基于单片机控制超声波测距仪毕业设计

I摘要在空气介质中，超声测距传感器因其性能好，价格低廉、使用方便，在现场机器人定位系统、车辆自动导航、车辆安全行驶辅助系统、城市交通管理和高速公路管理监测系统，以及河道、油井和仓库及料位的探测中都有应用。由于超声波传播不易受干扰，能量消耗缓慢，在介质中传播的距离较远，因而超声波经常用于距离的测量，如测距仪和物位测量仪等都可以通过超声波来实现。为此，深入研究超声波的产生与传播规律、开发高性能超声波换能器及其收发电路，对于超声波检测技术的发展具有十分重要的现实意义。本设计介绍了基于单片机控制的超声测距仪的原理：由AT89C51控制定时器产生超声波脉冲并计时，计算超声波自发射至接收的往返时间，从而得到实测距离。并且在数据处理中采用了温度补偿的调整，用四位LED数码管切换显示距离和温度。整个硬件电路由超声波发射电路、超声波接收电路、电源电路、显示电路等模块组成。各探头的信号经单片机综合分析处理，实现超声波测距仪的各种功能。在此基础上设计了系统的总体方案，最后通过硬件和软件实现了各个功能模块。相关部分附有硬件电路图、程序流程图，给出了系统构成、电路原理及程序设计。此系统具有易控制、工作可靠、测距准确度高、可读性强和流程清晰等优点。实现后的作品可用于需要测量距离参数的各种应用场合。关键词：AT89C51；超声波；测距；电路IIAbstractThefeaturesofthegoodperformance,lowcost，easyuseareinearnatedintheultrasonicdistancemeasurementsensor.Theultrasonicdistancemeasurementsensorisusuallyusedatthescenerobotpositioningsystem，automaticvehiclenavigation，thesafetyofvehiclestravelingsupportsystem，theurantrafficmanagementandthehighwaymanagementmonitoringsystem，aswellasthedetectinrivers，oilwells，storagesandmaterials.Theultrasonicwavetransmssionisnoteasytodisturb，itsenergyconsumptionisslowlyanditcanbetransmitteddistantlyinthemedium，soitisfrequentlyusedinultrasonicdistancemeasurement.Forexample，therangefinderandthemateriallevelfindercanbeaehievedbyultrasonicwave.Therefore，thein-depthstudyofthegenerationandtransmissionlawofultrasonicandthedevelopmentofhigh-performanceultrasonicsensorandtransmitandreceivecircuitsisofgreatpracticalsignificanceinthedevelopmentofultrasonicdetectiontechnology.ThedesignintroducestheprincipleoftheultrasonicdistancemeasurementinstrumentbasedonSCMC-controlled:AT89C51controlstimerstoproducetheultrasonicwavepulseandtime,countthetimeofultrasonicwavespontaneousemissiontoreceiveround-trip,thusobtainsthemeasureddistance.Andthetemperaturecompensationadjustmentisusedinthedataprocessing,withfourLEDnixietubesdisplaydistanceortemperaturebyswitching.Theentirehardwarecircuitiscomposedbyultrasonictransmittercircuit,ultrasonicreceivercircuit,thepowercircuit,displaycircuit,andothermodules.TheprobesignalsareintegratedanalysisedbySCMCtoachievethevariousfunctionsofultrasonicdistancemeasurementinstrument.Basedonthishasdesignedsystem'soverallconcept,finaladoptionofhardwareandsoftwaretoachievethevariousfunctionalmodules.Therelevantpartshavethehardwareschematicsandprocessflowchart.Ithasgiventhesystemconstitution,thecircuitryandtheprogramming.Theinstrumentsystemhasfeatures:easeofcontrol,stabilityofoperation,highnessofprecisionanddistinctnessofprogrammeprocess,etc.Aftertherealizationoftheworkscanbeusedforneedsofthevariousparametersmeasureddistanceapplications.Keywords:AT89C51;Ultrasonicwave;Measuredistance;circuitIII目录摘要.......................................................IAbstract......................................................II1绪论.........................................................11.1课题研究的背景..........................................11.2课题的提出及研究意义....................................21.2.1课题的提出.........................................21.2.2课题的研究意义.....................................22超声波的介绍及超声波测距的原理...............................32.1超声波的介绍............................................32.1.1什么是超声波.......................................32.1.2超声波的特性及特点..................................32.1.3超声波的应用........................................42.2超声波测距的原理及误差分析..............................52.2.1超声波测距的原理...................................52.2.2超声波测距误差分析.................................52.3单片机实现测距的原理....................................63系统硬件设计.................................................73.1系统结构设计............................................73.2AT89C51单片机简介.......................................83.2.1AT89C51单片机的功能................................83.2.2AT89C51单片机主要特性..............................9IV3.2.3AT89C51管脚说明....................................93.3DS18B20温度传感器简介..................................113.4T40、R40超声波传感器简介...............................123.4.1超声波传感器的基本介绍............................123.4.2超声波传感器的主要应用............................123.4.3超声波传感器的工作原理............................133.5LM7805端稳压集成电路...................................143.5.1LM7805介绍........................................143.5.2LM7805的特点......................................143.5.3LM7805的实际应用..................................143.6LM567锁相环............................................153.6.1LM567的概述.......................................153.6.2LM567的功能叙述...................................153.6.3LM567主要参数.....................................153.7超声波发射器电路.......................................163.8超声波检测接受电路.....................................173.9显示电路...............................................183.10LM7805电平转换电路....................................193.11AT89C51复位电路.......................................204系统软件设计................................................214.1主程序流程.............................................214.2子程序设计.............................................23V4.2.1超声波发送子程序及超声波接收中断子程序.............234.2.2测温子程序.........................................254.2.3距离计算子程序.....................................265总结........