxh p^Ecfs) or "7' : ' : zre-z-zr The sirnsszri d dsfzs qr E-tde rndls iaenvsson tr Fu 33 Erer the tec =d ds^i. k&z lhe testotbt ji other Segnat piJbksasrE and Tha ze^"'c! Ezirzr'^eiz z - . _ z z z= e...L' - tied fe +e — © Segment b*v 2004 Printed m the Netherlands i 12/2504 - tl-klcrr daflfcnits 5 Home automation does not stop at remote control for audio & video equipment. Although an increasing number of manufacturers jump the bandwagons called Home Automa- tion and Smart Home, there are no signs as yet of a real breakthrough 'for the millions'* The l 2 C bus has been used many times to provide a simple connection between a PC and home-built circuits. This often made use of a simple interface con- nected to the parallel port of the PC. This now seems a bit dated, so we've designed a USB/I-C interface for you to build. This flashing LED mini Christmas tree is not only dead simple to build but the design is also repeatable and very reliable in operation. In fact an ideal lost-minute project to brighten up the house or office in the run-up to Christmas. Informative Articles Regulars 1 2 On the Buses 5 Foreword & Colophon 1 6 Back to the Future 8 Mailbox 10 News & New Products 69 Retronics: Heathkit TC2-P 78 Guizz'away: Wondrous Light Chain 82 Readers Services Cumulative Index 2004 84 Sneak Preview pp. 74 - 76 84' Index of Advertiser Volume 30 December 2004 no* 338 MALL CURCUmrS COLLECTION 5 volts from the Mains 28 Attitude Sensor 20 BTX 27 Car Central-Locking System 26 Dimmer with a MOSFET 24 Direction-Sensitive Light Barrier 22 Discrete Robot 25 Flickering Light il 35 High Voltage Amplifier 1 8 ! 2 C and SMBus 29 « HR Tool 36 IR Multi-Position Switch 40 IR Transmitter with HTI2E 50 LM4096 Boomer Audio Power Amp 41 Low-Drop Constant Current Source 46 Model Railway Short-Circuit Beeper 42 Mod ern SMD Packages 48 Negative Auxiliary Voltage 2 1 NiMH Charger for up to six Cells 32 On/off Button 3 1 On-line Conversions 39 On-train Radio Camera 33 Resistor-Equipped Transistors (RETs) 43 SATA 47 Simple Audio Peak Detector 37 Stable Filament Supply 49 Thrifty 2-Hz Clock 38 Universal Mains Filter 34 Unusual LED Blinker 30 Voltage Mon i tor 38 Bold article title = includes PCB tayouf Construction Projects 52 l 2 C / USB Interface 60 l 2 C Home Bus 70 start here: Continuous F|ow Soldering Voltage Regulator Calculation Power Supply for USB Devices 72 kitchen table: LED Christmas Tree We thank all ^ readers and adver risers for the*. « tinued support dur in§ the past yea and wish therm happy ■ and peaceful 2005 . * iicilbox Message from South Africa Dear jan — in the April 1980 issue, which was devoted to Automotive Electronics, Elektor published an Intelligent Windscreen Wiper Delay' circuit This used about 8 ICs, not least of which was a 2 1 102 memory! I built two of these over the years, and it was quite ihe cleverest and most useful device of its hype I have ever encountered. The only change I made was to extend ihe delay cycle to up to about 4 minutes — very handy in my country where we don't get o lot of rain! Unhappily, many of the devices needed are no longer available, not least the 21102. Even getting the origi- nal ones was a problem — I had to go all the way to a side^street electronics shop in New York City to find them! I know you published a sort of update a few years back, and I have the article in my files somewhere, but os I recoil it didn't do quite what the original had done. And in any case it too is probably out of date by now. So my question is this — is it possible that you might come up with a 'modem' version of the 1980 design? It can probably all be done with a single PIC 1C these days, far all I know! I think the new Elektor style and layout is just great! Not that there was much wrong with the old one, Chris Graham (South Africa) its wonderful to see how readers of this magazine cherish designs published so tong ago they ore no longer remembered by any- one on our current staff. A possible source for (long obso- lete} RAM chips like the 21102 are the spare pans suppliers serv- ing the vintage pinball machine and arcade game communities . I'm sure the Internet will enable you to get in touch with a trader. Your request for a PIC based windscreen wiper control has been copied into cur design lab. Sometime next year we will pub- lish on issue focusing on automo- tive electronics and maybe a suit- able design is ready by then . Connector parts Dear Sir - — Ive been an avid reader of Elektor since I was a young lad the mid 7G'$. I've followed the changes in style and presentation over the years and must agree that the present new look is on improvement, if one can improve on perfection! The two photos of some sin- gle wire connectors illustrate the problem I am having. Whot I am trying to find is single connectors like those in the two photos, on a 0.1 " pitch. These can be connect- ed to flying leads and plugged up to 0.1 headers os illustrated in any combina- tion so desired, I know they exist, since most PC's use them to connect case front switches, USB ports and other case hardware. But try os I might, and i've phoned quite a few manufacturers as well as the usual suppliers (Farnetl, R$, Moplin) 1 con not find these receptacles In single format. The ones fea- tured In the photos were made by cutting up multiway blacks and filing them down, a time fond nail) consuming task. Do you know where on earth I con get my hands on some of these. I know of several other users of Atmel boards who would like some as well. Any ideas, please? Richard Austin Readers having information that could help Air. Austin are requested to contact the Editor Meanwhile. Lvc Lemmens from the Elektor lab tells me single 0. 1 - inch pitch receptacles can he cut off strips of the type shown in ihe photograph. As there is no clamping mecha- nism , fhe wire end needs to be soldered and then protected using heat shrink sleeving. Probing around Dear Editor — recently 1 hod o problem here at work, moni- toring high frequency digital quartz clock oscillators. I needed to adjust each crystal loading capacitance and absorb the board strays to bring the frequency in toler- ance. Some of our crystals are accurate to 15 ppm and the highest frequency is 54 MHz. Without thinking enough I had used o Tektronix 500- MHz, lOx passive scope probe feeding an 8-digit 2GOMHz frequency counter. For accuracy I used a Quartzlock Off-Air standard to give me a precision 1 0 MHz reference source for the counter traceable to NPL. However I didn't spot the 8- pF loading of the scope probe! Consequently my results did not agree with our RF team who used their Agilent 89441 A Vector Signal Analyser with a 'snif- fer lead held in Ihe vicinity af each dock circuit. Hence their loading of each oscilla- tor was negligible, resulting in my readings being around 20 ppm too Sow! Problem resolved by using a new Tektronix TDS57704B, 4-chonnel digital scope. This gear happened to be in ihe lab on evaluation. Tektronix have wisely brought out one of the 4-channel analogue signals (prior to digitisation) to the front panel I was then able to use one of their active PET probes and con- nect the frequency meter to the scope analogue output. Hence around £ 40k of active probe! This resulted in the loading error compared to our RF team's measurement closing to around 5 ppm worse case. An alternative to tying up the 4:,:c r snoz r C arcxnnErr LagP.J rt-JE -1-rt E2C | Ziif — r f i— Jj! find it at, among others, www. m odu I -bus . de /m bne ws / mbn ew$02Ziso. h frrt . Open the [parameter' menu in the fop left-hand corner of the screen; next select the COM port and then DK7JD . (Mr. Vooys has since advised us by email that this solution worked perfectly , Ed.) [screendump 045080-62] lost Bt Found Dear Editor — A short time ago, a friend brought to me a power supply which, he said, 1 had made for him some years ago. Frankly, 1 has no recollection of so doing but at is bore oil the hallmarks of my mechanical handywork, I accepted that what he said was true. He had connected the PSU the wrong way around to a battery. It no longer worked; would I repair it? Clearly, it was on EE project. Buf when was it published? The only clue was the code mark on the PCB. 1 sent this to you and asked if the year of publication, at any rote, could be given. Within days, a received a reply by email giving the year, date and page number. I looked up the article and have been able to repair the damage (blown frock ond a projection diode shorted). Again, thank you for your excellent service. I continue to enjoy your magazine and like the new format. Edward Benson/ G3MUX Credit is due to our Editorial Sec- retariat who traced the PCB num- ber [ 98C024- 1 ) to the respective arii cle ( ‘ Va nable Po \ ver Supp ly , A]orch 1998). Anyone con do this, however. Finding past arti- cles by production number PCB and/or software item number has been a standard feature o: our fl? ( Elektor Item Tracer) for over 1 0 years as well as of the search engine implemented in our year volume CD-ROMs as of 2003. Both products should prove extremely useful to owners of complete year volumes of our magazine. The EfT starts of 1 985, the CD-ROM engine at 1 996 . MaiJBox Terms - Publication of reader's correspon- dence is at the discretion of the Editor. —Viewpoints expressed by cones- pendents s-e not necessarily those of the Editor or Publish sc - Correspondence may be translated or eolteo to; length, c'arity and style. - When replying to Mali box corre- spondence. o'ease quote Issue number, - Please sene your Mai Sox corre- spondence to: editor @etakSG r-ef ectr a n Ics-CQu k or Bektor Bectronics, The Editor, RO. Sox ISO Tunbridge Te e TN5 7-.VC England. 1 2/2004 ^ eiektar efettrcrla 9 news & new produ cts Diagnostics and Development Tools for SMBus and S 2 C AVIT Research Lid. has released a low cost DC Bus Too! for the diagnostic and development of embedded system SMBus and HC communications. The Tool combines ease of use with com- prehensive facilities to monitor bus activity and powerful func- tionality for participating on the bus. Messages can be sen! and received as either Master or Slave on Standard and hast Made Busses. The Bus Tool complements AVIT Research's existing Bus Monitor and RS232 products. The bC Bus Tool provides a sim- ple means of examining and interacting with bus traffic on an |2C or SMBus system using a standard PC — without the need for external power supplies or the installation of driver soft- ware. It provides a user interface via the HyperTerminal applica- tion (supplied with Windows). This interface allows messages to be composed and sent when acting as a bus master and to receive data from slave devices through the master receive func- tion. The interface also allows the l-C Tool to be configured to act as an 1 2 C slave device to automatically receive data and respond to requests for data from Master devices on the bus, I-C messages can be colour ceded according to the l-C device address and timestamps can show the time of each mes- sage with a resolution of 1 ms. Filters can be applied so that only messages for devices of interest are shown. The supplied Windows Software Development Kit (SDK) provides an alternative to the HyperTermi- nal interface far writing custom software using VB, VBA, C/C++, Delphi or Java, The SDK gives the programmer access to all the functionality of the PC Bus Tool and using this it is possible to emulate slave devices such as EEPROMs, ADCs and DACs. Example code and applications are included. The Trigger connection allows an oscilloscope !o be triggered in reaction to □ sequence of bytes on the bus or to act as an input where transitions an the probe are shown as time-stamped events within the PC data. The PC Bus Tool is packaged as a standard size 9-pin D-Type connector suitable for connecting to a PC serial port. It is supplied with approximately 0.6 m of cable with four probe clips for connection to the PC system. The connections are Ground, PC Clock, PC Data and Trigger Features: — Monitors bus traffic an SMBus' or PC systems at up to 400 kHz (Fast-Mode). — Master Transmit and Receive including Repeated Start Requests. — Slave Emulation - Slave Trans- mit and Receive (Ack of Data bytes). — Multi-Master Bus Compatible. — Trigger Line provides an output to an oscilloscope or can be set to an input for timing events. — Shows acknowledgements (ACKs) and negative acknowl- edgements i'NACKs). — Connects lo standard PC serial port or USB to serial adapter. — No power supply required. — Compatible with 5 volt and 3.3 volt Buses. — Compact; all circuitry is inte- grated within the D-Type con- nector. — Con be used with standard ter- minal programs supplied with Windows or Linux. — Supplied with Windows Soft- ware Developer Kit that pro- vides l-C functionality to VB, VBA, C/C++, Delphi or Java applications through an OCX. Help and Example Code included. The l-C Bus Tool including Win- dows SDK is available directly from AVIT Research at only £ 250*00* AVIT Research ltd. Compass House, Histon, Cambridge. CB4 9AD* Tet (+44) [0)1223 257758, Fax [+441(0)7092 111293. Email; l2c@avitreseflrth.co.uk Web site: www.avrtresearcfito.uk ;.:+7 r . Process Interface for Electrical Drives LEM has introduced the Pll process interface for its NORMA power analyser family. The inter- face allows measurement of up to four speeds and torques simul- taneously quickly and precisely, and can calculate the mechani- cal power. The NORMA analyser measures the respective electrical power far the calcula- tion of the efficiency under dynamic conditions. It Is not enough lo measure the efficiency in a steady state, because the biggest losses usu- ally occur during the starting and stopping phases of the drive. Therefore electrical and mechanical power values must be measured very quickly and, above all, simultaneously. This can be achieved with LEM's NORMA 3000, NORMA 4000 and NORMA 5000 analysers. Mechanical powers are sampled at 34 kHz; electri- cal values at either 1 1 3 kHz, 340 kHz or 1.02 MHz, according to the model. Through the eight inputs for mechanical values, the system can measure multiple motor sys- tems or conduct measurements before and after transmissions. The efficiency can, therefore, be measured with a single measuring instrument. LEM HEME Ltd, 1 Penkelh Plate, West Pimbo, Skelmersdflte, Lancashire WN8 9GX. Teh +44 (0} 1243 531123. E-mail: eflp Slem.com. Website: www.lenuom C47 -? : 10 efeklor detfrorucs - 12/2004 Extremely F Turnaround! IAD our free CAD software mm your two or four layer PC boards -I... -=- ■ ■ ii — - ■ — , m HQ us your d esign with just a click CEIVE top quality boards in just days Layout Software mf flfir b;t.- mu mum hr ^53 ,::il it-v ii Nfcfc h-a r :ot o8 oo- 3 ® Smptf sand your Oks ond order QHUHt WWW. PCS- oread j .inii.- w i 1 SERVfciNG Your Complete Prototype Needs FREE srLT In* 7T--.r O Prototypes st a faction of the cos! •O Too-mg snd setup titiudsd 0 Any contour O Fr 4 L 6 nvn, 35 fim Cu O In Pus try sfmfard qua-; ty O Folk)!'/ up series runs O GAM / CAD consulting E UROCARD Krr* + Tooling + Phofoplots VAT £ 29 . *SlBftng rate may way. ftra = Extensive I/O:- Serial, rDA, SPI, PC, Analogue, imers/Counters, RTC, etc • Large Memory Capacity Flash, SRAM, DRAM. •Supports:- J* . Mom & Colour LCD's, |k Touch Panels & Keypads, Verv Low Power. Si ‘C’ compiler, assembler if oil WinrliMjirt'IO Ktoa^ I r " W tio. E r all Windows32 baseu. >urce Level Debug. Driver Support with V Libraries. ITime Multitasking OS with i free run time licence. EE Unlimited email support./ >jT’i i rjfl m2 f {ffl JfiBpj 1 ( . 1 “ . 1 ! L . m JL— =• Jf 1 j 1 | >] 3 i www. cms. uk. com see our web site for full details CAMBRIDGE MICROPROCESSOR SYSTEMS LTD Unit 17-13 Zone 'D' Chelmsford Rd. ind. Est. Great Dunmow, Essex CMS 1XG Telephone: 01 371 875644 emari: sales@cms.uk. com 12/2004 - ekVfci d Miron Jg On the buses David Daamen Being able to control a TV or a stereo from the comfy chair is taken for granted these days. However, home automation does not stop at remote control for audio & video equipment. Although an increasing number of manufacturers jump the bandwagon called Home Automation or even the Smart Home, there are no signs as yet of a real breakthrough 'for the millions' . Allhough several systems are currently available on the market to automate various functions in and around the home, the large number of different, competing, stan- dards and proprietary developments is a large stumbling bock on the road towards the Home of the Future. tn an earlier issue we wrote that developments in home automation were being slov/ed down by the possibilities and impossibilities of facility engineering ('Home Bus Sys- tems', E/ektor Efecfron/cs February 2001 ). Apparently, developing and marketing a compatible system is time 12 tltktor electron! - \% 2004 Last station still far off 7 6 5 4 3 2 t SOURCE Application Presentation Session Transport Network Datalmk Physical INTERMEDIATE DESTINATION Application Presentation Session Transport Network Daiallnk — — Physical M 0363- 11 Figure h Ire Open Systems Interconnect \ 05',} mod si developed by the ISO , consuming to the extent that manufacturers ore always one step behind reality. One of the main problems seems to be Flaky exchange of data between different applications. Once the main hitches have been recognised, it is often impossible to make amends at the high pace that rules in the electron- ics industry. This situation has resulted in a plethora of different protocols and standards which only seems to aggravate the problem. Lessons have been learned, however, because today the trend is not just to look at the connection method, but increasingly at the actual application. OSI the fact ihat it has taken so long for the system designers to spend time on the application is nor surprising in iiselF Since the mid-1 980s, there exists a standard describing the aspects to take info account when implementing the network functionality. At that time, the ISO (International Standards Organization) published a reference model called Open Systems interconnect [OSI), see Figure 1. A bit further on, well see that besides many standards concentrating on the actual connection and/or the man- ner of communicating, there are now also standards giv- ing due attention to the highest layers of the OSI model: the area where the actual application is concerned. For convenience's sake, we will divide the standards (professional networking and home automation) info three categories derived from the OSI reference model. The subdivision is info (1) the network layer; (2) the com- munication layer and (3) the application layer. Networking Standards like RS-485, Ethernet FireWire , HomePNA, f7omeP/ug, MoCA USB and A' 70 are primarily descrip- tions of ways to communicate over a physical medium. HomePNA , for instance, is a standard with widespread use in the USA, describing how connections with speeds up to 240 Mbit/s con be established within the home using the (existing) telephone wiring. The Multimedia over Coax Alliance has published a standard based on the some principle: making use of existing cabling — in this case, coax cabling already Installed in many homes for the distribution of (analogue) radio and TV signals. According to the MoCA, the standard is future-proof and capable of speeds up to 1 Gbit/s. The HomePlug standard now on the rise' in Europe also employs existing cabling — the mains wiring installed in your home. Speeds up to 14 Mbit/s ore said to be within reach. Arguably, wireless standards like Bluetooth , ZigBee, DECT, WiFi and IrDA also belong to the network cate- gory. The Bus Systems' inset provides links to more information on all these standards, fn the network layer, the focus is on physical interoper- ability (connectivity), hence most standards do not go beyond the first layers of the OSI model. The upshot is that such standards are nor terribly useful without agreements on how data is being transmitted and this is where the need for a networking protocol becomes apparent. Today, IP [Internet protocol) is ihe most fre- quently used. Communication The comms layer comprises standards like BACnef, Bah iBUS, EIB , E1BA , ton Works and KNX. The totter will be reverted to below. These are primarily communications systems. The standards describe the data packers trav- elling up and dov/n the network between machines (fer- 3 2 / 20 G 4 - t!^ktDF dtrfreni’cs 13 L' Figure 2. HAVr is based on a Firewire link for conveying dig tic / audio and video signals. 5*364 - T -I mi'nals), without a connection having been set up beforehand. In this context, inter-operability is crucial. One of the ways to achieve it is So agree on a transmission scheme that's not dependent on the data being sent. This will fit in very well in an 'open' system, the protocols being uni- versal and free for use by anyone. Incidentally, a system based on 'open specifications is eventually dosed of its own accord when it is used in a certain application or configuration! Application Within the standards normally associated with this layer, the emphasis is on system and application management Consequently, the main aim of the standard Is to define a so-called network-independent API (Application Program- Bus systems Network layer RS-485 Recommended Standard AN51/T1 A/El A-4 85-A-9 8 www. t i go n 1 i n e . org IEEE 802.3 Ethernet standards.ieee.org IEEE 1394 FireWire www r apple, com HomePNA Home Phoneline Network Alliance www. ham epno.org HomePlug HomePlug Powerline Alliance www. homeplug.org MoCA Multimedia over Ccox Alliance www. mocalliance. org USB Universal Serial Bus www.usb.org X10 X10 Wireless Technology www.xl G.com IEEE 802.15 Bluetooth www. bluetooth.com ZigBee ZigBee Alliance www.zigbee.org DECT Digital Enhanced Cordless Telecommunications yaav. d ec tweb .com IEEE 802.11 Wireless Fidelity (WiFi) / Wireless LAN wv Av.wl-fi.org IrDA infrared Data Association vA-Av.irda.org Communication layer BAG net Building Automation and Control Networks www.bacnet.org BatiBUS BatiBUS Club International wvav. batibus.com EiB European Installation Bus VAVW.eiba.cam KNX Konnex Association vAsw.konnex.org La n Works Local Operating Network Works wv/w, ec h e! a n . c om Application layer CEBus Consumer Electronics Bus www.cebus.org Modbus Mad icon bus www, modbus.arg PROF IB US PROFIBUS International www p rofi bus.com HAVi Home Audio Video Interoperability wvav* havi.org EHS European Home System www, s m a rth om e fa r u m . co nn OSGi/RG Open Service Gateway Iniriative/Residential Gateways www.osgi.org Salutation Salutation Architecture www. salutation, org UPnP Universal Plug and Play VA*Av.upnp.org 14 elcklar dHfronks - 12/2MM mlng interface). I his category comorises standards like CEBUs , ModBus, PROFIBUS , HAVi, EH5 t OSGi and UPnP ' Whereas CEBus is used predominantly in the US of A, initiatives like HAW and UPnP refer to truly global devel- opments. You may already have heard of UPnP, the con- cept of plug-and-play being familiar from She Windows/PC environment where it is fully integrated in the hardware and software concepts. Far clarity's sake we should mention that there is an amount of overlap in the categories mentioned. For example, certain standards from the network category ore often complemented with solutions for management and control. The opposite also applies where a certain medium is sometimes chosen as the basis for an applica- tion group. This applies to, for example, HAW, a system with its roots firmly in Firewire (IEEE 1394] and intended as a connection standard for digital audio and video sig- nals (Figure 2). Konnex A full discussion of every available standard is unfortu- nately beyond the scope of this article hence we will pick out one we think is particularly interesting. The stan- dard proposed by the European Home System Associa- tion (ESHA) is a good example of how it should be done. Apart from supplying specifications on medium and com- munication protocols, the consortium aims at furnishing a solution that's brand-independent, auto-configuring (plug and play), modular and future-proof. The fact that ESHA, BatiBus and ElB decide to team up to form the Konnex Association (Figure 3) is sure to help achieve the origi- nal goals. Because the standard Is open and platform-independent while also supporting various real-v/orld media, we believe it will see Increasing coverage in the future. in practice So what does the future hold in respect of home automa- tion system? With a well-founded base approaching rap- idly, the possibilities are in principle only limited by our fantasy - — or that of the manufacturers, of course. Today's ability to control the TV or stereo rack from the comfy chair is just a harbinger of what vve can expect to see in a few years time. Meanwhile we have to make da with remote control lighting systems now available from builders' markets. However, this will not be terribly Inter- esting until other systems are integrated (Figure 4). Just think of a voice-controlled computer assisting you with measurement and control Functions in ond around the home, or the central heating activity linked to a time pro grammed on an alarm dock. A quarter of an hour before you get up, the domotics system provides a comfortable temperature in the bathroom I Taking ihls one step further, the coffee machine is switched on automatically when you leave the shower. Home automation may also contribute significantly to security. For example, in your absence o central system may simulate activity In the home and even text you when an alarm condition arises from intruder, Hood, high/low temperature or smoke defection, so you get an alert when you've left fhe oven on! Figure 3. Logo of the Kan n ex A ssc-c ra Hon. i Figure 4. Eventually, all equipment in the home wifi be ob/e to communicate with each other. will be discussed in a future instalment of E-Online. Meanwhile, why not have a look at what's brewing on the websites of Homeseer' and 'Home Automated Liv- ing', which supply examples of hardware ond software that allows you to start integrating and automating your home right here and now. The relevant web links may be found below. Web links www. homeroys.com www. sma rthomeforum.com Software and hardware www. homes eer.co m www. automated living, com Previously oo-j Elektor Elektor Electronics has a long history af articles on bus systems suitable for DIY home automation. The most Important contributions are listed below'. - RS485 meets CAN; two systems on one bus (Elektor Electronics October 2001) - RS232 to RS485 Half-Duplex Adapter; advantages of balanced lines (Elektor Electronics May 2002] - DO Bus; RS485 home network with a maximum of 64 terminals (Elektor Electronics December 2002) - U5B-R5232 Interface; a compact solution for missing ports (Elektor Electronics April 2003) - Controller Area Network (CAN bus); intelligent data communications in practice (Elektor Electronics September through December 1999] Do it yourself domotics With consumers watting for fhe industry to come up with proper and affordable systems, it is not surprising to see a flood of DIY solutions an the Internet. A couple of these Elsewhere in this Issue you'll Find references to a number of recent construction projects that fit in with this month's focus on Domotics. With a little Inventiveness all of these con be bused! 2004- tkkter dsdiuruB 15 Back to the Subscribers and regular readers of Elektor Electronics are accustomed to seeing circuits for use in and around the home. In many cases, these circuits lend themselves to DIY Home Automation. Around the cartoon we've listed a number of interesting projects from past issues. Burglar Alarm Elektor Electronics January 2004 p. 46 Rolling Shutter Control Elektor Electronics July/August 2003 p.30 DTMF Remote Telephone Switch Elektor Electronics September 2003 p. 46 Parallel Port Switching Interface Elektor Electronics February 2004 p. 38 Switched-outlet Power Bar wit R5232 Control Elektor Electronics April 2003, p. 32 J Sl ms w* C as 1 X Acoustic Sensor Elektor Electronics JuEy/Augusf 2004 p. 79 ' . elektor cfcClmnks - 1 2/2004 Home electronics from the (recent) past Wind Speed & Direction Meter Elektor Electronics May 2004, p. 24 Passive-Optical Person Detector Elektor Electronics February 2003 Simple Sump Pump Control Elektor Electronics December 2000 h— p, 88 Night Light Control Elektor Electronics June 2003 ^ p. 24 Remote Light \ Control with Dimmer Elektor Electronics July/August 2003 \ p. 18 ^ iAccess Elektor Electronics February 2004 p. 42 You have Mail! Elektor Electronics July/August 2004 p.57 Back copies t( you do not hove ihe magazine issues referred la in this arti- cle, conlocl our sobs office m sales® ebklQF- ebctroniG.co.uk lor price and availability of back issues of itie mag- ortne or photocopies of post articles. See also Readers Services else- where in I his issue. 12/200-t - ebkinr ebctrcsiis 17 High Voltage Amplifier Audio analysers, such as the Audio Pre- cision series have signal generators that for certain test purposes do not hove o sufficiently high output voltage. That is why we have designed this booster' amplifier stage. It provides the same amount of voltage as a 3GQ-W amplifier into 8 O. Applications For this amplifier include the testing of measuring filters cr an automatic range-sw itching circuit. The amplifier can, with o =75 V power supply, generate 50 V?, v . Sf with an input signal or 5 from the signal gener- aior. In other words, the voltage gain Is set to 10 times. In many cases the full bandwidth of the generator is not avail- able at maximum output voltage. For this reason the amplifier gain is a little more than v/har is actually required for this application. The graph shows the distortion (THD+N) os a function of output voltage. It Is obvi- ous that at 1 kHz (curve Aj, from about 10 V with 10 k il load, the limit of the Audio Precision has been reached. The steps in the curve are caused by range switching in the analyser. At less then 10 V, the measurement is mostly noise. COMPONENTS LIST Resistors! R1 ,R16,R17 = !0kD R2.R6 = 1000 R3 = IkillO R4 = IQkQQ R5 = 5kH6 R7,RS - 47kn R9,RI0 - 270Q RM,R 12 = 82 Q R 1 3/R 1 4 = 220a R1 5 - lka R1 8,R1 9 = 270 R20 = 470 R2I-R24 - 12ko Capacitors; Cl - 22 gF C2,C3 = 47nF 25V radial: C4-C7 = lOOnf [C6/C7: 1C0VJ) C8 r C9 = 470uF 10QV radial Semiconductors: Dl,D2 f D5-D8 = 1N4148 D3,D4 - rectangular LED. red D9,D1 0 = zener diode 22V L3W Ti = BF470 T2 - BF469 T3 - 2 SC 291 1 T4 - 2SA1209 T5 = MJE350 T6 - /AJE34Q EC 1 = NE5534 Miscellaneous! K1 ,K2 = cinch socket, PCB mount, T- 70 9G from Mon a cor/Man arch Heatsink, 2.5 K/W (e,g. Fischer type SKI 00, 5Qmm height) PCS, order code 044036-1 from The PCBShap 18 daktDf ehitronics - 12/2Q-04 From 20 kHz (curve B) the distortion increases slowly, but with only 0,008% at 50 V remains small even at nearly full out* pul! Both curves were measured with a bandwidth of 80 kHz. The amplifier is built around ths old faith- ful NE5534 and a discrete buffer stage. The buffer stage has been designed as o symmetrica! compound stage, which max- imises the output voltage. The advantage of the compound stage is that It is passi- ble to have voltage gain. This possibility has been taken advantage of, because the NE5534 can operate from □ maxi- mum of only ±22 V [and that is pushing it!). We make the assumption that the opamp con supply 1 5 V^,. without distor- tion. There is, therefore, 4. 7-times gain required in the compound-stage. This is set with (he local negative feedback R] 5, R16 and R17, The values are as small as possible to enable the use of normal resisr tors. At first glance, the gain should in the* ory be 6 times, but the stages T3 and T4 influence the local feedback. When driven with DC, the dissipation in R16 (R17) will be a maximum of about 0.3 W. For 15 and T6, the MJE340 and MJE350 were selected. This pair has been practi- cally unrivalled for many years. At a col- lectar/emirter voltage of 150 V, the MJE350 can carry a collector current of 40 mA_ The output stage is, with an idle current of 35 mA through T5 and T6, well into da 55 A operation. Local and total feedback requires a maximum of 20 mA, Despite this no load' the output transis- tors are well within their safe operation area. The minimum load is a few k Q. The amplifier is not short-circuit proof. If necessary, R20 can be increased to 1 k Q or a current limit circuit can be added. However, this is likely to reduce the qual- ity of the amplifier. The drivers T3 and T4 are a couple of new transistors from Sanyo. These have a considerably better linearity (hf?) and have a lower capacitance than ihe MJEs. The maximum collector/emilter voltage is 160 V. At this value [DC) f up to 7 mA may be processed (or 20 mA for 1 s). The actual operating voltage for these will in practice be about 100 V, With o current setting of 7 mA, these transistors are oper- ating well inside their safe operating area. These are derails that have to be taken into account because of the high power supply voltage, T3 and T4 are, with the aid of four 1N414B diodes, biased ai a fixed cur- rent, so It Is not necessary to adjust the 12/2004 - elektor Eledrarra 19 quiescent current. The current through these d codes is set with two symmetrical current sources to □ value of about 4.5 mA [T1 and T2). BF-series devices were selected for this application because they have even lower capacitance. Should the availability of the BF469 and BF470 prove to be a problem then it is possible to substitute ihe same devices as used far T3 and 14, ls. 25C291 1 (NPN) and 25A12Q9 (PNP) respectively. This stage is driven from the middle of D 5 through D8 f so that the opamp only needs to deliver the amount of current to compensate for the difference in current between T3 and T4. R6 protects the out- put of 1C I from any possible capacitive feedback from the output stage. The over- all feedback loop is set with R4 and R3. This has been quite accurately adjusted for a gain of 1 0 times (A = 1 + R4/R3), so the actual value is 10.09 times. R5 and Cl are the compensation network for ihe entire amplifier by providing the opamp with local feedback. Note that if you change the gain of ihe amplifier, ihe compensaiion network has to change as well. An NE5534 has Internal compen- saiion when the gain is 3 or greater. So ihe ratio between R5 and R3 musi be greater than 2. The bandwidth of the amplifier at 1 1 MHz is quite good [measured at 40 V rm5 ). R2, D1 and 02 provide input protection. R1 determines the input resist- ance, which is 10 kQ. The value of R1 may he increased, but the result will be a higher output offset. The bias current of 3C1 can easily be 0.5 pA and that explains the offset of 50 mV at the output. For most applications this value will nor cause any problems. The power supply for the opamp is derived from the ±75-V power supply using two zener diodes. This is designed with two parallel resistors so that it is not necessary to use special power resistors. C6 through C9 decouple the output stage and C2 through C5 decouple ihe opamp. The total current draw of the prototype after it hod wormed up, was about 57 mA. The 'High voltage supply' else- where in this issue can be used as the power supply. Attitude Sensor Bernd Oehlerking The circuit presented here [In two ver- sions) uses a light barrier as a position sensor. In the first version (Figure 1), the light barrier consists of an LED (Dl) for the light source and a LDR [R2] for the receiver. The LDR is part of a CMOS oscillator that generates a digital signal (pulse waveform) whose high/low ratio (duty cycle) and frequency depend on the Intensity of the impinging light. With the arrangement shown in the photo, the sensor is used together with a posi- tioner. The light-dependent resistor is more or less obscured by a pendulum, so the duty cycle and frequency of the output signal depend on the position of the actuator. If the LED and pendulum are omitted, the light foiling on the light- dependent resistor can also be used to 20 dekscr tkdnfilcs - 12/2001 directly determine the Frequency and duly cycle. The second version (Figure 2) repre- sents o refinement of the positioning mechanism. As can be seen in the photo, it differs from the first version by using a slotted light barrier. The pendu- lum that swings in the slot of the light barrier is formed by two simple sTrips of tinplate (which can be cut from o tin), which ore bound together using a cloth- covered elastic band. A bit of solder applied to the end of the strips provides ihe pendulum weight. As in the first version, the light receiver (photodiode) of the slatted light border is more or less obscured depending on t he position of the positioner. The phok> diode in turn drives a pulse generator made from two CMOS Schmift-trigger inverters, whose duty cycle and fre- quency are highly variable. A dc volt- age that directly indicates the position of the pendulum can be generated from the pulse waveform using a low-pass RC network connected to the output of the generator. Suitable types of slotted light barriers ore for example the TCST 1018 and TCST2000 (Conrad). The idea for this positioner came from working with a multi-rotor helicopter whose motor speeds had to be adjusted if the helicopter threatened to tip over. There are certainly other possible appli- cations (such as o tremor sensor) for this sensor, which is easy to build and adjust and which responds to only a few degrees of tilt with a large change in duty cycle, 303187- 2 D2 1N414B 101 5 = 74HC14 D5Q1E7 - 12 Negative Auxiliary Vol^c ge ci OmA 0m A3 T mA 2mA j.tuI 5mA rfrnA l_Ju s =*3Y JJu ft =*wv [Tju^+tsv - - i Ludwig Libertin Some circuits need o negative supply volt- age that only has to supply a small cur- rent. Providing a separate transformer winding far this (possibly even with a rec- tifier and filter capacitor) would be a rather extravagant solution. It can also be done using a few gates and several pas- sive components. The combination of gate 1C la and the other three gates (wired in parallel) forms a square-wave generator. D1 and D2 convert the ac voltage into a dc voliage. As a CMOS 1C is used here, the load an the negative output is limited to a rev/ mil- liamperes, depending on the positive sup- ply voltage (see chart), despite the fact that three gates are connected in paral- lel. However, os the figure shows, the negative voltage has almost ihe same magnitude as the positive input voltage, but with the opposite sign. If a clock signal in the range of 10-50 kHz is available, it con be connected to ihe input of iC 1 a., and R 1 and C 1 can then be omitted. TIT IT5-I 12/2004 - elektor Electron :u 21 Direction-Sensitiv OgGif Harrier Model railway hobbyists who want lo trig- ger tro in-con trolled switching operations depending on the direction of trove! often have things easy with systems such as Mar kiln HO or Miniclub Z gauge, since the corresponding switching frock sections can be actuated individually in both direc- tions. Things are different with other sys- tems, such as ihe Markliri Maxi/1 gauge. Here It's necessary to use selective switching hardware for this pur- pose. A papular approach Is to use reed switches together with per- manent magnets fitted to the bases of the vehicles. Unipolar and bipolar Hall switches can also achieve the same objective. How ever, a permanent magnet must always be present on the train to act as a trigger element. Although normal light barriers cannot be used for direction-dependent control, with a bit of additional effort and expense they can be built such that trains selectively tng- 0 e r switching operations in the desired direction. To pre- vent the gaps between car- nages or wagons From gen- erating undesired pulses, an adjustable dead time is added after the sensor. The light barrier is bosed on a flip-flop mode from the four NAND gates of o 4093 1C, each of which has two Schmitt- trigger inputs. Two of the inputs (pins 6 and 8) are connected to identical photo- transistors [T1 and T2) and collector resis- tors, and in the quiescent state when the photo transistors ore illuminated ond thus Robert Edlinger 22 ektlor iktc antes ■ 12/2004 COMPONENTS LIST Resistors: Rl ,R2 = 1G-lGGkQ (see text) R3,R4 = lOOkD R5,R6 = 4 7kf2 R7 = 1MQ5 R8,R9 = 27kQ PI ,P2 - 1M12 preset Capacitors: Cl-C4 = 10nF C5 t C6 = lOQ^F 16V radio! C7-C10 = IQOnF Cll = 4uF7 16V C 1 2 = 470^F 35V Semiconductors: B1 = B80C1500 (BOV plv, 1.5A] Dl-04 = 1 N4148 1C1 =4093 IC2 - 556 !C3 -7812 T1,T2 - BPW40 Miscellaneous: RE1, RE2 = 1 2V relay (4000), 1 -changeover contact K1 - 2 solder pins K2,K3 - 3-way PCB terminal block, lead pitch 5mm PC8 r order cede 030333-1 from The PCS Shop conducing, they remain Low. Bolh gate outputs (pins 4 and 10) are then High. IF a vehicle now blocks one of the photo- transistors (for example Tl, although the circuit naturally works the other way around as well), the signals on the input and output of gate 1C Id change levels. The output of gate IC1 c is not affected by this, even though its internal input (pin 9) goes low. IF the vehicle also blacks T2 as well, nothing changes until if has travelled past T1 . When that hap- pens, Ene pin 4 output goes High again, but the pin 10 output toggles Low. When the vehicle has finally passed both pho fa transistors, pin 10 also goes back fo ihe High level. The flip-flop Is then restored to Its original state. For this behovlour to take occur, photo- transistors T1 and T2 must be arranged such that when a vehicle passes by, at first only one of them is blocked, them both, and finally only the other one. This means that the distance between the photoiran- sisters must always be Jess ihan the length of the vehicle. When on output level changes, a pulse with a duration of around 1 0 ms appears at the input of gate 1C 1 b [pin 1 2) or 1C 1 o (pin I ]. The time constants ore determined by the timing networks (R3/C1 and R4/C2}. As a High level (generated by the obscured phototransistor) is required on the other gate Input (pin 13 ar 2) to allow the pulse to pass through the gate, only one of these two pulses con proceed further ro act as a trigger signal for the subsequent timer stage. The two identically configured timers of the 556 duel timer 1C function os mono^ stable multivibrators, and thus act as pulse stretchers. Each of them drives an output relay with switchover contacts. The time constants of the monostables can be var- ied over the range of 3-170$ using the adjustment networks P1/R8/C6 and P2/R9/C5, independent of the supply voltage. RC network R7/C8 ensures that the two timers ore in the quiescent state (outputs tow) offer power is switched on. Freewheeling diodes D2 and D4 are essentia! with inductive loads; they bypass the counfer-EMFs generated by ihe relay coils. D1 and D3 keep the voltage across the freewheeling diodes away from the timer outputs. If you want fo have a visual operation indicator, D1 and D3 can be replaced by red LEDs with a voltage drop of 1 .6-2.0 V. As the circuit dissipates a fair amount of power, a small heat sink is recommended for the fixed voltage regu- lator (IC3), to keep it from overheating. We have designed a circuit beard layout for Inis circuit, which can be fitted with components fairly quickly. Don't overlook the (single) wire bridge between C6 and R5, and ensure ihar ihe electrolytic capac- itors, diodes, transistors and ICs are fitted the right way around. The ICs can be fitted in sockets if you wish. As the circuit board is relatively large, it probably should be mounted under the floor'. In that case, the photafransistors will have to be Fitted off the board. The leads from the photoiranslsfors to the circuit board should be screened and certainly not be longer than around 1 0 cm. The values of the two collector resistors [Rl and R2) for phototransistors II and T2 can be varied over a wide range ( 1 0 kQ to 100 kfl) in order fo match the sensitivity to specific conditions. However, increasing the resistance not only Increases the response sensitivity and thus the range, if also increases the suscepti- bility fo Interference From stray light (which Is any how rather high). If you hove to deal with bright stray light (direct sunlight or fluorescent lamps in the imme- diate vicinity), you should Fit the transis- tors with lengths of smalbdiameter plastic tubing blackened on the Inside and/or 1R filters with maximum sensitivity In the rnvls^ ible spectral range of 800-900 mm. Small incandescent lamps (16 V, ? W], which naturally also emit IR light, are suit- able as light sources. IF a visible light source is undesirable, the lamps can be 1 2/2004 - thitcr detirenlG 23 almost completely 'camouflaged' using infrared filters. The other option is to invest in IR diodes: high-power types such as the SFH485 [100 mA max, 950 nm] allow barrier widths of more than 10 cm without any lenses. With suitable reflec- tors [with or without lenses], the range can be significantly increased. A value of 1 8G Q / 1 W is recommend for the series resistor. This bidirectional light barrier is suitable for a variety of tasks. For instance, one relay output can serve as a layover switch in one direction, while a train travelling in the other direction con cause a turnout or points fo be actuated. A voice recorder prepared with whistle or bell signals con also be triggered by one of the relays. Flashing warning lights can also be driven, or the relays can act as an auto- mated 'signalman' for barrier gates. Naturally, this light barrier circuit can also be used for all sorts of counting tasks or as an alarm generator in domestic situa- tions, if the nature of the object to be detected makes this possible. If only rela- tively short pulses [an the order of a tenth of a second} are needed, for instance to drive a counter, the RC networks that determine the timer values must be corre- spondingly modified. Photoresfstors in miniature packages can be placed so close together that entomologists could even use the circuit to count exactly how many bees or bumblebees fly in or out. imiZL-i Dimmer with a MOSFET tsrf LA\ C44&41 - It Ton Giesberts This circuit shows that dimmers intended for use at mains voltage do not always have to contain a iriac. Here, a MOSFET (BUZ4IA, 500 V/4.5A) in a diode bridge is used to control the voltage across on Incandescent bulb with pulse- width modulation [PWM). A useful PWM controller con be found elsewhere in this issue. The power supply voltage for driv- ing the gate is supplied by the voltage across the MOSFET. D6, R5 and C2 form o rectifier, R5 limits the current pulses through D6 to about 1 ,5 A fas a conse- quence it is no longer a pure peak recti- fier). The voltage across C2 is regulated to a maximum value of 1 0 V by R3, R4, Cl and DC An opiocoupler and resistor (R2) are used for driving the gate, R1 is intended as protection for the LED in the optocoupler R1 also functions as a normal current linv iling device so that a 'hard' voltage can be applied safely. The optocoupler Is on old acquaintance, the CNY65, which provides class-ll isolation. This ensures the safety of the regulator. The transistor In the opiocoupler is connected to the positive power supply so that T1 can be brought into conduction as quickly as possible. In order to reduce switching spikes as a con- sequence of parasitic inductance, the value of R2 has been selected to be not too low: 22 VQ is a compromise between inductive voltages and switching loss when going into and out of conduction. An additional effect is that T 1 will conduct a little longer than whot may be expected from ihe PWM signal only. When the volri age across T1 reduces, the voltage across D1 remains equal to 10 V up to a duty cycle of 88 %. A higher duty cycle results in a lower voltage. At 94 % the voltage of 4.8 V proved to be just enough to cause T1 to conduct sufficiently. This value may be considered the maximum duty cycle. At this value the transistor is just about 100 % in conduction. At 230 V mains voltage, the voltage across the lamp is only 2.5 V lower, measured with a 1 00-W lamp. Just to be clear, note that this circuit cannot be used to control inductive loads. Tl is switched asynchronously with the mains frequency and this can cause DC current to flow. Electronic lamps, such os the PL types, cannot be dimmed with this circuit either, these lamps use a rectifier and internally they actually operate off DC. A few remarks about the size of R3 and R4. This is a compromise between the lowest possible current consumption [when the lamp is off) and the highest pos^ sible duty cycle that is allowed. When the duty cycle Is zero, the voltage across the resistors is ot maximum, around 128 V with o mains voltage of 230 V, Because (depending on the actual resistor) the volt- age rating of the resistor may be less than 300 V, two resistors are connected in series. The power that each resistor dissi- pates amounts to a maximum of 0.5 W. With an eye on the life expectancy, it would be wise to use two I -W rated resis- tors here. 24 tlddor dedtonks- 12/2004 Discrete Robot Gerhard Nocker This simple robot, which responds to light and avoids obstacles, con be built without using a microcontroller, pro- grammer or PC. The only 'special' com- ponent in the circuit is a window dis- criminator (□ fancy version of a window comparator). Resistors R] and R2 in combination with light-dependent resistors LDR1 and LDR2 form a voltage divider (with the current being limited by R1 and R2 for bright light). Window discriminator TCA965 compares the mid-point volt- age with an upper threshold value (adjustable using PI) and o lower threshold value (adjustable using P2). Outputs Au, Ai r Ag, and Aa go High if the voltage lies below, inside, above or outside this window, respectively; oth- erwise they remain Low. Output Aa switches transistor Tl, which drives the right-hand motor. The light-dependent resistors can be attached an the left and right sides of the vehicle, or af the front and rear. This causes ihe robot to turn to the right, due to the motor on one side being stopped, until the desired lighting relationship is restored. The vehicle will then continue to travel In a straight line until the lighting relation- ship again changes, at which point if will ogain turn, and so on. You can experiment with various behav- iour patterns by using the other outputs of the window discriminator. If a transistor is provided for each of the Au and Ao out- puts of ihe TCA965, the robot can be mode to travel toward or away from a light source, depending on the connec- tions, Using the window discriminator, the robot will operate under the rules of a three-point controller (left, straight ahead, or right). If you fit the light-dependent resistors in a box under the vehicle together with a light source, you can try to have the robot follow a block line on a white background. A reflective IR sensor enables the robot to respond to obstacles. This not as sim- ple as if might seem, since the Sharp 1S471 operates the IR LED with pulsed light and uses sophisticated detection processing. When an obstacle is detected, the output (pin 2) goes Low and blocks transistor T2. This causes the +U 0 motor to stop, and the vehicle will rotate about the stationary wheel until the obstacle is no longer in its path. The sen- sitivity of the 1547 1 can be set using P3. As Its range is only around 10-15 cm, ihe vehicle must not travel too quickly, since otherwise If will not be able to avoid obstacles in time. This part of the circuit is also open for experimentation. If a relatively large and fast robot requires an obstacle defector (or isn't fitted with the 15471), an ultra- sonic defector can also be used. Suitable complete construction kits are available from Conrad, for example. You can also fit a suitable mechanical pushbutton switch mounted on a flexible rod. The obstacle detector can also drive a warning buzzer or a lamp; the circuit leaves lots of room for your own ideas. The circuit works over a wide range of supply voltages from 4.5 to 1 6 V. If larger motors are used, transistors with increased power-handling capacity and heavier batteries are necessary. The author connected two 4.8-V rechargeable batteries in series and used 8C388 transis- tors as drivers for Lego micromotors. You con build the robot entirely according to what you have In your parts box. The mechanical elements can also be freely selected, but they partially determine the behaviour and operation of the rebel. The author's robot Is made from a Lego chas- sis with a prototyping board holding the circuitry attached using elastic bands. The motors are fitted on the left-hand and right-hand sides. The third wheel of the front con turn freely. One problem must be mentioned: if an obstacle is defected while an incorrect lighting relationship is present, the vehi- cle remains standing. In this case, o bit of logic could be added to cause both motors to rotate in reverse. However, that would require directional switches for She motors or motor driver ICs (L293D). The simple circuit would become more com- plicated and larger, and ot some point you would end up using a microcontroller offer oil — but that's just fhe point of the story. jTOWl dgrtiDnits 25 Centra I -Locking ysftem polarity of the motor, of course. Christian Vossen For o Few pounds you can buy a kit From any automotive accessory shop that will allow your car to be fitted with a central- looking door system. Such a kit essentially comprises o number of motors. There is also a control unit that enables the whole system to function. Here we show an example of such a unit. There ore 5-wire moiors and 2-wire motors. The 5-wire version is used in doors that have a key-lock. There are 2 connections for the motor itself and 3 connections for the sensor part [on 'open' and a 'close' contact). These sen- sors determine whether the door is to be unlocked or locked. If there is no key lock in the daor r these sensors are superfluous and a 2-wire motor can be used. The polarity of the motor determines whether the locking mechanism goes up or down. By making a circuit that simply reverses the polarity of the motor, the door can be either locked or unlocked. The winding of the motor Is connected between Ml and M2 in the schematic. When relay Re 1 is energised, all motors will, for example, rotate anti-clockwise. By activating Re2 the motors will rotate clockwise. This depends on the actual The sensors are connected to R i and R 1 0. Here you have to pay careful atten- tion. If Rel causes the door to unlock, then Rel has must obviously be con- nected to the 'open" contact. In that case, Re2 is far locking the doors and R 1 0 is then connected to the dose' con- tact. The R/Gcom hi notions R16/C3 and R15/C4 ensure that the relays are ener- gised for a certain amount of time [obvi- ously this can be changed if this time is too short or too long for your doors). This time has to be just long enough to lock or unlock the doors. The third wire of the sensors is the common and has to be connected to + 1 2 V. The RC circuits at the inputs 5 open en $ c [ c5e ensure that the motors are driven only once when the door is locked or unlocked. in addition, there is o provision to allow the unit to be connected to o car alarm. There ore two types of alarm available. 26 d-fclof ^kclrcnirs - 12- 2004 with positive or negative control. In order to make the unit universally applicable, both types of alarm can be used. The cir- cuit around J 3 and T4 makes this possi- ble. The diode inputs [D3 and D8) react to a rising edge, R6 and R8 react to a foiling edge. An RC lime constant is used here os well to ensure that both relays are energised only once. Maybe this is stating the obvious: a motor unit has to be built into each door. All motor wires and sensor wi res are con- nected in parallel to the electronics. The actual type of relay is not critical. The type indicated has the following proper- ties: coil 1 2 V/40Q £2; max. switching current 1 2 A [AC), max. switching power 1 200 VA. Finally, a car is a hostile environment for electronics. Ensure good connections, use automotive connectors ond crimp these on the wires using the appropriate crimp- ing tool. Solder connections in wires are best avoided. They have the tendency to break where the wire transitions info the solder connection when the wire is sub- ject to vibration. Fasten the wires at reg- ular intervals. COMPONENTS LIST Resistors: R1 ,R5,R1Q,R14 = 4kfi7 R2,RT3 = 22k£2 R3,R1 2 = IGkn R4,R1 1 - 47kO R6,R8,Ri5,RI6- I5kn R7 ( R9 - 2k07 Copacifo rs: Cl ,C2,C5,C6 - 2pF2 25V radial C3,C4 = I OpF 25V radial Semiconductors: D1-D8 - 1N4148 T1,T2 = BC547B T3 ,T4 - BC5578 Miscellaneous: RE 1 ,RE 2 = PCB mount relay, 12 V. 1 x changeover, size 1 9x15.5x1 5.5 mm (e.g Conrad Electronics # 504289) PCB, order code 040060-1 frcm The FCBShcp Karel Wa I raven What did you say 8TX was again? Well, it s just the successor of ATX! ATX is the collective term for the electrical and mechanical characteristics of the present generation of motherboards in your PC. There is now a new standard in its place, BTX (Balanced Technology extended Form Factor), with the main advantages of more compact dimensions ond better heat removal. When grouping the components on the PCB, careful attention is paid to power dissipation ond the possibility of efficiently removing the heat This is necessary because the CPU meanwhile needs to dis- sipate 100 W and o respectable video card con easily dissipate 50 W. That is why there has to be serious consideration of how the heat can be removed from the case, where wide cables and other obsta- cles are no longer allowed to be in the way (also refer to SATA elsewhere in this issue). That the energy consumption is continually increasing can be deduced from the ever more powerful PSU units. While 10 years ago a 150-W power supply was quite adequate, these days 350 or 400 W is the norm. With the BTX standard, there is the assumption of a bn for the power supply [just as before), but also a separate second cooling circuit for the motherboard, drawing in cold air from outside the case ond blowing out warm air via a separate path, completely independent ot the bn in the power supn pty- BIX power supplies will also be able to supply more power. There is a new starv dard for the power supply connector that increases the number of pins from the cur- rent 20 to 24 ('Main power connector'). The first 20 pins keep the same functional Pr. J4 Ph H W'-r C&nnertor f :■ 3^ - 12 YDC = COU cov ^f2V Power Connector f-h ity as with ATX motherboards [only -5 V hos been amittedf). The extra 4 pins ore for more 3.3-V, 5-V and 1 2-V connections (refer figure). In addition, there has to be a separate 4-way connecter ('+12 V power connector') that's intended to power the CPU only. 1 2/2004 -cfdctsr dedTunie 27 5 volts from the Mains Paul Goossens Sometimes we would like to hide certain equipment to prevent cluttering up our liv- ing mom or any interior in general. A number of devices lend themselves to be built into a wall odapter. Think of a remote-control extender, for example. All these devices need a power supply and we would prefer to use the mains so that no externa] connections are required for the power supply. The power supply in this article is intended For exactly these situations, namely converting the mains voltage to o 5-V power supply voltage. The accompa- nying PCB fits exactly in a round wall socket enclosure. A power supply is usually fitted with a transformer to reduce the voltage and also provide galvanic isolation between the device and the mains. In this power supply o transformer cannot be used because of lack of space. ic why we use o ste pd own regulator here. A problem with most step- down regulators is that they cannot be supplied directly from the mains. Hence, In this schematic (Figure 1) we first create a rough power supply voltage of □round 40 V using passive ca m po n e n 1$ a nd su bssqu e n Hy present it to step-down con- verter 1C1. The converter can operate from g maximum input voltage of 45 V. The mains voltage is first fused by fuse f ! and then converted to full rectified sine wave by the bridge rectifier. FET T2 is used os o switch, which is turned off when the voltage Is greater than 40 V. The gate of T2 is driven via R3 and R4. As soon os the voltage exceeds 1 rl EUZ41A the value of 40 V, transistor T1 will con- duct which causes the gate-drain voltage of 12 to be so small thot T2 stops conduct ing. Because oF this, electrolytic capacitor Cl cannot charge any further and the maximum voltage across Cl is therefore limited to about 40 V. This voltage is converted by 1C 1 and sur- rounding components to a 5-V power supply voltage. The maximum output cur- rent is 1 A. The PCB (Figure 2] that has been designed For the power supply firs, as mentioned before, in a round wall socket enclosure. Note that resistor Rl and the link have to be soldered first, then comes R5, in the air above Rl because of the tight space. 28 tlfklor ciEdremca - 1 2/5004 Populating the remainder of the PCB should not present any difficulties. When mounting the PCB, do note that it is directly connected to the mains, so make sure no conductive parts can be touched when ihe circuit is in use. The mounting COMPONENTS LIST Resistors? R1 = lOkTl R2 - 39kD R3,R4 = 150kQ R5 = 330 holes are separated less ihan 6 mm from the PCB traces so ihe board has to be secured with plastic screws in order to sat- isfy the safety requirements. Also, after Fit- ting the board, o cover has to be mounted over the PCB so that it is impos- Capacitors: Cl - 220uF 63V radial C2 = 12 GliF 25V radial C3 - lOGnF Semiconductors: Bi - B250C150Q, round case D1 - zener diode 39V, 0.5W D2 = MB R 745 IC1 = LM2595T-5.0 sible to touch the PCB when the v/atl socket is opened. As always, you cannot be too careful when dealing with mains voltages! :4 030124 -11 12/2004 -EhfctGFeSHtrcniG 37 initially turn the wiper of PI to the +12 V extreme — LED D3 should remain out. Then apply line" level audio fo K1 and K3, preferably music with lots of peaks (for example, drum n bass). Carefully adjusi PI until the peaks in the music ore indicated by D3. The circuit has double RCA connectors For the left and right channels to obviate the use of those rare and expensive audio splitter (T'j cables. E3S3:2+I) 2-Hz ■ Z 3 oc k P.C. Hogenkamp CMOS circuits are known for their low current consumption. This is particularly important for battery-powered circuits. Unfortunately, oscillators often require quite a bit of current. We therefore pro- pose this oscillator circuit that has o very low current consumption (about 3 pA). The circuit is powered from o iype LM334Z current source. The current has been set with R4 to about 3 uA. This is sufficient to power 1C 1 and the oscillator circuit around XI. The oscillator gener- ates, with Ine old of a cheap watch crys- tal and a few surrounding parts, a signal that is subsequently applied fo the divider in the 4060 and results in a frequency of 2 Hz at pin 3 (output Q13), The level of the output pulses is a lot lower than the nominal 5-V power sup- ply voltage (1C 1 is after all powered from a current source with very low cur- rent). That is why the signal on pin 3 of 1C 1 is amplified and inverted by T1 . [C3a finally turns It into a proper square wave with acceptably steep edges. : 23317 2-n Voltage Monitor Paul Goosens It is often necessary to monitor the power supply voltage in a piece of equipment. When the device takes its power from a battery, the input voltage con change and provide an indication of how much energy is left. Even a device powered from the mains can benefit from keeping on eye on the (various) power supply volt- ages in the circuit and fake the necessary steps in the event of a fault condition. If a slightly intelligent reaction is required for this situation, it Is obvious ro do this with a microcontroller. This requires the 38 elskter detiro: its - 12/2004 microcontroller to periodically meosure the voltages with one or more A/D converters and decide whether the values are correct or wh ether something is the matter. This naturally costs processor time and makes the Firmware a little more compli- cated. This can become o problem, par- ticularly when other Functions have to be carried out an a regular basis as well Fortunately, chip manufacturer Maxim has a number of JCs in its line-up specifically for this purpose. These ICs all have os task to monitor a number of voltages and when these do not conform to certain requirements the IC generates an inter- rupt, which indicates to the microcon- troller that something has gone wrong. The MAX 1 153 ond MAXI 154 are pro- vided with a 1 0 bit ADC, while the MAXI 253 and MAXI 254 are provided with o 1 2-tit ADC. All these ICs are capa- o!e of monitoring 8 externa! voltages and 2 internal voltages. These 8 external volt- ages can also be programmed for tem- perature sensors, where an external diode can be used as a simple and cheap sensor. For each channel, a maximum and mini- mum voltage or temperature can be spec- ified. As soon as the input voltage or tem- perature foils outside this range the inter- rupt output goes low. If desired, a glitch suppressor con be individually configured for each channel. A recursive averaging filter is also available and it is even possi- ble to specify how many successive sam- ples have to be outside the range before the interrupt is generated. The sample-rate of Ine ADC is also adjustable, to a maxi- mum of 90 ksamples/s. The SP1 bus serves as interface to the con- troller and requires only four signals to communicate. For mare information you con visit the Maxim website; www. maxi m-ic . c am ohssi : On-line Conversions Luc Lemmens rrom time to time you may come across o unit of measure that's completely unfa- miliar. It also happens that the name sounds vaguely familiar, but you just can't remember the fine points. Althoug the Internet probably contains numerous sites that can help out, the most comprehensive one is probably ■■wav, o n I i n ec o n 1 ve r s i o n xom . Here you con convert physics quantities such as, for example, lengths, velocity and forces. There are also conversion tools for currencies, clothing sizes and ter- minology used in cookbooks. Although ine title of this article may imply other- wise, some ports can be downloaded and used off-line. Welcome to OnlineConverston.com Electric Current Conversions Convert what quantity? T From: abampere ampere biot centiampere co u b mhj&eoo r>d deciampere dekaampere electro magnetic unit of current electrostatic unit of current frank! i abscond P To: abampere ampere biot centiampere coubmbteecond deciampere dekaampere electromagnetic unitofcurrent electrostatic unitofcurrent franklin'second Convert Result {rounded to 7 decimal places}! fnfo: Amp is the most gommon symbol for am per*. Amps is ampere, miifiamps is miltiampere, k if o amps is kibampere, etc. 1 2/2004 - elektoi tietfre tia 39 Peter Verhoosel IR Multi Switch This multi-position switch is operated by the IR transmitter with HT12R described elsewhere in the issue. The signal transmitted by the transmitter enters the circuit through infrared detec- tor IC4. At the output the demodulated signal is available, that via R2 and II is routed to the input of 1C1 (decoder type HT12D). Like the encoder 1C, ibis IC has already been described in E/ektor Elec- tronics on multiple occasions and we will therefore not describe it again here. On the PCB the address lines of IC 1 are by default connected with a thin trace to ground. The default address is therefore zero. By cutting the trace with o sharp knife the corresponding address input can be mode logic high. This change of address is only necessary if multiple transmitters are active in the same house. When the programmed address code cor- responds with the address code of the IR transmitter, pin 17 of IC1 will be high for as long as the transmitted signal is avail- able. LED D4 will light up. This pulse is presented to the dock input of IC3, a decade counter. After each pulse the decade counter will make the next output high and the previous output will go low again. When the power supply is switched on, C4 and R6 ensure that the IC is reset; the first output is high and all the others ore low. This is the reason that relays are con- nected only from the second output onwards. +12V 40 efectrensa - 1 2/2004 COMPONENTS LIST Resistors: R 1 = 47n R2,R3,R6 = lOOfcfi R4 = 51 kill 85 = 1 LQ5 R7-10 = 10ka Capacitors; Cl = 220uF 16V radial C2 = lOOnF C3 - 47uF 1 OV radial C4 = 1 jif 1 OV radial Semiconductors: 01 ,D2,D3 = 1N4148 D4 = LED, red, high-efficiency T1 = BC 557 T2 12 = BC547B IC1 = HT12D (HoffekJ IC2 = 78105 ICS - 4017 IC4 = SFH506-40 or equivalent Miscellaneous: Re1,Re2 = 1 2-V relay, e.g,, Siemens V23057BG002-A 1 0 1 K1 t K2 - 2-way PCB terminal block, lead pilch 7.5mm PCB, available from The PCBShop After the firs! pulse is transmitted, Rel wilt be switched on via R7 and T1 . The next pulse causes both Rel and Re2 to be switched on. After the next pulse only Re2 will be on. The reset-input of the decade counter is connected vio D3 to output G4. This causes the switch to return lo the rest posi- tion offer the next pulse. LM4906 Boomer® Audio Power Amp Source: National Semiconductor The well-known LM386 is an excellent choice for many designs requiring a small audio power amplifier (l-v/att) in a single chip. However, the LM386 requires quite a few external parts including some elec- trolytic capacitors, which unfortunately add volume and cost to the circuit. National Semiconductor recently intro- duced its Boomer© audio integrated cir- cuits which were designed specifically to provide high quality audio while requiring a minimum amount of external components (in surface mount packag- ing only). The LM4906 is capable of delivering 1 watt gF continuous average power to an 8-ohm load with less than 1% distortion (THD+NJ from a -s-5 V power supply. The chip happily works wilh an external P5RR LM4906 Audio Inpul • v2 Vbd © JcT' SELECT 6, ” dB Tj 3 >iUD5] - IS (Power Supply Rejection Ratio) bypass capacitor oF just 1 pF minimum. In addi- tion, no output coupling capacitors or bootstrap capacitors are required which makes the 1M49G6 ideally suited for cell- phone and other law voltage portable applications. The LM4906 features a low-power con- I2y 2QG4 --ftkl'f Etedronks 41 sumption shutdown mode (the port is enabled by pulling the SD pin high). Additionally, an internal thermal shutdown protection mechanism is provided. The LM49G6 also has an internal selectable gain of either 6 dB or 1 2 dB. A bridge amplifier design has a few dis- tinct advantages over the single-ended configuration, as it provides differential drive to the load, thus doubling output swing for a specified supply voltage. Four times the output power is possible as compared to a single-ended amplifier under the same conditions (particularly when considering the low supply voltage of 5 to 6 volts). When pushed for output power, the small 5MD case has to be assisted in keeping o cool head. By adding copper foil, the thermal resistance of the application can be reduced from the free air value, result- ing in higher PDMAX values without ther- mal shutdown protection circuitry being activated. Additional copper foil can be added to any of the leads connected to the LM49Q6. It is especially effective when connected to VDD, GND, and the output pins. A bridge configuration, such as the one used in LM4906, also creates a second advantage over single-ended amplifiers. Since the differential outputs, Vo 1 and Vo2, are biased or half-supply, no net DC volt- age exists across the bod. This eliminates the need for an output coupling capacitor which is required m a single supply, single- ended amplifier configuration. Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor is needed to couple in low frequencies with- out severe attenuation. But in many cases the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 100 Hz to 150 Hz. Thus, using a large input capacitor may not increase actual system performance- Also, by minimizing the capacitor size based on necessary low frequency response, turn-on pops can be minimized. Further information from: www. national .com . Model (Railway Short-Circuit Beeper R. Edlinger Short circuits in the [rocks, points or wiring are almost inevitable when build- ing or operating o model railway. Although transformers for model systems must be protected against short circuits by built-in bimetallic switches, the response time of such switches is so long that is not possible to Immediately localise a short that occurs while the trains ore running, for example. Furthermore, bimetallic pro 42 eliklcr dEtfromts- 12/2D0-4 tection switches do not always work prop- erly when [he voltage applied to Ehe track circuit is relatively low. The rapid-acting acoustic short-circuit detector described here eliminates these problems. However, it requires its own power source, which is implemented here in the form oF a GoidCap storage capac- itor with a capacity of 0.1 to 1 F. A commonly available reed switch (rilled with an inert gas] is used For the current sensor, but in this case it is actuated by a solenoid instead of a permanent magnet. An adequate coil is provided by several turns of 0.8-1 mm enamelled copper wire wound around a drill bit or yarn spool and then slipped over the glass tube of the reed switch. This technique gener- ates only a negligible voltage drop. The actuation sensitivity of the switch (expressed in ampere-turns or A-f]] deter- mines the number of turns required for the coif. For instance, if you select a type rated at 20-40 A-t and assume a maxi- mum allowable operating current of 6 A, seven turns (40 + 6 = 6.67] will be suffi- cient. As a rule, the optimum number of windings must be determined empirically, due to a lack of specification data. As you can see from the circuit diagram, ihe short-circuit detector is equally suitable for AC and DC railways. With Mark! in transformers (HO and I], the track and lighting circuits can be sensed together, since both circuits are powered from a single secondary winding. Coil LI is located in the common ground lead ['O' terminal], so the piezoelectric buzzer will sound if □ short circuit is pres- ent in either of the two circuits. The [posi- tive] trigger voltage is taken from the light- ing circuit (LJ via D1 and series resistor RT Even though the current flowing through winding U is an AC or pulsating DC current, which causes the contact reeds to vibrate in synchronisation with the mains frequency, the buzzer will be activated because a brief positive pulse is all that is required to trigger thyristor Thl * The thyristor takes its anode voltage from the GoidCap storage capacitor (C2J, which is charged via C2 and R2. The alarm can be manually switched off using switch 5 1 , since although the thyris- tor will return to the blocking state after C2 has been discharged iFa short circuit is present the lighting circuit, this will not happen if there is a short circuit in the track circuit Cl eliminates any noise pulses that may be generated. As a continuous tone does not attract as much attention as an intermittent beep, an intermittent piezoelectric generator is preferable. As almost no current flows dur- ing the intervals between beeps and the hold current through the thyristor must be kept above 3 mA, a resistor with a value of 1.5-1 .8 kQ is connected in parallel with the buzzer. This may also be necessary with certain types of continuous-tone buzzers if the operating current is less than 3 mA. The Zener diode must limit the oper- ating voltage to 5. 1 V, since the rated volT age of the GoidCap capacitor is 5.5 V. IteiuifeG^lq] Transistors c Paul Goossens Developments in the electronics area (or is if an arena?) are never at a standstill. Whenever there is something substantially new to report If Is almost always related to complex chips. However, Philips proves lhaf new developments are possible even with what you thought were dead-standard components. For example, take ihe new range of transistors with ihe name "RET" - meaning Resistor Equipped Transistor . The novelty with this new range of transis- tars is that ihey have a base resistor included. Some versions also have a resis- tor from base to emitter. These new transistors enable engineers to design even smaller devices because the space required on ihe PCB has been reduced as o consequence. An additional advantage is that the fatal component count is reduced. The new transistors ore available in both PNP and NPN versions. For the package, the designer can choose from a number of 5MD packages as well as the familiar TO-92. The maximum power dissipation depends on ihe package and varies from 1 50 mW to 500 mW for the single tran- sistor chips. There are also chips with two transistors, where each chip is provided with either one or two resistors. With these you con choose between □ maximum dissipation oF 300 mW or 600 mW. A complete overview of the available RETs can be found on ihe Internet at: h ttp ://www,£em iconductors .com/acro- b at/] i Jera fure/9 3 97/75 0 1 25 1 4.pdf. saurcs: Philips 1 2/20QT - dcller eleUreriics 43 Read eiektor electronics. leading the way Take out an 18-month subscription to elektor electronics and receive a free MP3 player with 128 MB Memory*. Please fill out the Order Form with this issue. Subscription rates and conditions may be found at the back of this issue. ' Offer available to Subscribers who have not held a Subscription to Efektor Electronics in the las! 12 Monies. Offer Subject to Availability. [L@w°^©p ; y©c©§fe¥H' Current Soy tree for Ultrabright LEDs Olaf Konig Ultrabright LEDs are becoming increas- ingly attractive for use in lighting and warning-signal applications, LEDs mu si be operated at a constant current to ensure that they continue to emit light at the same brightness. The usual approach is to use a series resistor, but in order to prevent the non-linear voltage/currenr character- istic, the NIC property of the LED and variations In the supply voltage from affecting brightness, we'd like to have something better. The circuit described here is o tow-drop constant current source for ultrabright LEDs with blinking capability, for use in headlights, taiHights, dag blinkers, light chains, car alarms and the like. It pro- vides a constant current of 20 mA with a supply voltage of 4.5-30 V, or 50 mA with a 4.5-1 2 V supply. The voltage drop of the circuit Is only 0.6 V, so practically the entire supoly voltaqe can be used for the LEDs. When the supply voltage is switched on, D5 generates a start-up voltage if the cir- cuit is exposed to light (an LED can gen- erate a photoelectric current). To enable the constant-current source to also reliably start up in the dark, R4 provides an initio! base current to Ti and T2. In any case, both transistors initially only pass a small amount or current. But since each transis- tor provides the base current for the other one, the current rises to its setpoint value. The setpoint Is stably maintained as fol- lows. The voltage across D5, less the bose--emirter voltage of T2, is also pres- ent across R3 [R5 has no effect a! the beginning). A stabilised current thus flows through R3. Most of the constant current flowing through 12 comes from D1 and P2, with only a secondary con- tribution from the base current of Tl . The voltage across D1 and D2 is also stable, due to the stabilised current. This voltage, less the base-emitter volt- age of Tl , is present across R 1 , where it causes a constant current to flow through Tl and D5 (and D4 if present). This doses the loop. The circuit thus consists of two constant-current sources that stabilise each other. That's the basic principle. R2 increases the voltage across R3. This causes the current to be reduced propor- tional to the supply voltage, which further stabilises the current R2 is thus config- ured such that the current actually decreases slightly as the battery voltage increases. This causes Tl to be driven into full saturation at low voltages. D2 is intended to compensate For the base-emitter voltage of Tl , while Sc hottky diode D1 provides the 'miserly' voltage drop across Rl. D1 and D2 are ther- mally coupled to Tl . As a result, with increasing temperature the current is more likely to decrease than increase. LED D4 is included in the circuit to pre- vent T2 from having to go Into saturation at low operating voltages. That wrings out an extra 0.2 V or so. in this way, the battery is mercilessly sucked dry when is +4V5...+15V ^OPT 1) +4V5...*3GV 46 dektor dscftiiflks- 12/20D4 becomes weak. It's totally defenceless. However, rechargeable batteries should never be deep-discharged! Overvoltage protection should be included if the circuit is intended to be used for general experimentation or with LED chains. In case of overvoltage, D3 starts conducting and takes current away from 12 [which is essentially what R2 does as well]. To prevent overheat- ing or II , particularly with a current of 50 mA # the current is sharply reduced for voltages greater than approximately 15 V. The upper voltage limit is then practically determined solely by the maximum collector voltage (Ucej ratings of the two transistors. An LED chain can best be inserted in series with the supply voltage, in order to ovoid making any changes to the circuit. Naturally, at least D5 must still remain in the circuit. R5 and C2 form part of the blinking cm cuif. R5 and C 1 smooth out large current spikes and RF oscillations during blinking operation. Low-impedance feedback is provided by C2. The resulting pulses ore long enough to be clearly visible and short enough to use as little energy as :: : MMFiMTS LIST Resistors: K1 = 6Q8 or 1 SQ {see text) R2 = 33 kll R3 - 8200 R4 - 1 GMO R5 = 22kO or 0 Q [see text] R 6 - 1 oka Capacitors: Cl = IGOuF 40V radial possible. The duty cycle is only 10 %. However, at base voltages less thon 5 V (with two LEDs htted] it increases to 50 %, with an accompanying decrease in cur- rent. Below 4,6 V, shortly before the cir- cuit "runs dry', the pulse heads toward to zero. The 1 Ch% pulses achieve the rated pulse current level of 1 00 mA for 50'mA LEDs, and they have such steep edges that two blinkers connected to a single power source blink in unison if they are not decoupled by at least 1 Q. The volt- age fluctuations on C2 are so small (approximately 0.6 V) that hardly any energy is lost. We have designed a small printed circuit board for the constant-current source, which could hardly be easier to build ond does not require any comments. Diodes D1 and D2 are placed immediately next to T1 and thus adequately thermally cou- pled. For o maximum constant current oF 50 mA, the value of R! should be 6.8 O, while for 20 mA a value of 1 8 Q should be used. Naturally she value of R1 can be increased even more to reduce the value of the constant current any the desired level. If T1 does not have the anticipated cur- C2 = 470 pF 40V radial Semiconductors: Dl ,D2 = BAT41 or similar Schottky diode with Ip >8 0mA 03 = zener diode 15V, 0.5W D4,D5 = LED (see text) T1 = BC557B T2 - BC550B Miscellaneous: Si - switch (see text] PCB, order code 040008-1 from ihe PCBshop rent gain of 140, R3 should be reduced to 680 Q. The current flowing through diodes Dl and D2 should be at least three times the base current of T1 . Natu- rally the base current flowing through T2 is not multiplied. The value of Ir3 is thus 4 x fen (since kn con be neglected). As D5 determines the voltage across R3 , we thus have the formula: R3 < (Tit x [(Ud - - 0.65 V) / (4 fcomfl The maximum permissible value of (An is 340 mV. From the author's experience, when setting the level of the constant cur- rent it helps to try several diodes for D2 with different tolerance values. In stub- born cases of excessively high current lev- els [or if you want to be on the safe side but don't want to or can't measure, adjust or whatever), you can simply connect two ]N4148s in parallel. This will cause the operating point to lie somewhat lower on the characteristic cur/e. Another important tip for avoiding eye injury (retina damage]: never look directly at an ultrabrig ht LED, especially in the dark! : 4 -:o:s-i am Karel Wal raven There is a new standard these days for connecting hard disks and DVD drives: SATA. You may o I ready have noticed that new PCs don't coniain the wide 40- or 80-pin ribbon cables any more, but the hord disk is connected with a slender 7- way coble. Even the corresponding power supply connector is different with a SATA drive and now has 15 connec- tions instead of 4. This is clearly illustrated 1 2/2004 - ekktw dettTGtuo 47 in ihe drawing; The /arge connector pro* vides power and ihe small connector is ihe data connection. The power supply connector provides 12, 5 and 3.3 V and two ground connections. SATA means Serial ATA. ATA is the con- nection standard that at present has been the most common for hard disks, CD and DVD drives. At the iime of writ- ing the ATA1 00 bus with o data transfer speed of 1 00 Mbyte/s is the most wide- spread. A number of manufacturers use the slightly faster ATA1 33 bus. That Is pretty much the end of the line; it has not been possible for ihe industry to Increase the speed even further using simple means. In order to increase the speed of the interface between motherboard and HDD. o serial conneciion was selected. At first glance this appears to be an per- plexing choice! The parallel ATA bus operates with 1 6 bits simultaneously; the serial bus therefore has to be at least 1 6 times faster to obtain ihe same equiva- lent speed. That is why SATA operates at a clock speed of 1500 MHz and reaches a dato transFer speed of 150 MByte/s; versions with 3 GHz and 6 GHz clack speed are planned. The industry made this choice because, in She end, if is cheaper to have a solution with one data channel at very high speed than frying to increase the speed of all 33 signals in the ATA connection. The data connection has a balanced outgoing and a balanced return connection, plus three ground connections. The signal amplitude is not 5 volts any more, but only 0.25 volts. The symmetrical conneciion and the small signal amplitude together result in a fast, low Interference and energy efficient connection. In addition, the coble is allowed to be much longer: 1 m instead of 45 cm with ATA. Another big difference is ihoi each device (HDD, DVD) has its own coble and con- nection to the motherboard. With the cur- rent ATA standard two devices can share the same cable. As a consequence vari- ous jumpers (master, slave) disappear and the interface can [in principle) always operate at maximum speed. Additionally, the contacts in the connec- tors are of different lenglh, so that hat- plugging [connecting or disconnection without switching the power off) becomes possible. The expectation is that this inter- face will satisfy the requirements for the next ten years. Modern SMI® P(o]€k@]g©s SOT346 (SC-59) SOT23 SOT323 (SC-70) SOT416 (SC-75) SOT490 (SC89) (5.27 mm 2 ) (4.2 mm 2 ) (2.97 mm 2 ) (1.62 mm 2 ) (1.615 mm 2 ) SOT883 bottom view (0.632 mm 2 ) -.v^= .• Paul Goossens Parts in SMD packages are becoming more and more frequent in DIY circuits. Sometimes they are used because of bet- ter performance, usually as a conse- quence of the shorter PCB traces between the various ports. The result of this is a lower self-inductance so the circuit exhibits better RF behaviour. Another reason components in an SMD package are selected Is simply because the equivalent pans in a Through-hole" pack- age are no longer being manufactured. All those different packages have naturally resulted in several new standards for pack- ages. Here we show a number of com- mon SMD packages with three terminals. In particular, note the difference in dimen- sions for the various packages. Arguably a SOT346 package is a lot easier to sol- der than a SOT490 package. It is obvi- ous then, that a 50T883 package is going to be the most difficult to solder. Not only is the package extremely small, but in addition, the terminals ore under- neath. This means that it cannot be sol- dered with a soldering iron. To solder these, you would have to resort to using a hot plate, an iron or even better: an SMD oven. 48 diktoieledniriia-R^OOl StCfl lb i @ Filament Supply Dr Alexander Voigf Valves are enjoying increasing popular- ity in audio systems. With the European E J series of valves, such os the ECC83 [12AX7) and EL84 (6BQ5), the filament voltage is 6.3 V. Depending on how the circuit is wired, the ECC 81-83 series of twin triodes can also be used with a fila- ment voltage of 12.6 V. In earlier times, the filament voltage was usually token directly from a separate transformer wind- ing, which [in parr) was responsible for the well known valve hum r . With regard to the signal path, current valve circuits have hardly experienced any fundamental changes. In high-qual- ity valve equipment, though, it is rela- tively common to find a stabilised □node supply. Mains hum can have a measurable and audible effect on input stages whose filaments are heated by an ac voltage. The remedy described here is a stabilised and precisely reg- ulated dc filament voltage. The slow rise of the filament voltage after switch- ing on is also beneficial. The exact set- ting of the voltage level and the soft start have a positive effect on the useful fife of the valves. Figure 1 shows a voltage regulator meeting these requirements that is built from discrete components. The two sets of component values are for o voltage of 6.3 V (upper) and 1 2.6 V (lower). Thanks to the fact that the supply works with a constant load, it can do without special protective circuits and the additional com- plexity of optimum regulation characterise tics for dynamic loads. The circuit in Figure 1 consists of a power MOSFET configured as a series-pass reg- ulator and a conventional control ampli- fier. Zener diode [D5j sets the reference potential. A constant voltage is thus pres- ent at the emitter of the EC547 control amplifier (T3). The current through D5 is set to approximately 4-5 mA by series resistor R 5. The output voltage Uo (the controlled vari- able) acts on the base of the control amplifier (T3) via voltage divider R6/R7. If the output voltage drops, the collector current of T3 also decreases, and with if the voltage drop across food resistors R1 and R2. The voltage on the gate of the MOSFET thus increases. This closes the control loop. The values of the resistors forming the voltage divider are chosen for buzii T2 1 Q40UH-11 2 ihe usual tolerances of Zener diodes, but they must be adjusted if the diode is out of spec (which can happen). The load resistance of the control ampli- fier is divided between R1 and R2. The current through the load resistance and the collector current of T3 are practically the same, since the MOSFET draws almost no gate current. Filter capacitor C2 is connected to the junction of R 1 and R2 to reduce residual hum. Electrolytic capac- itor C4 and power supply filter capacitor C 1 serve the same purpose. The hum volt- age also depends on the magnitude of ihe food current. The voltage drop over the series-pass reg- ulator is nearly ihe same for an output voltage of 6.3 V or 12.6 V. With a BUZ1 1 and a load of 1 A at 6.3 V, for instance, the average voltage across the source-drain channel is approximately 7 V. The power dissipation of 7 W requires a corresponding heat sink. The slow rise of the ouiput voltage is due to the presence of timing network R3/C3 and T1 , When power is switched on, T1 holds the gate of the MOSFET at nearly ground level. As C3 charges, T1 con- ducts increasingly less current, so ulti- mately only the control transistor affects the gate voltage. The mains transformer must be selected according to the required load current. The required value of the input voltage can be read from the chart. The trans- former should have a power rating at least 30 % greater than what is necessary based on the calculated load dissipation. Where possible, preference should be given to a filament voltage of 12.6 V. When twin triodes in the ECC81-83 series are used, for example, the power dissipation in the series pass transistor is lower with a voltage of 1 2.6 V. 1 2/Z0O4 - elekfor dsdmeks 49 OIK TransmifiSer with 111121 Peter Verhoosel IR [infra-red] transmitters containing the enccder-IC HT12E from Holiek have been published m E/ekfor Electronics on previous occasions. The interesting aspect or this design is that the entire IR- transmitter has been squeezed info o handy key ring. The operation of the encoder 1C HT12E has already been thoroughly dealt with in earlier publications. It will suffice to men- tion here thal an address can be pro- grammed on inputs At through to A8. This address has to be set the some as in ihe receiver. On the circuit board, the address lines are connected to ground with a Inin piece of track so ihot address zero is selected. By cutting trie track with a sharp knife the cor- responding input can be made logic high. This change of address is only necessary when more than one transmitter is active in the same house. The some story applies to the four data fines, but that is not relevant if you use the IR Multi-Position Switch published else- where in this magazine. The generated code is available on pin 17 of IC1 , which is modulated with ihe aid of IC2 on a carrier of 40 kHz. Transistor T1 drives the infrared LED via R4, so that an IR code is transmitted. Two lithium cells of 3 V each power the circuit The circuit is only powered when transmit pushbutton 52 is pressed. The life expectancy of ihe batteries is during nor- mal use mare than a year! The construction itself should be no prob- lem. However, note the height of the com- ponents. For this reason an 1C socket carv not be used. A paperclip soldered to the bottom acts as a boirery holder, this is ground. Far the top part of ihe battery holder we use an automotive connector and an M3 bolt. Because the height of It can be a prob- lem when dosing the enclosure, the device is best bent Hof on the PCS before soldering. COMPONENTS LIST Resistors: Rl = 976kQ R2M= IQkQ R3 = 1 GOkn R5 - l on Capacitors: Cl = lOOnF C2 = IGOuF 10V radial C3 - lOnF C4 = 22GpF Semiconductors: D1 = 1M4148 D2 - IRED (e.g., LD274J IC1 = HT1 2E (Hoftek) EC2 - TLC555 TT = 8C337 Miscellaneous: S t “ miniature pushbutton (HAK) Enclosure: KM series Box UM14 PCB, available from The PCBShcp 50 dfklor eledronks ■ 1 2/2004 No, not at all! The hobby electronics market in Australia has been historically very strong with large numbers of enthusiasts seiviced by dynamic electronic magazines and vigorous commercial suppliers. The most dominant company in this ' Down Under" market/ Jaycar Electronics/ is now in a position to offer its great range of products to a wider audience, thanks to the Internet. jgffliWfte Concerned about dealing on the Internet? Well, you should be. At the same time, the amount of legitimate internet trade exceeds the fraudulent trade by millions and millions to one. World internet trade today easily exceeds the Gross T — National Product of many large countries! ^Mnroinfn Jaycar has been doing business on the Internet now for over 10 years. The thousands of happy repeat customers on our hies is a testimony to how safe it can be when you deal with a reliable supplier [ike us. Worried about freight costs? 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You can get one FREE by logging on to our website M i and filling out the catalogue request form at wwwq ay carelectronics.co.uk/catalogue M I We Stock: J * A huge range of exciting kits ( * A g rest ra n g e of robotic components M , , f ■ The best range of electronic components ? * The largest single-source range of gadgets ** * Security, Surveillance, AucSo/VJdeo, Lighting, Computer & Telecoms Parts etc, ^ |; Check our website! * Entire Jaycar 2004 Catalogue on-line — over 6000 products. . j-s/l - 128-bit Secure on-line ordering - safe R secure. * Express ordering. * Tej^pJ SB if * Search by category, keyword or catalogue number, & advanced search. ^ S / * Over 3500 product datasheets R application notes available on-line, l wwwjavcareleciianlcs. oo.uk High performance Electronic Projects for Cars Book - Silicon Chip Publications (Australia's Leading Electronic Hobbyist Magazine Publisher) B5-5080 €6.35. | r All the instruction, and morel It shows, in full i | ^" colour, the constructed modules, has colour I 3 -1 3 fc* j' : ! overiay diagrams, detailed build guides, and j fj T X fitting instructions. It also includes chapters on j jj [ J J j ^ hovj engine management works, advanced rT ^ 1 engine management, electronic car systems like ABS and traction control, DIY electronic modification, and more! It is a definitive ■ _ must-have if you are building any of these kits, -j ■ ? j or would fust [ike to know how your car's [I ^ ^ ^ K I electronics work. Over 150 panes! A Cheap Nitrous Fuel Mixture Controller KC-5382 £7.25 Nitrous oxide systems can be expensive to set up, but now you can do it for much less. This project pulses a fuel injector at a preset rate, adding a fixed amount of _ — nitrous fuel when you activate it. It will save - you a bundle on dedicated fuel solenoids and (9in ! Jt" jets. It can also be used to control y J y electronic water pumps, cooling fans, _ and more. Kit supplied with 0 fljL L J Mr PC B and all electronic * ' components. r PIease check - flJJJJflft 1 LjiJi local laws regarding the use of *7 KsT Nitrous OxJde systems in your x \ jEfe? vehicle. ^ Theremin Synthesiser AM-4025 £27.25 ~ This Is a built up Theremin from a Jaycar kit. The Theremin is a weird musical instrument that was invented earfy last century but is still used today. The Beach Boys hit: “Good Vibrations" featured the Theremin. You can have one of these kits Icat no. KC-5295) for £12.95. Ail kits have first class instructions written in dear English text with plenty of i] lustrations and component identification. www.jaycarelectronics.co.uk 0800 032 7241 (Monday - Friday 09.00 to 17.30 GMT + 10 hours only) For those that want to write: 100 Silverwater Rd Siiverwater NSW 2128 Sydney Australia HIGH PERFOMANCE 1 £ | 1 Ml 1 ; 1 f 1 C I T | thjlpul r tT Since the introduction of the l 2 C bus in the eight fri - Vys^M - by Philips it has been used many times to provide a simple connection between a PC and home-built circuits. This often made use of a simple interface connected to the parallel port of the PC. This now seems a bit dated, so we've designed a USB/I 2 C interface for you to build. 52 elsklor ekcUenSts - 1 2/200 4 Articles about the I 2 C bus have appeared several times in Elektor Elec- m ironies. We have even published designs for a whole range of modules that communicated with a PC via the I 2 C bus. At that time we used an ISA card to provide an I 2 C interface. Another type of interface that was fre- quently used was a simple circuit that connected to the parallel port. But with the introduction of modem operating systems it became much more difficult to control the parallel port correctly. The old software would often no longer function properly. We have designed a new I 2 C interface, which uses the USB bus instead of the parallel port to connect to the PC, so that it can be easily used with newer PCs and modem operating systems. PC history Philips originally developed the I 2 C bus to provide communication facilities between the various chips found in tel- evision, video recorders, etc., without ^ taking up too much space on the PCB. The result is that the 1 2 C bus requires only two signal lines instead of 8 datelines, several address lines and a few control lines, which was the case up to then. Once this bus was in common use, various other chips were designed with an I 2 C interface by Philips as well as other manufacturers. Many chips were designed for use in audio and video equipment, such as tone controls, synthesizers, volume con- trols, and so on. The range has been extended since then and now includes digital I/O buffers; A/D converters etc. T giving us a wide range of I 2 C devices to choose from. PC operation The I 2 C interface is a so-called master- slave bus. This means that every I 2 C l-square-C rules... Quick specifications - Compacl - USB 1.0 full-speed interface “ Compatible with USB2.0 hosts - Works with Windows 985E to Windows XP - Doesn't require separate driver software - The maximum cable length between the interface and modules is at least 100 metres! - \ 2 C frequency: 1 00 kHz - Simple to use by means of a DLL ~ Source code far the firmware, DLL arid example program is avail* able ~ Uses a 9 V mains adapter as the power supply bus has one master device, with all other devices acting as slaves. The master is always responsible for sup- plying the clock signal on the bus. Every transaction may be initiated by the master only. A slave should there- fore never start transmitting data on its own accord! Each slave on the I 2 C bus has its owe unique address. Every transaction begins with a START condition, fol- lowed by a 7 -hit address and a R/W hit. If a slave with this address is pres- ent on the bus it will send an ACK (acknowledge) signal to confirm that it has recognised its address. All the other ! 2 C slaves will now ignore the data on the bus and will only start lis- tening again after a STOP condition has been detected on the bus. The R/W bit is used to inform the slave whether the master wants to read or write data. When this hit is a T, the master wants to read data. In this case, the next byte will be put onto the bus by the slave. If this bit is 0 1 (Write), the following hyte{s) will be transmitted by the master. The master still generates the clock signal in both cases. At the end of the communication is a STOP condition and the v/hole process then repeats itself. Bntorfesee The interface we’ve designed should satisfy several requirements. We would like to keep the installation under Windows as easy as possible. What's more, it should be (relatively) easy to control the interface. It would also be nice if we could run longer cables between the interface and I 2 C modules, so the user can connect devices that are a long way away from the PC. Our Sr st task was to search for a suit- able controller with a USB interface. We decided to use a TUSB3410 made by Texas Instruments, as this micro- controller has both a USB as well as an ! 2 C interface. Tills is described (some- what misleadingly) as a ‘USB to Serial Port Controller'. In fact this is an 8051 compatible controller with a USB inter- 12/5091 - dtkiw ektfronia 53 Figure 1 - The circuit for the interface is built round a / USB 34 10, face, 16 kBytes of program memory, an enhanced serial port and an I 2 G inter- face. All these goodies are contained within a small 32-pin 5MD package. To satisfy the requirement for the ! 2 C connection to work over greater dis- tances, we have given the signals an extra boost with the help of a P32B715PN I 2 C bus extender Cfreyrff diagram The circuit diagram for our interface is shown in Figure 1. At the heart of the circuit is the 7USB3410 (IC1) with its associated oscillator (XL C5 and C6). We’ve used an external mains adapter for the power supply Its 9 V output is stabilised down to 5 V by IC4. There is also a requirement for a 3.3 V supply for the processor and the I 2 C EEPROM. For safety reasons we decided not to supply the circuit with power directly from the USB bus. The 5 V supply is also brought out on this connector and an overload or short could damage the USB interface in the PC, The data lines from the USB connector (K!) are connected via resistors R2 and R3 to the appropriate data inputs of the controller. The Dt line is con- nected via a lk5 pull-up resistor to the PUR (Pull-Up Resistor) output of IC1. Normally this resistor is connected to the positive supply This is required for a USB hub to detect that a full-speed USB device is connected to the USB port. By connecting this pull-up resis- tor to an output of the controller, the controller itself can tell the USB hub that a device is present. The reverse is also possible in that the controller can fool the hub that the device has been disconnected, by forcing this output low. This process is important during the booting of the chip (refer to the inset on booting the TUSB341G). The firmware is stored in an I 2 C EEP- ROM (IC2) and is connected to the con- troller via the I 2 C bus. Diodes D1 and D2 absorb any potential voltage spikes and protect both I 2 C signal inputs of the controller. R5 are R6 the pull-up resistors that have to be present on every I 2 C bus. You will have noticed that the I 2 C bus of the controller works at 3.3 V. These signals are not suitable for use in com- bination with a 5 V chip. Unfortunately the I 2 C bus-extender is a 5 V device, so both I 2 C signals first have to be con- verted to a 5 V level This is taken care of toy components Ti, T2, R9 and RIO. The F82B715PN I 2 G bus extender along with Rll and R12 allow longer cables to be connected to the I 2 C bus by lowering the impedance and increasing the current output. These signals are then taken to the outside world via K3. The double-sided PCB shown in Fig- ure 3 is very small, but still has all the required connectors on board. Mount- ing the components shouldn’t be very difficult, with the exception of the SMDs: IC1. Tl and T2. It's still possible to solder the two transistors using a soldering iron with a fine tip, but it becomes more difficult with the 1C. The IC should first be fixed in the right place on the board with a drop of glue. Then solder all pins together as well as to the solder pads. You should work quickly to avoid the IC becoming too hot. After everything has cooled down again you should place a clean piece of desoldering braid across the pins and remove the excess solder (l.e. the shorts between the pins). Don't attempt this with a solder sucker! Take 54 dfklcr ekrironks - 12/2004 care at all times that the IC doesn’t overheat. You should finally inspect all pins with a magnifying glass and multi-meter to check that they are con- nected properly and that there aren't any shorts left. This completes the trickiest part of the construction. An example of a suitable module that can Joe connected to the interface is shown in the PC Home Bus article. If you prefer to use the PC bus without the PC bus -extender, you should make the following modifications: IC5, Rll and R12 can be left out. Pins 3 and 2 on 1C5 have to be connected together, as do pins 6 and 7, This is easily done by putting two short +5V Figure 2. Input circuit for PC modules when the PC I/O- extender (!C5j is used. COMPONENTS LIST Resistors: R1 - 15kn R2,R3 = 330 R4 = lkQ5 R5,R6,RS,R9,R 10 = lOka R7 - 5kOd R1 1 # R1 2 = 3300 Capacitors: C 1 ,C4 - 1 pF 16V radial C2,C3$ici 1 = IGOnF C5,C6 - 22pF Semiconductors: Dl r D2 - BAT85 D3 = 1 N4001 1C1 - TU5B34 1 0 (Drgifcey # 29b 12699ND) ... - 24LC64 programmed, older cods 040334-2 1 IC3 - LM1 11 7-3.3 orLDll 17V33C (Digikey # 497-1 49 2-5- ND) 1C4 =7805 1C5 = P82B715PN (Farnell # 559-258; R5 Components # 821-784] T1 J2 = FDV301N (Farnell # 995-848; RS Components # 354-4907) Miscellaneous: K 1 = US 8-8 connector, angled, PCB mount (Farnell # 152-754) K2 - mains adapter socket PCB mount K3 “ 6-way RJ-t 1 connector (Farnell # 393-8359) X I - 1 2 MHz quartz crystal USB cable PCB, order cods 040334-1 (see Readers Services page) Disk, project software, order code 040334*! 1 or Free Download Figure 3. The PCB for the interface , tCl f T1 and T2 are SMDs and have to be soldered carefully using a fine tip . (capper track layout tram our website) 12/2004 -ilskfo! ehrirom +5V © — 2 Cl loan K1 RJ-11 !C1 12C LSDA 3 LSCL Hi © IX^ SY t> lY R2 13 SDA *4 SCL PE2B715PN IC2 IS © Bit pa pi 5CA P2 SCL F3 Pi AO F5 A1 PS A2 P7 PCFB574 C4&334 - 13 Figure 4, This circuit can be built to help test the interface. wires into the IC socket. The modules may now connect the SCL and SDA lines directly to the I 2 C connections of their ICs, If the I/O extender circuit is included on the PCB, it is essential that all con- nected modules have the input circuit shown in Figure 2. Installation and DLL Installing the circuit is fairly straight- forward, First you have to connect the mains adapter, then you can connect the circuit to the PC using a USB cable. Windows (from 98SE onwards) will immediately recognise it as a HID device and after some rattling of the hard drive Windows announces that the device is ready for use. But there is more to it than that of course. We also need to write a pro- gram that makes use of the interface. Its functions obviously depend on the modules that are connected and what you want to do with them. We realise that controlling a HID device isn't exactly a piece of cake for the average programmer. This is why we've made a DLL available which was specially written to control our USB interface. We would recommend that this DLL is c o pie d to the C:\ Win do ws \ System 32 folder. This makes the DLL available to the operating system at all times and you don t have to copy the DLL to the folder where the application using this DLL is stored! This DLL canbe used with any pro- gramming language that supports the use of external DLLs. A few examples of such languages are Visual Basic, Visual C — , Delphi and Borland C t - Builder Two methods You can use the DLL from your applica- tion in one of two ways. When we wrote the DLL it seemed logical to make the application pass an array of bytes, where the DLL could either store the received bytes or read the bytes to be transmitted. Most programming languages don't have a problem with the use of arrays as arguments in DLL functions. But lt*s a bit different with Visual Basic. Although it is possible with this pro- gramming language, it is a lot trickier for the novice Visual Basic program- mer For this reason we have included a few extra functions and procedures which make it easier to use the inter- face under Visual Basic. To help you on your way we have writ- ten two simple examples hi Visual Basic and Delphi, which control a stan- dard I 2 C I/O extender. These examples show the two methods in which the DLL can be used. The circuit of the module required for the examples is shown in Figure 4. The circuit is simple enough for it to be built on a piece of experimenter s board. Get {?© work with Wmrd In the June edition of Elektor Electron- ics we showed how the well-known word processor MS -Word could also be used to write your own programs. Since most Windows users have a copy of this word processor, it made sense to show you a simple example, written using Word. We have of course kept this example fairly simple and didn't use any arrays when communi- cating with the DLL! Figure 5. An example program in MS-Ward. 56 elektor ekrinrta- 12 y 2 OH 4 The required iUe is part of the project software (order code 04033441) and can be found in the folder ‘Word exam- ple 1 . When you open this document you may, depending on the security settings of Word, get a question asking if you want to use macros in this doc- ument, You should answer this ques- tion with "yes', otherwise the example won't work. You should then see the document on the screen as shown in Figure 5 . When you press the top button the software searches for the interface. The box next to this button shows whether the inter- face has been found or not. Before we can use the interface, it must first be opened. This requires a mouse click on the button ‘Open inter- face 1 . Once you have finished using the interface, it should be closed with a click on the button 'Close interfaced The result of a click on these two but- tons can be seen on the associated yel- low pane. The next two buttons are used to turn the LEDs on and off (you have of course built and connected the circuit shown in Figure 4 P haven’t you?). You can obviously tell from tire LEDs on the module if the data was successfully sent, but as you may have gathered, this is also shown in the box to the right of these buttons. The final button is used to show the status of the inputs of the PCF8574. The value returned by the PCF8574 is shown in the window to the right of this button, A more detailed explanation is given in the sidebar for + Using the DLL without arrays'. This sidebar and the source code of the Word document should be enough for a programmer to under- stand how it all works. Delphi Our second example is a very simple application written in Delphi. A ques- tion we're sometimes asked is why tv e use the Delphi language so often in our examples. The reason this pro- gramming language is so useful for examples is that it is derived from Pascal and easy to follow. A C pro- grammer should also be able to follow it without problems. The opposite is not true, since a Pascal programmer would have great difficulty in follow- ing a C program. The files for this example can be found in the folder 'Delphi example'. The DLL functions Standard: type TReporf = array[0..200] of Byte; function l2C_USB_Present : Boolean; stdcall; function 12C_USB_Opened : Boolean; stdcall; function i2C4J$B_Open : Boolean; sfdcall; procedure l2C_U5B_C3ose; s idea If; Communication using a program buffer: function l2C_USB_V/nte (a dr : Byte; length : Byte; data : array of Byte) : Boolean; sfdca!!; rundian f2C_USB_Read (adr : Byte; length : Byte; var data : array of Byte) : Boolean; sfdcall; Communication using the DLL buffer: procedure i 2 C_U5B_CfearWrite Buffer; sfdcall; procedure l2CJJSB_C!earReadPointer; sfdcall; procedure ]2C_USB_FilIBuFfer (dato: Byte); stdcall; function l2C_USB_GetBuffer : Byfe; sfdeal; function 1 2C_U S B_Wr if e Wi tfiB uffe r (adr : Byte) : Boolean; stdcall; function l2C_USB_ReadWithBuffer [adr:8yie; !englh:Byie] : Boolean; sfdcall; Booting the 7USB34 10 The TUSB34K) has a unique way of initialising itself at power-up. in contrast to many of Its modern contemporaries, this controller doesn't hove on-chip flash mem- ory for storing programs- Instead, it has ordinary RAM for the programs. Consequently, this memory will be completely blank at ihe start-up. Texas Instruments has included a small program in ROM that is executed at startup, which cleverly loads a program into RAM. This can happen in two ways. The boot program first checks if an S 2 C EEPROM is connected to the l 2 C bus. if this isn 't the case, the controller announces itself on the USBbus with a certain VendordD and ProducTfD. As long as the correct driver hos been installed in Windows (freely available from the website of Texas Instruments, http://www.ti.com), it will be recognised by Windows as o TUSB3410 boot device'. This then couses Windows to send the firmware to the controller. The exact mechanism of this process is explained in the documentation from Texas Instruments. The controller stores ihe received firmware in its program RAM and ihen disconnects from the USB bus. The controller then switches to its normal oper- ating mode and starts executing the firmware in the program RAM. The first meinod oi starting up is the one we've used for our controller. With this method all of the Firmware Is stored in on i 2 C EEPROM. The boot program in the conlroller knows from the header (the first few bytes in the EEPROM) that this EEP- ROM contains the firmware. Once it has verified that the header Is correct, the controller will read the rest of the EEPROM and store it tn its program memory. Once that has completed the controller switches to its normal mode and starts exe- cuting ihe firmware. This method has the big advantage that ihe end user (that's you) doesn't hove to install the device driver from Texas Instruments on the PC. You may well ask what happens when you have two different devices, each using o TUSB341G, but with totally different firmware; how would Windows know what firmware had to be sent to which device? The way round this problem is to pro- vide each USB device with a unique combination of a Vendor-ID and Product-ID These are stored in ihe EEPROM and are transmitted by the boot program when it announces itself on the USB bus. The documentation provided by Texas Instruments explains haw you con edit the 'inf' fife for the TU5B3410 and make it use different firmware for different combinations of the VID and PID. More information regarding the boot-up process of the TU5B3410 can be found on ihe website of Texas Instruments. i 2/2004 -ddtlcr eIkIioru source code has been kept as compact as possible, which resulted in a single procedure (Timer 1 Timer) for all com- munication with the interface. This procedure is also responsible for detecting and opening the interface. Immediately afterwards the program reads and writes to the PPC8574, which you had already connected to the 1 2 C bus, of course! We would like to reassure you that it's not a problem if you open the inter- face as soon as your program starts and if yon close it when the program finishes. In this case we did this in a timer routine that is called twice a second. You can therefore connect and disconnect the USB interface at will while the program runs. F@l8@W"Sgp This edition of Elektor Electronics also contains an application for this inter- face, where we can control various peripherals (see T 2 C Home Bus 1 ). It is also possible to design your own modules and to control them using this interface. You will of course need some programming experience under Windows for this. -ww: Using the DLL without arrays In general: !2C_U5B_Open This is colled to gain access to the inter- face. The function returns true' when permission is granted. Reading an 1 2 C chip: l2C_U5B_CIearReadPainter This should be used lo ini- tialise a new read command. 12C_U5B_ReadWith Buffer takes care of the reading of bytes via the l 2 C bus. This function takes two arguments. The first is the l 2 C address of the device from which we want to read. The second argument specifies how many bytes (maxi- mum or 255) have to be read. This function returns True' when the bytes have been successfully read. The function !2C_USB_GetBuffer can then be used to read these bytes one by one. Writing to an ! 2 C chip: Before we send any data we should call the procedure l2C_U5B_CiearWriteBuffer, This procedure makes sure that we begin with a clean slate. Next we use the procedure J2C_U3B_FillBuffer to send the data to the DLL one byte at a time. The only argument for this procedure is the byte to be sent. After all bytes of the message hove been sent to the DLL we only need to coll the function S2C_USB_WriteWilhBuffer to get these bytes sent via the PC bus to the desired 1 2 C device. This function takes the address of the receiving ! 2 C device as argument. with arrays In general: I2CJJ5B_Open This is called to gain access to the inter- face, The function returns 'true when permission is granted. Reading an 1 2 C chip: In this case we only need one function to read data from the \ 2 C device, which is 12C_U5B_Read. This function takes three arguments. The first argument specifies the l-C address of ihe device that we want to communicate with. The second argument states the number or byies we want to read. The final argument points to a buffer where the received bytes can be stored. This function returns 'true' when the communi- cation went fault les sly. Writing to an 1 2 C chip: Th is command also requires just a single call to the DLL. The function l2CJJ5B_Wri! , e takes care of this task. The first argument specifies the l 2 C address here as well. The second argument specifies how many bytes we want to send. And finally, this function requires a buffer that contains the bytes to be transmitted. Just as with the previous function, the return value tells us if the communication went fla wlessly. N.B, Keep in mind that it s the responsibility of your program to make sure that the buffer is big enough to receive oil the dotal Double Sided, 1.6 mm. Plated Through, Green Solder mask, Hot Air Level, 1 White Legend. Price including tooling + plotting + VAT 100 mm x 160 mm 1 pc = 45,74 Euro 100 mm x 80 mm 5 pcs = 68.97 Euro 58 ekktcr dednamts - 12/2004 m *Msk i •s* New Powerful functions FEATURES • Instruments - Meters.Scopes, .^g Transient Recorder, Function VIRTUAL Generator, Power Supply INSTRUMENTS • Test mode, equivalent to the standard SPICE analyses and a separate continuous transient simulation mode that allows you to interactively alter device and circuit parameters and examine the results immediately • Layered sweeps, meaning you can step almost any device or circuit parameter on top of any Test e Monte Carlo analysis available for all tests » Easier part selection, including a customizable Parts Palette • User-friendly interface with buttons and control tabs • Live updating in Simulation mode • Circuit wizard makes it easy to generate standard circuits including Attenuators, Power Supplies, Filters, Op-Amp and Tube-based Circuits • Tabbed-based Windows • Highly flexible graphing • 3D graphing '&sm weh CALL 01603 872331 FREE 30 DAY . ▲ FULL - OPERATIONAL SINGLE USER VERSION Used worldwide by higher education, research and industrial professionals B2 SPICE is a powerful and most importantly, ACCURATE software package for professional and enthusiast aiike. { !&, Ah n H * NEW “realistic models for caps, resistors, inductors N interactive parts including switches fuses, LEDs, etc. Layered Sweep tests (expanded). Expanded Monte-carlo tests B2 SPICE is backed by comprehensive technical support ^ both local rate telephone and online, full user manuals and tutorials and a NO QUIBBLE, FREE 30 DAY EVALUATION OFFER www.spice-software.com i = i ji.,1 VISA This unit, in combination with the USB/PC interface described elsewhere in this issue, may be used to switch four mains-powered devices on and off via the PC. Eight of these modules may be connected to a single interface, allowing up to 32 loads to be controlled. % The system is ideal for a small home bus! 60 eitVluw- IJ/JC04 +5V +5V +5V R13 Figure L The essential elements in the circuit diagram are on PC driver !C and a fcus extender Triggered by other articles on home automation In this issue, you may feel like investigating the possibilities of automating, or at least remote control- ling, a couple of electrical devices in and around your home. If you do not want to rush off to the high street stores to buy a box full of ready-made modules working on a more or less familiar protocol, then home construc- tion of a small system is a perfectly viable alternative. An I 2 C system can be used without problems for a small home bus com- prising a couple of features for control and switching. Provided extra bus drivers are applied, distances of the order of tens of metres are easily cov- ered. The connecting cable between the modules is reasonably simple as we employ 6-wire UTP cabling with RJ11 plugs. Also, there Is a wide choice of ICs with I 2 C compatibility, serving an, impressive number of appli- cations. At the PC side we already have a suit- able circuit in the form of our USB/I 2 C interface. Thanks to its design, this interface is capable of covering large distances and so forms the perfect starting point for a simple I 2 C -based Home Bus. At the "device 1 side there are a great many possibilities when it comes to creating an I 2 C connection. In this article we describe a circuit that allows four mains -powered devices to be switched (TV, lighting, coffee machine, etc.). Several modules may be connected to the bus, so quite a lot of electrical equipment in and around the home may be l bussd ? in this way. 61 Figure 2. 1 1 you use this board hardly anything can go amiss when building up the project, /copper frock layout on cur website) C7 = IGliF 16V radio! C8-C1 1 = IGnF, safer/ class X2 Tri2’Tri5 =TiC206D [Conrod Electronics # 186333) Miscellaneous: FI = fuse, 20m AT (lime lag), with PCS mount holder K3-K7 = 2-way PCB terminal block, lead pitch 7.5mm K1,K2 = 6-v/ay RJ 1 I connector (Parnell # 393-8359) S i - 3-way DIP switch RJ1 1 cable [Farnell # 75 A948) FCB r order code 040333-1 (see Readers Service page or website) Disk; ell project software, order code 040333-1 1 or Free Download COMPONENTS LIST Resistors: R1 = 47Q R2 - 1 OkO 4-way SIL orray R3,R4 = 5LQ6 R5-R8 - 2700 R9-R12 = lkn R1 3,R1 6,R)9,R22 =3900 R14.S17 R20.R23 = 3300 R 15.R1 8,R2 1 ,R24 = 39‘2 R25.R26 = lOkO %iupuvtiuj a ■ Cl ,C2,C3,C5,C6 = lOOnF C4 = lOOnF 16V radial Keep if simple As you can see in the circuit diagram in Figure 1, the active part of the cir- cuit consists of a remote 8 -bit I/O expander type PCF8574 and an I a C bus extender type P82B715PN. The PCF3574 in position IC3 contains an 8-bit bidirectional port and an I 2 C bus interface. The eight open-drain outputs can source’ sufficient current to drive LEDs directly. Th anks to inter- nal latches, the 10 remembers the most recent configuration. Four output pins control the four status LEDs in the cir- cuit; the other four connections each serving a mains output. Actually the LEDs and triacs are controlled sepa- rately via the bus, but the software written for the system will automati- cally ensure each LED rail always Indi- cate the status of the associated mains Semiconductors; SI = B8GC1 500 in round case (80V plv r 1 .5A) D1 = LED, green, low current D2-D5 = LED. red, low current IC1 - P82B715PN [Fcrnell # 559-258) O f IC5,IC6,lC7 = MOC3043 [Farnell # 885-710) ICS = PCF8574 (DIgikey # 296-13106- 5-ND) IC4 - 7805 Tri - mains transformer, PCB mount, sec. 2 x 6V/2 x 1 .5 VA (Famelt # 92<>280] connection (Le., triac). Three pins (wired to D1L switch SI) allow one of up to eight module addresses to be set; meaning that up to eight of these circuits may be con- nected to a single bus — and addressed individually. It should be noted that the -A version of the PCF8574 has a different slave address range. If you use the PCFS574A in another eight modules r up to 16 mod- ules may be connected to the bus. The bus extender IC r IC1, acts as a 'booster 1 ,, increasing the currents through the I 2 C bus and so making it less susceptible to external interfer- ence. If, as in our example, DTP cable is used, then a distance of about 200 metres may be covered between PC interface and module — more than enough to ‘wire 1 your average home we’d say Note that the extender IC has to be applied in ail modules connected to the bus if it is also present on the U$B/I 2 C interface board (or similar modules of your own design). The connections with the I 2 C bus are * 4 ' routed via two RJ11 connectors on the board. The mains-powered loads are switched on and off using a combina- tion of an optoisolator and a triac. In this way we have a good electrical iso- lation between the mains on the one hand and the circuit and the Home Bus, on the other The MOG3043 is an optoisolator with an internal diac and zero -crossing detector, which make it ideal for driving a triac. The friacs used are the common-or- garden type TIC2Q6D. They require a so-called snubber network to protect the device against voltage surges 62 dcktmji' 12/IQ 04 across the anodes. In this case, we’ve added a series network of a 39-_ resis- tor and a IQ-nF capacitor for each triac. If yon want to use so-called snubber- less triacs, then resistors R15/R18/R21/R24 and capacitors C8/C9/C10/C11 may be omitted. The low-voltage logic circuitry is pow- ered from the mains using a trans- former, a bridge rectifier, a reservoir capacitor and a 7805 voiiage regulator. This power supply affords electrical isolation between the circuit and the mains network. Construction The printed circuit board designed for the circuit (Figure 2) has a spacious layout with all connectors carrying mains voltages conveniently located at one side. Mounting the components onto the board is not expected to cause problems. However, do pay attention to the orientation of polarized components like electrolytic capaci- tors, LEDs and ICs. It is wise to mount the circuit into a sturdy enclosure. For guidance on aspects related to electrical safety consult the Electrical Safety page. The mains appliance socket fitted in the case has to be fitted separately as the fuse shown in the circuit diagram only protects the mains transformer. Fused IEC appliance sockets are eas- ily found. Once the board is populated, you need to check if the logic is properly isolated from the mains. This is best done by measuring the resistance between logic ground and both mains wires (Live and Neutral). Do not connect the circuit to the 1 2 C bus until the results of these isolation test s are satisfactory. Moifwe ire In order to enable you to get cracking with the USB/1 2 C interface and one or more device’ modules without having to do your own progr ammin g, we’ve written a small Windows pro- gram that allows module outputs to he controlled easily just using the mouse. This program not only verifies the proper operation of the hardware but also forms a good starting point for your own experiments in programming. The main window shows an overview of selected outputs with associated names, with switches to the right of them. The setup window allows one of the connected circuits to be selected (including the test circuit with the Figure 3. This little program allows □ simple mouse click to control any individual module output USB/1 2 G interface) and subsequently add any number outputs to the ’switch list: as well as tag them with a name. The name tags then show up in the overview seen in the main window. Both the executable program and the Delphi source code file are available free of charge from the Free Downloads section of our website. The actual use of the modules in or around your home is left to your imag- ination and personal requirements. In any case, there should be plenty of possibilities — for a start, you could automate the cofree machine. How- ever, do make sure manual control is also possible, else your project will be depreciated (to say the least) by your housemates. •-4 12/2004 -sliiluui 63 u Visit our wabsite I www.disteLco.ukj 11 HE ORIGINAL SURPLUS WONDERLAND! 1 r HIS MONTH'S SELECTION FROM OUR VAST EVER CHANGING STOCKS Surplus always I wanted for cash? | GIANT 10" 7 SEGMENT DISPLAYS I IC's -TRANSISTORS - DIODES A bdk pun±s5c Eftatfes us to trfag to i fog- 9 ? GIANT 7 Setyneri cg-j assays S' a no*H/ Effoccfabie prcri- j he HIT UikidUef size g%ss Efflef0:ra‘ read- scwi:/ S tong dstonees end ententes a test cf ^do& :cns ridLdhg score bosnk ctotel clocks, coun- ters, event timers &tz As flie imte zre □ s _ - l etecsrzmecrrarrcte -le.-ce -raid Ecestee ton 12 V DC, Srroe ^I'Sting vs zvtozrez resy^ RC cr PC may be tted fa oxteiteig|tecriTiJi|fed|p& L s^axre rcagrar Zara Fzv,*ra mejnexy Arch g^szy sirpres des^i. 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BRAMD NEW - Ortfer as AIYOO, Only £39. 9 5 otkfa (B) See w‘A'rt’.d/sfe/.co.uJ£''data_/nyPO.iffmj forpioJu/E + full details HARD DISK DRIVES 2VS - 14 " 27V TOSHIBA MK1D02MAV 1.16b |aptop(12.5 mm H) New £59 95 2 J i 1 TOSHIBA MK4313MAT 4.3Gb laptop (^2 mm H) 7/ew£105,£H3 2!4 m TO SH I BA M K£A I = ' 1 A V 6.1 Qi laptop ( 1 2,7 mm h) New £93.00 2V TOSHIBA VKt0:3-3AV Vz G: 2i::i -‘2 r. Nz *-£149.95 2 T ,A to 354“ convecsnn lot tor Pels, complete wi@i connect: to £ 1 5.95 3 : y CO M PAQ 3 1 37C6-B 21(1 BM) S gb U LTi SCS 13 Weiv £1 93. 0D 354' FUJI FK-309-26 2Grrto PJR.1 OF RFE £59 95 3%' C OH HE R CP3024 20 mb IDE l/F (or equrv.V RFE £59.9 5 314" C OH HER CP3Q44 40 mb IDE VF jnreqiHV.S RFE £59.00 c’3 T QUANTUM 40S Prodrive ^2=-.b SCSI LF r ^e.v RFE £49.00 Six’ MIHISCRJB1 3425 20mto HtFM t F {cr eqiiv. ) RFE £49.95 5 : V S EAGATE 3T-23BR 30 mb RLL W Reform £69,95 51V C D C 942£®-51 40mb H H f/FM LF RFE tested £69-95 5V*“ HP 9754B ESO l to SCSI RFE tested £99.00 57/ H P C 30 1 D 2 Gbyte SCS I tfiffe ren tis I R FE lasted E 1 95.00 6 " NEC DZ24S 85 LtoSMD interface. New £99.00 5 ■ FU J RSU h I2322K 1 6GLto S?, F D I F RFE tested £1 95.00 8 T FU J ITS U ?i ?2392K 2 Gb S' M D L r RFE tested £345-00 Many 0 the/ floppy & H ririves r iDE T 5C5L ESDI &ec from sfock, see website for full stock list Shipping tjn all drives is codie (C) Legacy products High spec genuine muttysync. CGA t EGA, VGA, SVGA Mitsubishi FA3415ETKL 14' S'/GA fcluttsync Ctinr monfetr w~ '"re Q23 &± ptori Lee- reszn_zon d 1324 t 7£o. A isri- eZy t> rpijto elo.vs zemezini to a bos of ccnrDjetto -z._z 13V PC's - CGA. EGA. VGA i SVGA mods EEC, COMMODORE frcajdrig Arri^ T2tMJJt ARCHFVEDES and APPLE, ?4sny fsajes L:^=ed ^cecfeta. v?'’ SH'.-r-ch'rg snj LOW RADIATION MPR sfl e c&a fen Futy gusranJsed, to EXCELLED 1 Ke used ccratcri. TEt& Swh-ei Bsse £4.75 vcucau.fcrfMiPCkdudBA Only £129 (E) °§?f ExtefTtiJ Gobies for i7t>zr types c4 ctxrigijt-to - CALL Generic LOW COST SVGA Monitors IV i s eftoose ihe make, which includes Compaq. \iits ubusni, l Shi etc. Supplied mady to run v/ith 3ll cables. Standard RTB 50 day guarantee. 14" 15" 17" £59.00 £69.00 £79.00 order iDS4 order IG21 order 1 JE6 Supplied in good used condition. Shipping cede (D) TEST EQUIPMENT & SPECIAL INTEREST ITEMS this section are pre owned.' MFTSUBUSHI FA344SETKL 14* Ind. SVGAmonitois £245 FARNELL 0-S0V DC @50 Amps, bench Power Supines £995 F ARN ELL AP3^30 CL3 jV DC @ 80 Amps, bench SUppy £1850 KINGS HILL CZ403fi b&fit ftDG 200 At ps - N E'A 1 £3950 IhW to 400 kW - 400 Ht3 pbse pcA-^r sources -ex stock £POA IBM 8230 j ype 1. 1 often mg base unit dfr^f £7£0 Wayne Kerr RA200 Audio ftsqu^tKy response ana^toer £2500 IHFQDEC UJ. 24 psn, RJ45 netAOTkpatchpajiEis. s;iH93 £49 3 CO M 1 £670 1 2 Pfot Eltoemet hub - RJ45 cqnnect&to =LE>97 £60 3 CO M 1 667 1 24 Fz rt EEhemel h - RJ4 E- cz-r, n ez' z to £69 3COM 1 6700 S Pori Ethernet hub - R3 45 cc'inez leto NEW £39 IBMi 53FS5Q1 1 often Ri;-g IC-3 20 f>zri kibe m-zdules £POA IBM MALI Token rbg i^rbufen panel B22S-23-5056N £45 AHA 501 Low ctistrwtxjn Oscfetor 9Hz to 330Khz, IEEE I/O £550 ALLGON 8350. 1 1305-1850 WHz hybrid power smrtffrejs £250 Trend D5A 274 Do to Analyser vi^hG703{2M) 64 tto £POA Marconi 6310 Prizgi^rrmtoL’e 2 to 22 GHz s'Aieeo generator £4500 Marconi 2022C lOKHz-IGKz RF signal generator £1550 HP 1 650 B Logic Ans.jji’ssr £3750 HP3781A Pattern generator 3 HP3782A Emsr DeLc-czar £POA H P 6 62 1 A Die I PragrcnBnabfe GPEB P5U 0-7 V 1 60 iratts £1 S 00 HP 6264 Rack mount variable Q-2GV ® 20A m.«;srtfd F5U £475 HP54 1 21 A DC to 22 G Hz fcu r channel tes t set £P O A HP 81 39 A apt 020 300 MHz pJse generatm, GPIB eto £7900 HP At, A.0 & pen H?GL h’gh speed drum ptodeto - fern £550 HP ORAFHitASTER 1 8 pen high speed ptotter £750 EG+G BreoVdeal 95035G PrerZisftCin tock in amp £1800 Keith Tey 590 CV eapaeto? / voStoge analyser £PQA Racs! CCR40 djsi 4-9 tnarjne -.t: ce resxjfder system £3750 Fes hers 4 5 KVA 3 ph On Line UPS - Hew hettertos £450 0 Erne rso n API 30 2.5KVA tostosb^l spec-UPS £1499 Mann Tatty MT 645 Hftq h sreed l re printer £22 00 Intel SBC 486433SE MuTiLus 455 system 8>’, r D Ram £945 HP 6030 A '3-200 V DC @17 Amps be*rcb power suDpfy £1950 Intel SBC 436‘125C0& E r 'b r :ez l . r /iaxis(M5A) Haw £1150 N ift on H FX-1 1 (Epbtpitot) exposure control li nil £1 4 50 PHELJFS F MSS 15 pro. TV sjgflsl generator £1250 k i'ztora!a VME Bus Boards 5 Ccmpmenfs LisL SAE . CALL £POA Trio 0-1B vdc I near T melere-z! 30 amptsench PS ’J. Hew £550 Fujitsu M3941R EEXJ LF.M n^h bsnd printer £1 950 Fujitsu .V.3041D -II _-V printer wtto netwcrit tnto^ze £1250 S is me ns K4400 64Kb to 1 4 QMb dsmiK r £29 50 Perkin Elmer 299 B infrared spectrophotometer £500 PerRin Elmer 597 Inhered spectrophotometer £3500 VG Electronics 1035 TELETEXT Decocfirg J/argto Veter £3230 UghtBend 60 cutout '"z" zzec '.'zez '.DA s £495 Sekonlc SD 150H 1 8 channel d"g :si Hybrid chart reco'der £1995 SiK 2633 Mjcrophona cjs amp £30 0 Tay ! o r H o bs o n i a. ys utf amp^Ter / rscorder £750 ADC SS200 Ca-z-z" z z.-.ze zas rietez'.z: rr.-tz :z- £1450 BBC AjM 20/3 PPM Meter (Ernest Turner) * drhto etec&nrats £75 Ati RlTSU 9 654 A Opf zsi D C-Z.5G 'd wsvefo mn nxjn zz - £5650 AN RlTSU ML93A opbosl potew meter £990 AHRFTSU Fifc.re cptic chare ct eristic tss L &st £ PO A RfiS FTDZ Dual sound un’t £650 R& S SB U F-E 1 V&on moAjfator £775 W1 LTROH 6630 B 1 2.4 1 206 Hz RF sweep generator £57 50 TEK 244a 1 SO MHz 4 trace csd-ToscDpe £1250 TEK 2465 21 j V~z ZI-I VKz zaz. z:-:zie rezft: — z_ -_ . £1955 TEK TOS35D 4 ICVnz dig reaJ&iia * (£sk cfefre. FFT etc £2990 TEK TDS524A il I Y " z espial realtime + colour cisbteyeto £5190 H P35B5A Opt 907 20Hz to 40 Mhz spectrum analyser £3950 PHILIPS F W1 7 30/1 0 60 KV XRAY generator & accesscriea £PO A VAR LACS - Large ran gs from stock - call or see our website C LAU D E LYOH S 1 2A 240V s : ‘die chass autb vc- l f eos £325 C LAU D E LYO H S 1 CCA 24C A 1 5V 3 p base auto. vod. reos £2330 m 19" RACK CABINETS Europe's Largest Stocks of quality rack cabinets, enclosures and accessories. Over 1000 Racks from stock This month's special 33/42/47 U - High Quality * Ail steel Rack Cabinets «/. Sr Mez^ by Eurocraft. Enclosures Lte to the highest pas- sible spec, razft; feotures sU steel construction 'ivrin removable front and back doors. Front and L=:'v CvC's Sts hinged for easy access arid a& i'Cok2ble vrith five secure 5 lever barrel locks. ' The front door is constructed of double ws ted | wbh a r das igner sty le' sme ft sd a cry : ic front f panel to enable status indicators to ns seen through the panel, yet remain unobtrusive, | Internally the rack features fully slotted rein- fzjrced vert cal fbeng merTterz- Id take the heavi- est oi 19 3 rack equipment. The tvra movable veritoel toting shuts (extras available) aw pra I punched tor sta^dteto 'cage nuts'. A mains dis- tribution panel “temafy mounted to the bottom I raa.r r fKtrrides B x 3 EC 3 p-;n Euro scckets arid ' x 13 amp 3 p.n switched utility scckeL G . era ! ent^a- Lz.n is pnr.itfed by fi±-y louvered back doer and bz_Z ; a sftin r :ed top saezen .'.nri top ante stee 'zevras. The tap panel may be removed for fitting of Integral fans to the sub plate etc. Chher feature ftolude: totted cstetora and T-. opr tovaters z ra z ^n-ziie-te ute; by pane' at totter rear lor cebte connector accsss eto- Suppteed .n eicellenL sfightfy used condition with keys, Ca-our Royal btoe. some gray avaiabte - GALL - Can be eupp^-aj in many other conbgwab-prs VIDEO MONITORS PHILIPS HCS35 (some sty to os C746B33} alLraclivety styled 14" z.z z_- tz _ to - to. both RGB and standard compcai'e 15.625 Khz video inputs ra SCART socket ante separate ph-orte jacks. Integral audio power amp and speaker fz - all audio visual uses. Wi connect dract to Amiga and Atari BBC computers. Ideal video monitoring / security scz'tes: :."i v. direct connsctton to most colour cameras. High tpra^y with many features such as front ccftcsatos Tisp ccshci:;. VCR correcbon button etc Gtxto used condriioo - fu iy tested - gu santeed pi n i. , rn ft n H D enertsionsz W 1 4“ x H I2Y/ x 1 5!te* D. Ulliy W3.UU {Bj PHILIPS HC531 LTzra compact S T cotour video monger w rih stan- dard composite 15-625 Khz video input via SCAR socket- Ideal for a.6 moritoring /secur?/ spp^eshons. High guafity, ex-equ^imest fu% tested & guaranteed (possihto ntirwr screen bums). In asrac- tive sqirare bfack ptosbc case measuring WIU” x HlO“ x 13 *£ w D. 240 V AC mains powered- ~ q n jy £79 QQ (D) INDUSTRIAL COMPUTERS Tmy shoebox sized industrial 40 Mhz 366 PC system measuring only (mm) 2G6 w X AS h X 272 d. Ideal far dedicated contra^ appti- zatzns nmning BGS, LLhxk pr even Windows ' Siae3 case ccn- tekts 85 to 265 V AC 50 / 60 hz 70 WaiS P3U, a 3 stat tSA passive hackpteiTfi and a Rocky 316 (PC tB4) stendard r board com- puter wfai a MByte NON VOLATILE soid state ’Disk On CW tf RAMDlSK. System comprises: Rocky 310 (FC1Q4) SBC ISA card with 40VHz AU 386SX CPU 72 pin SIMM stot with 16 Mbyte SIMM AMI B'CS battery backed tp reel time cteck. 2x9 pin D 16550 serial ports. EFFVECP prmtor pori, mail DIN keyboard con- oectoT, Poppy pofL IDE pen ferhard drives up to 528 VBjte zs: = ri:y. ■■. =’ totozo ir.S' toto 1C4 z^s zZZ-tob ; re E ME,:e 5 : z state ' d-.sk cn"a chip* has rto BlCS r ar>d can be fdiskEd. fannatted 0 bz-z:edL S up-p-Ied B RAN D NEW fuiy tested and gigr- snfeed. For r_ d^ia s&s featured Hem on wehsiia. Order as QG36 100 T s of applications inc: caq nn fire wal I . rn me ra . ra batics etc U n 1 y t u a - U U \ D) 33U Order as BC44 External dinrenstons tt¥tt^ 1625H x B35D x 603 VL (64’ H x 25' Dx23V/’.V} Only £245 42U Order as DT20 E.-to-ra j--rara': x -3 rrra=2L:'SH a 63zD a E‘j 3> .V. (79 5’ H x 25’ Dx23H H Vt Only £345 47U Order as RV36 External dimeristons [T' - =2235H x £35 D = £Q3 VT i35 r HiZf D x 235-/ W ) Qnty £410 Cat! for shipping quotation COLOUR CCD CAMERAS M I TP-T* r*w Lfziiziizted y 5 miracle- of mndem lechnoEogy i ctxr sz^ztaJ hujing povj-er t A quality product tea;- 4 faring a fui=y cased COLOUR CCD camera at a ^ _ gS r a s’Aay pdpe 3 Ur“ teafaras fa J autz znt seaslr-g far sss in low light 5 high light applicstEons, A ig mm tocus ivide angto tons q -es excel ten l focus jf and res □ I ut ion from close up to tong rerge. ;. be composite video cutout iV correct to £j tj CttT.pzsns mordo r cr W , : a SOAR! sobfteii and most video recorders. Und runs from 12V DC so toeal for security i portable applica- tions where rriato.s pbr*ef itci £v£ "SE'e. O’ v era-! efimenstons 66 mm wsfe x 117 deep x 43 high. Supplied BRAND NEW 0 fudy giEranteed with user date, IGOto of appfifs- borss fadvtf ng Securif/, Home Video Web T'. Web Cams eto. eto. Order as LK33 ONL Y £79,00 or 2 for £149.00 jbj SOFTWARE SPECIALS NT4 Workstation, complete with service peck 3 and licence - OEM packaged. QNi. y £39-00 m EH CARTA 9 5 - C D ROM , No l th e latest - but a t thi s price ! £7 95 DOS 5.0 cn S^cSsfcsw^h concise bocks eriir QBasic. £14-95 WlndoviS for Work groups 3.11+ Dos 6.22 do 3.5" disks £55,00 V/indoYi's 95 CD ROM Oniy - No Licence - £19,95 V/ ord pe rfect 6 for DDE szzz ed on 3%“ efrdts ifliiih mams! £24 ,95 shipping charges for software is cods 3 SOLID STATE LASERS . ' r l i red. 67Cnm toss - efroda assembly, UnHaBs fmen 5 V DC at approx 50 mA_ Originady mate for con&mous use fa intfoshtel bar- cods scanners, the laser is mounted tn a removsbte sofid a-urr^msn bfioefa which hincSons as a heatstoX and r^xf opficaf mocml Dsns of block are 50wx50dx15h mm. Integral features Hicktde over tern- ze raters shutdown, current control, laser OK ouput and gated TTL ON f OFF. Many uses for experimental opdes. comms & Ightshwra etc. Supp'tod cctfitpleto iv.to -zato sheet Order ss TD91 ONL Y £24-95 {A} DC POWER SUPPLIES Virtually every type of power supply you can imagine. Over 10,000 Power Supplies Ex Stock - Call or see our web site. t RELAYS -200, m FROM STOCK Save GjCTs by choosing your next wiay from our Massive Stocks ■iD.=--g i/les f-bh as M :s. # ) G;:s. f Crsds ^ Stoto, CottisnenlaL Contactor*. Time Defay, Reed tdemiry Wetted, SoSd State, Printed Circuit Mounting etc , CALL or see our web site wuw. distnLco. uk for more fri&trnatkML Many obsolete types from stock. Sava Ellis > a A: * * « ■ -ft ft ft ft ft 1 ft ft i « ft a ft ■ * ft ■ • ft a- ftfta • ft • a ft a ft a * ft * • ■ ft • ft • a- « ■ • « • « ft * * * * ft • EiECJR0IT.es- ALL MAIL TO Dept EK 5 29 1 35 Osborne Rd Thornton Heath Surrey CRT EFD, UK Open FAon - Fri 9.00 - 5:30 18 Million Items On Line Now ! Sect/re Ordering r Pictures, Information ^■tsign www.distel.co.uk ema /7 = admin la-dis tel-co.uk Sc-ZL-ra Ste ALL ® ENQUIRIES 0208 653 3333 FAX 0208 65 3 8888 AJ ntoes dr UK Mafafai xt UK customers add iTSi-. VAT to lOTAL Oder ?Tr;m. ™ ; grte" £10 Foe arm ry otoara as raifTi C z i a=TTT tto. i’STzfici rW A A, ITS* 03 1 Uhher^s arc Licra AtoSiiritis - nxrintjn actrirt crdsr£100. Cheques OierLi'ZO are =LDto^ to 7 vtorieng dea ra rm Carriage rhsges (AJ^OSL (BFF650. (C^lO, (D-PCIS-OO. (EfCiaCO. {FHCALL Aiav sprat 3 rfa-ys for - fessr CALL M gcods zr.rja-n to cur Standard CorsjHjns cf Safe v-fach be vlassd ^ erwiisfe and tries stotod gsaitosd tor 9j arra . 4J n_Brantoss cn a re&cn to base txs« Al righfa^ reserved to change prices / speesDcaSdns wttiout pijf rebze zuz^z-c: r aao_ DszcutoE ■br 7 ,to'_rre. Toe pnres prad faraxpLs gDocte Al brazerranz. eto-3ano,%^etojfi± z Dzpra/ Eacrznics 2QG2 Ei.Oz 64 ekklor eSntfG^ics - 12/2094 BS2-IC i BS2-SX BS2E-IC BS2P/24 BS2P/40 ”| 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 Servo Drivers Motor Drivers DMX Protocol U/Souiid Ranging Animatronics and Specialist Interface-Control Modules Quadravox SensoryJnc Parallax !' Tech- fools BASlCMicro MP3 & Speech Systems Voice Recognition Ubicom Tod Kits ! PIC & Rom Emulators PIC BASIC Compilers Development Toots Milford Instruments Limited Tel 01977 683665, Fax 0 1977 681465, sales@milinsf.com :: Special Offers :: TEKTRONIX 2445A(^) Cursors efc. Elsjz.e d \vffi 2 Ttfironix pnAes. Ttiiriir. i 2112 I'l '-L v: mm 2 _l iDCAt'j 1031*5 iito prefer OnV E525 ILF. SISfM Osc. iGOtMr-Lfr _ ms CIRRUS tnilzA E:_- : _= , - Vi- .. - frahr am ®*12&3 l£D __ £55 clllhah UDita 35 09a bua* 73 fcrgs irtft v-i _ i i orijfrg Caic £33 WAYK£ KEFIR &«4 ftaificMt 0ft3gi ESD RAUL 63*3 J _-: r'. r 6 - l-ttZ-TiJIitR' -'='=■ = " £flU&[ £5Q rawi §5::b Sz it' 1 1- £75 H P. 3312A ~T. fen iZKZ-t IU lRZ AV.-V Sua^-Trl 2vv Ejtftt j*: SMffii^rfifDaijifFl^ . : E3M Fi flHFIl AU 14755 4 *'.”**,• It . T Mj-jf 1 zV ^3" LHBd £333 FARHOt 0561 Lo* Frig S>* &3 fen .£35 _:■., _ F-- -- ; _ ; I_LMi G."'," £*4 HUE BSKftlkzMj Tree HUS DHM 45 E&ji sanr»». Uis3 £33 H P. 33 ISA fm OCe®C-SUHZ - _ £175 se ^ mTm h.i- ; ? _■ :-i FAftHRl UW Sr-S= IGHI-TWH U-c? ::”4'.x TTl C m: . ’ A - : - , 3t -«Sst H.r.>i:A Lie jl Fm : i r i-i£A _jj= i F^ M* C-.Tr"t Tr—— FLU iCt 77 V ra&f 3 54 ■; ‘ M FLITAE 77 Si M^ £70 KEME EsseUO x? (tmOE-CUS THU!^fcT*tPtl10 FkcSm -VMM I EZa 2Utrl^Pr tw TKURUr/IHMiDER PSU F - C-?A ■ I.MH: . Ft v£-D jT5 :■ Racal Automate ,». Dalron 1] H gh Quabt; 6.5 Dig:.! Ben:r v^HimEter’ Tru 3 R !.! S 4 a re C l te nt Ca f t -" .... Just In ... H.P. B64SA Sgpl BssreDT AV.rV E "l ■ -i-E 'IV-r £250 KEHWMD C-S4525 G 3 C>:s.:cvt Em iv Ejl.r-- _ £125 Leads LB8S23 Gtsedascope Dual Tries 3S4JRI £140 C 0 HID Q 5380 lm-: <& it- :* E:_l Tixs 2-3Mhz £S5 RATIO HAL PANASONIC VF77DSA D^sstsoi teases . £T7S « WOOD VT17S V. '.Mf £50 KDflfaOD FLT40 iVm, & FaiTa £53 KEM^DDO FLleTA iV.”.- i Fjr.fr Ifesr UseJ £75 Knr £52 BWdjfetrtetS £75 EifMjfrS fgf: svmlV £25 ’Li£j3'Ll :^-L A r: : vVri’ i l: 'Vi:_ :~:m i^_icG £1» tiico E5S hUR £0 Mi “51 1 True F-U5 ttffiHSSt. AHoaegiig =Hz - ?^7 £155 GOEJ1D J3S sirSSg tec 1 Cfir - 1 ^^Tnirw osCrs&s; • •'•' ' ~ ' £75' £115 AVD3US " iif.'M.iiz, _i:= .s. ', C4»AVOrto : GODOW1LL EYT427 ftei Ca AC UdEvjfcaffitf tOUn^QO ]£ ranges lCtij'i Vm: SCURTROH 7f ST DUU fc&fifliTn * Farnell DTV 12-14 Oscilloscope OiJil Tr^De 12 MHz TV Coupling Only ope I 4SEP SOLASIftOii 7i:E 1 M SlU r ViJLiSr _ ‘ 1 9M3U LCIt tfe^siigs. Qg&i v~f-“ cl R. G LGl D HURTROH T HACKER V:- Partab i ,9 G jIW A tAuiigyii^ PaJCWr&56AlQ0CriV APSQSO H.Vj FARXELL - FAR Ji ELL j-57. 7-2: 1 Farnell LF1 Sine/Sq OsciJIoscopc IOHz-IMHi Only, OSCILLOSCOPES TBrntOnS ms-fti Osi Tto ?K3l&ir tes airsssJ lUMKOtOA TOSS) Oad Tooe 1JC4&5 303AS ranRC<]iit “eej: :jl ei'j-j LECftOT 94BHi Dui Trafc irewrtr 5S HTA£H 1 <'5632a Oeal Tnra SLfeii wslps -vjcea u:vn t; FKHP5 =V2-:-;j -tKTF! -:s "W^i .MMM-fM TEXT S - j'i.: Tnce ICC 'Arc E'J'iVi ”'_i' ~ T K m . 1® _ -Cf IS3U.-J L^J E . E.L T-i*e lyjvjiz Ce iOK£L Dtia -r — z 'fri!UfSf1A3C63 2 __ FMMLiPS . 727; FviAtfs me - too . Etse zi l€S=iF _ £57 = " : -^PT: y.'1-Z - - !-&€. LEE- DgdM- tt; LLP. S657A I'jT 10HMZ - I3SW5C G*ti h r. : : Tic Ej“ 3 [Old - 3TCILF.-Z 2 - Zn _ H_P_ .SkoA Sjcfis TuJCKKZ. - SSOWe Sjj Gi(= JUS APS5J si* IKr^KStfe Sg fes r;"’ EM4S £13:7 St H*S30 1 0 03ff 2 C-U3A FARliELL E ji Pi.'j '.AE.E-Z 7 MsV *>ZA " .if QVD LCD fep'a/ ne a FAfiWQl IBM S4&A CF7A . . £33 FARRtLJ- 133-1 C~3fjV 5-1 A ££3 Miif z'ztJ ri iirr iriiittif. te&Sng TraEsfemer 24tfV fcv6.1 5DQVA £49 i;.:-' :' _Mi_r LEO L'&nil ■ I-- n -:--i vvvj- -- :>:c - rv=;“ Co.rt— — RIUI SCSI 41.1 -v St: :-:■ tV.-c-t?:- 1 '-: H. P_ .rv r A SjM- F_r,-c-- Z-:.- TTUHi HARCQW ES3 AacAfcjdi tatfjttf H P, 4 ISA ^HSEfxe Ati^tes HJ=. |£S Ifear Qizt-IQUEtl _ _ ftp. 29CEA Dsrurar. . STEWART of READING 17A, KING STRE^ f.tOFTflP.lER, NR READING RG7 3RS Tel: 01 1 89331 1 1 1 * fax: 01 1 S9332375 www, Stewart- a f-r aadlag. c o .uk .1 i'hJccoj i iverr s?oieh te TriJt fyfjiH Eiftet Ji iryri^BOUfflt) WAKE K WSi — ILP. II ILL =u» Baa iraur 50HHI tUACCU ZUt ?TKJ CltiBBS H.P- CMI33 30E5Sr ftp. sicA tCHi > laafjfirtj n&maw hp. i§m ngc sc cssw^ 'l in; l^dihtes 53f5Kr £42= .-£££■ £215 E:I I £l;-Pl £=:•::• £27:^ ClCCC EHSL £1154 Cli;5 E2Z1Z ti.; _ t?:' Spectrum Analysers H_P_ SacTB SU! H>, H_P. »M54f S‘Z J j-2SS{’ LLP. SiZlE ‘ f. r .-_ ■ ' II-.- ~ zt~ . mu DM £A;c: n::c DM H P f=ji ..-M i::i- ■ V-:-:- >: H_P. gp$m *!Ti IAbs rant ldCKHM5SCUKr, H.P. IZIiA. ZMr-JIVrti LLP. 33804 9*— 5»Er AETASTfST EUtjlS 1C*Jt35Etr EAH' 5 :;■ : iOTl-fflatr. 5-FJ.-Z I Z M ll-.il - ril-jD-ICV-J - ; - : : iu.~co.4i ?ir: :.j-j naA-> HP. TI2 *ia 5S7 iaet-C'S; , f -_- H.F.H17 ES3 t KHMtrUHZ ;Z5 i ECH'-flz- • HZ j ltd luA Frfr^i^TC/ A Tine 1 fft* P. £75tt A^jssr JVKtJSCOUHz £1751 ILP- S77A IfefigjA . Araijii? 5H1-2CGUKI DM ILF. 5331 CA. L-izan Ate,^ 0r< 0515153 SMI ObO Men CF3CC Polite RT te&m E15M H.P. ttlizi PSI I Z77 l >2A EM ilp. sesiis pai g-sc eub ILP. K30SO PSU Dud G-1H CH5A_ _ _Erai HLP. S?S FSJi>27//t>5A £: *C ILP. CS73A PSU Trpfi! ijfl$hg frm OSS' •>-i :-:A m cu “T j C-^JTA DUU £5dgfc E4K.T4SA £311 RULE tl Rlffli psd EfcttUg j £4 £7 1HIHET TrDI EHU.U 75 ngi ETi: AifTHUET 6T7 Fr^jrp-r-sgfe FHOiTira^ £1159 ILP. -T33i£ £15M FJOLii]cnfl*E Ijp* 1995 2c SC fSM H.?. IclVzit a3t?lA E E-J tli> H f, AS45KT 33120A F«ft^ C^vARa .;,- ■ ■ ■_■ . ..^- : SCarf TtrTRCDttf A75320 A-3ary fitficSM £1753 HJ£ $3EHASf3 Fandna San DC - tCOGil {SBAfOSt iUEI STJtR JCIFfTOa J!J53 Fii?££nS 5n: Q2Kh3fii». El 41 ■■m -MT'ifnr, :-,n? ELF. I11EA ftua Sanfc3nif 1i4t£&£& E1958 K J. Ec E“E : ■ - Sjirf GiQ Z1’ZI®3UKf £2M8 ZS±*m. 'WTEH 1 53HI . £« £is Radio Commumcatirms Test Sets ttMSCOdS55>19SS : : - : i i I'^aARicin-: vtootu^j i7-.-L R,EL-:” -I-I rrzi^mi: r.fLi E75I Used Equipment - GUARANTEED. Manuals supplied. is a VHiV SAm SAJMf Of STOCK: SAE to Qsss. Please cf^i arai ortfcsmg. CARfllASE all unte £56. VAT to te sfei to T$y d feeds sd C±f^oa GC'Cr N o1 Number One Systems I^cl ly = PC 1 The world beating PCB design software Jjku. S a At a. * Easy-PC version 8 is released Winning accolades the world over, Easy-PC for WmdowsVS is a major milestone in the evolution of this extremely popular software tooLTry a demonstration copy of Easy-PC and prepare to be amazed at the power, versatility and remarkable value for money. SrtlL m ft New in Version 8 tt Sketch Mode Routing H ODB++ Format Export H import Bitmap EH Single-Sided AutoRcute H Customisable Toolbars M Auto Smooth & Mitring of tracks H Wires & Jumpers 9 Unified Quality Check Plus lots more..,..,. Fully integrated Schematics & PCB layout in a single application complete with forward and back annotation. Design and rules checks at all stages ensure integrity at all times. Profesional manufacturing outputs allow you to finish the design process with ease. Stop press... Stop press... Stop press... Stop press... Stop press... By customer demand now with Eagle import as well asTsien Boardmaker 2 import. call for a brochure, prices & CD on ^44 (0) 1684 773662 or e-mail 5 sles@number 0 ne.com you can also download a demo from www .number one .com ZX,:. ii-JL kL ft-rmi'."' Number One Systems - Oak Lane - Bredon - Tewkesbury - Glos - United Kingdom - GL2G 7LR UK 66 ekktor dcrtroriki- i 5/ 2004 Quasar Electronics Limited FO Box 6935, Bishops Stortford, CM2 3 4WP Tel: 9B7G 246 1826 Fax: 0870 460 1045 E-mail: sales@quasarelectronics.com Add £2S B P&P to all UK orders « 1st Cfass Recorded -£4.95, Next Day (insured £250)- £7.95, Europe -£6.95, Rest of World - £9,95 (order online for reduced price UK Postage), We accept all major e re ditfdebrt cards. Make cfiequedPO's payable to Quasar Eiecfronles. Prices include 17.57a VAT. Call now for our FREE CATALOGUE V¥rth details of over 300 kits, projects, modules and publications. Discounts; for bulk quantities. MAIL ORDER ONLY. QUASAR electronics Hagtog yaj mao flgr# cemss-fcra/ 0871 CREDIT CARD SALES 717 Motor Drivers/Controllers Here are just a few of our controller and driver modules for AC. DC, uni polar; bipolar stepper motors and servo motors. See website for full details. NEW! Bidirectional DC Motor Controller Controls the speed of most common DC motors (rated up to 32VDC/5A) in both the forward and re- verse direction The range of control is from futfy OFF to fully ON in both directions. The direction and speed are controlled using a single potentiometer. Screw terminal block for connections. Kit Order Code: 31 65KT - £1495 Assembled Order Code: AS31 66- £24.55 DC Motor Speed Controller (5A/100V) Control the speed of almost any common DC motor rated up to 1 0OV/5A. Pulse width modulation output for maximum motor torque at ail speeds. Supply: 5-15VQC. Box sup- plied. Dimensions (mm): 60Wx1 0QU60H. Kit Order Code: 3G67KT- £12,95 Assembled Order Code; AS3067 - £19.95 NEWI FC / Standalone Onipofar Stepper Motor Driver Drives any 5, 6 or 8-lead unipolar stepper motor 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: 31 79KT - £9.95 Assembled Order Code: AS31 79 - £16.95 Assembled Order Code: AS31 1 3 - £2495 NEWI Bi-Polar Stepper Motor Driver Drive any bipolar 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: 75x65mm Kit Order Code; 31 58KT - £12,95 Assembled Order Code: AS3158 - £26.95 Most items ate 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 PSU445 £8,95 Rotting Code 4-Channel UHF Remote State-of-the-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: AS31 80 - £49.95 Computer Temperature Data Logger 4-channel temperature log- ger for serial port. c 0 or *F. Continuously logs up to 4 separate sensors located 200mA from board. Wide range of free software appli- cations for st ori ng/u sing data. PCB just 38x38mm. Powered by PC. Includes one DS1820 sensor and four header cables. Kit Order Code: 31 45KT- £19.55 Assembled Order Code: AS3145 - £26.95 Additional DS1820 Sensors -£3.95 each NEW! DTMF Telephone Relay Switcher Call your phone number using a DTMF phone from anywhere in the world and remotely turn on/off any of the 4 relays as desired. User settable Security Password, Anti- Tamper, Rings to Answer, Auto Hang-up and Lockout. Includes plastic case. Not BT ap- p roved . 130x11 Gx3Gm m . Po we r: 1 2V D C . Kit Order Code; 31 40KT- £39.95 Assembled Order Code; AS3140 - £49.95 Serial Isolated I/O Module - ROM: notches • Flash MJETDEcntrcHer Starter Kit, Stuffed & tested PCS only £ fiS-OO FRUSTRATED ! Looking for 10s TRANSISTORS? A phone call to m could gel a result. We offer an extensive range and with a world- wide database ai our fingertips, we are able to source even more. We specialise in devices with the following prefix (to name but a few). 2N2SA 2SB 2SC 2SD 2? 2SI 2SK 3N 3SK 4N 6N 17 40 AD ADC AN AM AY BA BC BD BUY BDY BDW BDX BP BFR BPS BFT BEX BFY BLY BLX BS BR BRX BRY BS BSS BSV BSW BSX BT BTA BIB BRY, BU BUK BUT BUY BUW EUX BUY BUZ CA CD CX CXA DAC DG DM D5 DTA DTC GL GM HA HCF HD HEF ICL ICM IRP J KA K3A L LA LB LC LD LF LM M M5M MA MAB MAX MB MC MDAJ MJE MJF MM MX MRS MPSA MPSH MPSU MRF NJM NE OM OP PA PAL PIC PX RC S SA.A SAB SAD SAJ 5 AS SDA SG SI SL SX SO STA 5TK STR STRD STEM SIRS SV1 T TATA A TAG TEA TC TCA TDA TDB TEA TIC TIP TIPL TEA TL TLC TMP TMS TPU V UA UAA UC UDN ULN UM UPA UPC UPD VX X XR Z ZN ZTS + many oihers We can also offer equivalents (at customers 5 risk) We also stock a full range of other electronic components Mail, phone* Fax Credit Card orders and callers welcome Cricklewood Electronics Ltd -10-42 Crickleivood Broadway London NW2 3ET Teh 020 8452 0161 Fax: 020 8208 1441 Micro Web Server for Internet and Intranet Our incredibly popular MSC1210 microcontroller board (also known as Precision Measurement Central'} now provides network and Internet connectivity, allowing the processor to publish its own data pages onto the web. The article describes a temperature logger allowing the user to enter, via the Internet, temperature limits and an email alarm address. The Micro Web Server can also switch network ports is available free of charge from our website! Order now using the Order Form in the Readers Services section in this issue. lectron from an Internet-connected PC. literally anywhere on the globe. Now available: • MSC1210 board (assembled and tested) • Network extension (assembled and tested) • Combined package (inch all related Elektor Electronics articles on diskette} £ 69,00 (US$112.50) £ 41.95 (US$ 73.95) £103,50 (USS 1 84.95) Elektor Eectronics (Publishing) RO. Box 190 Tunbridge Wells TN5 7WY England Telephone -f 44 (0) i5S0 200 657 Fax +44 (0) 1580 200 616 See also www.etektor-electromcsxo.uk 63 ekktor deef resits - 12/2004 refronics Heathkit TC-2P Tube Checker Jan Suiting I came across this gem in an unexpected place,, namely a flea market far vintage motorcycle parts! Standing between heaps or pistons, wheels and engine parts, the owner claimed it was some kind of electrical instru- ment' capable of testing "well, a lot of things i guess '. When the small case was opened I immediately recognised a Heathkit tube tester that hod def- initely seen better days. Once I had intimated to the owner that I had no idea what the instrument was actually sup- posed to do, plus that it was ramshackle, grimy, grossly incomplete and so on I paid 10 pounds, closed the lid and walked away in exuberance. Rising damp My TC-2P [build: approx. 1962] was badly affected by moisture, probably as a result of having been stored in a damp cellar for years. The control panel had large blots of what looked like calcium deposits. Fortunately, these were easy to remove by first loosening them up with a soft toothbrush and then rubbina with just a touch of car wax. I pur- posely left one area untouched. All knobs and the moving coil meter were removed and the control panel lacquer soon appeared in all its former glory. On the inside, however, more serious problems were seen. The mains cord |1 1 0 VAC] had gone as crusty as cornflakes and was now a real hazard. The same for the tiny power an/off slide switch 'which was totally blocked by white stuff. All easy to clean and repair, however. The most troublesome port was the moving-coil meter, of which the needle appeared to be stuck. On closer Inspection I discov- ered that the meter's anchor/coll assembly (a wonder of precision assembly], had been eaten way by corrosion hence was beyond repair. An alternative was found in the use of another vintage 1- mA meter from which I removed the scale plate, replacing it with the still intact Heathkit plate with its delightfully simple BAD - - GOOD print. Having drilled four holes In the control panel I mounted the J nev/ meter It 'worked a treat. The wheel-operated tube selec- tion chart in Heathkit tube testers is o notorious item because it is easily damaged by all too fre- quent as well as infrequent use! In my case, the part of the chart that had been horizontal for years had dried up and gone so rigid it was In danger of ruptur- ing when I attempted to turn the wheel. The chart was disassem- bled; rolled off and on again; creases and a small tear were repaired. Today it con be turned again but not to the extremes. This problem was solved by downloading the chart from the Internet and referring to printed pages to find the various settings far a specific rube I want to test. Th is also allows me to use updates of the chart far later (past-1 965] lube types. Practical use In the mid 1970s, a friend and fellow radio amateur occasion- ally allowed me to use his mighty J !-l tube checker to see which tubes in my collection were still any good! As it turned out, preciously few! Working with a lube tester soon becomes second nature. Using the rolling chart, finding the pin-out codes and moving the controls and levers ro match the tube you want to test needs to be done with core, else you get very strange results when ihe TEST switch is finally pulled down! Most people will at least smile when I demon- strate the TC-2 testing the 'quality' of a couple of tubes plugged into ihe various sockets and then watching the merer indication — youngsters are bewildered if you test a brae tube like the SO 7. The TC-2 Assembly and Opera- tion Manual is a fine example of no-frills US-sfyb instructions on kit assembly at home. I have no idea haw many TG2's were sold but the occasional look at Ebay USA tells me a genuine TC-2P is o rare find at the price I paid. Anyone have a set of spare plas- tic cops for the lever switches? Web pointers wwv/. j eg Is-roehrenb ude.de / Roehren-Geschichtliches/Roe- Pruefer/Heathkit-TC-2/ Heoth-TC-2.htm h tip : //bam a . she . ed u / h ea th.ht m Retrcnics h a mcnrhly caLmr, cover- mg vintage electronic* including leg- endary Etskfor designs Cor m bu- ttons, and requests ora welcomed: p ease zEhcl on eroa So ed Uoee ! eetre n Jcs , co . uk subject: Retronlc? E B 12 20D4 -eIAEvJ ElsdrorJis 69 start Oiere Continuous Flow Soldering From reader correspondence we know that lots of you are still hesitant about soldering SMDs (surface-mount devices], particularly integrated circuits. We won't soy it's a piece of cake, but maintain that there's no rea- son so start panicking about SMDs, as accurate soldering does she trick. Using the right tools and some basic skills, sol- dering SMD ICs with 'gull wing or '}' leads should be within your reach. What's needed In any case, make sure sufficient solder flux (How agent) is avail- able, so that the liquefied solder will easily flow towards the desired solder pad instead of lo creep up adjacent pins or fill unwanted hales! Small pieces of cloth and flux cleaner are also recommended to mop up solder spills. The actual soldering is best done using an iron with a so- called 'wave' tip. This tip has a hollow part capable of holding an amount of liquid solder. Finally, we would recommend the use of an illuminated desktop magnifying bmp. What to do 1 . Apply flux to the copper pads in the corners of the 1C foot- print. 2. Put the 1C on the footprint, carefully aligning the pins at diagonal corners with the sof der pads. 3. Place the wave tip on the junction between the 1C pin and the pad in one of the cor- ners. If necessary add some solder flux. 4. Remove the tip. Wait for the solder to solidify. Next, solder the opposite solder pin. 5. Put some solder in the wave tip to create a 'bead'. 6. Hold the solder tip such that the bead is in contact with (he upper surface of the 1C pins. Slowly, in one smooth move- ment, move the solder tip across the contact row, such that a uniform amount of sol- der is applied to each pin. 7. Repeat step 5 ana 6 for the other side(s) of the 1C. 8. If necessary dean and inspect the result. The above method may also be applied to ICs with J leads. Background Far clarity's soke: the a dv outage of the proposed method is that you do not have to add solder to the tip for each 1C pin. The dispens- ing of solder from the 'bath' in the solder tip is based on a principle from physics called 'capillary action'. Because every solder pad/ pin surface ratio is identical, each contact will attract an identi- cal amount of solder, the excess amount being retracted by the sol- der tip. In addition, solder is attracted by a heat source, in this case, the solder tip. The above process only works if sufficient flux is present on the sak der pods. After all,- solder does nothing except melt during heat- ing. For best results, however, it should fiov/ and bond. too. Copper, tin and lead are 'porous' metals that protect themselves from corrosion by forming a thin oxide layer. Agents like solder flux have an etching effect that removes oxide layers, it is recommended to use solder fluxes based on resin, as they are the easiest to remove using (inex- pensive) flux cleaners based an alcohol. Solder iron tips for continuous flow soldering ore produced by, among others, JBC, Xyfronic, Met- cal, Weller and Pace. ■3-40323— C Illustrations: courtesy Circuit Technology Center. The internet site for all professionals and hobbyists actively engaged in electronics and computer technology www.elektor-electronics.co.uk 70 debar elKtrcr.ics - 12/2004 LM317 ADJ l> U|N (2> v r JM -sc 1V2 ^ImA R2 s (UoiFT-1V2) tnKQ UoUT ♦ Uqut <2) 040157-11 Voltage regulator calculation Power Supply for USB Devices Victor Himpe Before you con design on adjustable voltage regulator into your circuit, or do a redesign, you need to calculate the values for two resistors. This is nof diffi- cult in itself, bul actually finding the right resistors may pose prob- lems. Fortunately a trick is avail- able to moke it all much easier* With most adjustable voltage reg- ulators like the LM317 and LM337 r the input voltage has to be 1.2 to 1.25 volts above the desired output voltage* This is because the voltage at ihe ADj (adjust) input is internally com- pared to a reference voltage with that value. The reference voltage always exists across Rl* Together with preset R2 it determines the current Rowing through the ADJ pin, os Follows: V D yt - V»0F [1 +(^2/R1 ]]+I AD j R2 If for the sake of convenience we ignore ! adj» 6n ^r the reference voltage ( 1 .2 V) and for R 1 select a value of one thousand times that voltage (i.e. 1 .2 kQ) then the equation is simplified fo: R2 = lOOOfV^ - 1.2) In practice, simply determine the voltage drop across R2 (output voltage minus reference voltage) and you get your resistance value directly in kilo-ohms. Far exam- ple, For 5 V R2 becomes 5^1.2 = 3.8 kfl which is easiest made by connecting 3.3 kT2 and 470 Q resistors in series. In the case of relatively low volt- ages, smaller resistor values are recommended. This is because sufficient current needs to Row to enable the voltage regulator to do its job* A simple solution is lo choose, say, 120 £1 for Rl , R2 then becomes: R2 = 1 00 (V^ - 1 .2) Roman Mittermayr More and more equipment is sold that runs off internal rechargeable batteries* Although a matching charger is usually supplied in the package, there are also devices that can only be charged via a USB port* That is not surprising in the case of USB MP3 players, which have to dock' in the PC onyway far some time for the pur- pose of file transferring. Still, the some feature' can be a serious disadvantage, for example, on computer-free'' holidays. Sometimes it makes you wonder how simple the solutions to such problems actually turn out to be. After all, if it s just a supply volt- age we re after, then a USB port is easily imitated* The circuit shown here is nothing but a 7805 in a dead standard configuration* The innovation, if any, might be USB connector fo which the MP3 player can be connected. The 7805 comes in different Flavours — most devices can sup- ply 1 A, but there are also more advanced variants that achieve up fo 1 ,5 A* Because a USB device is never allowed to draw mare than 500 mA from the port it is plugged into, the circuit shown here should be able to supply charging and/or operat- ing current to up to rwo (or three) USB devices at the same fane. The input voltage may be a direct voltage of anything between 7 ond 24 volts, so for use at home or abroad a simple wall cube with DC output is sufficient. Another useful bit to make your- self might be a cable with on in- line fuse and a cigarette lighter plug so you con tap into a vehi- cle supply (note that this may be up to 14.4 V with a running engine)* At on output current of 1 A and an input voltage of just 7 V. the 7805 already dissipates 2 watts. Assuming you re using the most commonly seen version of the 7805, the TCT220 case with its metal tab will have a thermal resistance of about 50 C 'C/W. Also ossuming that the ambient temperature is 20 °C r the 7805 s internal (chip) temperature will be around 120 "C. In most cases, 150 c C is the specified maxi- mum, so ample cooling must be provided especially in a car and with relatively high input voltoges* 12 2G{M - ebklijr dcrtierits 71 kitchen toble Plus additional seasonal circuits... Th is flashing LED mini Christmas tree is not only dead simple to build but the design is also repeatable and very reliable in operation. In fact an ideal last-minute project to brighten up the house or office in the run-up to Christmas. It can sometimes be satisfying for the electronics enthusiast to build some- thing that adds a personal touch to a special occasion. The mini Christmas nee design described here fits the bill and should strike a suitably festive note. This particular flashing Christ” mas decoration cannot be purchased ready made but needs instead to be assembled. The circuit design is just about as bullet-proof as Is possible using a PCB, battery and just a few components. It is aimed at the less experienced constructor Those of you who would like to try their hand at alternative seasonal projects may be interested in some additional circuits that have been made available for free download this month from the Elektor Electronics web site at www. el ekt o r- electronics.co.uk (see editor v s footnote ax the end of this article). So simple The circuit for the Christmas tree proj- ect is ideal for the complete electronics novice. The same circuit was used for various flashing ornaments that were built from kits of parts at our E/ektor Electronics exhibition stand recently Even nve-vear olds were seen success- fully assembling and soldering the parts together to produce working Mrs in less than 30 minutes! The circuit in Figure 1 is about as sim- ple as it gets. A single IC r two resis- tors, one capacitor and eleven LEDs comprise the total circuit. LEDs were used here because they consume less power than filament lamps and are also far more reliable. The circuit will run for 48 hours on end from a fresh 9-V alkaline battery, so a single battery should last you through the whole Christmas week if it is only used in the evening. The IC is a CMOS 4060 oscillator/ divider with ten outputs. The oscillator operating frequency depends on the values of Cl, Ri and R2 and should be approximately 2 Hz with the compo- nent values given. The outputs Q3 to Q9 and Oil to Q13 switch at the oscillator frequency The LEDs are wired so that it looks like they are switching in a random manner but if you study the LEDs a bit more closely you will notice that there are always three LEDs lit at any one time. The PCB layout shown in Figure 2 is already cut into a Christmas tree shape. Component placement and sol- dering should not present too much of a problem so long as you study the lay- out closely. It is important to fit the LEDs the correct way round (remem- ber, the shorter or cut lead is the cath- ode). An IC socket is used to fit IC! to the PCB. Ensure that the socket is the correct way round before it is soldered to the PCB and that the IC is correctly onentated before it is pushed Into the socket (a pip 1 on the package always indicates pin 1). Once all the components have been fit- ted solder the battery dip leads to the PCB. The red lead is soldered to the positive (*r ) pad and the black lead to Soldering 71 d&fclai e!;cfr&"Ics - 12/2004 Figure 1 .The LED Christmas tree circuit really has been tried and tested a thousand times! the negative (-) pad. The battery clip contacts are pushed through the two holes at the foot of the tree so that the battery can be fitted to the other side and acts as a stand for the tree. If everything has gone to plan the LEDs should start to tw inkl e once the bat- tery is connected. Merry Christmas ! Figure 2. The mini Christmas tree component placement. COMPONENTS LIST Resistors; R1 = 10k (btack-brown-orangej R2 = 1 0Qk_ ( b f q c k-b r g w/vy e I J o w) Capacitor: Cl - ] nF Semiconductors: D I'D 12 = LED, low current (oil colours possible exceoi white] !CI = 4060 Miscellaneous: 1 6-way DEI sacks! for tC 1 9-V (PP3/6F22} battery with dip Kit a: FCB & pans, order cade 010019-91 Free Christmas circuits From www.elektor- electronics.co.uk We are truly gelling the festive spirit at NWA'/.eiehor'electronics.co.uk where you will find five Christmas circuit designs [hot are available for free downloading. Each circuit includes a FCB layout and, if applicable, software IS slings: - FEashma Christmas {downed - 990074-1 2| - An Electronic Be! (download #000116-12| - Pc3iry light; [download n 014056-12] - A Star for Christmas {download = 020040-12) -LED Christmas Decoration [download # 030157-12] 32 2 0 D 4 - diktor dtcfrcrics 73 cumulative index 2004 - ? Notation: Article title \ month page number] Example: . 06 — 35 = June 2004 F page 35 Cumulative Indexes 1996 - 2004 also available from ’■ ■■ ■= : "'-: l :: - (Free Downloads) Soundcard as Test Instrument -*..,**,.,...-,-10 — 40 Tom! Engdahl, the man behind Epanorama.net . . * .07 — 120 Up, up and away .*,***,** .05 — 39 USB Converter Controlled via HTML .......... .07 — 65 USB Memory Stick ....,...***** .1 0 — 74 Virtual Soldering [labView] .10 — 28 Wireless USB 09 — 08 Working with ActiveX . . .07 — 112 Audio/ Video / Photography Audio Power Amps on the Internet Canon EOS Cameras go Wireless .... ClariTy 2 x 300 W Closs-T Amplifier (1) ClariTy 2 x 300 W Closs-T Amplifier (2) ClariTy 2 x 300 W Closs-T Amplifier (3) Codec Complete High Voltage Amplifier High-End Preomp (1} High-End Preamp (2) LM4096 Boomer Audio Posver Amp . . . Noise Suppression Filters OTL Headphone Amplifier Pandora's Sound & Music Box RIAA Preamplifier with FETs Simple Audio Peak Detector Slave Flash for Digital Cameras That $ Class... 04 — 68 07 — 1 02 06 — 24 09 — 70 10 — 50 07 — 67 12—18 04—10 05 — 16 12 — 41 11—50 01—40 04 — 52 01—28 12 — 37 10 — 58 06—18 Computers / Software / Internet Analog University ************.****, 06 — 55 Analogue Filter Design .01 — 72 Digital halation up to 100 MBit/s 07 — 58 Dream Team (DRM) 04 — 32 Elektor Electronics Year Volume CD-ROMs on Hard Disk 04 — 17 Equations, equations 1 1 - — 42 Home Network for ADSL .................. .07 — 81 hC / USB Interface ...................... .1 2 — 52 \K Home Bus *...12 — 60 HR Tool . , 12 — 36 line-2-mic for Notebook ................... .1 0 — 76 Measurement and Control via the Internet ...... .07 — ■ 28 Micro Webserver .07 — 1 2 Monitor Lire Xtender ..................... .07 — 40 Of Mice and light ....................... .04 — 58 On-line Conversions ...................... 1 2 — 39 Parallel Port Switching Interface 02 — 38 Profilab-Expert ......................... .1 0 — 32 Programming with Word *.*,.* .06 — 69 Proteus VSM ,09 — 56 Remote Control for your PC .**.*.**,*****., *02 — 64 SATA . ......... .*.*.***12 — 47 Software? We i! do that ourselves! (stepper motors) 05 — 64 Hobby & Modelling Bike Tail Light with Stand light . . 09 — 40 Bluish Flasher *...***** . .07 — 74 Digital Motors _ . . 06 — 62 Discrete Robot ******* * .1 2 — 25 Ear Boggle 1 1 — 70 Electronic Switch For Modellers .............. .07 — i 36 Electronic Valentine Heart .02 — 56 Flickering Light II . .12 — 35 FM5 Flight Simulator Encoder .01 — 22 Four in a Row 10 — 66 Intelligent Flickering Light .................. .0/ — -38 IR Servo Motor Interface for RCX 07 — 88 Irregular Flasher ******* .0/ — 46 LED Christmas Tree 1 2 — 72 LED Light Pen * .07 — 48 LED Roulette .01 — 52 Law-power LED Flash *04 — 60 Model Railway Short-Circuit Beeper ..12 — 42 Multichannel Failsafe for Radio Controlled Models .03 — 36 One-Component Metal Detector 10 — 76 On-train Radio Camera .... * * . .12 — 33 Personal Sound to light Unit ....**** .06 — 58 Pocket Pong .06 — 50 Pseudo Track Occupancy Detector 07 — 50 R/C Analyser .07 — 96 Roil Router .06 — 64 Relaxation Machine .01 - — 50 Resounding Truth .......*** .05 — 56 Rolling Dice .09 — 34 Smooth Operator i06 — 38 Steam Whistle .07 — 66 Unusual LED Blinker ..**** .*.12 — 30 UV Torch Light * * * * * * . . .07 — 62 Whistling Kettle ,07 — - 54 Home & Garden Back to the Future .... Burglar Alarm ....... Code Lock Digital Alarm Clock . . , Doorbell Cascade .... Home Network for ADSL PC Home Bus * . .12 — 16 . . .01 — 46 * . .03 — 52 * * .02 — 1 8 . . .07 — 35 . . .07—81 * . *12 — 60 {Access 74 dckior- 12/2U34 If? Multi-Position Switch 2 40 IR Transmitter with HT 1 2 E , ~ . . 12 — 50 Multi-event Alarm Clock ........... 01 — 32 On the Buses 12 12 Simple Darkness Activated Alarm ............ .07 — 33 Wind Speed & Direction Meter .05 24 You have Mail! 07 — 57 Reset Sequencer .............. Swiss Army Knife Trends in Microcontrollers ........ TV Commercials Killer . . USB Embedded Host Controller . „ . . XilinxJTAG Interface ........... Xpert . . . ,07 — 44 09 — 22 . . . .09 — 10 07 — 20 , . . .09 — 58 07 — 79 . . . .07 — 80 Informative / Educational Bogus Electronic Ports .09 — 66 Bring out your Dead [recycling electronics) ...... .1 1 - — 30 Continuous Flow Soldering . . ] 2 70 Design your Own 1 C ( 1 } . .05 — 1 0 Design your Own IC (2) .06 — 32 Foil Capacitor Polarity . .02 — 35 light Sensor Technology .07 — 82 Modern SMD Packages . . 12 48 Project c+ .04— 28 Project c+ Solved ...................... . .05 — 36 Guizz'away: energy transfer 1 1 — 79 Guizz'away: high-gain transistor amplifier . , . . . . .10 — 79 Quizz'away: infinite resistor array . . , . . 09 “80 Guizz'away: wondrous light chain ........... .1 2 — 78 Ready, Steady, Fatty (body fat meters) 1 1 — 74 Resistor-Equipped Transistors (RETs) ............12—43 Wind Power . . . ..... . .03 — 56 YEDA & Young Engineers far Britain .......... .10 10 Microcontrollers 500 Links on Microcontrollers . . ,03 64 64-K 80C552 Flash Board . . 01 60 Alternatives far Battery-Backed RAM .......... .04 — 39 Blacklin DSP Development Kit , . .03 — 60 Bluetooth Remote Control _ ,09 — 48 Code lock , . . . . .03 — 52 CoolRunner-l! 02 52 Data Storage on Compact Flash Cards ,03 — 46 Drop-in Microcontroller Board 04 62 DSPs at 1 GHz ......... ............ .04 — 6.8 FlexiPanel IR (IrDA) . . . . 05 — 40 Free PICProg ...... ...... 06 — 54 Goodbye ' 1 6 , Welcome PIC 1 8 F ( 1 ) 10 62 Goodbye '16, Welcome PIC18F (2) } 1 _ 38 Hands-On CPLDs ( 1 ) ....... t 02 1 2 Hands-On CPLDs (2) - . . . . ,03 — 28 i Access . . . . , 02 — 42 IR Servo Motor Interface for RCX .07— 88 Micro Webserver 07 1 2 Microcontroller Buyers Guide ...... , .09 — 16 Multi Programmer . .......... .06 — 1 0 Pandora's Sound & Music Box 04 52 PICXEX 1 8 and PICWin 18 II — 34 R/C Analyser . 07 — 96 Reset 1C with Selectable Voltages . .07 — 39 Miscellaneous Electronics 30-mA LED Dimmer ......... J 1 — 76 Bistable Relay Driver ......... ....... 1 1 — 66 Blinker Indicator . . 07 — 62 Car Central-Lacking System J 2 — 26 CMOS Crystal Frequency Multiplier ,07 — 34 Combi-gate Oscillator 1 C . . . . . .05 — 60 Digital Motors . . . . ...... ...... .06 — 62 Dimmer with a MOSFET J2 — 24 Direction-Sensitive Light Barrier # , J2 — 22 DIY RF Inductors . . . . 02 — 24 Electrical Safety page ...07—122 EMC page ........ ...... 07 — 1 24 First Steps [stepper motors) . . . . 05 — 30 Foil Capacitor Polarity . .02 35 Gated Alarm . . . . .07 - 44 HV9901 [Application Note) .01 — 36 1 2 C and SMBus . _ , , 12 — 29 Luxury Car Interior Light . . .07 — 53 MAX6954 Display Driver ,07 — 1 06 Motor Turn/Stall Detector _ .07 — 63 On/OFf Button .............. 12 ^ — 31 One Component Oscillator for 1 to 1 0 MHz 07 — 58 Power Flip-Flop Using a Triac ............... ,07 — 59 Pressing Matters with Flateahle Connectors ...... ,05 — 62 Programmable-Gain Amplifier .07 — 55 Push Off / Push On ... .07 — 70 PWM Modulator .07 — 78 Relay Coil Energy Saver ................... ,07 — 72 Reset from Multiple Power Supplies ........... ,07 — 47 Self-tapping Screws ...... , , , . . ,05 — 62 Simple Infrared Control Extender , .07 — 56 Stepper Motor Generator .07 — 37 Temperature Switches in SOT packages 04 —40 The Eternal 555 ..... _ . . . 07 — 39 Thermoelements 11 56 Thrifty 2-Hz Clock ,12 — 38 Through-hole Plating Double-sided PCBs 04 — 39 Touch-controlled Switch ........ ...... ,02 — 36 Ultra Low-profile 1C Socket 10 — 76 USB Cyberclocks _ . . 11 — 46 Very Low Power 32-kHz Oscillator 07 — 74 White LED Lamp .07 — 46 Zero Gain Mod for Non-Inverting Opamp .07 — 33 1. contmued overfeff/ 75 Power Supplies & Batteries 1 00 V Regulators . . . * 07 — 36 3.3 V or 5 V Direct from the Mains ..*.*..,*.* *07 — 4 1 5 volts from the Mains ,.*12 — 28 ABC of Rechargeable Batteries ...............11 — 14 Adjustable Zener Diode .07 — 43 AVR450 Battery Charger (Application Note) 03 — 40 Battery Charging on USB 11 — 76 Battery Polarity Protection .................. -07 — I 1 0 BIX .12 — 27 Suck/Boost Voltage Converter .............. .07 — 60 Global Power Supply .05 — 61 Inductor I ess 3-to-5 Volts Converter 07 — 76 Ufespan of LUon Batteries . .07 — 42 Low-Drop Constant Current Source ............ 1 2 — 46 Mains Failure Alarm .07 — 70 Master/Slave Switch ..................... .07 — 75 Negative Auxiliary Voltage .................. 1 2 — 21 NiMH Charger for up to six Cells ............ .1 2 — 32 Power Supply for USB Devices 12 — 71 Repairing the Damage Caused by leaking Batteries 04 — 38 Save Energy . *07 — 50 Sealed Lead-Acid Batteries .............. .... 1 1 - — 26 Simple 1 2-1C-230 V Power inverter ........... .02 — 30 Simple NiCd Charger 07 — 51 SMPSU with a Relay ..................... .07 — 36 Solar-Powered High Efficiency Charger ........ .07 — 64 Stable Filament Supply ***.*.**. I 2 - — * 49 Stable Zener Reference . .**.... *07 — 77 Storage Battery Exerciser .................. *07 — 48 Switch less NiCd/NiMH Charger . . .07 — 35 Triple Power Supply .07 — 49 Universal Mains Filler * .1 2 — 34 Vehicle Battery Jogger + ........... 1 1 — 20 Voltage Monitor 12 — 38 Voltage Regulator Calculation 1 2 — 71 VHF4aw Explorer . .04 — E 8 Wavecatcher . . _ . . * .04 — 44 Test and Measurement Acoustic Sensor .07 — 79 Air Quality Sensor 1 0 — 46 Airflow Monitor . . . *.*.*. .07 — 32 Attitude Sensor 1 2 — 20 Climate Logger . .01 — i 2 Heafhkit TC2-P Tube Checker (Retronits) ....... .1 2 — 69 Linear RE Power Meter .07 — 42 Long-Interval Pulse Generator .,***.. .07 — 45 Mains Voltage Monitor . * * 07 — 61 Measurement and Control via the Internet 07 — 28 Meter Adapter with Symmetrical Input .07 — Multifunction Frequency Meter .03 — 20 Poor Man's 1-GHz Probe .................. .1 0 — 36 Precision Function Generator . * * * *06 — 56 R/C Analyser .07 — 96 Room Thermometer 1 1 — 62 Scope for 'Scopes: 22 oscilloscopes tested .10 — 14 Sensors For Humans *05 — 50 Sensors go Systematic .................... .05 — 44 Servo Tester using a 4538 .07 — 64 Simple Audio Peak Detector .1 2 — 37 Soundcard as Test Instrument . . ... 1 0 — 40 The Sense Resistor 01 — * 56 TwoLED Voltage Indicator . * *07 — 73 Voltage & Continuity Tester .03 — 50 Voltage Levels Control Relays *07 — 52 Voltage Monitor ................ . _ .12 — 38 Wind Speed & Direction Meter . * *05 — 24 Wireless Tyre Pressure Monitoring .05 - — - 69 Corrections and Updates Radio & TV 2 Transistors, 1 Crystal, Shot s it (DRM) ......... .04 — 4 1 Automatic Preselector ***** .1 1 — 60 Bluetooth Remote Control 09 — 48 Build Your Own DRM Receiver .............. .03 — 12 Canon EOS Cameras go Wireless ........... .07 — 102 D1Y RF Inductors ............ .02 — 24 Dream Team (DRM) .04 — 32 Linear RF Power Meter 07 — 42 RF Control Interface .......,..*.**.*.......10 — 76 Shortwave Monitor 07 — 72 Single-Chip VHP RF Preamp ................ .07 — - 66 SSB Add-On for AM Receivers . , .07 — 56 Ten Years After (DAB) * * 06 — 44 Tuned Radio Frequency (TRF) Receiver 07 — 76 TV Commercials Killer 07 — 20 Atmel Programmer (09/2001) . .10 — 09 Canon EOS Cameras go Wireless (07/2004) . . . .10 — 09 Digital Logic Compared 12/2003) ..**...... ,02 — 41 Directional Microphone [1 1/2003) . .01 — 74 Electric Charge Meter (1 1/2003) ... * *01 — 74 FMS Flight Simulator Encoder (01 /2GG4] ....... .05 — 73 Lambda Probe Readout for Carburettor Tuning [07/2003] .05 —73 LED Roulette (01/2004) 05 — 73 MIDI Lights and Slide Control (03/2001) ....... .06 — 73 PIC Frag 2003 FAQ (09/2003) .... * .02 — 41 Rev Counter far R/C Models (1 1/2003) ....... .01 — 7 4 Seconds and Minutes from DCF 77 (07/2003) . . * .Go — 73 Stepper Motors Uncovered (2) (12/2003) *0i — 73 Supercap Battery - .0 1 — 74 USB-RS232 Interface (04/2003) 01—74 76 ster-l 7/2004 Matrix Mufti media Limited sa I es@malri xmultimed ia co.uk L 0370 700 1 831 f, 0870 700 1832 mm ii ...see www.matnxmultimedia.co.uk ©BLOCKS E-t-:ccK3 are smafi dnait boards each of unjcfi contains a btocfc of Bfe Unufc s typk^ly found in an eSecfnyvc system. E-c'ocks can J>s prograiTrnGd in C, rrJ>'y and are Eighty integrated wtn FIqwghJb - wtvch irLi^nty corrva.'ts f sfa charts fcifo PICmicrQ cocte. Lcw cost USB PJC programmers fSts^ng si £27, r»W ifKMTTI £55) .plus a wide range of add-on boards ano accessories... — plus fncred'bE/ easy to use software based on flowcharts— -.equals extremely rapid system development I ke tfvs mobile text messaging system built from E- blocks. ...and solutions for learning and Hands on training courses Resources for learning CPLD programming Complete courees in electronics and programming Equipment for datalogging, control and PC 'scopes training courts in PJCmjcrc^R} programming, CPLD programming end ECAO * *■ T „and mors at: lektor lectronics i ? p . iww-* 1 ***“ ECD (Edition 2) Elektor’s Components Database RRP £12.95 (USS 22. GQ) The program package consists of four databanks covering ICs : transistors, diodes and optocoupEers. A further nine applications cover the calculation of* for example* zener diode series resistors, voltage regulators, voltage dividers and AMVs. A colour band decoder is included for determining resistor and inductor values. The ECD gives you easy access to design data for over 5*700 ICs, more than 35.000 transistors* FETs* thyristors and triacs, just under 25.000 diodes and 1,800 optocouplers. All databank applications are fully interactive* allowing the user to add* edit and complete component data. This CD-ROM (Windows XP compatible) is a must-have for all electronics enthusiasts. Now extended with even more ICs, transistors, FETs, thyristors and triacs! v 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 S57 Fax +44 (0) 1580 200 61.6 See afso w ww.ef ektor-e I ectro n i c s , co. u k 1 2/2001 -elddsr tfecfionlcs 77 Professor Ohsmonn in e-magician's disguise during his Christmas lecture when the Wond'rous Light Chain 1 was first demonstrated. \ Wond'rous Light Chain With the Festive Season upon us, it seems Fit- ting to devote this month's Gurzz'av/ay instal- ment to the perennial problems associated with Christmas tree lighting. Conventionally, lamps are connected in series (Figure I) and this immediately creates a problem: when one lamp fails, it breaks the series network and all other lamps will also go out. But that's not all, because in the dark you will have hard time finding the defective bmp in the first place. A solution to this problem could be to simply wire up the lamps as shown in Figure 2. Let s assume each lamp is powered by way of a cable with a length f of 4.5 m. Twisted-pair wires from Ethernet cobles ore used because of their attractive colours. Close to the power supply, the cable ends are connected in series again. A photograph of the practical version is shown in Figure 3. Normal lamps rated at 12 V, 0. 1 A are used. So far so good; let's connect the lot to a suit- able 36 VAC power supply. This time, much to everyone's surprise, failure or removal of one lamp does not couse overall darkness — all other lamps in the Wond'rous Light Chain remain on and even light o little brighter! In this manner, the total brightness remains almost constant and the Christmas festivities are not spoilt, plus you will be able to easily spot the faulty lamp. Can you explain what is happening? Qvizz'away sjfflgf win! Send in the best answer to this month's Qulzz'away question and win one of three Varta Charge & Go Battery Chargers complete with 4 'Go' AA batteries worth £50. Alt answers are processed by Martin Ohsmann in co-operation with Elektor editorial staff. Results are not open to discussion or correspondence and a lucky winner Is drawn In case of sev- eral correct answers* Please send your answer to this month's Quizz'away problem, by email, fax or let- ter to: Quizz'away/ ilektor Electronics, PO Box 1 90, Tunbridge Welts IN 5 7WY, England, Fax (+44) (0)1 580 200616- Email: edilorSelelcfor- electronics* co.uk/ subject: 'quizzaway 12-04'* The dosing date is 22 December 2004 (solution published in February 2005 Issue). The outcome of the quiz is Final. The quiz is not open to employees of Segment b.v h . Its business partners and/or associated publishing houses. 78 Emitter dttlionks - 12/2004 As of the September 2004 issue Quizz^away is a regular feature in Elektor Electronics . The problems to solve are supplied by Professor Martin Ohsmann of Aachen Technical University , , Solution to the October 2004 problem (p. 79; very high gain two-stage transistor amplifier) . Figure 4. Small-signal equivalent circuit. The circuit diagram clearly shows that rne first transistor is operated in com- mon-emitter configuration. The second transistor is operated in common-collec- tor mode hence does not contribute to the voltage gain. By approximation, the voltage gain equals the product of Tl's slope (in biased configuration] and its operating resistance. The slope (or transconduc- tance] S is proportional to the collector resistance. For a high voltage amplifi- cation A , a high collector current ond a high operating resistance are required. In the classical circuit, the above prod- uct is the voltage drop across the col- lector resistor and therefore limited by the supply voltage. Typically, the collec- tor will be at half the supply voltage. Dividing it by the thermal voltage = 26 mV results in a maximum amplifica- tion A = 6 V / 26 mV -230. Here the circuit leaves the beaten track, the second stage acting as the operat- ing resistance, i.e., presenting a (virtu- ally) constant-current load to the first transistor. The crux is resistor R4 which takes an unusually small value. Because its base voltage is an almost constant 0.7 V, T2 keeps the voltage drop across R4 virtually constant. The current through R4 so determines TVs collector current at about 0.7 V / 4.7 k - 1 50 pA independent of the input sig- nal In this way, the second stage forms a very high-impedance load that, unlike a fixed resistor, will allow a rel- atively high collector current to flow. In order to arrive or a quantitative result, we have to calculate the interna! resist- ance of the load. This requires looking at it in greater detail ond accounting for the small-signal resistances of the tran- sistors operating at their biasing points. The diagram in Figure 4 shows the small-signal equivalent circuit compris- ing all relevant components. Resistor R4 - 4k7 is in parallel with 72 's base- emitter resistance r eE ~ 2k5. T2's gain is just below unity (in this case, 1-1/250 = 0.996), so that the input resistance of the second stage is about 250 times R4//rg£ f which works out at about 400 k_. The internal resistance of the second stage is effectively in par- allel with the output resistance ~ 1 MQ of the first stage. The result is that T] sees a small-signal operating resistance of 1 MQ//400 kQ or about 300 kQ. Now we can calculate the slope 5 of II as 5 = / c /Ut = 1 50 pA / 26 mV 5 = 0.0058 £H hence A = 300 kQ x 0.0058 - 1740 which Is quite dose to the measured value of 1 800. Source: James D. Keith, The Starved-Circuif Amplifier is revived in a transistor version. Electronic Design April 2001 , pp. 131, The internet site for all professionals and actively engaged in electronics and comp www.elektor- •co ji n • rj l licij TOE D; wit. | S- j* ’• I &Xii ft’ RtJH i ftsis I | IlmMuvi ■ .) Ewtruii. Km Ciiti Kaa Th< f:? tt prztf ir-i ii’i & L r *n^*9*d in t—j-'.C r: t f •f ^ LS Vtcth 1 7 ui -’t i -r4 i fra* ¥3 %I5 VOUA* ■ r I ys’j l_' ; 1 . cf I '.=■ — r i: «ji CS-3 jVI - : ; .n; st i & Lice J vi r [s X Thai y^saj^in f 5 «jvs3> fz* jtda £ 7 -S3 1 2/2Q04 - etskfor efedronics 79 LINKS To book your website space contact Bernard Hubbard Tel 44 (0)1242 510760 Fax: 0044 (0)1242 226626 ALLGOOD TECHNOLOGY www.„ a! Igou titech no! og y. co m Low- medium volume sub-contract assembly. SMT specialist since 1990. 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I wish lo promote mv company, please book my space: " ~ ~ * Text insertion only for £120 + VAT - Text and photo for £300 + VAT NAME: .....ORGANISATION: i i t T I JOB TITLE:.. _ i ~ ™ i i t ADDRESS: .TEL: PLEASE COMPLETE COUPON BELOW AND FAX BACK TO 00-44(0} I 243 226626 COMPANY NAME.,.. i WEB ADDRESS 25-WORD DESCRIPTION.. i I r .. i i - i i ■ i — 4 ROBOT ELECTRONICS http:/ robbt-electronics.cQ.uk * Ultrasonic rangefinders * Motor H-Bridge controllers * Magnetic Compasses * RC servos and controllers * PIC programmers and components * Electronic Design Development and Manufacturer to industry TECHN0B0T5 = - http : w w .v te c h : b of s . c o . u k Welcome to Technobots - the one stop shop specially for the remote operated robot builder radio control and engineering hobbyist, TELNET http:- www.telftetuk.com The site shows graphically Telnets wide range of quality second-user test and measurement equipment, including oscilloscopes and spectrum analysers. ULTRA LEDS h tip: ■ . vavw u Itral ed sxo . u k let: 0371 7110413 Large range of low cost Ultra bright leds and Led related lighting products. Major credit cards taken online with same day despatch. USB INSTRUMENTS n tip: ' WWW. us b-in stm m exits . com USB instruments specialises In PC based instrumentation products and software such as Oscilloscopes. Data Loggers, Logic Analaysers which interface to your PC via USB. VIEWCOM http: //www viewcQrra9xG.uk tel: 020 8471 9338 fax: 020 8552 0946 * r.^aii Order supplier of: * Integrated Circuits and Components. * Kit and parts for Elektor projects. * Transistors, FETs, Capacitors, Resistors, Crystals, etc and hard to find devices. Viewcom Electronics. 77 Upperton Road West. Plalsto’w, London El 3 9LT @LfI€™@R 30 (S mi Only one magazine tests its projects and circuits in its own lab before publication Contact; Worldwide Subscription Service Ltd, Unit 4 Gibbs Reed Farm, Paihley Road, Thehiirst T 7 JS 7 HE Telephone; (+ 44 ] [OJ 1 S 80 200657 Fax: [4 441 | 0 ] 1580 200516 Or visit our Website; wvAv.efektor-clectronks.co.uk 1 2/2004 - shbof UcdfOfiiQ 81 readers services Please Hale SflJtfci’e .'tts @ i '- 1 i.iJzt's f^ucn tns Rt= Da-flricijs page of the Fufrjgfet^ wshate a a tv tfeitoHlafrws co n* . I : ■■:"-? : e _ :e l z r -:i:££ iv;:.: ".e - :: eiitee READY-BUILT PROJECTS C I a riTy 300 VI Ciass-T Amplilier 05 Jl 17-^1 -.T:‘"frr- f E*rd A T- SVDs lG^S for Li i l2 Flash Microcontroller Starler Kit 0‘0£&3'Si PCS safiwsjt let:. 12 i rE.'ilfd Gamebny DlgiEaE Sampling Oscilloscope (G B DSOJ 990152-31 r^ZETj-EEE:-— i>rj &aa/d LfbCL tTE5 FC S0fM2TE ET.-j T“’E!E=j a/tSEfeS Micro Webserver wilh MSC121G Board Oi " DSv -51 Y ; s.r c : r -: : a g: ■: ■: E :a r d rsai/-3ss&T£'-=::S 044026-91 tetwwfc Eti&nsinn Boasd, ready-assgntfeq D44026-92 C: Trimgd pa: - zg e a 044026-91 3 ra::a: ciikiss) EVERGREENS Elsklor ElcGlronics Help Disk &pc#22-1 IKsSl iV _ 6: as vassal £ Rtitakio^ fco-nis tPCS^K sc S-asSs^fr ftwi par^ ^ ftOW$, EPfMKfe . FALs r SSLs. nsoocOrr &A i5si£fl£s for po{9Gl3 Hfidl fiSVt tz ~ i f^: E r” ;- ££ - i_, ;•:■ -i tJ-t Form prinsal oppc^ES. Tl« torn tntf ^ &e isal to enisr MeSe {prtv^ custaEisss oriy}- 34-59 55.70 » TTee srtnat for malStig a PCS «tac& e net ar^h £7 r :r = i, -£:t :'£ =££::” 5 : may be fo^id in the lEfievss arfete. mm 11259 - EFROlis, GAU. PAl$, «ACfe. PtCs and etlsef sre auppfljed resdysF^ ’"■■4-rr: - jd. eo-DO moo Pnces saj a&n srf^eet to chs^. He prjfc^as rcstr.^e tte r^a id press w^out prior lajSfcato. ptiew aad ft&>~ GtKrijsfr^s jfcjwn &9-DQ 11250 r = 7= "I przi M iSE.i S E ill 41-95 73,95 IK-50 134.95 Rail Reuter E 030403-1 ® 030403-11 030403-:-: If 14.45 PCB Dear, FiC i EC sc-torae ; : f=r i: ; :::i — e: Smooth Operator PAST ISSUES Flit dsues f iviSaSt fc;- cnSafefl trim Wurilh.-i StMcripCsn SErricc Ul Li-ji 4. (bits Retd Finn. PaifitEi FfoiJ, TICEHUfiSt Tha 7H£. tfiJtptCBt t^44| 15SD ZCVE57. In 1^44] lal-O 200511. K38" vuis g is.€s.-5xlc a.'.k Prices dC pas? issues {ejcspt J^/Aj^js? and fteeanba), mdutiov pgs&gs for copfes. as £4 75 i b ■; r : E ■ E5 30 • => - 52 y.. EE l u ■ ii-i :.!£■:£ E .■■::■■:■■ z ~':a •:* :^ m - j irt, [>£■:£ ~:£' j: _ :_= -; jc 'v i >: : capes as £5.65 ire Bfc>: €7.35 terms* E_:-v-r;. i - : EE 45 ■:'?! ti-tyc PAST ARTICLES to: - l -.—i:o^ '* _ir, snioti, OrGE: cur ■ : : 1 i--i ■' : £V£i .£ f :^£ t;; : - 01 SS€ • 00-557. in 2005 T 6 g - .;' 55ies@e5c£S> --- £ USJ ltm 1945 4-90 B.65 21-45 37.95 ElBklar Electronics Hem Tracer 19B5-20Q3 14 5093- 1 1 “j rds csiii ase * \\ ~ K 4t vers •:•- SIS 14 35 Universal Piulolyping Boards 11F3S-1 PCs 245 4,39 UFdS- 2 2 RGBs 4 10 7^ yPBS-4 4 PC S5 655 n.M No. 33 8 DECEMBER 2004 l 2 C Home Bos .g, 04S333-1 FC3 12-10 21.49 t .140333-1 ■ j:\ scarce & pe.€ l«S= f.^s 4^0 S 55 LED Chrislmas Tree 0 IC0 19-91 K* ££3*35143 6-25 11.00 USB l^C Interlace :5 040334-1 PCS 7-t5 13 59 ;S Q40334-T1 E>^ £*:>:: «*A-=rr 4-9=5 6.65 040434-21 24LC64. pfC^rrn^-3 4-80 850 No. 337 NOVEMBER 2004 Noise Suppression Fillers § 443217-3 PC 3 1335 23 65 Vehicle Battery Jogger § Qi4021-1 PCS 6-75 11.95 No. 336 OCTOBER 2004 CEariTy 30DW Ciass-T Amplifier g t&il-tf-l F€3 15-90 23.19 Four in a Row § 0401 43-1 PCS 1315 23.25 % 330 1 45-11 KB. 1 STMlS & iT€J cods 4-SQ S.65 j o 30)46-4 1 AT-K 525 1 3^ 1 0PC, pfegrarrsmet 749 13.10 No. 335 SEPTEMBER 2004 Roiling Dice z 04G24E-T PCS [n suites) 13-75 24.30 @ &4G24S- r E : ■ sa-' c-3 i “ r.« i7i= 4 99 E.B5 g I4424S-41 AT69C2GEi-12P« progwwried 5-76 15.40 Swiss Army Knite @ D3944&-1 PC 3 s* VDi. RS232. bEO 9-50 15.40 @ (3044EP11 (a^-b), aff prefect soffwae 6-40 11.50 ^ D3044S-4T ATE4SE 2 5Z-24 PC. C7i-g“T-r^ 25-E5 45.75 No. 334 JULY/AUGUST 2004 IR Servo Meier interlace @ 0 244 1 1- 1 ‘ D 5- R C X pTOEcm an a Pi C some; 5 cig: e cod ; 4-96 S.65 v2v556’4i P.C16F823. pflogrsmTCd KH» 17.70 02Dm-i2 RC16P623. p=fogJ3Swr«i 1000 17J0 Micro Webserver with MSC1210 Board a, Q4402S-1 \ G"-. Estens^in B534d ?C3 or y 10-45 18,59 R C Analyser ol L-3D1 i 5-1 1 Cii*. P.C E-i-L _ c4 CC'14 4-90 8.65 Q43173-41 FfrC1EP627^ pfBgssmnsd IQ-25 16.15 USB Converter Control led via HTML Hi 4-44544- ' 1 C l £4. 0£T5»te prograniS 4-9Q 8.65 Worlctng with ActiveX % 030431-11 m*. 4-90 S.S5 No. 333 JUNE 2004 Multi Programmer T 920336-1 PCS 6-£0 15.60 -§ 022445-11 D i- finijbszjc 5 SEKiiee ct :; 4PJ 8.65 Pocket Pang @ 0355320-11 O':- F.C SSltiiVHIE 45Q 8.65 @ D3Q209-11 Ds'. P.C 4-90 565 ” 03^209-4 1 F: Cl EF44-1 CP pfegraTunBEl 14-70 26 :: No. 332 MAY 2004 D&sign Yaur Own 1C @ 030365-1 PCS 15-65 27.7 D High-End Preamp g 020046-1 PC 3 — mssi dslU 845 14 95 .a. 026646-2 P€3 — rsSay hosd 7 52 13-30 @ 020Q46- 3 PCS— PSUbosnf 570 11 .85 g 022246-11 Dfe? 4S0 8.65 Q2&34&41 F?ClELf452-L L pru^TSTRisd 2S20 49.90 Wind Speed 8 Direction Meier 4 030371-11 D ;- cro)5Ct SORwsrs 4-90 B.65 030371-41 PtCiefB7t]iograTi(red 17-55 31.05 No. 331 APRIL 2004 Drop-in Mlcracontreller Beard •1* 0201 4fr t FC3 0-60 15^0 3 0201 43-1 1 &£* ;£T:£ 4-SO 5.65 Pandoras Sound 8 Music Box g D384Q2-1 FOB mm 18.75 X 030402- ? l Ds7_ siume srti tiex c-:-Ct f r> 490 &.65 03£4ff£41 PlCtSFB'i P progfajnTtd 20-55 35.40 VHF-Low Eiplorer @ 026416-1 PC3 a -60 15.50 No. 330 MARCH 2004 Build Your Own DRM Receiver @ 55246.5-1 PC3 9-10 18.10 H 030365-T ’ ObSl DRV as pJB^sm 4-90 6.65 Code Lock g. 020434-1 PC3 9 69 18.55 g 02&434-1 1 te_« ssaite 8 74.' cede f^es 4-90 S 65 020434^1 P/C16F34A-4P pfD^mied 14-79 2aoa Hands-on CPLDs (2) g Q3G052-1 PCS fi-9Q 15.75 % CBMS2-11 Sc-hA-sfE 4-95 B.65 03QQ52-4 t 6P.V 71 285LC £4-15. pfegrafrensd 33-40 59.10 Multichannel Failsale tor Radio Controlled Models H 020332- H Da*, s&jrre coda 4-95 365 ' 020332-41 4J6Se52-24JL pDcraivr^ S70 15.40 Mnltifenciion Frequency Meter @ 030136-1 PCS 9-35 16 55 @ 030158-11 !>:=• psra^ct soiiii'ere 49*3 5.65 ” 03 01 36-4 1 AT90S23 1 3-1&PC r pmgRsnrned 795 14.D5 No. 329 FEBRUARY 2004 Digital Alarm Clack X 030095-1 ' W£< P.C e~j hn coir 4-90 fi.65 D30S9&41 FLC16634-C- p pr^fsinfTKd 15 20 26.90 tAccess @ 020163-1 1 D’S’c set sours code and awfen 1 7-5Q 1339 ’ 0251 S54 1 AT895B252’ 1 2?C . pn^sraned 13*90 24.BO Simple 12-tn-230V Power Inverter @ 020435-1 PCB 3-50 15.05 Touch-controlled Switch @ 03-92 '4-1 ' Dsf-_ F:b sc-Lfte csfe 4-90 6.65 050214-41 F1C12C5Q3A04-50& pmarartlred £15 10 90 No. 328 JANUARY 2004 64 'K 60 C 552 Flash Board @ 030042-1 PCS 9-95 16.55 82 flekfw tfirtrcnia - 12/2004 £ £/S5 © 040Q4Z-1 1 Dia, msc. preset software 4-0Q 8.55 03004 2-21 2;FOi 0 . pity rammed RHJO 17.70 03EkH 2'S 1 GAL 1 6V3Q 1 5GR pTEj®^jined 6-10 10.60 Climate Logger © 030076-5 FOB 7-75 13.70 S t f 50075*11 &=<. 'iV 'Saws software 4-9Q 3.65 FMS Flight Simulator Encoder @ O30O56* FCB 1D-2B 16.05 05^086-41 67LPC/67S'i. preorir-Hrd 1705 30.15 LED Houtelle @ Q30T63-1 PCS 17 90 3140 © 0501 £-3-11 D*K scwm sreJ texfites 4-90 3.65 0301 £3-4 1 89C2Q5 1 -1 2PC. peogr^mjctt m* 1425 MuHi-evenL Alarm CiQCk ■S 020304-11 Dis'k, G : ! code ffiss 4*0 5.65 22035 041 P': Z 1 EFB4- 1 f R irig^T T£d 1315 23.25 Stepper Motors Uncovered {2} S 058127-1 1 G ;e>_ 5 ^ res ccd? tUi- 4-90 6.65 Universal Clock Generator j5 020555-11 D44 soars cafe fie 4’9Q 3.65 Wireless RS232 Link ■S 030204-1 FCB B-70 15,49 No* 326 NOVEMBER 2003 Precision Measurement Central m B30060-4 F£g S-7G 15.40 No. 326 NOVEMBER 2003 Rev Counter for R C Models © 024111-1 FCB I/SO 31,00 024 111-11 De>l rce find net cote 4-90 3,65 02411141 83C2051 -1 2 PC . paucrammed e-55 15.65 Running Text Display @ 026407-11 D-S" *■; u *tc srad tei 4*0 3.65 USB Analogue Converter @ 020374-1 FCB 7-fiS 1150 © 0203744 ‘ Dsv. fa docs j _ j iVratows sotfA-are 4*0 6.65 020374^1 BCie£7e5 p^sinr^ 13-25 23.45 No, 32S OCTOBER 2003 DDS FtF Signal Generator © 020299*2 PC 5 ccnnH'arp-prj 1 1210 2145 020293-41 - T &;3 5 55 1 5 E PC. pnsgrajTUTEd 30-55 54.05 Minimalist Induction-Balance Metal Detector 2. 020200-1 FCB B-95 15.65 kilim PROM Programmer @ Q'O "DS-i" 4-90 §.65 No, 324 SEPTEMBER 2003 AFV Picture Generator @ 020255-1 ■ :-iL £olt= i tei. cede r -^e 4 -SO 6.65: 020295-4 1 AT 905851 o-8-PC r f'C^iiiTsl 15 20 20.03 02029542 AT90S12OM2PC. laoQrartrai 13-95 24 60 DTMF Remote Telephone Switch @ 020294-1 PCS 11-65 20.60 4 ’--0294-11 C j ■_ A’C l t-i' ? iTJi L'e 4-90 B.65 020294-41 FvC i 6F84A-2U P programmed 14-70 LC Display with l?G Bus e CbtKfeO-2 PCs PEGProg 2DQ3 7-35 13.06 s 010202-1 FCB 0-05 16.0G W 610202-11 0*.%. ! iV-33W5 5CT7A-S?? 4'90 3.65 01 0202-4 ■ RC1 67674 -20 R p icgwxnsd Polyphonic Doorbell 23-55 41.65 @ 020354-11 [fe& project software 4*0 :■ 65 029354-4! 25.55 Precision Measurement Cenlral F. Cl c?54.n- 1 0 F pc cgiifjTt-d 14 45 03x060*31 112.50 Valve Preamplifier (1) Reatfy-xis^nbfcd & tested bo^d m-m 2 BK3KH FCB. zto j =r bererd 11-55 23.40 12/2004 - eleStfor efetlrenits £ USS @ 020333-2 PCS. ptM-y su3£y teiid 11-40 20.20 © 020333-3 FCB. ‘CteLd 1010 1730 No, 323 JULY/AUGUST 2003 Add a Sparkle W. 029293-11 D HE* =nd ss^rca f hs 490 54a 020233-4 1 F . Cl ZG5G9A- j4 S V . progminm^ 7-40 13.10 AT90S2313 Programmer @ B34D36-1 PCS S-D5 16 CO Hard Disk Selector @ 034Q50-1 PC3 945 16.75 Mini Running Text Display S 02036 5-11 i z-.jTce coda f?s 499 &.65 Mini Test Chari Generator @ 020403-11 C PfC source cede 4*0 S, 55 Programming Tool lor ATlinylS a 0Q903O-T PCS 7-55 13 35 § &2553']-'i ffisd saftAfire 4-K) 5.65 Quad Bridge Car Amp © 034030-1 PCS B-70 15 35 Remote Light Control with Dimmer .§ 029337-11 D.sk. HEX ^4 ^ 4-90 3.65 020337-41 AT65C2051-1Z, pfugjqim^d 6-25 it. 65 No, 322 JUNE 2003 AVR TV Tennis @ 030026-1 '.fen PCS 8-70 15.40 @ 034SU2&-2 PushbiniDn PCS S-60 1525 © 036026-11 D-jx. AVR Scarce cate 4-90 6.65 030026-41 AT905515, 15-20 26.90 Electronic Knotted Handkerchief © D2C355-1 1 PC sr-dcoiiirc t. r SvTT»vi. r e 4-90 9,66 020303-41 ATSSS2353-1CFC. pragramens! 1260 2232 Low-Cost LCD Conlroller (2) © 02GH4-1 PCB 870 15 35 % 02 0 114-11 De * _ preset so-ttAHra 4-90 3.65 Night Light Control © 020115-11 C.5*. r«E;t: and aource cede 4*3 t £5 02C115-41 AI90S2313-1DPG, psKfarreiKd 12-85 22.75 Universal XA Development Board ® 0101 93-1 FCB 13 20 23.35 U 010193-1 i 04 v GAL code. EPS&M te.. XADEV 450 10-00 5.65 0 1 01 03 -2 i Er R. * M 1 D 6 .2702; 0-9D . enja rarr, iriEd ■7 70 01 01 03-22 EF R OV 1 : 9 . 27C256-&0. : cog 10M 17.70 019103-31 G-L 7dj. ]. pmgrsiiT^d 4-BO 3.I J D No, 321 MAY 2003 Counldawn Timer © 020226-1 1 o:s*. source End Esse code 4-90 8,65 030295^1 AT9OS12C0. prugrarwred 13*3 24.60 USB Audio Recorder © 012013-1 1 Dvs--. EFR G w te. c c-de 4*6 S65 012013-21 EPS DU 27C512 12-60 22.M Valve Final Amp (2J © 020*07; 7 Amplfef boerd i;th‘e 15-10 25.75 .8 02CG71-2 SL.’.e? s-Cvj rz-E.'X 10-65 17.75 No, 320 APRIL 2003 6-Channel Disco Light Controller ©910X31-1 PCS " 13-16 2315 010131-41 S 7C7 50 »:-r §7C71 , : Tzmjned 2303 40.70 PECO PLC ft OI0G59-1 FCB 18-70 33.10 © 010059- 11 DS" tsst pnig&Tt 4-SQ 3 65 Single-Chip Tone Cnnlrnl m 02O654-4 FCB 10*0 1930 Switched-Oullet Power Bar wilh RS232 Control @ 020205-1 PCS 10-80 13.10 @ 020292-1" D^.i pT&)ECt sOftA-Se 4-90 5.65 Temp era lure Indicator tor the PC 3 0203£d-l' Ds7 sxi.? i‘-z c f j r.>jj 4*3 365 020-3-50-41 ATBSC2951 . pn^amred 1025 13.15 No, 3 T 9 MARCH 2003 17 V/ ID A Switch-Mode Power Supply @ 020054-3 PCS 9-45 1665 Add-un Switch unit far R C Models @ 02S1 26-1 PC a B*5 15 55 S 029126-11 D.'i». fir-3 saura ftw 4-90 5.55 0201 26-4 T PfClSCTl 2-041 5Q, pfD^Rxed 15-20 26.&0 AVReb Development System @ 020351-1 FC5 13-2C' 2325 S 020351-1 ! Dr?, SQ~pae pfogrEms 4-90 6.55 sneak preview Cuk Converter The Cuk converter is a type of electrical inverter converting power at one DC voltage to power at a different voltage. Unlike most other types of converter which use an inductor, it employs o capacitor as its main energy* storage compo- nent, The converter is named after Slobodan M. Cuk of Ins California Institute of Technology, who Brit presented the design in the early 1990s. In good Efekfor tradition we describe the theory as well as a practical design in the form of an adjustable 0’5GV, 0-5A power supply unit. This project was previously announced For publication in the November 2004 issue. It was moved to the January 2005 magazine to hi In with the theme of the month: Power Supplies. The Road to Delphi (1) In the January 2005 we launch □ new course on prac- tical use of the Delphi higher programming language for hardware control. For example, we describe in detail ho w a Delphi program is written on a Windows FC and subsequently transferred to a microcontroller to enable it to run a turnkey application. Further exten- sive and practice- oriented instalments ore planned to form a series of articles you can use as courseware. ATX PSU Tester FC power supplies come at an excellent price/performance ratio, especially when supplied as spare parts (NOS — new old slock). However, before actually using the replacement PSU you will want to be sure it works. The tester we've designed far that purpose excels in ease of use. All ATX PSU output voltages are checked under loaded’ conditions and the results are displayed an six LEDs For a quick Go/Non-Go indication. Optionally, the exact test results may be viewed an an external LC display. Also.*. Super Lithium Batteries; Ultrasonic Distance Meter / Liquid Level Gauge; PIC1 8F Microcontroller System; Intelligent Clop Switch; RFID Read /write Station. RESERVE YOUR COPY NOW! The Jamrary 2005 Issue goes on sob m Friday 17 Becember 2004 (UK Eliitrikfi&n only). UK eubsmhen will receive the meg mine c few days before Shis dote. Article titles and mugozme contents subject to dionp. NEWSAGENTS ORDER FORM SHOP SAVE / HOME DELIVERY Please save / deliver one copy of EleMor Electronics magazine for me each month hj 3-1 £ 10 *- * B ■ 4 ■ * B! * * » B- ■ -# * B’ V + fr B- B * i h i -B -fi * « -B * + + + + + * # 4 »'*'«■* » * j^kCie r r ss s ■. a ■ + + ? * * ■ * ■ ■ * ■ ■■ ■ ■ * ■ ■ ■■ ■ ■ ■ ■ » ■ * Post code: ' ft * 1 ■ ■¥ t - ^ ***■* + # d - * «#-» H - * + -# «- «- + «- ■--»+ * ■# S **-«-** V ® ■■■■■»■ ■ Oitr a . iBBiai - ia , ■ ib »■■■«■ ai A ■ ■ ■ ■ AiiAaAiiiBiBtti ib iB * # !P B ’ fr A IS 1 j»-j L LI T" 6 r 4 . ^ B- I B lektor lectronics Please cut out or photocopy this form, com- plete details and hand to your newsagent. Elektor lectronics' is published on the third Friday of each month, except in July, Distribution S.O,R. by Seymour (NS). AOgooti Technology, Net Links '.v; w^§owM^mk)g^mri Aydiaxpress, Net links zwiw/.suti. omiess. com .... Amt RfSraTC h ... IK* , . : jfE 5 BaTCf} 00 . L- * ... B 5 b Layout l M links ; v s *. . p :: -zzz Lcsm ...... Bum Technology LTD. Net Links ivy, vv r_ Tte~.cn n CMS .... iYAY/.Ems Lk.com ... Com pu cut, tot Links wAViCz - ui -zuitsis-. com .. . Cofifom Bedrunjcs, i?iet Links ....... . . avayc r •- fords, : eu.co.l - .... Gffcftewood .......... ....... . . Danbcsry, Net Links m-n tier or- c-z- . . . Debug Innovations. Net L : ”-s ■ ; -£ ;cm Display Becircnics .vaw.c ste>.c : . *• zn \i -: Lhks mm =. ric ::.-a ..... EteHJf, Net Links ... m msimotcom Ones, Net Links .mme&wccow? Ervan IntemaEfonal, Net Links vAV/.eran- v ....... Eurocircusts va ,\:mpcmmp.cur ExpressPCB .WA\\\z*r- y ssrzo. cc t, Forest, Net Links ivv. vv f c yl c ? - Future Technology Devices, Net Links : ■ r :: - .... Futurtec, Net Links ..... .AVAYiumieccQm ........ Hammond Pec francs. 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Net Links . — r . kfev. com, Net Links .............. . YfV / wJecMfguk ........... ....... .00 , ^ W -i v: mstrism&ti meti ''ZCO.uk 77 .wwa'JTi!:. nsLdBir-on.CG.fik 65 .wav/. roqp&ccPQ^cs. co.l'^ .81 .60, 81 jwnK/ieiV'irai^aJ/fC^ls. com .81 ZA w AV/.nh mheroc-B.cori .66 :a \ iw.pagm. co. ck ........ ,'ii'i w. peb 'A >z no. -z rg. uk . ViVtW.psskS-vC.CO.uk MMVpiffZX.COM .vr.ViV.cmQ.com ■, v v. •/;. 5 ' 5 ' f C tZC Z. Z E . ZZ ” ^ViVvspicE-soihme.CQtn . . .rtViVi rQpot-eiBctror: ze.zd 2 31 81 81 81 .2 67. 81 . ,'j V j v/.ste a -e r t-of ■ : = 2 ~ — CD-ROtA Robotics E 1 2.05 2x300W Amplifier board with SMDs pre-fitted E 34,50 Micro Web Server. MSC 1210 board E 69.00 Network extension £ 41,95 Combined package E 103,50 Flash Microcontroller Starter Kit £ 69.00 Prices olid item {rcscripticms subfett to changs. 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Sorting Code 60-2245. 1 BAN code: GB40 NWB K6 022 15 3512 5225 BIC code: NWB KGB 2L COMPONENTS Components for projects appearing in Elektor Electronics are usually available from certain advertise in this magazine. T difficulties in the supply of components are envisaged, a source will normally be advised in the article, Note. fiov. a v it. that the soirees ■ given is (are) not exclusive. TERMS OF BUSINESS Delivery Although every effort will be made to dispatch your order within 2-3 weeks from receipt of your instructions, we can not guarantee tins time sca'e for ail orders. Returns Faulty goods or gzods seat in error may be returned for replacement or reiuud, cut nci bc'ore obtain no our consent. All goods returned should he packed securely In a padded bag or box, enclosing a covering letter staling the dispatch note number. If the goods ere returnee because of a mistake on our part we will refund the return postage. Damaged goods Claims for damaged goods must he received at our Tunbridge Walls office within 10-days (UK): 14-days (Europe) or 21 -days (all other countries). Cancelled orders Ail cancel fed orders will 29 subject to a 10% handling charge with a minimum charge of E5-G0. Patents Patent protection may exist w rospectof circuits, dev - ees, components, and so on, described in our books and magazines. Elektor Electronics (Publishing) does not accept responsibility or liability for failing to identify such patent or other protection. Copyright A'l drawings, photographs, articles, printed circuit boards, programmed integrated circuits, diskettes and software carriers published in our books and magazines (other than in third-part;, advertisements) are copyright and may •lot ce reproduced or transmitted in any form or by any means, deluding photocopying and recording. 4 whole or in part, without tbe prior permis- sion of Efskior Electronics (Publishing) in writing. 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Conversely, no refund Ml be made, nor expiry date extended, If a change c! address allows the use of a cheaper service. Student applications, which qualify te r 3 20- : twenty per cent) reduction in current rates, must be supported b.. evidence of studentship signed by the head or the college, school or university faculty. A standard Student Subscription costs £31.60, a Student Subscription-Plus costs £37 60 (UK only). Ptesse note that new site sc piions take stout teur wee As Tom receipt of order to become effective. Cancelled subscriptions *.T he subject to a charge o l 25-. {£, verity- five pe' cent) of ihe full subscription price or £7.50 whichever Is the higher, plus the cost of any Issues already dispatched. Suteciptions cannot be cancelled after that nave run ter six mo mbs or more, January 2004 CD-ROM Audio Collection 2 This 3,5-inch diskette i runs under Windows) con- tains the digital contents list of all articles published in the elektor electronics A unique CD-ROM for the true P : audio lover, containing no I fewer than 75 audio desiqns from the past five year volumes 1 1 ] - 'M i of elektor electronics magazine. i ! The articles on the CD-ROM ^ h cover test & measurement equip- £12.05 (US$ 21,25) meni, amplifiers, digital audio and loudspeaker technology. Highlights include the Crescendo Millennium Edition, Audio-DAC 2000. Audio-ADC 2000 and the IR-S PDIF Transmitter and Receiver. Using the included Acrobat Reader you are able to browse the articles on your computer, as well as print texts, circuit diagrams and PCB layouts. magazine \ over the period 1 985-2003. It offers an attractive graphics interface and the program allows searching for various keywords or combinations. Robotics _ A large collection of data- 1 MiCill - I ' —Z- Z=. * sheets, software tools, tips. 1 ' il ” tricks and Internet links to I J’ assorted robot constructions \\ b - and general technical infer- | -5 mat ion. All aspects of modern | |p robotics are covered, from I sensors to motors, mechanical | ? ^ ~ t parts to microcontrollers, not forgetting matching programming tools and libraries for signal processing. CD-ROM £12.05 (USS 21.25) Flashboard Starter kit Contents of Starter Kit: 89SS252 Flash Micro-controller board (ready-assembled and tested PCB), 300mA mains adapter, serial cable for COM port and a software- bundle on CD-ROM. £69.00 (USS 112.50) Article compilation on CD-ROM: ■ 89S8252 Flash Microcontroller Board (December 2001) * Microcontroller Basics Course parts 1-6 (January through June 2002) * Microcontroller Basics FAQ (September 2002 ) * Port Line and ADC Extension for 89S8252 Flash Micro Board (December 2002) * Chess Computer using the Flash Micro Board (February 2003) PC-lnterfaces f under windows PC Interfaces can be used for more than just the printer, mouse. modem and joystick! While it was relatively easy to directly access PC interfaces using a DOS computer, under 1 Windows things are not all that \ \; simple. This book shows you 1 how it can be done. In addition to exact, practically oriented descriptions of the traditional PC interfaces (what can they do and how they are addressed via software), the authors describe the DIY construction and programming of a number of highly interesting circuits, ail of which can be connected to the PC ports. BOOK £25.95 (USS 52.00) Gameboy Digital Sampling Oscilloscope The GBDSO is a plug-in module that turns the popu- lar Nintendo Gameboy Classic, Pocket, Colour or Advanced into a versatile dual-channel oscilloscope. An optional link to a PC even allows measured oscil- lograms to be viewed or stored on the PC. The GBDSO rocked the electronics hobby world and thafs why we continue offering ready-built GBDSO modules (Including the associated PC software and the magazine articles). Order now using the Order Form in the Readers Services section in this issue Elektor Electronics (Publishing) P.Q. Box 190 • Tunbridge Wells TN5 7WY ENGLAND Telephone +44 (0) 1580 200 657 • Fax +44 (0) 1580 200 616 More information on www-efektor-electroiiiDs.co.yk FAVOURITE PRODUCTS EVERY MONTH IN THE ELEKTOR SHOP ID il. _ hr- 1 1 ■ -“TB Hjjj • “ * ~r*~J ligL PC ; ItntRFACSS l! Wi HDOVJS n Powerful & flexible schematic capture. Auto-component placement and rip-up/retry PCB routing Polygonal gridless ground planes. Libraries of over 8000 schematic and 1000 PCB parts. Bill of materials, DRC reports and much more. Berkeley SPICE3F5 simulator with custom extensions for true mixed mode and interactive simulation. 6 virtual instruments and 14 graph based analysis types. 6000 models including TTL, CMOS and PLD digital parts. Fully compatible with manufacturers' SPICE models. Supports PIC, AVR, 8051, and BASIC STAMP micro-controllers. Co-simulate target firmware with your hardware design. 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