BasedonmonolithicintegratedcircuitautomobilesecurityalarmsystemdesignAbstract:Decodestheautomobilesecuritysystemusingthemonlitchisintegratedcircuitinteriorresourcesrealizationjumpcode,iteachtimeusestheremotecontrolpasswordallischanging,bothenhancedthesystemsecurity,andgreatlyreducedthecost.Keyword:Monolithicintegratedcircuit,Automobilesecuritysystem,Code/decodeIntroductionIsunceasinglyprogressivealongwiththesocialeconomyandthehightechrapiddevelopment,intheroutineworkandthelife,theautomobilehasbecomethepeopleidealtransportationvehicle.Butthefollowingmotorvehiclethecasewhichrobbedgraduallyisalsoincreasedhascreatedthepiloteconomicalpropertyloss.Inordertoreducetheautomobiletorobtheeventtheformationrate,forhastheautomobiletheusertoprovidethesafetycontrol,simplydevelopsonekindtobereliable,theeaseofoperation,cansendoutinthediscoverynormalconditiontothepilotreportstothepolicethereminderandthesecuritywarningsafetysystemhasthepracticalsignificance.Thisarticlebasedontotheexistingautomobilesecurityalarmsystemgeneralizedanalysis,developsonekindofbrand-newsecurityalarmsystem.Thissystemhasmainlyusedthejumpcodecode/decodingprinciple,causestheoverallsystemtobesafer,greatlyreducespasswordexplainingrate.1.SystemprincipleofworkTheautomobilesecurityalarmsystemtheremotecontrolwhichcarriesbythedriverandinstallsintheautomobilethecontrollertwopartscomposes.TheremotecontrolandthecontrolleralluseeightCMOSwhichAmericanAT-MELCorporationproducestheAVRmonolithicintegratedcircuit,thisseriesmonolithicintegratedcircuitbasedonnewsimplifiesinstructionRtheISCstructure,includestheservicelifemosttobefewis1,000timewrites/scratchesthecirculationtheFlashprogrammemory,aswellastheservicelifeatleastis100,000timewrites/scratchesthecirculationEtheEPROMdata-carrierstorage,some2onlyhavewhentheentirepiececleaningcancleantheprogrammingencryptionlocksthelocalization.1.1SystemdesignTheautomobilesecurityexaminationusestheultrasonicsensor.Theultrasonicsensoriscomposedbytheultrasonicwavetransmissioncircuitandthesupersonicreceptionelectriccircuit,intheautomobilecabappropriateposition,installstheultrasonicwavelaunch/receiver,aswellasswitchelectriccircuitT1.Whentheautomobileparksthevehicleownerpersonmustleavetheautomobile,withremotecontrolclosedswitchT1,theautomobilealarmsystemsatgarrisonsthecondition,aroundthesystemuseultrasonicwaveexaminationvehicleobstacle.Launchesthepartialelectriccircuitslikeschart1toshow.WhenitsP1mouthP1.1,P1.2totheDtrig,theP1.0controlultrasonicwavelaunch,are0,thephotoelectricitycoupleroutputstheTP1endis1,thepermissionultrasonicwavelaunch,launches/thereceiveultrasonicwaveinturn,thecirculationrepeatedlycarrieson.Simultaneouslythemonolithicintegratedcircuitinteriorcounterstartstocount.Thesteamdistancebetweenvehiclesobstacledistanceisthetimewhichsendsoutthroughthesoundnavigationandrangingreflectsspendsdeterminesandcarriesonthecomputation.ThereflectionsignalcausestheDtriggertoproduceinterruptrequestsignalINT1,simultaneouslystopscounting,readstakescountsthevalue,calculatestheactualdistanceaftertheformula,thencarriesonthecomparisonwiththedatumdistance,ifexamineswhentheactualdistanceisbiggerthanreferencevalue80cm,doesnotcarryontheaccustom-opticstoreporttothepolice；Ifsomepeopleapproachtheautomobiletoenterthecab,theexaminationactualdistanceissmallerthanorwasequaltowhenreferencevalue80cm,throughmonolithicintegratedcircuitP2.2andtheP2.3port,actuatestheindicatinglampdisplaycircuitandthesoundalarmcircuit,sendsoutthreetwoflash.Andtriggersahighlevel,theactuationiswirelesssignaltransmissioncircuit.Chart1Ultrasonicwavetransmissioncircuit1.2Code/decodingprincipleThepresentautomobileremotecontrolsecuritysystemaremanyisusesVD5026/27,PT2262/72,HT12E/Dandsoonthegeneralcode/decodestheelectriccircuit,itspassworddecidedbythecomponentaddress,eachsetofsecuritysystemsuseafixedinvariablepassword.Alongwiththemicroprocessingtechnologydevelopment,throughthereceiveremotecontroltransmittingmessage,mayinterceptthisfixedpassword,moreovergeneralarrangesthedecodingaddresstolosethepersontocarrythecomponentsizelimit,itsquantityisimpossibletoomuch,canobtainnotrepeatedlycodesveryisalsolimited,alsocanveryquicklyexplainthepasswordwiththeautomaticscanner.Therefore,thiskindofpasswordfixedinvariableautomobilesecuritysystemhasreceivedtheseriousthreat.Decodestheautomobilesecuritysystemusingthemonolithicintegratedcircuitinteriorresourcesrealizationjumpcode,iteachtimeusestheremotecontrolpasswordallischanging,withthepasswordnolongerduplicatesuses,causestheinterceptionpasswordalsoismakesafutileeffort,inaddition,itmayincreasetheenoughmanypasswordsfigure,enhancesthesystemresistanceillegalscanningtheability.Theremotecontrolcodingaltogetherhas12bytes,separatelyby3bytescodeschannelscode,3bytescodesforewordsnumber,5bytesjumpscodes,1bytepressedkeyoperationcodeiscomposed.Encodedfrontaddsonlogicineachbyte0totaketheoutsetposition,encodedbehindaddsonalogical1achievementineachbytetostoptheposition,andinmostfrontaddsonseverallogic1totaketheguidancesignal,thisconstitutedtheserialcodedsignalwhichusesintotransmit.Thecodechannelcodeusesintoexpresstheremotecontrolstatus；eachsetofsystemsuseafixedchannelcode.Thecodeforewordnumberusesintorecordtheencodedorder,itsstartingvalueis0,themonolithicintegratedcircuiteverytimecodesatime,thecodeforewordnumberupwardlycountstime.ThecodechannelcodeandthecodeforewordnumberdepositsinmonolithicintegratedcircuitEEPROM,guaranteesthempowercuttheinfluence.Thejumpcodeisthesystematictruepassword,itpassesthroughthecomplexspecialalgorithmbythecodechannelcodeandthecodeforewordnumbertoextract,thisspecialalgorithmforeignsecurity.Thepressedkeyoperationcodebythepressedkeywhichpresseswasdecided,whenthehypothesisthekeyispresseddown,itscodedecidesas01H；Whenrelievesthekeypressesdown,itscodedecidesas00H.Whetheristhedecodingconfirmsreceivethecodelegitimateaseriesofoperatingprocess.Wasconfirmedthelegitimatecodeneedstosatisfythreeconditions；(1)codesthechannelcodeandthedecodingchannelcodeissame；(2)codedtheforewordnumbertobebiggerthanthedecodingforewordnumber(decodingforewordnumbertorecordonlegitimatelyhasusedcodeforewordnumber,thisconditionmightguaranteebeforehasusedcodewasinvalid)；(3)jumpsthecodetobeequaltoreusesthespecialalgorithmtoextractchangesthecode.Afterthemonolithicintegratedcircuitconfirmedreceivesisthelegitimatecode,writesthecodeforewordnumberinthedecodingforewordnumber,andcompletescorrespondingoperationprocessingaccordingtotheoperationcode.ThedecodingchannelcodeandthedecodingforewordnumberalsodepositsinmonolithicintegratedcircuitEEPROM,guardsagainstbecauseofpowercutloses.1.3SecurityreportstothepolicerealizationIfwillhaverobberChenZheRutheroom,startstheautomobile,afterwrongpassword,thentheautomobilestoragebattery+12Vvoltage,theignitionelectriccurrentwayignitionlock,theignitionoutage,theengineextinguishes,againstarts,willduplicatetheaboveprocess,likethis,thebanditsandthievesalwayswillnotbeabletostarttheautomobile,willnotbeabletoachieveitsanticipatedgoal.ThealarmcircuitmainlyiscomposedbytheintegratedblockandthespeakerandelectronicswitchingSCR.Triodeorthemultiple-unittube,areforenhancetheelectriccircuitmeasurewhichthepowerbutoftenuses,ithascomposedacurrentamplificationfactorverybigequivalenttransistor,totalenlargementfactorforthesetwoenlargementfactorproduct.SCRistheelectronicswitchingwhichconstitutesbythesilicon-controlledrectifier,theelectriccapacityandtheresistanceconstitutionnegativeboosterconcurrentlyfilter,provides+3+4VtoICthevolta