I山东科技大学毕业设计（论文）摘要近年来，我国的汽车数量正逐年增加，在公路、街道、停车场、车库等拥挤、狭窄的地方倒车时，驾驶员既要前瞻，又要后顾，稍微不小心就会发生追尾事故。因此，增加汽车的后视能力，研制汽车后部探测障碍物的倒车雷达便成为近些年来的研究热点。为此，设计了以单片机为核心，利用超声波实现无接触测距的倒车雷达系统。工作时，超声波发射器不断发射出一系列连续脉冲，给测量逻辑电路提供一个短脉冲。最后由信号处理装置对接收的信号依据时间差进行处理，自动计算出车与障碍物之间的距离。目前，国内外一般的超声波测距仪，其理想的测量距离为0.5m～5m，因此大都用于汽车倒车雷达等近距离测距中。设计根据声波在空气中传播反射原理，并且也介绍了基于STC89C52单片机的超声波测距器。该设计由超声波模块HC-SR04、LED显示电路、键盘控制电路以及报警模块等部分组成，在探测范围内数码管显示出汽车与障碍物的距离，当距离小于所设计的安全距离时，蜂鸣报警器发出报警声，辅助驾驶人员能够安全倒车驾驶。关键词：超声波；测距；STC89C52；HC-SR04；倒车雷达II山东科技大学毕业设计（论文）AbstractInrecentyears,thenumberofcarsinChinaisincreasingyearbyyear.Onhighways,streets,parkinglot,garageandothercrowded,narrowplacewhenreversing,thedrivershouldbeforward-looking,wanttolookbackagain,abitnotcarefulcollisionoccurs.Therefore.Increasethecarrearviewability,detectobstaclesofdevelopingthebackofmycarreversingradarhasbecomeahotresearchtopicinrecentyears.Therefore,designedwiththesinglechipprocessorasthecore,theuseofultrasoundtorealizenon-contactrangingreverseradarsystem.Work,ultrasonictransmittercontinuouslyemitaseriesofconsecutivepulse,Forlogiccircuitprovidesashortpulsemeasurement.,theidealmeasuringdistanceof0.5m~5m,somostlyusedintheclosedistancesuchascarreversingradar.Designaccordingtotheprincipleofthereflectedsoundwavesintheair,andalsointroducestheultrasonicrangefinderbasedonSTC89C52single-chipmicrocomputer.Thedesignbytheultrasonictransmitting,LEDdetailedintroducestherangingsystemhardwarecomposition.UltrasonicreceivingcircuitusingHC-SR04transceiverdiscreteintegratedultrasonicprobe,themoduleconsistsofultrasonicemitter,receiverandcontrolcircuit.KEYWORD:Ultrasonic；Measuredistance；STC89C52；HC-SR04；ReversingradarIII山东科技大学毕业设计（论文）目录摘要...................................................................................IAbstract.............................................................................II目录................................................................................III第1章绪论........................................................................11.1项目研究背景........................................................................11.2目前国内倒车雷达的发展现状............................................21.3项目研究内容与方法............................................................4第2章总体设计方案及论证............................................52.1系统的总体框图....................................................................52.2各模块的功能........................................................................6第3章超声波测距原理....................................................73.1超声波测试分析....................................................................73.2超声波测距模块....................................................................9第4章硬件实现及单元电路设计..................................134.1单片机STC89C52RC.........................................................1...
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