0 3 744708929510>Vol.25 No.10Nuts & VoltsTRANSISTOR RADIO TURNS 50October 2004Circle #154 on the Reader Service Card.Cover.qxd9/10/20042:46 PMPage 108C Ci i r rc cu ui i t tS Sp pe ec ci i a al l i i s st ts s. . c co om m C Ci i r rc cu ui i t tS Sp pe ec ci i a al l i i s st ts s. . c co om m C Ci i r rc cu ui i t tS Sp pe ec ci i a al l i i s st ts s. . c co om mC Ci i r rc cu ui i t tS Sp pe ec ci i a al l i i s st ts s, , I I n nc c. . 2 22 20 0S S. . C Co ou un nt tr r y yC Cl l u ub bD Dr r. . , , M Me es sa a, , A AZ Z8 85 52 21 10 08 80 00 0- - 5 52 28 8- - 1 14 41 17 7/ / 4 48 80 0- - 4 46 64 4- - 2 24 48 85 5/ / F FA AX X: : 4 48 80 0- - 4 46 64 4- - 5 58 82 24 4Digital Storage Oscilloscope ModulePC based Digital StorageOscilloscope, 200MHz 5GS/sequiv. sampling USB interfaceConvert any PC with USB interfaceto a high performance DigitalStorage Oscilloscope. This is asophisticated PC basedscope adaptorproviding performance compatibleto mid/high level stand alone prod-ucts costing much more! Comeswith two probes. 40 Watt Soldering KitItem# ZD200BItem# 320113.8V, 6ADC RegulatedPower SupplyItem#CSI1862Ideal for mobile tranceivers, high ampstepper motors and CNC machines.Circuit Specialists 20MHz Dual Trace Scope*60MHz Bandwidth*Dual Channel*Alternate Trigger *Autofocus*Large 6 CRT*Alt-Mag sweep for simultaneous dis-play of normal & X10 trace*Sweep speeds to 10nS/Div.*10kV acceleration voltage*Internal sync separator circuit for sta-ble triggering of video signals Item# 6506$349.00 !$269.00 !Innovative 5 in 1 DMM*20Mhz Bandwidth*Alt-Mag sweep*1mV/Div verticalsensitivity*Alternate trigger*X5 sweep magnification*Large 6CRT/autofocus*Comes w/2 (x1 & x10) probes) Item# CSI6502Item# CSI8209Integrated Sound/Light/HumiditySensors*Alt-Mag sweep*1mV/Div verticalsensitivity*Alternate trigger*X5 sweep magnificationRF RF FieldS FieldStr trengthengthAnalyzer AnalyzerThe 3201 is a high quality hand-held RFField Strength Analyzer with wide bandreception ranging from 100kHz to2060MHz.The 3201 is a compact &lightweightportable analyzer & is a mustfor RF Technicians. Ideal for testing,installing & maintenance of MobileTelephone Comm systems, CellularPhones,Cordless phones, paging systems,cable &Satellite TV as well as antennainstallations.May also be used to locatehidden cameras using RF transmissionsPROGRAMMABLE DC POWER SUPPLYFC5001 FC5001 2 Way FM Radio Tester/ FC6002 FC6002 Radio Frequency Tracer3M DataCom Cable Tester 3M DataCom Cable Tester*Stores up to 10 settings for fast & accurate recall*Backlit LCD display*High Resolution (1mV)*PC compatible (with optional RS-232 adaptor module)*Easy programming w numeric keypad or fast rotary codeswitch*Power shut down memory functionPDF Manual available atCircuitSpecialists.comVisit our website for a complete listing of our offers. We have over 8,000 electronic items on line @ www.CircuitSpecialists.com. PC based data acquisition,industrial computers, loads of test equipment, optics, I.Cs, transistors, diodes, resistors, potentiometers, motion control products, capacitors,miniature observationcameras, panel meters, chemicals for electronics, do it yourself printed circuit supplies for PCb fabrication, educational D.I.Y.kits,cooling fans, heat shrink, cableties & other wire handleing items, hand tools for electronics, breadboards, trainers, programmers & much much more! Some Deals you wont believe!Normal brightness LEDs now available inRED RED,GREEN GREEN orYELLOW YELLOW in 3mm or 5mm sizes.Yourchoice. Each bag contains 100 of the same LEDs.BAG-RED3MM BAG-RED3MM..............$1.50 BAG-RED5MM BAG-RED5MM.............$1.50BAG-GREEN3MM BAG-GREEN3MM........$1.50 BAG-GREEN5MM BAG-GREEN5MM.......$1.50BAG-YELLOW3MM BAG-YELLOW3MM....$2.00BAG-YELLOW5MM BAG-YELLOW5MM...$2.00This unit allows for mapping, testing andtroubleshooting of various lines, includ-ing installed data communi-cations, phone wiring andcoaxial cable runs.Performsmultiple test on the followingcable types, up to 1000 feet in length:Unshielded telephone cables with RJ-11and RJ-45 connectors; Ethernet 10 (100)Base-T; Token Ring; EIA/TIA-568 A/B;AT&T 258a; USOC; 50 or 75 ohm Coaxwith F or BNC connectors.Only Only$49.00 $49.00Only Only$199.00 ! $199.00 !Only Only$9.95 ! $9.95 !Item# CSI3645A$49.00 NewFantastic NewFantasticLowPrice: LowPrice:$1299! $1299!Programmable DC Electronic Load BAG of LEDs DEALKEY FEATURES:*Maximum admissible power: 150W*Maximum current rating: 30A*Maximum voltage input: 150V*Maximum voltage and current settings can be adjusted in10mV/10mA increments*Storage for 10 different voltage/current settings*Monitored by PC software*Can be used in a parallel connectionItem# CSI3710AA programmable electronic DCload capable of supporting up to150Wof power. Can be usedwith supplies up to 150VDC and30A. It features a rotary selec-tion switch and a numeric key-pad used to input the maximumvoltage, current and power set-tings. Perfect for use in laborato-ry environments and schools, orfor testing DC power supplies orhigh-capacity batteries. It alsofeatures memory and can be con-nected to a PC, to implementremote control and supervision. Only Only$349.00! $349.00!Details & Software Downloadat Web Site> > Test Equipment> > Oscilloscopes/Outstanding PricesDetails at Web SiteDetails at Web SiteDetails at Web SiteDetails at Web SiteCompare at Over $2000 !Details at Web SiteDetails at Web SiteDetails at Web SiteDetails at Web SiteDetails at Web Site> > Test Equipment > > Oscilloscopes/Outstanding Prices> > Test Equipment > > Specialty Test EquipmentItem# DT-2000> > Semiconductor Devices> > LEDs, Displays & Lamps> > Test Equipment > > Power Supplies> > Test Equipment > > RF Test Equipment> > Test Equipment > > RF Test Equipment> > Test EquipmentPrices> > Digital Multimeters/World Beater> > Test Equipment > > Oscilloscopes/Outstanding Prices> > Power Supplies> > Test Equipment$24.95Item# 200DSO ..Only$859.00S Super B BrightLEDs Deal53B3SCS08...5mmBlue Blue SB LED(1500max MCD)1+ $0.70 /10+ $0.65 /100+ $0.605G3UTB-2... 5mm Green Green SB LED(1100max MCD)1+ $0.45 /10+ $0.35 /100+ $0.305R3UT-2/R...5mm Red Red SB LED(3500max MCD) 1+ $0.25 /10+ $0.20 /100+ $0.1553BW3SCC08..5mmW Wh hi i t t e e SB LED(3500max MCD)1+ $1.69 /10+ $1.49 /100+ $1.185Y3STC-2....5mm Y Yellow ellow SB LED(3500max MCD) 1+ $0.25 /10+ $0.20 /100+ $0.15*WFM/NFM/AM/SSB modulated signals maybe measured. *Signal Levels up to 160Channels can be displayed simulaneously on the LCD *PLL tuning system for precise frequency measurement and tuning *Built-in Frequency Counter *LED Backlight LCD (192x192 dots) *All fuctions are menu selected. *RS232C with software for PC & printer interface *Built-in speaker (Limited Offer)(Includes Antenna)> > Test Equipment > > Power SuppliesDetails at Web SiteProtek 60MHz Dual Trace ScopeWhile Supplies Last!Super SuperBlowout BlowoutPrice! Price!Sold by others Sold by othersfor Over $700! for Over $700!The FC5001 FC5001 2-way FM radio tester has the ability to lockautomatically and almost instantly on to any FM signal with-in its frequency range. The FC6002 FC6002 radio frequency traceris useful in locating stuck transmitters or bugging devices ina room or automobile. It excels at silent detecting RF signalsfor RF security and counter-surveillance applications. < > FC6002: $149.00 FC5001: $99.00A 40 watt soldering iron with a 3-wire powercord, fast heating ceramic element and agrounded tip to protect static sensitive devices.Comescompletewithasolderingstand Comescompletewithasolderingstandandthr andthreer eereplacementsolderingtips eplacementsolderingtips,which include a conical tip, chisel tip and a 45chisel tip. > > Soldering Equipment & Supplies Details at Web SiteComplete Kitas shownLimited Time OfferUNBEA UNBEAT TABLE PRICE ABLE PRICEIncludes: Holster, Case, 7 Remotes & Telecom Alligator ClipsCircle #106 on the Reader Service Card.Circle #59 on the Reader Service Card.CoverInside.qxd9/8/20043:07 PMPage 23 Retail/Wholesale Locations:MainOffice-MailOrders...3500RyderSt.SantaClara,CA95051Santa Clara 1-408-732-1573Sacramento 1-916-338-2545Rohnert Park 1-707-585-7344Since 1963!...Order Toll-Free:1-800-4-HALTED(442-5833)or...ONLINE, AT: www.halted.comTerms: Some quantities limited; all items are subject to prior sale. 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Force X86 plug-inincluded at no extra charge!!CompleteX86 computer, 233MHz, w/VGA, PIO, SIO, USB,10BaseTandfloppydiskdrive!!Unused - removed from installationHSC#20249$495.00!Fujitsu 36GB SCA SCSI Hard Drive10,000RPM36GB HD$79.95!System AccessoriesDigitalMultimeter#AEEC1504$14.95!18GB SCSI Hard DriveHSC#20290$29.95!Fujitsu MAN3184MP - Ultra160 LVD10,000 RPM,Xfer rate: 160MBps 68-pin HD D-Sub connectorAvg. seek: 5mS, 8MB buff.4 heads, 512 Byte p/sec.HSC 90-day warrantyRack Mt. for Monitors!Std. 19 rack cabinet for your displayKontron Model No. 6531-BUMMThick Lexan screen coverFront panel lifts upFor up to 15 displaysNew, boxed unitsHSC 90-day warranty.HSC#20257 $75.00!H45 QuickDriveFor 3.5 IDE drive typeSpecial shock mountFor DOS & W95+Boxed, w/diskettes & cablesCircle #72 on the Reader Service Card.3OCTOBER 2004Page 3.qxd9/8/200410:55 AMPage 3Vol. 25 No. 10OCTOBER 20044p. 71p. 66p. 94p. 24FEATURES COLUMNSDEPARTMENTSPROJECTS66DIGITAL CONTROL WITHOUT PROGRAMMINGInteresting uses for a dedicated digital controller chip withfeedback!by David Caldwell71THE TRANSISTOR RADIO TURNS 50You get them for free inside ofcereal boxes now, but this wasntalways the case. Learn about theorigins of this pioneer.by Sarah Lowrey42PALM PROGRAMMINGEnhancing your gadgetry.by Walter Krawec50ENERGY SAVER Have fun and save on your utilitybills with this project.by Ron Newton54MULTIPLEXING FORMORE OUTPUTSOvercome limited output lineson your microcontroller.by Tom Dickens60STAND ALONE WATCHDOG TIMERAn external circuit guardian forimportant applications.by Gary Peek8JUST FOR STARTERSBuilding an event counter.16TECHKNOWLEDGEY 2004Neutron microscopes;miniature hotplates; and more.24STAMP APPLICATIONSIR distance measuring.32Q&AConverting USB, SCSI, and PCsound; optocouplers; and more.83IN THE TRENCHESYou might be an engineer ...89OPEN COMMUNICATIONOptions for short rangewireless communication.94DESIGN CYCLELearn the secrets of serial portdebugging.Note to our readers: In order tobring you more of the projects youhave requested, we have made thePersonal Robotics and NearSpace columns bimonthly. Lookfor Near Space in the Novemberissue and Personal Roboticsfollowing in December.105 Advertisers Index76 Classified Display Ads14 Electro-Net40 Electronics Showcase28 New Product News20 Newsbytes64 NV Bookstore6 Publishers Info6 Reader Feedback79 Tech ForumNuts & Volts (ISSN 1528-9885/CDN Pub Agree#40702530) is published monthly for $24.95 per year byT & L Publications, Inc., 430 Princeland Court, Corona, CA 92879. PERIODICALS POSTAGE PAID ATCORONA, CA AND AT ADDITIONAL MAILING OFFICES. POSTMASTER: Send address changes toNuts & Volts, 430 Princeland Court, Corona, CA 92879-1300 or Station A, P.O. Box 54,Windsor ON N9A 6J5; cpcreturns@nutsvolts.comOCTOBER 2004Cover by Jean Von Trende Photographywww.jvtphotography.comTOC.qxd9/10/20043:14 PMPage 4One Supercircuits Plaza, Liberty Hill, TX 78642Phone 1-512-778-6950Fax 1-866-267-97771-800-335-9777Prices, specifications and availability are subject to change without notice. Publishedterms & conditions apply. 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Covers almostany room with30 obliquecamera angleOnly$249.95!Only$249.95!View any cameraor video signalremotely anywherein the world withstandard internetbrowsers Only $11.95Worlds Best ValueVideo Camera!700 foot wireless version available com-plete with receiver andpower supplies for$189.95$59.95PRO 4 CAMERA QUADVIDEO SECURITY SYSTEMComplete system, great forstores!Its easy to set up a complete, full-featured professional videomonitoring security system with 4of our PC-152C video camerasand lenses, a realtime quadprocessor, a high resolution 12monitor, and much more.$399.95$11.95$499.95Worlds smallest hard-drive based digitalvideo recorder!Ask about or super stealthversions for phenomenal lowlight rating of 0.0003 lux.UNDERWATER VIDEOSYSTEM WITH MONITORAND BATTERIES5OCTOBER 2004Full Page.qxd9/8/200411:00 AMPage 5Dear Nuts & Volts:IamwritingaboutTheStereo6T9tubeamplifierintheAugustissue of Nuts & Volts. I have a coupleof suggestions.Regardingnegativefeedback,there is a simple way to use both thebypasscapsandnegativefeedback.Connect a 100 ohm resistor betweenR102 and ground. Connect a bypasscapinparallelwithR102(thecapisnotconnectedtoground).BecauseR102islargerthanR105,asmallercap can be used here, maybe 33 F. ReduceR108bytheratioofthe100ohmresistortoR104(1/22),making R108 1,500 ohms. The valueofC105shouldbeincreasedsimilarly. (If too large a value is usedforC105,itmayproduceratherthanpreventultrasonicoscillation,especiallyifadifferentoutputtransformerisused.Ifthisisaproblem,trychangingthevalueofC105. Also try increasing the value ofR108.)Justincaseanyoneusestheamplifierwithavacuumtubesignalsource, the volume controls in Figure6shouldhaveahigherresistance,250K or 500K ohms.InadditiontoAntiqueElectronicSupply,dualaudiotaperpotsareavailableinseveralresistancevaluesfromMouserElectronics1-800-346-6873, www.mouser.com).Bill Stilesvia InternetDear Nuts & Volts:Thanks for a very good article onSmithCharts!Onpage77,theequationforaseriesinductorandanswerareincorrect,though.Itshould read XL= 2 2.1E6 L = 0.850,whichyieldsananswerof0.3H series. IalsolikedtheLORANarticleandthehistoryofHugoGernsback.As an engineer for over 50 years, I amstill learning from your magazine.Robert H. MillerGarner, NCDear Nuts & Volts:IjustreadtheReaderFeedbackintheSeptember2004issue,whereBob E. Baker is talking about Ohm'sLaw.IhavetosaythatIagreewithhimwholeheartedly,butinsteadofwaiting for someone else to write thearticlewhydoesn'tBobdoit?C'mon, Bob, do it!T. Morrisvia InternetDear Nuts & Volts:ThearticleontheStereo6T9tubeamplifierwasjustspoton!Mypersonalhobbyistbiasisslantedtowardanalogelectronics,anywaybecause as a software developer I work with the digital world every day.Forthoseofuswhohavegrownupinthetransistorage,there'sabitofmysteryandacertainretronostalgiafortheoldvacuumequipment. Plus, anyone with a bit ofaudiophilefamiliarityorhamradioknowledge is aware of the high powervacuum tube-based equipment that isinvogueinthosecircles,atleastinthe high end sphere.Thanksforpublishingaprojectarticlethatputsavacuum tube experience withinreach of the rest of us.Roger VossMaple Valley, WADear Nuts & Volts:SteveLawson'scommentsabout the development of whitelightinhisarticledealingwithwhite LEDs in the August issueneedfurtherclarification.Hestatedthat,yellowisacombination of red and green. Itistruethattheperception of yellow can result Reader Feedbackby J. Shuman6NUTS &VOLTSEverything For ElectronicsPublished Monthly By T & L Publications, Inc.430 Princeland Ct., Corona, CA 92879-1300(951) 371-8497FAX (951) 371-3052www.nutsvolts.comSubscription Order ONLY Line1-800-783-4624FOUNDER/ASSOCIATE PUBLISHERJack LemieuxPUBLISHERLarry Lemieuxpublisher@nutsvolts.comASSOCIATE PUBLISHER/VP OF SALES/MARKETINGRobin Lemieuxrobin@nutsvolts.comMANAGING/TECHNICAL EDITORDan Danknickdan@nutsvolts.comASSOCIATE EDITORAlexandra Lindstromalexa@nutsvolts.comCONTRIBUTING EDITORSSarah Lowrey Gerard FonteDavid Caldwell TJ ByersJeff Eckert Gary PeekJon Williams Walter KrawecTom Dickens Ron NewtonLouis Frenzel Peter BestMark BalchCIRCULATION DIRECTORMary Descarosubscribe@nutsvolts.comSHOW COORDINATORAudrey LemieuxWEB CONTENT/NV STOREMichael Kaudzemichael@nutsvolts.comPRODUCTION/GRAPHICSShannon LemieuxSTAFFJanessa EmondKristan RutzCopyright 2004 by T & L Publications, Inc.All Rights ReservedAll advertising is subject to publisher's approval. Wearenotresponsibleformistakes, misprints, ortypographical errors. Nuts & Volts Magazine assumesno responsibility for the availability or condition ofadvertiseditemsorforthehonestyoftheadvertiser. Thepublishermakesnoclaimsforthelegality of any item advertised in Nuts & Volts. This isthe sole responsibility of the advertiser. Advertisersandtheiragenciesagreetoindemnifyandprotectthepublisherfromanyandallclaims, action, orexpensearisingfromadvertisingplacedinNuts&Volts. Pleasesendallsubscriptionorders,correspondence, UPS, overnightmail, andartworkto: 430 Princeland Court, Corona, CA 92879. (Continued on Page 41)OCTOBER 2004readfeedOct04.qxd9/9/20043:45 PMPage 6RE A L WO R L D SI G NA L PR O C E S S I NGwww.ti.com/atc2004800.477.8924, ext. 1012Worlds Lowest Power MCUReal World Signal Processing and the red/black banner are trademarks of Texas Instruments.3232-04 2004 TIMSP430 0.1-A RAM retention 0.8-A RTC mode 250-A/MIPS active 6-s clock startup 50-nA low-leakage pins Vectored interrupts DMA High-performance analog ideal for precise measurements 16-bit RISC CPU enables new applications with less code ISP Flash permits flexible code changes Complete integrated development environment $99 Device pricing as low as $0.49If youre not already using the MSP430 in your design, its time for a change.Its Time for a Change!Online RegistrationData Sheets and Samples Experience cutting-edge ultra-low-power technology Meet with TI MSP430 experts,third parties and other MSP430users from around the world Witness demonstrations of the highest-performanceMSP430 yet Sharpen your knowledge of MSP430 in an interactive,informal setting Attend in-depth workshops,seminars and presentations on MSP430: Architecture Peripherals Coding/design techniques Applications2004 MSP430 AdvancedTechnical Conference (ATC)Seating is limited, registertoday at www.ti.com/atc2004Full Page.qxd9/8/200411:03 AMPage 7Areaderrecentlyaskedmehowtodesignacounter.Counters are a basic digitallogicbuildingblockandhavea multitude of uses. Counters advancethroughaconsecutivenumericalsequenceeitherupordowneachtimeaclockpulseis driven. They are used to divide highfrequencyclockstoyieldlower frequency clocks, for state machinesandbasiceventcounting.YoucandesignacounterfromscratchwithtruthtablesbyapplyingBooleanlogic.Inthisarticle,wewilldiscussusingoff-the-shelfcounterchipstotakeadvantageofpre-fabricatedbuilding blocks.Thecommon7400logicfamilyhas numerous four-bit counter chipsavailable.Fourbitsisapopularsizebecause the counter is small enoughto fit in a 16-pin package and can beeasilycascadedtoformlongerwidths:twofour-bitcountersgiveyou a byte counter. A four-bit binarycounternormallyadvancesfrom00002to 11112or 0 to 15 decimal.Thisnaturalpower-of-twocountsequenceisusefulinmany applications.Someapplications,however,aremoresuitedtoadecade counter that advances from00002to10012or0to9decimal.Decadecountersareoftenusedwhen counting events that are to beinterpreted by people, since peopletendtothinkindecimal.ThetermbinarycodeddecimalorBCDreferstoabinarycounterthatwrapsfrom10012to00002ratherthancontinuingwithanormal binary count sequence.74LS190 DecadeCounterA well-known decade counter isthe 74LS190. It has been around foralongtime,asevidencedbytheoriginaldateofDecember1972printedonthedatasheetthatIdownloadedviatheweb.TheLS190isasynchronouscounter,meaningthatitoutputstransitiononlyonalow-to-highclockedge.Thisgivesthecountervery predictable behavior.Figure1showstheLS190pinassignment.Asidefromtwopowerpins, the chip has four count inputs,fourcountoutputs,aclock,and severalcontrolsignals.Thecountinputs,DN,enablepre-loadingthecounter with a specific value, givingyou the option of not always startingthecountfromzero.TheLOAD signaltransferstheDNstateinsidethechip,whichisreflectedattheoutputs, QN, on the next rising clockedge.Wewillusethisfeaturetoresetthechiptostartcountingatzero.Next,thereisaDOWNsignalthattellsthechiptocountdownwhenDOWN=1ortocountupwhen DOWN = 0.Aside from the clock, CLK, thereis a count enable signal, CTEN , thatqualifiesCLK.WhenCTEN=0,thechipincrementsordecrements normally on the clocks rising edges.WhenCTEN=1,thecounterdoesnotadvanceandretainsitspresentvalue,unlessanewvalueisloadedviatheLOADsignal.CTENandthetwooutputs,RCO(ripplecarryout)andMAXMIN,facilitatecascadingmultiple counters to yield practicallyany size counter.A Cascaded CounterSohowdoesthisallcometogether?Figure2showsa byte-widecascadedcounter comprisedoftwo74LS190chips.Note that both chips have commonCLK and LOAD signals. This meansthat both chips can advance togetheronthesamerisingclockedge.Italsomeansthattheycanbereloaded together. The example hasDNtiedlowsothatthecounterisreset to 0 when LOAD = 0 and CLKisdrivenlow-to-high.TheDOWNsignalissetlowonbothchipstoindicateanadvancingcountsequence from 0 to 9 for each chip.Finally, the counters are cascadedtoformonesinglecounterby drivingonecountersCTENsignalwiththeothersRCOsignal.TheleastsignificantdigitsRCO pulsesloweachtimethecountvalueis9.ThisenablesthemostsignificantJust For StartersBasics For BeginnersBuilding an Event CounterOCTOBER 20048NUTS &VOLTSEverything For Electronics74LS1908115 321216GNDVCCDBDAQAQBQCQD67MINMAX13RCO910DDDC115LOADDOWN144CLKCTENFigure 1. 74LS190 pin assignment.Just For Startersby Mark BalchJustForStarters.qxd9/3/20043:57 PMPage 8digits counter for one clock cyclesothatitadvancesonthenextCLK edge. Afterthisnextedge,theleastsignificantdigitwrapsaroundtobecome0,whichrestoresRCOtoitshighstateanddeactivatesthemost significant digit counter until it isagain time to advance.Control InputsAtthispoint,wehavethecoreofacountercircuit,buttherearetwodanglinginputs:CLKandLOAD.Thesecanbemanual push buttons so that youcancontrolwhenthecounterisreloadedwith0andwhenitadvances.LOADcanbedirectlytiedtoapushbutton.CLK, however, is not as simple becauseitregulatestheentirecircuitsbehavior.CLKmustbeacleansignal with uniform high-low tran-sitionssothatthecounterbehaves correctly. If we directly connect a pushbuttontoCLK,thecounterislikelytobehaveerratically. Thereasonforthisisthatamechanicalbuttongenerateselectricalnoiseasitsinternal surfacesmakeandbreak contact.Thisnoisemaybeimperceptible to a person, but asynchronouslogiccircuitwillreactwildly.Adebouncecircuit(such as the one shown in Figure3) can fix this problem.Asitsnameimplies,a de-bouncecircuitremovesthebounceornoisefromaninputand generates a clean output. Therearenumeroustechniquesto de-bounceapushbutton.TheoneshownhereusesanRCfilteralongwith a Schmitt trigger inverter (madefromaNANDgate)tofilteroutthenoisypushbuttonclocksignal.TheRC time constant is 100 millisecondswhendischargingfrom5Vto0Vand 200 milliseconds when chargingback to 5 V. You can adjust the time constanthigherorlowertosuityourspecificneeds. Afterconnectingthisportionofthecircuit,thecountercleanly incrementseachtimeyoupresstheCLKbuttonandreloadswhenyouholddownLOADandpresstheCLKbutton.Seeing Is BelievingThecounterisnowfunctional,butdoesnotgiveyouverymuch indication that it may be working as itcurrently stands. Weneedtoconnectavisualindicatortoseewhatcountvaluesarebeinggenerated.ThesimplestthingtodoisconnectanLEDtoeach of the eight outputs and watchtheBCDpatternchangewitheachCLK press. Itismoreinteresting,however,toreadarecognizable0-99countsequence.Forthis,weturntothe74LS47BCD-to-seven-segmentdecoder/driver.Youmayobserveseven-segmentdisplaysallaroundyou:microwaveovens,digitalwatches,stereos,andVCRs.EachOCTOBER 20049+5V74LS1908115 321216GNDVCCDBDAQAQBQCQD67MINMAX13RCO910DDDC115LOADDOWN144CLKCTEN74LS1908115 321216GNDVCCDBDAQAQBQCQD67MINMAX13RCO910DDDC115LOADDOWN144CLKCTEN+5VleastsignificantdigitmostsignificantdigitCLKLOADQ0Q1Q2Q3Q4Q5Q6Q7Figure 2. Byte-wide counter.ch Just For StartersJustForStarters.qxd9/3/20043:58 PMPage 9display contains seven independentlight elements often LEDs thatcanformarecognizabledecimaldigit. The 74LS47 converts the BCDoutputofthe74LS190intoahuman-readable,seven-segmentformat.Figure4showshowone 74LS47chipconnectstotheleastsignificantdigitofthecounter that we have already created. (A second, identical 74LS47 andseven-segment display connect to themost significant digit.)Itisasimplehookupwithjustthreecontrolsignalstotiehigh.The74LS47hasactive-lowoutputsthatare designed for common-anode LEDdisplays. Acommonanodedisplayhasall of the LED anodes connected toasinglepin.Theindividual cathodesconnecttothedecoderchipthroughcurrentlimiting resistors.TheresistorspreventtoomuchcurrentfromflowingthroughtheLEDintothe74LS47and damagingeither.Eachsegmentoftheseven-segmentdisplayis identified as a through g.Counters and MoreCountersThere is virtually no limit to whatOCTOBER 2004Just For Starters 10NUTS &VOLTSEverything For Electronics123147VCCGND+5VCLKLOAD10 F10 K74LS1321/410 K10 K Figure 3. Clock debounce circuit.Circle #93 on the Reader Service Card.JustForStarters.qxd9/8/200412:51 PMPage 10youcandowithcounters.Theyarepresentinoneformoranotherin almost every complex digital logiccircuit.Youcandesigncustom counterswithyourownlogicoryoucanemployoff-the-shelfcounters.Youcanreadmoreaboutcounters,counterdesign,currentlimiting, and LEDs.Fortunately,therearemanyresourcesandcomponentsavailablethatwillallowyoutoexperiment andbuildwhatevercountersyouareinterested in.NVOCTOBER 200411Just For Starters

"%41/dapLive 0igiLal Signal rocessing3UPERIOR.OISE2EDUCTION%ASYTO!DDs%ASYTO5SE7ORKSWITHMOST4RANSCEIVERS/0S2 gives a clearer signal Lhanany base sLaLion 0S available. Jwo levels o noise reducLion, up Lo 26 d8 inprovenenLs in signal-Lo-noise raLio! Jhree proprieLary bandpass ilLers. /uLonaLic Lone rejecLion up Lo 65 d8. 4($ "%41

#PBSET0LEASEINQUIRE3PECIAL/%-PRICESAVAILABLEPHONEUSAT800.259.7331Jo learn nore visiL WWWSGCWORLDCOM:PVS )' 4PMVUJPOLo Power Cat. # 70-llHi Power Cat. # 70-l233074LS47817 1 312916GNDVCCDBDAabcd1110e15f62DDDC4RBO53RBILT14g+5V+5VQ0Q1Q2Q3+5VFigure 4. Seven-segment display circuit.MarkBalchistheauthorofCompleteDigitalDesign andworksintheSiliconValleyhightech industry. Hecanbereachedthoughhiswebsiteatwww.completedigitaldesign.comAbout the AuthorCircle #104 on the Reader Service Card.JustForStarters.qxd9/3/20043:59 PMPage 11www.jaycarelectronics.com1-800-784-0263(Monday - Friday 09.00 to 17.30 GMT + 10 hours only)For those that want to write:100 Silverwater Rd Silverwater NSW 2128 Sydney AustraliaFREE424 pageCatalog2004 Catalog - all 424 pagesOurJaycarcatalogpricedinUSDollarsiscrammedwithover6000excitingproducts. You can get one FREE by logging on to our website and filling out thecatalog request form at www.jaycarelectronics.com/catalogCheck our website! Easy, safe, fast ordering & lots of information Entire Jaycar 2004 Catalog on-line over 6000 products. 128-bit Secure on-line ordering safe & secure. Search by category, keyword or catalog number, & advanced search. Over 3500 product datasheets & application notes available on-line. And were from Australia so you can trust us!Get the Best Quality Video from your Home Theatre SystemKC-5390 $58.00VIDEO SIGNAL STABILISERDid you know you are not getting the best picture from that expensive movie collection you paid good money for?? Movie companies deliberately tamper with the video signal to restrict copying, but this robs you of the true high quality picture your system is capable of and you deserve. Get the picture you paid forand strip out these annoying signals, including copyright protection,by connecting our Doctor Video Kit inline with your DVD player orVCR. Kit supports S-Video and composite video signals. Case, circuitboard, electronic components and comprehensiveassembly instructions are supplied.Some SMD component solderingrequired.Theremin Kit KC-5295 $25.90This is a built up Theremin from a Jaycar kit. The Theremin is aweird musical instrument that was invented early last century butis still used today. The Beach Boys hit: Good Vibrations featuredthe Theremin. You can have one of these kits (cat no. KC-5295)for $25.90.All kits havefirst class instructions written inclear English text with plenty of illustrations and component identification.Part of our extensive build-it-yourself kit rangeCaution: During signalconditioning, this unitremoves copyright protection. Piracy is a crime,and Jaycar Electronics takes no responsibilityfor its potential for unlawful use.Stock...Electronic ComponentsElectronic Project KitsTest & Measurement EquipmentPower Products & AccessoriesAudio & Video Equipment & AccessoriesComputer & Telecoms AccessoriesSecurity & Surveillance EquipmentWe9VAC WallAdaptor required(Jameco part no.226131CD $4.49)Log on towww.jaycarelectronics.com/catalogfor your FREE catalog!This product is now available built and fully tested - Cat. AM-4025$49.50Circle #81 on the Reader Service Card.Full Page.qxd9/7/20044:13 PMPage 12Check our website! Information & easy, safe, fast ordering. Entire Jaycar 2004 Catalog on-line - over 6,000 products. 128-bit Secure on-line ordering - safe & secure. Search by category, keyword or catalog number, & advanced search. Over 3,500 product datasheets & application notes available on-line. And were from Australia so you can trust us!These projects offer fantastic tuning and performance modifications for your car. All projects are fromthe book High Performance Electronics Projects for Cars - published by Silicon Chip Magazine, Australias leading Electronics magazine, available soon! See 2004 catalog pages 12 & 13 for details.www.jaycarelectronics.comORDER on-line: www.jaycarelectronics.comwww.jaycarelectronics.comTOLL FREE ORDERING 1-800-784-0263(We are open 6pm to 2:30am East Coast time, which equates to 9am to 5:30pm our time)For those that want to write: 100 Silverwater Rd Silverwater NSW 2128 Sydney Australia A Cheap Nitrous Fuel Mixture ControllerKC-5382 $14.50Nitrous oxide systems can be expensive to set up, but nowyou can do it for much less. This project pulses a fuel injectorat a preset rate, adding a fixed amount ofnitrous fuel when you activate it. It will saveyou a bundle on dedicated fuel solenoids andjets. It can also be used to control electronic water pumps, coolingfans, and more. Kit suppliedwith PCB and all electroniccomponents. *Please checklocal laws regarding the use ofNitrous Oxide systems in yourvehicle.Simple Voltage Switch KitKC-5377 $17.30Suits a huge range of applications! Use it to trigger an extra fuel pump under high boost,anti-lag wastegate shutoff,and much more. Can detectrising or falling voltage, andfeatures adjustable hysteresis(the difference between trigger on and off voltage). Kitincludes PCB, and all electroniccomponents.High Range Adjustable Temp Switch Kitwith LCD ReadoutKC-5376 $40.30Range up to 2100F! Keep aneye on critical temperaturessuch as brakes, turbo manifolds, intercoolers, andmore. Trips a relay at a presetlevel to trigger an alarm, waterspray cooling, and more! Kit supplied with PCB, LCD readout,and all electronic components.Intelligent Turbo Timer KitKC-5383 $25.90There are turbo timers, and there areintelligent turbo timers. Itdetermines how hard the carhas been driven, and idles foran appropriate time after ignition switch cutoff. Kit supplied with PCB, and allelectronic components.Duty Cycle Meter Kit KC-5375 $31.70Super fast real time sampling! Automatically cut-in an extra fuel pump when your injectorsreach a certain level and more!Includes a simple duty cycle generator for testing. Kit supplied with PCB, and all electronic components.Hand Controller Kit for Digital AdjustersKC-5386 $34.55Real time or programming display! Thiscontroller is used for all of the digitaladjuster kits available. It can be connected for programming thenremoved, or left connected for realtime display. Kit supplied with silk-screened and machined case,PCB, LCD, and all electronic components.Digital Pulse Adjuster KitKC-5384 $46.10A huge revolution in DIY performance!Control and tune the operation of a solenoid that is run by the engine management system. You could alterauto transmission shifts, control an extrainjector, and more! Kit supplied withPCB, machined case, and all electroniccomponents. Requires KC-5386 HandController below.Explanation of icons used for kits.The kit may require several sittings to complete, and possiblyrequire some mechanicalassembly. Troubleshootingtechniques a must.The kit requires a goodknowledge of electronicsto understand its operation, and troubleshooting techniques may berequired.Indicates an approximateconstruction time foreach project for a competent constructor. Itdoes not however,include any installationetc that may be required.Circle #81 on the Reader Service Card.Full Page.qxd9/9/20049:05 AMPage 13Electro-Net Go to www.nutsvolts.com click Electro-NetGo to www.nutsvolts.com click Electro-NetMCUmart.comBASIC CompilersDevice ProgrammersPrototyping BoardsExperimenter BoardsBooksPICmicro MCU Development ToolsGeiger Counters: Digital, PC & AnalogAs sold to NASA andUS GovernmentIMAGES SI INC.www.imagesco.com/geigerwww.allelectronics.comSee the Worlds Largest Collectionof LCDs and LCD Productswww.gatewayelectronics.com(Electronically Speaking, Gateways Got It!)MAIL ORDERS CALL TOLL-FREE-1-800-669-5810NUTS &VOLTSEverything For Electronicswww.onepasinc.comONE PASSircuitTMThe Futureof Proto-typingFor the do-it-yourself audio enthusiast Helpful articles Hands-on projects Expert advice New technologiesCall 1-888-924-9465 to subscribe today!Subscribe & Save 65%!12 issues just $29.95 save $54!www.audioxpress.comElectronetOct04.qxd9/9/20042:21 PMPage 14Lower costs, higher outputits easy to measure the value of eBay.My company counts on me to get great deals on test equipment. Thats why I count on eBay. Oscilloscopes, lenses, transformers, signal generatorsall the gear I want is there for less. So far, Ive bought $40,000 worth of new and used equipment for just $20,000. With a well-equipped lab, were troubleshooting more efficiently and getting products to market faster.www.ebaybusiness.com 2004 eBay Inc. All rights reserved. eBay and the eBay logo are registered trademarks of eBay Inc. Designated trademarks and brands are the property of their respective owners. All items subject to availability. 2004 eBay Inc. All rights reserved. eBay and the eBay logo are registered trademarks of eBay Inc. Designated trademarks and brands are the property of their respective owners. All items subject to availability.Stan Searing eBay User ID: searing (595)Application Engineering Manager, Pixim, Inc., a 50-person manufacturer of imaging platforms in Mountain View, CA.Circle #36 on the Reader Service Card.Full Page.qxd9/8/200411:11 AMPage 15OCTOBER 2004TechKnowledgey2004AdvancedTechnologiesNew Way to Look at ThingsAprototype microscope that usesneutronsinsteadoflighttoseemagnifiedimageshasbeendemonstrated at the National InstituteofStandardsandTechnology(NIST, www.nist.gov). The hopeis that neutron microscopes mayeventuallyofferadvantagesoveroptical, X-ray, and electron imagingtechniques,includingbetter contrastforbiologicalsamples.AdelphiTechnology,Inc.(www.adelphitech.com), designed anddemonstratedthemicroscopewiththehelpofNISTscientists,who routinely use multiple lensesto focus neutron beams for otherresearch. Stanford University alsoparticipatedintheresearch,whichwassupportedinpartbythe US Department of Energy.The imaging process involveshittingasamplewithanintenseneutronbeam.Theneutronsthatpassthroughtherebycreatingapatternthatreflectsthesamplesinternalstructurearedirectedtoarowof100dimpledaluminumplates.Eachdimpled plateactslikeaweakfocusinglensforneutrons,divertingtheirpathsslightlyateachinterface.Theimageisthenprojectedontoadetector.Inprinciple,neutronscould providebetterimageresolutionthanvisible light because they have shorterwavelengthsasshortas1nm.Inthisdemonstration,themicroscopeproducedaresolutionofonly 0.5 mm and a magnification of about10.However,Adelphihopes tosubstantiallyimproveimage resolution through research to reducelensaberrations.Thecompanyalsohopes to build a compact, laboratory-scale neutron source.Moreover,neutronsoffersomeuniqueadvantages.Unlikeotherimagingmethods,neutronsinteractstrongly with hydrogen an importantcomponentofbiologicalsamplescomposedmostlyofhydrocarbonsandwater.Also,neutronseasily penetratesamples,therebyreducingtheartifactsproducedwithothertechniquesthatrequirethinslices,staining, or fixing.Miniature Hotplates Reach1,100 CEvents, Advances, and NewsFrom the Electronics WorldNeutron micrography, such the image of a rats foot shown at right (b), may offer advantages over existing X-ray and electronimaging techniques (a). Courtesy of Adelphi Technology, Inc.Silicon carbide micro-hotplates, each consisting of a central plate surrounded bycurved tethers. The largest is less than 100 m across.TechKnowledgey 2004 by Jeff Eckert16NUTS &VOLTSEverything For ElectronicsCircle #64 on the Reader Service Card.Tech2004.qxd9/7/20044:46 PMPage 16Engineers at Boston MicroSystems,Inc.(www.bostonmicrosystems.com), have come up with a series ofmicro-hotplatesthatareonlyafewdozenmicrometersacrossandcanachievetemperaturesexceeding1,100 C (2,012 F). Built with siliconcarbidetotoleratetheextremeheat,theyreachpeaktemperatureinlessthan0.001second.Siliconcarbideisnot only stable at high temperatures, itis also impervious to chemical attackfrommostmaterials.Asaresult,thehotplatescanbecleanedbymerelyburning debris off the surface.Containedonamicrochip,thehotplatescurrentlyareusedintinylabsinsideatransparentpolycar-bonatechamberthatcanendurenear-vacuumpressures.Portsonthechamberssidesallowgasestopassthroughandfeedexperiments;researchers can observe experimentswith a microscope. The hotplates alsocontainanintegratedtemperaturegauge and a pair of electrodes. Thesecomponents allow researchers to testtheelectricalpropertiesofvariousmaterials that may be deposited ontothe hotplates.Usingthestable,thin-filmdeposi-tion properties and integrated circuitryofthehotplates,researchersarealready developing applications, suchasoxygenandengineemission sensors. The sensor may have severaladvantagesoverdevicesintodayscombustionenginesduetothe micro-hotplateschemicalstability,smallsize,rapidresponse,andlowpowerconsumption.Prospectiveapplications are in such diverse areasasheattreatmentanalysis,thinfilmmaterial characterization, automobileemissionsandotherenvironmentaltestingandinstrumentation,and biological adaptations.Thetechniquesforcraftingandoptimizing these microelectromechan-icalsystems(MEMS)weredevelopedwithsupportfromtheNationalScienceFoundationSmallBusinessInnovationResearch(SBIR)programandSBIRprogramsattheDepartment of Energy, EnvironmentalProtection Agency, and NASA.Computers andNetworkingGrand Haven, MI: Hot CityItsjustalittlewaterfronttownknownforsportfishing,itsOneSky, One World International Kite Flyfor Peace, and its stewardship of theworlds largest musical fountain. Now,the12,000residentshaveonemoredistinction:GrandHavenisthefirstcityintheUStoprovidewirelessfidelity (WiFi) networking everywherewithin the city limits and it lays claimto being the nations first hot city.DevelopedandmanagedbyOttawaWireless(www.ottawawireless.net),thesystemusesseveralhundredstrategicallylocatedWiFi(802.11a,b,g)radiostoblanketitssixsquaremilesandprovide coverage15milesintoLakeMichigan.WiFigivesusersthe freedom to receive and transmit dataover the Internet at high speeds fromanywhere within the broadcast signalrange.VoiceoverIP(VoIP)Internet-based phone service is also availableon the new network.Inadditiontofixed/mobilehighspeed Internet access, Ottawa Wirelessprovidespoint-to-pointdedicatedVPNconnections,remotewirelessvideosurveillance,andhighspeedaccessfor boaters up to 15 miles offshore andatspeedsofupto55milesperhour.City-widemobileWiFiVoIPtelephonecalling is currently in beta testing, withafulllaunchexpectedinthenextfewmonths.Monthlypricesforalways-onbroadband Internet starts at $19.99 for256kbpsandunlimitedmobileVoIPcalling is $29.99.Storage Format AnnouncedIfyouhavebeenworkingwith computersforadecadeormore,you no doubt have acquired quite a fewstoragedevices,someofwhichnowfunctionperfectlyaspaperweights.Somewhere between your desktop andcloset,youmaystillpossessSyquestdrives, magneto-optical drives in varioussizesandformats,Zips,tapebackupdevices,andothers,plusthemoremodern CD and DVD technologies. Well,getreadyfortheBlue-rayDisc,devisedbyaconsortiumthatincludesDell,Hewlett-Packard,Hitachi,Sony,TDK,Matsushita,Pioneer, Royal Philips, Samsung, andothers,knownastheBlue-rayFounders. Version 1.0 of the BD-ROMhasbeenapprovedandisnow availabletodiskmanufacturers.ert TechKnowledgey 200417OCTOBER 2004Maryland8006383328Fax: 8008883293Florida* 8003658030 Fax: 800 9993293*Showroom in Florida1306 Continental Drive Abingdon, MD 21009-23341952 NW 93rd Avenue Miami FL 33172-2925www.tritronicsinc.comTrue RMSMultimeterWith InfraRedThermometerNon-contactInfraRedthermometer measuressurface temperature ofobjects difficult to reach. Auto power off & DataHoldCapacitance,Frequency and Duty Cycle Complete with CATIII leadsPart #: EX470$12989MultimetersRequest our new catalog!AnalogDigital AC/DC Volts:15, 150 500V DC current:150mA Resistance:1K, 5K dB: -20dB to + 56dB Battery test: 1.5V & 9 V under loadPart #: A-800$489 3 1/2 digit 2000 count DC Volts to1000V AC Volts to 750V Resistance to 2 meg DC Amps 10 Diode test single rotary switchfor all functionsPart #: D-901$589 Stackable 392 - 896 range Includes iron holder & spongeOrder Part #: 936-9/PAlso available: ESD modelPart #: 936-12/P...$78.89We carry tips for virtually all solder stationsFamousIndustryStandard Solder Station$6989Serving the industry for over 30 years!Circle #97 on the Reader Service Card.Tech2004.qxd9/9/20043:26 PMPage 17Apparently designed to compete with the HD-DVD formatbackedbyNECandToshiba,itmaybecomingtoa computer near you sometime in 2005.Drivenbybluelaserdiodetechnology,theBlue-rayDisc provides storage of 25 GB on a single-layer disk or 50GB on a dual-layer one. The 12 cm diameter is the samesize as a CD/DVD and it offers transfer rates of 36 Mbps.Keyapplicationsincluderecordingandplaybackofhighdefinition video (for which one disk can provide up to fourhoursofHDTV),butitisalsoapplicabletoPCdata storage.Fordetails,youcanvisittheBlue-rayFounderswebsite at www.blu-raydisc-official.orgCircuits and DevicesSingle-Chip Car Radio AnnouncedRoyalPhilipsElectronics(www.semiconductors.com)recentlyintroducedafamilyofone-chip analogcarradiosolutionsthatpromisesuperiortuningperformance and reduced overall system costs in factory-installed automobile radios. BycombiningPhilipsfront-endtuningandanalog signalprocessingtechnologies,theTEF690xchipsaresaid to reduce the number of external components neededtobuildhighperformancecarradiosandsimplifythedesign process to reduce system costs by 20 to 30 percentas compared to existing two-chip systems. The TEF690x devices include an AM/FM tuner, stereodecoder,adaptiveIFbandwidthcontrol,precision adjacent-channelsuppression(PACS),andadvancedweaksignalprocessing.Inaddition,thedevicesoffer flexibleinputselectionandtheoptionofanintegratedRDSdemodulatorand/ortheconnectionofanexternalsoundprocessorornavigation/beepinput.ThisvariablefeaturesetenablescarradiomanufacturerstoserveworldwidemarketsinAsia,Europe,andtheUSwitha single platform.The devices are sampling now, with mass productiontobeginin2005.Fourdifferentdeviceswillbeavailable,includingtheTEF6902whichincorporatesallthe standardfeaturesoftheTEF690xrangeintoa64-pinpackage and the TEF6901 which will also feature anintegrated RDS demodulator in a 64-pin package. PhilipsTEF6903(withanintegratedRDSdemodulator)andtheTEF6904willincludeexternalprocessorI/0andwillbeavailable in 80-pin packaging. Pricing was not disclosed asof press time.Laser Diode Driver Improves Optical DrivesNationalSemico-nductorCorp.(www.national.com)hasannouncedanewlaserdiodedriver(LDD) for use in opticalpickupunits(OPUs).TheLMH6533offersfastswitchingrates,very low output currentnoise,andlow powerconsumption.Thereducedpower consumptionprovidesbetterheatdissipationinthe system, while the low noise improves read times for opticaldiskdrives.TheLMH6533isdesignedforcombinationDVD/CD recorder optical storage devices used in desktop,notebook, and consumer DVD video recorders.TheLMH6533laserdiodedrivercontainstwohigh current outputs for reading and writing DVD (650 nm) orCD(780nm)lasers.Itachievesread,write,anderase functions through four separate switched current channels.The LVDS interface delivers DVD write speeds of 16x andhigherwhileminimizingnoiseandcrosstalk.Thedeviceprovidesone300mAandtwo150mAwritechannels,plus a 150 mA read channel. Additionally, it minimizes electromagnetic interference(EMI),allowingdiskdrivemanufacturerstodevelopdeviceswithouttheextracostofshielding.AvailableinLLP-28packaging,thedeviceispricedat$0.85inhigh volume quantities. OCTOBER 2004Nationals LMH6533 is geared for higher performance DVD and CD drives. Courtesy of National Semiconductor....see www.world-educational-services.bizComplete courses in electronics and programming For rapid development of electronic systems...Low cost USB PIC programmers ...equals extremely rapid system development: like this mobile phone system built from E-blocks.+=..plus a wide range of add-on boards and accessories.........plus incredibly easy to use software based on flow charts...+...and solutions for learning and development...eblocksTME-blocks are small circuit boards each of which contains a block of electronics typically found in an electronic system. E-blocks can be programmed in C, Assembly and are tightly integrated withFlowcode - which instantly converts flow charts into PICmicro code.E-blocks can be put together to form a variety of systems that can be used for teaching and learning electronics and for the rapid prototyping of complex electronic systems....and more at:NEWEquipment for datalogging, control and PC scopes18NUTS &VOLTSEverything For ElectronicsCircle #105 on the Reader Service Card.TechKnowledgey 2004Tech2004.qxd9/7/20044:52 PMPage 18Industry and theProfessionDigital Over Power LineStandard UnderDevelopmentThe ability to send high speed digitaldata over the power lines betweensubstationsandhomesandofficesisattracting increasing attention becauseit can make every wall outlet a portal totheInternet.Inseekingtohelprealizethis potential, the Institute of ElectricalandElectronicsEngineers(IEEE,www.ieee.org)hasbeguntodevelopIEEE P1675, Standard for Broadbandover Power Line Hardware. Whenfinished,IEEEP1675willgive electric utilities a comprehensivestandardforinstallingtherequiredhardware on distribution lines bothundergroundandoverheadwhichprovidetheinfrastructureforbroad-band-over-power-line (BPL) systems. ItwillalsoincludeinstallationrequirementsfortheprotectionofthosewhoworkonBPLequipmentandensurethatsuchsystemsdonotplacethepublicatrisk.Thestandardis targeted for completion in mid 2006.Adding broadband capability to alocalpowerdistributionsystemis relativelystraightforward.Acomputer-routercombinationandacouplertakethesignalfromanopticalfibercableasitentersasubstationandimposes it on the electric current. Thesignal travels over the medium-voltagelines, with repeaters placed every 0.5to 1 mile to keep the signal viable.Arepeater/routerneararesi-denceorbusinessextractsthesignaloff the medium voltage just before thetransformer and injects it onto the lowvoltage wiring on the other side of thetransformer. The signal is now on all ofthe low voltage wiring within the struc-ture and can be accessed at any outletby plugging in a modem. Anyone fromtheutility,Internetserviceprovider,and BPL equipment sectors who wantsto help develop this standard is invitedto join the IEEE 1675 Working Group.For more information on this standardanditsworkinggroup,visithttp://grouper.ieee.org/groups/bopDubious Achievement for USRecentresearchatCipherTrust,Inc.(ciphertrust.com)anEmailsecuritycompanyindicatesthatmorethan80percentoftheInternetProtocoladdressessendingspam are located in three geographicareas: Korea (28.58 percent), the US(28.41 percent), and China and HongKong (23.30 percent). However,intermsoftotal volume,theUSisclearlythekingofallspammers,generating85.93 percent, compared with 3.02 percentforKoreaand2.3percentforChinaandHongKong.Onlytwoother countries(UkraineandAustralia)accountedformorethan1percent(1.47 and 1.24, respectively). NVTechKnowledgey 2004OCTOBER 200419Circle #50 on the Reader Service Card.Tech2004.qxd9/7/20044:53 PMPage 19News BytesGrow a Thick SkinMostofusintheprogrammingindustry aren't very impressedwiththepatentsgrantedtoMicrosoftoverthepastfewyears,butthreeresearchersrecentlystruckgoldwiththeiridea.USPatent6,754,472wasawardedtoWilliams,Vablais,andBathichefora,"methodandapparatusfor transmittingpoweranddatausingthehumanbody."No,thisisn'tthedawn of the Matrix, but a novel wayforwearablecomputerstomoveinformationbetweeneachotherwithoutgettingyoutangledupintheir wiring. As the patent abstract explains,thehumanbodyisusedasa conductivemediumoverwhichpoweranddataisdistributed.TheinventorssuggestusingpulsedDCorAC,whiledifferingfrequenciescouldbeusedtoselectivelypowerdifferentdevices.Nottoworry,thecurrentmovedisontheorderofpicoampsmuchlessthat theshockfromadoorknobona winter day.Imaginethefutureofwearablecomputing:Nikeshoesconvertsmallamountsofenergystolenfromyourwalkinggaittopumppowerthroughelectrodesatyourankle.Asmallcomputerthe sizeofaBand-Aidtapedtoyourheadbehindyourearusesboneconductiontofillyouinontraffic conditionsduringyourdrivehome.Accelerometersinyourwatch measurethedifferentialaccelerationofyourmovements,andcorrelatethattoa"stressindex"callingahead to make sure that gin and tonicawaits you at home ...Wash-n-WearElectronicsWhileonthetopicofwearablecomputing,itwouldbegoodtomakenoteofthecleverpressuresen-sorsdevelopedbyPeratech,Ltd. QTC thenovelmaterialincorporatedwithinPeratech's components was discovered whenacompanyco-founderwaslookingfor a conducting glue and created amaterial that was an insulator undernormalconditions(resistancein theorderof1,012ohms),but turnedintoaneffective"metal--like"conductorwhenpressurewasapplied(resistancedropstolessthan 1 ohm).QTCsarenovelinthatunlikenormalelectricalconductorstheyexhibitconductanceviaquantum tunnelingeffectsandhavearesultingimmenserangeofresistancewhencompressed,stretched,ortwisted. Thetransitionfrominsulatorto conductorfollowsasmoothandrepeatablecurvewiththeresistancedropping exponentially. QTCTextileSensorscanbedesignedtointerfacewithmostelec-tronicdevicesthatarecurrentlycon-trolledoroperatedusingswitchesor keyboards. Thefieldofwearableelectronicshas already grown in momentum, butOCTOBER 200420NUTS &VOLTSEverything For Electronics(continued on page 78)NewsBytes.qxd9/9/20049:29 AMPage 203 Input 100MHz Analog DSOClassic Analog Scope using a standard x1/x10 BNC probe. Additional inputs on the POD for dual channel operation.8 Channel 40MS/s Logic AnalyzerCapture digital signals down to 25nSwith arbitrary trigger patterns.8 + 1 Mixed Signal ScopeTrue MSO to capture an analog waveform time-synchronized with an 8 channel logic pattern triggered from any source.Real-Time Spectrum AnalyzerSee the spectrum and waveform of analog signals simultaneously and in real-timeWaveform GeneratorLoad up to 32K arbitrary waveform and replay via the onboard DAC (10MS/s) or a digital pattern from the POD (40MS/s)Standard 1M/20pF BNC Input200uV-20V/div with x10 probeS/W select AC/DC couplingS/W select 50ohm terminationArbitrary Waveform GeneratorBitScope and your PC provide an array of Virtual InstrumentsBitScope DSO 1.2 software for Windows and LinuxBitScope "Smart POD" Connector8 logic channels, 2 analog channelsDual channel capture from POD A/BAsync serial I/O for external controlLogic Pattern generator 32K 40MS/sBUS Powered USB 2.0 DeviceSingle USB cable to your PCCompressed data transmissionSimple ASCII control protocolBitScope Scripting LanguageBitScope Pocket Analyzer uses highly integrated Surface Mounttechnology to provide functionality you would expect from scopesmany times the size and price. Its programmable Virtual Machinearchitecture means new functionality can be added via software.For custom Data Acquisition, export directly to your spreadsheet.External/Passthru Power SupplyAuto senses an external supply -removes power load from USBfor use with unpowered hubs.Supplies up to 500mA via POD R&D Education Robotics Lab Scope Fast DAQ Service DebugSee inside your circuit in the analog and digital domains at the same time tomake tracking down those elusive real-time bugs much easier.Pocket Analyzer combines a high speed sample-synchronized storage scopeand logic analyzer with a programmable waveform and logic pattern generator.Also included is an integrated real-time spectrum analyzer and powered "SmartPOD" expansion interface so you've got all bases covered!About the same size and weight as a Pocket PC, this USB powered BitScopeneeds no bulky accessories. It's the perfect low cost "go anywhere" test anddebug solution.USB Oscilloscope & Logic AnalyzerThe new generation Scopefor the age of microelectronics.

www.bitscope.comTurn your PC or NoteBook into a powerful Scope and Logic Analyzer!$29521OCTOBER 2004Full Page.qxd9/8/200411:20 AMPage 21Plasma GeneratorThis new kit was conceivedby one of our engineerswho likes to play with thingsthat can generate large, loud sparks,and other frightening devices. Duringthe process of looking for parts for one of his latest experimentshe discovered how difficult it was to find a high voltage trans-former that met his requirements. Well, we had a super unitdesigned expressly for us!The result... the PG13 PlasmaGenerator designed to provide a startling display of high voltage!This is one of the neatest Halloween kits around.It really servesno purpose other than producing stunning lighting displays,drawing big sparks, scaring the neighbors and performing lots ofhigh voltage experiments.In the picture, we took a regular clearDecora style light bulb and connected it to the PG13 - WOW!A storm of sparks,light tracers and plasma filled the bulb.Holding your hand on the bulb doesnthurt a bit and you can control the discharge!It can also be used for poweringother experiments; let your imagination be your guide!Can also be run from 5-24VDC so the output voltage can be directly adjusted. Generates 2 sparks to a handheld screwdriver! Light fluorescent tubes without wires! Build your own plasma balls! Generate up to 25kV @ 20KHz from a solidstate circuit!PG13 Plasma Generator Kit $64.95PS21 110VAC input, 16VAC output power supply $19.95Multi-Color SMT Blinky KitSBRGB1 Multi-Color SMT Blinky Kit $29.95LED Strobe LightYou have all seen those strobe lights atthe special gift shops in the mall.Theyhave been around for a long time, howeverthey all feature one thing... a high voltage glassXenon tube, that is both fragile and dangerous.Now you can illuminate your next party or scaryHalloween setting with the same motion stopping dis-play without worry!A plug-in 3x3 array of super bright TeluxTMLEDs creates a bril-liant sharp flash just like a Xenon flash tube.The LEDs can also bemounted directly on the main PC Board if desired.In the standard flash mode, avariable rate control varies the flash frequency from approx 1 to 220 flashes persecond.In the audio sync mode, the flash is triggered by any audio input youprovide into the standard RCA audio input connector.Built-in low and high passfilters allow you to select either bass or treble music triggering!Just picture thestrobe reacting to those Halloween sound effects CDs!An external trigger in/outconnector lets you connect multiple units together for simultaneous flash.Optional plug-in display boards with 8 or 20 LEDs are available for even morestrobing power!These are perfect to put inside a pumpkin!Runs on 12-15 VDC,and unlike the high voltage Xenon strobes of the past, the LEDS1 is safe for thekids to build!Includes a matching custom case and knob set to give your strobelight a great finished look.The plug-in display boards may be mounted on top ofthe case, or remotely locatedLEDS1C High Power LED Strobe Light Kit With Case $44.95LEDS8 Display Board, Inline Array of 8 LEDs $17.95LEDS20 Display Board, 5x4 Array of 20 LEDs $29.95AC125 110VAC Power Supply $9.95 Bright full color LED - red, green blue elements! 8-pin microcontroller! Operates on 6 VDC to 12 VDC Extra SMT components are included!If youre looking to put some stunning color into yourHalloween displays, this is the kit for you!It was origi-nally designed as a way to show off the latest technol-ogy in RGB (Red, Green, Blue) full color LEDs whileproviding kit builders with a fun and economical SMT practice kit.Uses PWM methods to generate any color with a simple 8-pin microcontroller,with switchable speed selection as well!The dual jumper control system tells themicroprocessor what scanning speed is desired for a full cycle of 16,777,216 possi-ble colors from the LED!It randomly selects different color scanning modes towow any observer to the point of distraction!This little attention getter is fun tobuild and has loads of possible applications.To say it is an attention getter is anunderstatement!Just wait till you see the LED smoothly change colors in front ofyour eyes!Operates from 6VDC to 12VDC, and will run continuously on a standard 9V bat-tery for several days!And if youre new to SMT technology dont worry, weinclude extra SMT components to cover your mistakes! Everlasting LEDs wont burn out! Variable flash rate & audio trigger! Bass & treble trigger modes! Safe low voltage operation!Halloween PumpkinThe perfect starter kit with a terrific Halloween theme!You wont be scraping the seeds and guts out of thispumpkin!Six transistor circuit provides a neat random flashpattern that looks just like a flickering candle.Then a super brightLED illuminates the entire pumpkin with a spooky glow!The pumpkin face is the actual PC board, and assembly is easy through-hole sol-dering of all components and LEDs.Your pumpkin is powered by a standard 9Vbattery (not included) which snaps to the back of the pumpkin.An on/off switchis also included.Create a new kind of pumpkin this year, and learn about LEDsand electronics at the same time! 25 bright LEDs! Random flash simulates flickering candle! Super bright LED illuminates entire pumpkin! Simple & safe 9V battery operationMK145 Electronic Halloween Pumpkin Kit $9.95High Intensity SMT Blinky KitThe BL2 is the perfect subminiature answer tohigh intensity flashing LED applications!UsingSMT technology, the BL2 is small enough toconceal anywhere to provide alternating highintensity flashes!Need eyes for your mask?Just remote the LEDs and youre all set!Install iton your kids candy bucket as a neat attention grabbing display and a safety indi-cator!The applications are endless.When complete, the BL2 provides alternating super bright red and blue LEDs.Runs on 6VDC, and we include two LR55 button cells and a cell holder to mounton the backside of the board.Its one complete unit!If you dont want SMTLEDs you can also use regular T1 LEDs (included). If you want to learn whatSMT is all about, the BL2 is for you!We provide a detailed instruction and assem-bly manual, SMT theory information, and we even include spare SMT chips tocover you when you goof up!If youre interested in learning all about SMT tech-nology and ending up with a really neat LED display, the BL2 is for you. Super bright SMT LEDs! Subminiature board, perfect for hidden applications! Runs on miniature button cell batteriesBL2 High Intensity SMT Blinky Kit $17.95Laser Light ShowLLS1 Laser Light Show Kit $44.95PS21 12VAC Output 110VAC Power Supply $19.95Blinky-Eyes Animated DisplayThe ultimate animated LED kit that will dazzleyou and delight your friends! Uses a microcon-troller to randomly select from many differentanimations such as a long pause before a wink, or a twinkleof the eye to startle passers-by!Four modes to satisfy any enthusiasts desires: 1. Off for long random periods,then blinks or winks.Designed to scare!2. On for long periods before perform-ing an animation, perfect for costumes and displays!3. Animates all the time forconstant motion, perfect display attention-getter.4. Random fire!When placed ina pumpkin will light it up like you wouldnt believe!As if this weren't enough, theBE66 can also control a small hobby motor to shake bushes at random intervalsor signal an external player to make a scary sound!Also has a CDS cell to senselight.In one mode, the display will dim as it gets dark for battery operation, andin the other it will turn off when its too bright, so it plays only in the dark! BE66 Blinky-Eyes Animated Display Kit $59.95 Audio input modulates pattern! Adjustable pattern & size! Projects neat motorized patterns! Uses safe plastic mirrors!You've probably seen a laser show atconcerts or on TV.Theyre prettyimpressive to say the least!Knowing thatyou cant afford a professional laser display wechallenged our engineers to design one thatsneat and easy to build, yet inexpensive.Well, the result is the new LLS1 LaserLight Show!This thing is sweet and perfect for your haunted house or halloweenparties!It utilizes two small motors and a small standard laser pointer as thebasics.Then, we gave it variable pattern and speed controls to customize the pat-tern!Not enough, you say?How about a line level audio input to modulate the patternwith your CDs, music, or spooky sound effects?You bet!Everything is included,even the small laser pointer.Runs on 6-12 VDC or our standard 12VDC ACAdapter (not included). Animated display of 66 super bright LEDs! Microcontroller controlled! Changes brightness automatically! Animated with constant motion!NutNVolt200404.qxd9/7/20044:32 PMPage 22Mini-Kits...Great Starters!Tickle-StickThe kit has a pulsing 80 volttickle output and a mischie-vous blinking LED.And whocan resist a blinking light!Greatfun for your desk,Hey, I told you not to touch!Runs on 3-6 VDCTS4 Tickle Stick Kit $12.95Super Snoop AmplifierSuper sensitive amplifier that willpick up a pin drop at 15 feet!Full2 watts output.Makes a great bigear microphone.Runs on 6-15 VDCBN9 Super Snoop Amp Kit $9.95Dripping FaucetProduces a very pleasant, butobnoxious, repetitive plink, plinksound!Learn how a simple transistoroscillator and a 555 timer can make sucha sound!Runs on 4-9 VDC.EDF1 Dripping Faucet Kit $9.95LED BlinkyOur #1 Mini-Kit for 31 years!Alternately flashes two jumbo redLEDs.Great for signs, name badges,model railroading, and more.Runs on 3-15 VDC.BL1 LED Blinky Kit $7.95Touch Tone DecoderStrappable to detect any singleDTMF digit.Provides a closure toground up to 20mA.Connect toany speaker, detector or even a phoneline.Runs on 5 VDC.TT7 DTMF Decoder Kit $24.95Electronic SirenProduces the upward and down-ward wail of a police siren.Produces 5W output, and will driveany speaker!Runs on 6-12 VDC.SM3 Electronic Siren Kit $7.95Universal TimerBuild anything from a time delayto an audio oscillator using theversatile 555 timer chip!Comeswith lots of application ideas.Runs on5-15 VDC.UT5 Universal Timer Kit $9.95Voice SwitchVoice activated (VOX) provides aswitched output when it hears asound.Great for a hands free PTTswitch, or to turn on a recorder or light!Runs on6-12 VDC and drives a 100 mA load.VS1 Voice Switch Kit $9.95Tone Encoder/DecoderEncodes OR decodes any tone 40Hz to 5KHz!Add a small cap and itwill go as low as 10 Hz!Tunable witha precision 20 turn pot.Runs on 5-12 VDC andwill drive any load up to 100 mA.TD1 Encoder/Decoder Kit $9.95RAMSEY ELECTRONICS, INC.590 Fishers Station DriveVictor, NY14564(800) 446-2295(585) 924-4560 Build It! Learn It! Achieve It! Enjoy It!WhereElectronicsIs AlwaysFUN!Prices, availability, and specifications are subject to change.Visit www.ramseykits.com for the latest pricing, specials, terms and conditions.Copyright 2004 Ramsey Electronics, Inc.MORE than just friendly on-line ordering!Clearance Specials, Ramsey Museum, User Forums, DealerInformation, FAQs, FCC Info, Kit Building Guides,Downloads, Live Weather, Live Webcams, and much more!AM & FM Broadcast KitsRun Your Own Radio Station!800-446-2295www.ramseykits.comProfessional FM Stereo Radio StationThe all new design of our very popular FM100!Designed new fromthe ground up, including SMT technology for the best performanceever! Frequency synthesized PLL assures drift-free operation withsimple front panel frequency selection.Built-in audio mixer features LEDbargraph meters to make setting audio a breeze. The kit includes metal case, whipantenna and built-in 110 volt AC power supply.FM100BSuper-Pro FM Stereo Radio Station Kit $269.95FM100BEX1 Watt, Export Version, Kit$349.95FM100BWT1 Watt, Export Version, Wired & Tested$429.95 Synthesized 88-108 MHz with no drift Built-in mixer - 2 line inputs, 1 mic input Line level monitor output High power version available for export useProfessional 40 Watt Power AmplifierAt last, the number one requested new product is here!ThePA100 is a professional quality FM power amplifier with 30-40watts output that has variable drive capabilities.With a mere onewatt drive you can boost your output up to 30 watts!And this iscontinuously variable throughout the full range!If you are currently using an FMtransmitter that provides more than one watt RF output, no problem!The drive input is selectable forone or five watts to achieve the full rated output!Features a multifunction LED display to show you outputpower, input drive, VSWR, temperature, and fault conditions.The built-in microprocessor provides AUTOMATICprotection for VSWR, over-drive, and over-temperature.The built-in fan provides a cool 24/7 continuous dutycycle to keep your station on the air!PA10040 Watt FM Power Amplifier, Assembled & Tested $599.95 Frequency range 87.5 to 108 MHz Variable 1 to 40 watt power output Selectable 1W or 5W driveSynthesized Stereo FM TransmitterNeed professional quality features but can't justify the cost of a commer-cial FM exciter? The FM25B is the answer! A cut above the rest, theFM25B features a PIC microprocessor for easy frequency programming with-out the need for look-up tables or complicated formulas! The transmit fre-quency is easily set using DIP switches; no need for tuning coils or "tweak-ing" to work with today's 'digital' receivers. Frequency drift is a thing of thepast with PLL control making your signal rock solid all the time - just likecommercial stations.Kit comes complete with case set, whip antenna, 120 VAC power adapter, 1/8" Stereo toRCA patch cable, and easy assembly instructions - you'll be on the air in just an evening!FM25BProfessional Synthesized FM Stereo Transmitter Kit $139.95 Fully synthesized 88-108 MHz for no drift Line level inputs and output All new design, using SMT technologyTunable FM Stereo TransmitterThe FM10A has plenty of power and our manual goes into great detailoutlining all the aspects of antennas, transmitting range and the FCC rulesand regulations.Runs on internal 9V battery, external power from 5 to 15VDC, or an optional 120 VAC adapter is also available.Includes matching case!FM10C Tunable FM Stereo Transmitter Kit $44.95FMAC110VAC Power Supply for FM10A $9.95 Tunable throughout the FM band, 88-108 MHz Settable pre-emphasis 50 or 75 Sec for worldwide operation Line level inputs with RCA connectorsProfessional Synthesized AM TransmitterRun your own radio station!The AM25 operates anywhere within the stan-dard AM broadcast band, and is easily set to any clear channel in your area.Itis widely used by schools - standard output is 100 mW, with range up to mile,but is jumper settable for higher output where regulations allow.Broadcast frequen-cy is easily set with dip-switches and is stable without drifting. The transmitter acceptsline level input from CD players, tape decks, etc.Includes matching case & knob set and AC power supply!AM25Professional Synthesized AM Transmitter Kit $99.95 Fully frequency synthesized, no frequency drift! Ideal for schools Microprocessor controlledTunable AM TransmitterA great first kit, and a really neat AM transmitter!Tunable throughout the entireAM broadcast band.100 mW output for great range!One of the most popularkits for schools and scouts!Includes matching case for a finished look!AM1CTunable AM Radio Transmitter Kit $34.95AC125110VAC Power Supply for AM1 $9.95 Tunes the entire 550-1600 KHz AM band 100 mW output, operates on 9-12 VDC Line level input with RCA connectorCircle #83 on the Reader Service Card.NutNVolt200404.qxd9/7/20044:36 PMPage 23OCTOBER 2004Stampby Jon WilliamsStamp ApplicationsThenightisdrawingcloser...myfavoritenightofthe whole year: Halloween. I love Halloween thecostumes,hauntedhouses,parties,andfriendlyexchangeswithtrick-or-treaters;Halloweenisthebest.WhenIhavethechance,somethingIliketodoisbuildHalloween-orientedpropsanddecorationsandyoucanbet that many of those props get some sort of automationvia the BASIC Stamp microcontroller.GoodHalloweenpropsaddanelementofsurprise,which,ofcourse,intensifiesthefrightandthatsthemost fun thing about Halloween, right? The only problemis that, as a society, we are far more sophisticated than wewere in the past (especially the teenagers). We can easilyseethroughacheesyeffectandfindthetrigger,whichruins the effect for those who immediately follow.Instead of using a fixed-point trigger for an automatedprop, what if we used a distance measuring device so thatwe could select a random trigger point? That would keepemguessing,wouldntit?Youbet!Weveusedsonicmeasuring devices in the past (SRF-04 and SRF-08); thistime,welldoitwithinfrared.Thedeviceweregoingtouse is the low cost Sharp GP2D12.Read Volts, Get DistanceThere is no great mystery to using the GP2D12: Wesimplyconnectittoanappropriateanalog-to-digital converter and read the output voltage. The voltage is thenconverted to distance.The first part is very easy. For this project, well usetheADC0831analog-to-digitalconverterapartweveused before and should have no trouble with. In order tosimplifytheprojectcode,wellconnectthewiperofamutli-turnpottotheVrefinputoftheADC0831andsetthis to 2.55 volts. What this does for us is set each outputcount to be equal to 0.01 volts (255 [max count] dividedby2.55[Vref]=0.01volts/count).Figure1showstheschematic for the project.Letshavealookatthecodethatreadsthevoltagefrom the ADC0831:Read_0831:LOW AdcCSSHIFTIN AdcDta, AdcClk, MSBPOST, [result\9]HIGH AdcCSRETURNThiscodeisstraightforward,butifyouhaventusedtheADC0831beforeyoumaybewonderingwhyweneednineclocksforaneight-bitvalue.Asalways,youshoulddownloadthedocumentationforany part youre working with and, when you look at theADC0831timingchart,youllseethattheADCconversionisstartedbybringingtheCS(chipselect)linelow,thenputtingapulse on the clock line. Heres where we gettheextraclockpulse.Thevaluebitsareclocked out, MSB to LSB, with the followingeightclockpulses.EachADCbitisvalidafter the falling edge of the clock, so we useMSBPOST to read the bits. Once all the bitsareclockedin,thedeviceisdeselectedbybringing the CS line back high. Okay,thatsdone,butwhatwere likelytorunintoisabitofjitterinactualapplication. An easy way to smooth this jitteristotaketheaverageofmultiplereadings.Lets do it:Measuring Up Up to 80 Centimeters, That IsAdd a bit of intelligence to your Halloween displays with IR distance measuring.Putting the Spotlight on BASIC Stamp Projects, Hints, and TipsFigure 1. ADC0831/GP2D12 connections.24NUTS &VOLTSEverything For ElectronicsStamp.qxd9/7/20044:26 PMPage 24Read_GP2D12:cVolts = 0FOR idx = 1 TO 3GOSUB Read_0831cVolts = cVolts + resultPAUSE 30NEXTcVolts = cVolts / 3RETURNWestartbyclearingtheoldcVoltsvalue, then, with a loop, take three readingsoftheADC0831andaccumulatethem.KeepinmindthatwewillneedtouseaWord-sizedvariableforcVolts,otherwisewedlikelygetaroll-overerrorafterthe second reading. At the end of the loop, wedividetheaccumulationbythenumberofloop iterations to get the average value.What happens, though, when were in apinchforvariablespace?Onewayaroundthis though likely to be slightly less accuratethanthemethodaboveistodivideeachreadingbeforeaccumulating.Keepinmindthatthelowerreadingsandlargerdivisorsresult in a greater likelihood for error. If youkeep the divisor small, this shouldnt become too much of aproblem. Heres the code for the alternate version:Read_GP2D12_Alternate:cVolts = 0FOR idx = 1 TO 3GOSUB Read_0831cVolts = cVolts + (result / 3)PAUSE 30NEXTRETURNStraightening the CurveNowcomesthetrickypartconvertingthevoltageoutput of the GP2D12 to a distance value. Have a look atFigure2andyoullseewhyIsaythisistricky.Overtheentire measurement range, the output from GP2D12 is notatalllinearinrespecttodistance,soasimplemx+bequation is just not going to work. I plugged the data intoacurvefittingprogramandfoundthatittakesafourth-orderequationtogetanywhereclosetothedataset.ms StampOCTOBER 200425Figure 2. GP2D12 output voltage versus distance.Circle #66 on the Reader Service Card.Stamp.qxd9/8/20043:24 PMPage 25Applyingafourth-orderequationwith16-bitinteger-onlymath is just not very practical.Thereareinterestingsolutionstothisdilemma,butmost of them were more than I wanted to wrap my brainaround, so I decided simple is better than interesting. (Mymiddle name, after all, is Simple.) Looking at the graphagain, we can see that the segments between data pointsarenotfarfromthecurvethatwouldfitbetweenthosesame points. What I decided to do, then, is to calculate theslope between data points and interpolate from there. I feltlikethiswasanacceptablesolution,giventheslightlyloosespecificationsoftheGP2D12.(Itisalowcostdevice.)FirstthingsfirstthatcurveinFigure2actually camefrommysensor,bouncedoffan18%graycard(somethingphotographersuse).Usingsomecardboardandfoamblocks,Isetupandmarkedatestjigat5 centimeterintervals,thenmeasuredthevoltageateachintervalfrom10to80centimetersusingthecodewevedeveloped thus far.Now what? As I just mentioned, the segments betweendata points can be treated as a line, so what we can do isfindthedatapointsthatsurroundourcurrentreading, calculatetheslopeofthelinebetweenthem,andtheninterpolate the distance. Lets have a look at the code thatdoes this, then work our way through.Heresthetableofdistancereadingsfrommytestsetup:Vout DATA251, 179, 139, 114,97DATA 85,76,67,62,57DATA 53,50,48,46,43DATA0Now, heres the code that uses the table and the cur-rent voltage reading:Estimate_Cm:FOR idx = 0 TO 15READ (Vout + idx), test2IF (test2 size2) {i = penx();if(i > size2) { // lower rightsersend("4"); // RIGHT command}else { // lower leftsersend("3");// LEFT command}}else {i = penx();if(i > size2) {// upper rightsersend("1");// FORWARD command}else {// upper leftsersend("2");// BACK command}}}else if(i == 5)// page up keysersend("0");// STOP commandelse if(i == 6)// page down keybreak; // quit}graph_off();// don't forget to close the graphics...}Listing 2Krawec.qxd9/7/20041:45 PMPage 44message).Forthis,youcanusethealert()command,whichwillactuallycreateaseparate dialogboxandoutputthetextthere.Evenbetteristheconfirm() command,whichnotonlycreatesaseparate pop up box, but also adds Yes and Nobuttons. Using this command, you can easily receiveuser input without any hassle.Thisshouldbeenoughbasicoutput commandsformostprograms,butwhataboutinput? While not all programs require any input, mostdo, and PocketC equips the programmer with severalofthesemuchneededcommands.Firstand foremostisthegets() command.Whenthis command is called, the Palm will create a new inputbox with two buttons: OK and Cancel. Here, theuser of your program will be able to type in an entire stringthat the gets() command will return if the user taps OK.IftheusertapsCancel,thentheprocedurereturnsanempty string. Not only does this procedure create a simpleinput box, but you can also give the procedure a string oftext to print out on the screen. For example, gets(Type in something), when runwillcreateapopupboxaskingtheuserforinput.However,thetextinsideofthatboxwillread,Typeinsomething.Therearealsoseveralgets() variants,suchasthegetsd() procedure.Thisnewproceduredoesthesamething as gets(), except that you can give the input box adefaultvalue.Alsoavailabletoyouarethegetsi() andgetsm() commands, which act like the original command,except that you can tell PocketC exactly where to place theinput box (instead of the default bottom of the screen). Thegetsm() procedure also adds the ability to control the sizeoftheinputboxinadditiontotheotherfeaturesofthegetsi() procedure.EventsWenowknowhowtooutputtexttothescreenandreceiveuserinput,buthowdoweknowwhattheuserisdoingtothePalmatanygiventime?Forexample,a program might need to know when a user taps the screenorpressestheCalendarbutton.Thisisallhandledthrough the Event System in PocketC.Whilethereareseveralcommandsthatcanbe considered a part of the event system, the command youllprobablybeusingmostistheevent() command.Thiscommand will basically check to see what the user is doingandreportbackwiththenumbercodeoftheevent.Say,forexample,theusertapsthescreen.Theevent()procedure will return the number 2. Later on, however, theuserpressesthePage-Upkey.Inthiscase,theevent()procedurewillreturna5.Allinall,thereare18differentevents that this procedure can track. If you need to knowwhat they all are and Im sure you will take a look atthe PocketC documentation.Palm ProgrammingOCTOBER 200445Figure 7. A screenshot showingthe resulting memo file from theCreating Memo Files section.Figure 6. A screenshot showing thegets() procedure.Circle #125 on the Reader Service Card.Krawec.qxd9/8/20043:26 PMPage 45Inadditiontotheevent()procedure,theEventSystem containsseveralotheruseful functions,includingthepenx()andpeny() procedures.Thesearetwoproceduresyoullproba-blybecallingalotifyoucreateaPalmGUI.Toputit simply,theseproceduresreturnthexandypositionofthe pen (or stylus). Letssaythatyourprogramcallstheevent()procedure, which, in turn, returns the value 2 (pen downevent).Now,allweknowisthatthepenisactually touchingthescreen.Maybethisisenoughforsomecases, but most of the time youre going to want toknowwhere thepenistouchingthescreen.Todothat,simply call the penx() and peny() procedures and theylltell you everything you need to know.Now, youre probably aware of the fact that, when youpresstheCalendarbuttonoranyothershort cut button, the appropriate applicationloads up automatically. This is because PalmOSisconstantlycheckingthesebuttons ...evenwhenyourprogramisrunning.So,ordinarily,eventhoughyourecallingtheevent() proceduretocheckforthestatusof these buttons, Palm OS will take over thesecond any of them are pressed. Thatswherethehookhard()procedure comes in. If your program needsto use these predefined buttons, youll haveto call this procedure before anything else isdone. If you pass a 1 to this procedure, allofthesebuttonswillbeprocessedthroughtheevent() procedurebefore goingthrough the OS. Otherwise, as I mentionedbefore,assoonasanyofthesekeysarepressed,theOStakesoverandlaunchesanother application.StringsEasystringmanipulationisoftenaweakspotinCcompilers,butthisisnotthecaseinPocketC!Infact,working with strings is as easy as working with any othervariable type. Just define them and you can set them upas easily as an integer. Of course, this isnt nearly enoughfor more advanced programs, so PocketC packs a bunchof easy-to-use string procedures.Included with these procedures is the strlen() procedure,whichreturnsthelengthofthestring.Also,thestrupr()andstrlwr() proceduresareavailabletoyou.These procedures will return any string you pass to them in eitheruppercase (if you use struper()) or lowercase (if you usestrlwr()). On top of all that, you can also call the strstr()procedure, which will actually search through a string for asubstring. If the substring is found, the procedure will returnthe starting character position of that string.MathematicsOfcourse,acompilerisonlyasgoodasitsmathcapabilities and PocketC packs quite a punch in this area.However,whilePocketChasseveralmathfunctions,thisfunctionalitydoesntcomenaturallytothecompiler.Instead,allofthemathproceduresaredefinedinanexternallibrarythatyouwillneedtoinstall.RememberwhenItoldyouthattherearenoexternallibrariestoinstall? I lied. Well,actually,notreally.Imeantthatyoudidntneedany external libraries to get started. However, if you want toadd functionality to the compiler (and Im sure you will), youwill, of course, need some external definitions for things.Fear not, though, for MathLib is here! In fact, MathLibactuallycomeswithPocketC,meaningthat,whenyouOCTOBER 200446NUTS &VOLTSEverything For ElectronicsProjectDevelopment Siteswww.orbworks.comOrbworks is the developer of PocketC. On their site, you can findinformation on PocketC, as well as other tools related to it.Plus, they have a great support forum. So, if you have a question,you can always ask.www.palmsource.com/developersPalms developer site. Everyone interested in developing for the Palm should visit this site.www.geocities.com/retro_01775/PToolboxLib.htmEven though I didnt talk about PToolBoxLib in this article, I have to mention it. PToolBoxLib is a free graphics library for PocketC.Basically, if you want to do anything involving graphics inPocketC, you need PToolBoxLib.http://www.geocities.com/waltsrobots/page3.htmlMy robotics website. If you have a question,dont hesitate to Email me.LinksFigure 8. My Palm device with cradle.Figure 9. All you need to easily developPalm applications. Neither the computernor the Palm has to be very powerful.Krawec.qxd9/7/20041:47 PMPage 46downloadthePocketCfilesfromOrbWorks,yourealsogetting this library full of mathematical knowledge. To useit, simply install it as you did PocketC. You should keep inmind, however, that if your program does use MathLib andyou do plan on releasing your finished program, not onlywillyouhavetotelltheusertoinstallthefreeversionofPocketC, youll also have to tell them to install MathLib, butthatsnottoobadbecauseMathLibcomesbundledwiththe free version of PocketC.So, now that we have that out of the way, lets get tothemath!OnceyouveinstalledMathLib,yourPalm program will be able to access a multitude of mathematicsfunctions,includingthetrigonometricfunctionssuchassin(),cos(),atan(),andalltheothers.AlsoincludedinMathLib is the pow() function, which takes two values (xand y) and returns x^y. Thats not all you also have thesqrt() function(whichtakesthesquarerootofthe argument),acoupleoflogfunctions,andevensome random number generator procedures.Sound and TimeEvery Palm device has a buzzer of some sort. (At least,IhaveneverseenorheardofaPalmthatcouldntbeep,somehow.)So,inordertousethesebuzzers/beepers/speakers, PocketC contains several easy-to-use proceduresthat you can call.First up is the beep() command. Short, sweet, and tothe point, this procedure simply generates a tone of somesort.However,itdoesntjustmakeasinglenoteonyourdevicesbuzzer.Ohno,youhaveuptosevendifferentsoundeffectstochoosefrom.Bypassinga1 tothis command,yourPalmwillgiveyouaninfosoundor,ifyou pass it a 5, youll get an alarm sound. If you wouldlike to learn more about all these fascinating sound effects,pleaserefertothePocketCusermanualunderthe appropriately labeled Sound section. Alongwiththebeep() command,youalsohaveatone() command,whichwillgenerateasoundusingthespecifiedfrequencyandduration.Whileslightlymore complicated,thisgivesyoumuchmorecontroloverthegeneratedsoundwhencomparedtothebeep()command.However,ifyouusethetonea() function,notonly do you have control over the frequency and durationof the sound, but you are also able to specify the volumethe tone will be played at. Pretty cool, eh?Whiletheremaybeanicevariet