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AppliedMechanicsandMaterialsVol.109(2012)pp248-25Intelligentvehicle-mountedalcoholdetectioncontrolsystemKeywords:intelligent;alcoholdetection;vehicle-mountedAbstract：Thepaperdesignedanintelligentvehicle-mountedalcoholdetectioncontrolsystem,whichisbasedonS3C2440chip.Thesystemtestedthedriver'sresponseabilityandeye-handcoordinationininteractivewaytodeterminewhetherthedrivercouldcontrolthevehicle.Thesystemintroducedpsychologymethodinnovatively.Itcanovercomethedisadvantageofonlydependingonthegasalcoholconcentrationasthecontrolbasis,andenhancetheapplicabilityofthesystem.IntroductionDrink-drivinghasbeenaheavytopic,Peoplehurtssomuchbytrafficaccidentcausedbydrinking-drivingandPeopletakesvariousmeasurestocurbdrinkdrivingphenomenon,Therearesomekindsofvehicle-mountedalcoholdetectioncontrolsystemwhichareusedtocontroldrink-driving,thosesystemusealcoholsensorwhichplacedinthecardetectthealcoholconcentrationandcomparethealcoholconcentrationvaluewiththesetgasconcentrationvalue,thencontrolthevehicleaccordingtotheresultofcomparison.Theycanreducethedrinking-drivingbehavior.Butthosesystemcontrolthevehicleignitionbythegasalcoholcontentexistbigdisadvantage.Duetothedifferencephysicalconditionofindividual,theaffectiononpeoplecausedbyalcoholisdifferent.Sothebloodalcoholconcentration(BAC)cannotfullyreflecttheimpactofalcoholonpeople’sdrivingskills.Furthermoreitisdifficulttojudgealcoholgasoriginandmeasurethebreathalcoholconcentration(BrAC)accuratelyinthecar’sclosedspacewithnosurveillance.Nomatterhowthealcoholsensorclosetothedriver,thegaswhichthesensordetectedisstillgasmixturesandBrACcannotbedetectedaccurately.Thenthesystemcontrolthecarusethegasalcoholcontentexistbigweakness.Inadditionthosesystemcan'tdistinguishthealcoholgascomefromthedrinkdriverfromthealcoholgascomefromcopilotorothersourceofalcohol,Moreoverthosesystemunabletodeterminewhetherthedriverwanttocoordinatewiththem.Basedonthediscussionupwards,anewintelligentvehicle-mountedalcoholdetectioncontrolsystemisputforwardinthispaper.ThissystemusethewayofHuman–Computerinteractionandintroducethemethodofpsychology.Themethodofpsychologyisusedtotestthedriver’sresponseabilityandeye-handcoordination,thenthesystemaccordingthetestresulttocontrolthevehicle,itovercometheweaknessthatusingagasalcoholconcentrationasreferencepointstocontrolthevehicle.Thesystemcanperceivetheinnerenvironmentbyitssensors,anditwillbemoreaccurateandflexibletocontroldrunkdriving,andthetestresultshowsthatthesystemcanworkeffectively.1HardwaredesignThefigure1showstheIntelligentvehicle-mountedalcoholdetectioncontrolsystemblockdiagram,thesystem’shardwaremainlyincludesaprocesschipS3C2440,alargecapacitymemory,analcoholsensorMQ-3，speedsensor,amplifier,A/Dconvertor.TheprocesschipS3C2440isdevelopedwithARM920Tcore,0.13µmCMOSstandardcellsandamemorycomplier.Itslow-power,simple,elegantandfullystaticdesignisparticularlysuitableforcost-andpower-sensitiveapplications.ItoffersoutstandingfeatureswithitsCPUcore,a16/32-bitARM920TRISCprocessordesignedbyadvancedRISCmachines,Ltd.Thehighestworkfrequencyoftheprocessoris533MHzanditsaddressspacereach1G.Allkindsofinterfacesand8channel10bitA/DconvertercansatisfytherapidresponsesystemanddrivinglargerLCDscreen.TheMQ-3sensorcanbeusedrangefromalcoholcontentofgas0.05mg/Ltoalcoholcontentofgas10mg/L，andMQ-3issensitivetoalcoholgas,selectiveandfastrecovery,andtheMQ-3sensorisreliable,usedwithsimpledrivecircuit.ThesystemwillusetheMQ-3alcoholsensor’ssignalasatriggersignal,andthenwecanreducethedependenceofthesystemtothesensor.Wejustadjusttwovalueofthesensorisaccuratewiththealcoholgasconcentration,oneis0.0454mg/LcorrespondtoBAC10mg/100ml,theotheris0.3636mg/Lcorrespondto80mg/100ml,theformervalueusedtoexcludetheuncertainvaluewhichisbroughtbytheothergas.Whenthedriverentersthevehiclethesystemdetectsthealcoholgasconcentration.Ifthealcoholgasconcentrationismorethan0.0454mg/L,thesystemstartsthetestprogram.Whichisusedtodeterminewhetherthedriverwasdrunk,whendetectingalcoholgasconcentrationabove0.3636mg/L,therelaywillbeturnoffandthesystemwillwatchtheinterfacestillthedrivergetoutofthevehicle.Theswitchturnsoffwhenthedriversetdown,andturnsonwhenthedriverstandup.Speedsensorisusedwhenthedriverhaddrinkandpassesthetest,thespeedsensor’ssignalfeedbacktothesystem.Relayandspeedcontrolcircuitcarryoutthesystem’scontrolsignal.Touch-screendisplaymessage,provideinterfaceforinteractionwiththedriver.Electricfanaccelerateairflow,itishelpfulfortherapiddetectionofalcoholsensor.2SystemsworkingprincipleNormally,thedrivergetsinvehiclewithoutdrink,sothissystemdesignedtoensurerapidresponsecapabilityasshortaspossible.Whenthedriveropensthedoorfromoutside,thesystemactfromstandbyintooperation,heatalcoholsensor,startelectricfan,disconnecttherelayandlockvehicles.Whendriveropenthevehicle’sdoor,theswitchundertheseatisoff,thesystemwillconsiderthedriverisgettingintothevehicle,whentheswitchison,andvehicle’sdoorclosed,itwillbeconsideredasthedriverhasenteredthevehicle.Whenthedoorlockisclosed,andtheswitchison,thesystemwillconsiderthedriverisleavingthevehicle,thedriv