基于 at89s51 单片机的微型土壤湿度检测仪设计.docx

基于 at89s51 单片机的微型土壤湿度检测仪设计.docx

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基于at89s51单片机的微型土壤湿度检测仪设计

山东理工大学

毕业设计

（外文翻译材料）

2011年6月

ThedesignBasedonAT89S51miniaturesoilhumiditydetectordesign

Abstract:

facilitatemastersoilmoistureconditions,designtheminiaturesoilhumiditydetector.Itshardwaresystemincludessignalamplifiercircuit,A/Dcircuit,SCM,microLCDdisplayandalarmcircuit,etc.;SoftwaresystemincludesA/Dconversiondriver,LCDdrivertwomodules.Proteussoftwareplatformbasedonthedesignofthesystemissimulated,andtheresultsshowthatthesystemhardwareandsoftwaredesigncorrectandreliableoperation.

Keywords:

soilhumidity;Detector;SCM;A/Dconversion;simulation

TP202classificationnumber:

Chinese

Literatureidentificationcode:

A

Section1Introduction

Agriculturalproductionintheeconomicdevelopmentofourcountryhasimportantposition,forfarmersIndustryproductiontoprovidetimelyandreliabllytechnicalservicehasbecometheheavilymeteorologicaldepartmentToresponseone.Alongwiththenationalgovernmentsatalllevelsofagriculturalproductionincreasinglyheavier

Dependeontheservice,myunitalsoserveforagriculture,promoteforincreasingfarmers'income

Manystudies,thevariousproblemsinagriculturalproductionalsowidelyadjustable

Inquiry.Researchfoundthatgardeningcultivation,greenhouseflowers,awningvegetablesone

Somevaluablevarietiesofsoilmoisture,soilhasahighrequirement,humidity

Atthetime,notonlyseriouslyaffectingitsnormalgrowth,andevencauseplantingproductdeathWu,causingseriousdamage.FarmersTherefore,engagedinthiskindofagriculturalproduction.Farmersveryneedalowcost,smallvolumeanddetectionreliablesoil.Soilhumiditydetectorforwatersupply,providesthebasis.Inordertosolvetheaboveasked.Ourproblem,Iunitcombinedwithactualconditionsofagriculturalproduction,andtherelatedunitsdesigned

Homeofhighprecision,todesignthelowcostofminiaturesoilmoisturedetectioninstrument.

Alongwiththesociallifeprogress,people'squalityoflifeisgettingmuchmorebetter,flowershasbecomeafashion.Flowerscannotonlyenrichpeople'sculturallifeandisgoodformentalandbodilyhealth，butalsocanimproveandpurifyair,improvehealth.Waterisnecessaryforflower’sgrowth,itinfluencesthegrowthofflowersgreatly.Toomuchwaterortoolittle,willaffectthenormalgrowthandthekindofflowerisverious,Differentflowersneeddifferentamountofwater.Theneedfulwater,mostlyfromthesoil,inordertocontrolflowersmoistureinthesoilproperly,usingPRO-Fsoilhumiditysensordesignanautomaticwateringtheflowerssystem,itmay,automaticallysetforflowerswateringaccordingtothehumiditylimit,inordertomeettheneedofimperativewater.

Section2compositionofthesystem

ThewholesystemconsistsofSCM,circuitofDAQ,keyboardinputanddigitaldisplaycircuit,outputcontrollingcircuitetc.circuitofCAQismadeof4SRHandadc,SRHmakesflower’ssoilhumidityconvertintoanalogvoltageoutput,adcmakestheoutputofanalogvoltageconvertintodigitalquantityandsendtomicrocontroller.AT89S52isadopted,thecollecttedvalueofsoilhumidityiscomparedwithapresetlimitsoilmoisture,anditmakescorrespondingjudgementaccordingtothecomparedresults,tocontroltheoutputcontrollingcircuit’saction.Key-inisusedtosetthevalueofsoilhumidity’slimit,LEDisusedtodisplaythecurrentsoilhumidity’svalue.

Miniaturesoildetectorsignalprocessingsystemincludingsoilhumiditysensor

Device,A/Dacquisitioncircuit,SCMandmicroLCD.ItsworkAfterchengis:

soilsoilwetdegreespreachsensor,willwetdegreeslettersenttoA/Dadoptsetelectricity

Road,theA/Dconversion,incomedatadigitalsignalintoSCMProcessing,finallywillprocessingresultssenttomicroLCDdisplay.

Section3thehardwaredesignofsystem

3.1thecircuit’sworkingprinciple

Thehardthingtheoriginalreasonsystemgraphasfigure2shows.ThisarticleselectsKSC-6Vintegratedrelativehumiditysensor,waitforafterinsertingthesoilabout5smakesensor

Implementfullycontactwiththesoil,signalbyintegratedampLM324Vinthesamephase

Inputterminal.Thesensor'srelativehumidity0%~100%RH,itscorresponding

Outputis0~100mV[1].Accordingtotheintegratedampwithphaseratioamplificationgain:

Kf=R1+Rf=1+47=48

ThentheoutputamplificationV0=48analogsignalvoltage,sooutputanalog,Vi,electricpressurefanlettersurroundedis0~4.8v.Thismode,turnintoA/DCH0sliceofreplacecoregeneralwayintolinechangeoverplace,havecuttoseveralwordsAT89S51single-chipletterNumbersagainintodataprocessingandtheLCD.

3.2A/Dconversionchipchoiceandcontrollingprinciple

ThisarticlechoosesA/DconversionchipsforADC0832,thischipis8

PindoublerowstraightinsertdualchannelA/Dconverter,canseparatelyforbothroadsimulationNorealnowbelieved/achange,canuseintheoclloseintomodeandbadpointstolose

UnderthewayofDIserverchannelselectedchoose,severalaccordingtoadoptsetsandDatatransfer[2].

TheworkofADC0832dosequenceasshowninfigure3.Rootaccordingtoourwebsite,whencovariance.ADC0832didnotwork,mustthepieceselectedinthehighlevel,theCS

Whenchipdisabled.WhenshouldundertakeA/DconversionshallbepieceselectedendCSoffsets

Inlowlevelandmaintainstoconvertover.Chipbegantowork,stillneedtomake

Monolithicmachinetocorechips,whentheclockCLKlosefaithintheclockpulsebluntwhenlose,

InthefirstclockpulsebeforethesinkingDIendmustbehighelectricflat,tables

Andstartsignal.Inthefirst2,3pulsesinkingDIendbeforeshouldbelost

Intotwodatausedtoselectchannelsfunction.Channelsareasfollows:

（1）thecontrolledconditions

InaccordancewithTheTimeswhenDIlostwith1,0,theonlywaytodoCH0tonggeneralturnedintosinglewordChange;

（2）whenDIordinalinput1,1,onlyforsingleCH1channelonTaotransformation;

（3）whenDIordinal0,0,willCH0asis,willCH0input0asitsnegativeinputINCH1-,asaretheinputIN+

3.3microcontroller’schoice

MCUisthecontrolofcore,comparedwiththeothers,wechoseAT89S51single-chipmicrocomputer.Theadvantagesofthistypeofsingle-chipmicrocomputeris[3]:

（1）Thesingle-chipmicrocomputerandthe8051seriesmicrocontrollerisfullycompatible,makeituseeasily,andintothetenpointsCheap;

（2）InternalmemorycanberepeatedCaXiebytheEEPRROM,behelpfulforrepeattingmodifytheprogram;

（3）hasthelowconsumptionworkingmethodsandtobeachievedOffelectricalautomaticprotection;

（4）hasstronganti-jamming,greatlyimprovingtheworthRoyalexternalelectromagneticinterferenceability,soitisespeciallysuitableforrelativelytoughinconditionsUnderthepoorconditionsofthejob.

3.4TheuseofLCD

UsingmicroLCDdisplaydevice,1602LCD,itsperformancepointis:

workingvoltageonly4.5~5.5V;Verylowpowerconsumption（workcurrent

Only2.0mA）;Andreliablework;Smallvolume（canshow16x2words

Operators）.ItscharactersaredisplayedbyinternalspecialdisplacementfunctionofHD44780dynamiccoreslice[4]

QuasiASCIIputintotheirnumberwithindepartmentsetintoreservoirwithdepositaccordingtoshowandeditor（DDRAM）,insidetheministryaccusedoflineofroadwillmovewillwordfromshebaoperatorspreachsendtoshow,Implement.Monolithicmachineandthenumberof1602LCDbetweengeneralP0intochangehadtoenterline,resistanceforP0mouthR9R2~thepull-upresistors

Section4Thesoftwaredesignofthecontrolofsystem

Thisrecordercontrollingsoftwaredesignadoptsmodularthought.

Accordingtothefunction,wemakethecontrollingsystemsoftwaredevideintotwobigmodules:

（1）ADC0832drivermodule,tocontrolthecollectionofvoltagesignal;

（2）1602LCDdrivermodule,showsoilhumidity.ThissystemdriverusingC

Languagedesign,itsmainprogramisasfollows

Main（void）

{

unsignedintAD_val;

Convertthevalueafterthe

unsignedintInt,Dec;

Theconvertedtheintegerpartandthedecimalpart

//storagesaveA/D

//pointsdon'tstoreinexistence

change

LcdInitiate（）;

//tobeliquidcrystalearlybeginning

}

2）theproductionofclock

Whentheclockpointsfrequencydevice（afteritcanhaveto4.5MHzinturnwhenthechangeinA/Dclock）turnchangewhenidleisempty,theholdafterAstateinADCRiswrittentotheSTARTfieldimmediatelySTART01（conversion）ortheselectededgeappearinchoiceofsignalsamplingclockcanimmediatelySTART.Thisfeaturecansavepowerconsumption.ADCconversionclockcomputationformulaisasfollows

FADC=FPCK/（CLKDIV+1）

Type:

Fpclk-coreslice;whentheclocksetAfterCLKDIV-pointsofADCconversionclockfrequency.

3）interrupted.

WhenDONEbitsis1,A/Dconversionmoduletovectorinterruptcontroller（VIC）issuedaninterruptrequestintheVICIntEnableVIC,ifBit8（A/Dconversioninterruptsenabledbits）makecan,thencanproducetheinterruption.ReadADDRwillresetDONEbits.ThispapermainlyA/DacquisitionClanguagedriversectiondesignisasfollows:

/***********************************

Function:

A/Dacquisition

Entranceparameters:

CH_i

/***********************************

voidAD_Change（unsignedcharCH_i）

{

ADC0R=（1<

（0<<16）

（0<<19）

|//BURST=0,softwarecontrolconversionoperations

|//normalA/Dacquisitionmodes

（0<<27）;|//decreasealongthestartupconversion

AD0DR;DO=//readtakeADCandfruit,andclearexcept

DONEmarkbits

while

（1）