The-design-of-the-automatic-temperature-control-fa

Thedesignoftheautomatictemperaturecontrolfan1.Missionrequirementsandtechnicalindicators1.1MissionrequirementsThepurposeofthisworkistomakeatemperaturerechargeablefan,whichcanadjustthespeedautomaticallyaccordingtothevariationofroomtemperature.Theelectricfancanbecharged,anditcanbeusedtocoolintheabsenceofpowersupply.Thepoweroftheelectricfanisusedtoprovideadditionalfunctionality.Inthisexercise,onlyusetheUSBtotheLEDlamp(simulationofdesklamp)powersupplyinterface.Fanusethesurplusspaceofhardware,attachthetiming,showingtemperature,andotherfunctions.1.2Thebasicfunction1)Temperaturemeasurementandautomatictemperaturecontrol.2)Displaythetemperatureandtime.3)Provideawiderangeofpowersupplyinterfaces.2.Theworkingprincipleofthecircuit2.1TheprinciplediagramSinglechipmicrocomputerTemperatureandtimedisplayTemperaturedetectionKeyboardinputMotordriverPowersupplyThemotorLED2.2Introductionofeachpart2.2.1Powersupply1)Inputpowerisconsistofthecommonterminalandthe2.5mmpowerplug,andtheinputvoltagemustwithin12v.2)PowersupplymoduleusesLM2576whichisaswitchingchipforvoltagestabilityon5vthensupplyingpowerforthesinglechipmicrocomputer,motordriverandotherdigitalchips.3)Themotorneeds12vpowersupply.2.2.2SinglechipmicrocomputerWeuseSTC89C51asthemaincontroller,whichisresponsibleforthedeterminationoftemperature,real-timedisplayoftimeandtemperature,buttonscanning,andthecontrolofmotordrive.2.2.3TemperaturedetectionmoduleWeuse18B20temperaturesensorfortemperaturemeasurement.2.2.4KeyboardinputmoduleItiscomposedofbuttons,usedtosetthemotorspeedandtime.2.2.5TemperatureandtimedisplaymoduleReal-timetemperatureandtimearedisplayedbysevensegmentofthesameanode.Segmentsignalisoutputby74LS47.Inaddition74LS138and9013areusedinthismodule.2.2.6Motordrivermodule298NisusedtodrivethemotorandtheinputsignalisseparatedwithSinglechipmicrocomputercircuitbyopticalcouplingtoensurethestabilityofthecircuit.2.2.7ThemotormoduleConsideringtheeconomyanddifficultyofcontrol,weusea12vbrushdcmotor.Ifpossiblewecanusebrushlessdcmotortoreducethenoise.3.TheprinciplediagramThecircuitprinciplediagramisdrewbyAltiumDesigner.TheupperleftcornerisLM2576whichisusedtostablevoltage.Theuppermiddleis74LS47decodertheoutputofwhichisconnectedwith510Ωresistance.Thetoprightcornerisdigitaltube.Theleftinthemiddleisthebuttoncircuit.Temperaturesensor18B20isbelowthebuttons.Thesinglechipmicrocomputerminimumsystemand74LS138areinthemiddleofthediagram.