3V供电的LED驱逐舰电路

3V供电的LED驱逐舰电路
GeneralTherearemany9Vchasercircuitsthatseemtowasteabout7VwhendrivingLEDsthatareonlyabout2V.Thisprojectisunique,becauseitusesonlytwoinexpensivealkalinebatterycellstotaling3Vforpower.Sincemostofthewasteiseliminated,thecellslastalongtime.Unliketheothercircuits,thisoneflashestheLEDsforonlyabout30mseach,furtherextendingthebatterylife.Foruserconvenience,ithasastepperspeedcontrolandabrightnesscontrol.Atslowerspeedsandwithreducedbrightness,thebatterylifeisfurtherextendedconsiderably.Mountedinacircle,theLEDsappeartorotateastheystepfromonetothenext.
Specifications•Battery:Twoalkalinecells(AAsizewereusedintheprototype)•BatteryLife:AAcellsCcellsDcellsMinimumspeedandbrightness8months2years4.9yearsMediumspeedandbrightness6months1.5years3.6yearsMaximumspeedandbrightness2weeks1.5months3.6months•Stepperspeed:2LEDs/secto2revolutions/sec•Brightness:ControlledwithPulseWidthModulation,fromverydimto161mcd(verybright)•PulseWidthModulationfrequency:1.4KHzverybrightto6KHzverydim•LEDcurrent:15mApulses,reducedto10.5mAatmaximumPulseWidthModulation•LEDvoltagedrop:1.76V(measured,notrated)@10.5mA•Minimumbatteryvoltage(totalofbothcells):1.24V,circuitisrunningbutLEDsarenotlit1.6V,LEDsareverydimatmaximumbrightness2.0V,LEDsreachalmostfullbrightness,batteryreplacementisrecommended.•Radiointerference:NoneCircuitDescriptionThe74HCCmosICsareratedfora2Vto6Vpowersupplyforhigh-speedlogiccircuits.Theycontinuetooperateatamuchlowervoltagebutnolongermeethigh-speedlogicspecifications.Toreachhighspeeds,theiroutputcurrentcanmomentarilyexceed400mA(lowvoltagedrop)butthermalconsiderationslimitmaximumcontinuousoutputcurrentto20mA.PerfectfordrivingLEDs!•IC2isa10stageJohnsoncounter/decoder.Ontherisingedgeofeachclockpulseitsoutputsstepone-at-a-time.ItdrivestheanodeofeachconductingLEDtowardthepositivesupply.•IC1aisastandardCmosinverterSchmitt-triggeroscillatorwithC3andC4totaling800nFforaveryslowsteprate.R2isthespeedcontrolpotwithR1limitingitsmaximumspeed.ItclocksIC2andfeedstheinverters/drivers.D1andR3reduceitsoutputhightimeto30mS.•IC1d,IC1e,IC1fandIC1bareparalleledinverter/driversforalowoutputvoltagedropanddrivetheemitterofT1toground.•IC1cisanotherstandardCmosinverterSchmitt-triggeroscillator.R5isitsPulseWidthModulationcontrolandwithD3performsdimmingoftheLEDs.D2andR4extendthePWM’smaximumpulsewidth.•T1isatransistorthatisusedasaPWMswitch.R7limitsmaximumLEDpulsecurrent.•C1bypassesthebattery’ssupplyvoltageatlowfrequenciesandC2bypassesathighfrequencies.ConstructionThetenLEDsmountonaCompact-Discwhichisgluedtoaplasticboxwithcontactcement.TheboxhousestheVeroboardcircuitinitslowermainpartwiththebatteryholderinitslid.MulticonductorribboncablejoinstheLEDstothecircuit.Thepotsmountonthesidesofthebox.PartsList1IC1CD74HC14NorSN74HC14NHigh-speedCmos,Schmitt-triggerhexinverters1IC2CD74HC4017NorSN74HC4017NHigh-speedCmos,decadecounter-decoder1T12N3904or2N4401NPNtransistor10LEDsMV8191HighbrightnesswideangleredLED(lessthan2V)3D1toD31N4148or1N914Silicondiode2R1,R3100K1/4Wresistor1R21MLineartaperpotentiometer(speed)1R4330K1/4Wresistor1R51MAudiotaper(logarithmic)potentiometer(brightness)1R66801/4Wresistor1R7221/4Wresistor1C1100uF/10Vor100uF/16VElectrolyticcapacitor1C20.1uF/50Vor0.1uF/100VCeramicdisccapacitor1C3330nF/63VMetalizedpolycapacitor1C4470nF/63VMetalizedpolycapacitor1C51nF/100VMetalizedpolycapacitor2misc.Alkalinebatterycells1misc.Plasticbox1misc.Batteryholder3misc.Vinylfeetforbox1misc.CompactDisc2misc.Knobsforpotentiometers1misc.HoleplugfortheCD’scenterhole1misc.9to11conductorribboncableNotes1)TheICsaremanufacturedbyTexasInstruments,andothers.2)TheLEDsaremanufacturedbyFairchildSemiconductor.3)Abovemanufacturersofferfreesamples.