FABLABDelhi

DhananjayV.GadreListofProjectsFlickeringCandleElectronicBatterylessdiceLedPenElectronicBirthdayBlowoutCandlesAudioSpectrumAnalyzerTwilightSwitchFlickeringLEDcandleFlickeringCandleAnLEDcanbeusedtomimiccandlelight.Thetricktomimickingacandleliesinrecreatingthewayacandleflickers.Thecandleflameswaysrandomly(orsoitseems)andsometimestheintensityoftheflameseemstovarywithaircurrents.WhileusinganLEDtobehavelikeacandle,itmaynotbepossibletomakethe‘flame’sway,butwhatcancertainlybeachievedistherandomvariationofintensityConcept–TheoryofOperationForrandomization,aparticulartypeofpseudorandomgeneratorsknownaslinearfeedbackshiftregisters(LFSRs)havebeenused.Concept–TheoryofOperation(contd…)AnLFSRisashiftregistertheinputtowhichistheexclusive-or(XOR)ofsomeofthebitsoftheregisteritself.ThebitpositionsthatareusedfortheXORoperationtoyieldtheinputbitarecalledtaps.ImplementationThepseudo-randomnumbergeneratorandtheintensitycontroloftheLEDhavebeenimplementedusingAVRATiny13microcontroller.Thecircuithasbeensplitintotwoboards:thecontrollerboardandtheLEDholderboard.TheLEDholderboardisplacedontopofthecontrollerboardsoastominimizethefootprintofthecircuitboard.Thiswayitoccupieslessspaceandcaneasilybepackagedinatubetogiveafeelofacandle.TheProjectHardwareElectronicBatterylessdice

ElectronicBatterylessdice

Therehasbeenalotofinterestinmusclepoweredelectronicdevices.ThemusclepoweredvoltagegeneratorisbasedonFaraday'slaw,consistingofatubewithcylindricalmagnets.ItisalsocalledFaradaygenerator.Insteadofatraditionaldice,itisniceandcooltouseanelectronicdicethatispoweredfromfaradaygenerator.Moreover,sincethefaradaygeneratorproducespoweronlywhenitisshaken,itmimicstheshakeofrealdice.Concept–TheoryofOperationFaradayGeneratorproducesACoutputvoltage.So,itisrectifiedandthenfilteredbyacapacitor.Thecapacitorvoltageisthenregulatedandusedtopowertheelectroniccircuitrequiredforthedice.Thediceismimickedbyseven3mmLEDsarrangedinthetraditionalpatternofdotsonthedice.Concept–TheoryofOperation(contd…)Thepulsedoutputfromthegeneratorisalsofedtothemicrocontrollertodeterminewhetherthetubeisbeingshakenornot.ImplementationTheProjectHardwareLEDpenLEDpenYoumighthaveseenadvertisementsbybatterymanufacturersinwhichimagesaredrawnintheairandcapturedbyalongexposurecameraNowimagine,insteadofaflashlight,youhaveamulticolorLEDpenwithwhichtodrawthesepicturesandimage?Thisisexactlywhatthisprojectachieves.Suchimagesandpicturesarecalledlightdoodles.LEDdoodlesConcept–TheoryofOperationTheLEDusedisaRGBLED.BytheuseofPWMoneachcolorcomponent,Itcanbeusedtogeneratemultiplecolors.Sixteencolorshavebeenselectedinthisproject.Thereisanon-offswitchtochangethestateoftheLEDandapotentiometertochangethecoloroftheLED.TheoutputofthepotentiometerisfedtotheADCinputchannelofthemicrocontroller.ImplementationTheProjectHardwareElectronicBirthdayBlowoutCandlesElectronicBirthdayBlowoutCandlesTheElectronicBirthdayBlowoutCandlesemulatetheconventionalcandles(arrangedonabirthdaycake)LEDshavebeenusedassmallcandles.Theyflickerrandomlytogivetheappearanceofrealcandles.Moreover,theyalsogooffinarandomfashionwhensomeoneblowsaironthem.WhenalltheLEDshavebeenextinguished,atoneof“HappyBirthdaytoyou”isplayed.Concept–TheoryofOperation20LEDshavebeenconnectedinamultiplexedfashion.Theirintensityisvariedtogiveaflickeringeffect.Thesensorpartconsistsofathermistorinserieswitharesistor.Thethermistorisalsointhermalcontactwithahighpowerresistor(1/2W)whichraisesitstemperatureaboveroomtemperature.Concept–TheoryofOperation(contd…)Whenuserblowsonit,thethermistorgetscooledwhichincreasesitsresistance.ThisisdetectedbythemicrocontrollerandrandomnumberofLEDsareextinguished.ThecontrollerusedisATmega8.TheProjectHardwareAudioSpectrumAnalyzerAudioSpectrumAnalyzerSpectrumAnalyzermadeisbasedon5FIRfiltersimplementedinATmega88microcontoller.Theaudiorangefrom200Hz–9600Hzhasbeenbrokendowninto5subbands.200–600Hz600–1200Hz1200–2400Hz2400–4800Hz4800–9600HzTwilightSwitchWhatistheTwilightSwitch?AnAVRimplementationofafullyautonomous

sensor-lessswitchforoutdoorartificiallightingthatoperatesattwilighttimeProjectaddressesthetwinconcernsofroadsafetyandenergyconservationAfterone-timeconfiguration,automaticallycalculatesandoperatesarelay/switchattwilighttimes.Concept–TheoryofOperationThecurrentlocationsgeographicalcoordinatesandlocaltimearerequired.Theseareconfiguredone-time.AclockismaintainedwiththeAVR’s16bittimerandcrystaloscillator.Twilighttimeiscalculatedwithpreciseformulae–amodifiedformoftheSunriseEquation.Aswitchisoperatedtoturnonlightingatendoftwilighttimeandturnitoffatbeginningoftwilighttime.ImplementationTheTwilightswitchcode,consistingofprecisetwilighttimecalculations,UARTconfigurationinterfaceandonboardtimekeeping,fitsonanAtmega8Aconfigurationanddisplayterminal(viaUART),alsoonAtmega8,withLCDandkeypadinterface,eliminatestheneedofaPCforconfiguration.AworkingprototypeisinoperationatCEDT,NewDelhiTheProjectHardwareTheConfigurationT