基于单片机的雷达倒车设计毕业设计.doc

基于单片机的汽车倒车雷达系统设计 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1m～5 m，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。该设计由超声波发射、接收模块、单片机处理模块、LCD显示电路、键盘控制电路以及报警显示模块等部分组成，文中详细介绍了测距系统的硬件组成、检测原理、方法以及软件结构。超声波接收电路使用收发分立集成超声波探头HC-SR04，该模块包括超声波发射器、接收器与控制电路。系统通过计算超声波发送和接受到的时间差就能较精确的计算出汽车和障碍物之间的距离，以此来判断汽车与障碍物是否处于安全距离，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，蜂鸣报警器的发声随着汽车与障碍物的距离越近报警频率越高，并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Car Reversing Radar System Based on Single Chip Design Abstract In recent years, the number of cars in China is increasing year by year. On highways, streets, parking lot, garage and other crowded, narrow place when reversing, the driver should be forward-looking, want to look back again, a bit not careful collision occurs. Therefore. Increase the car rear view ability, detect obstacles of developing the back of my car reversing radar has become a hot research topic in recent years. Therefore, designed with the single chip processor as the core, the use of ultrasound to realize non-contact ranging reverse radar system. Work, ultrasonic transmitter continuously emit a series of consecutive pulse, for logic circuit provides a short pulse measurement. Work, ultrasonic transmitter continuously emit a series of consecutive pulse, for logic circuit provides a short pulse measurement. Finally by the signal processing device for receiving signal according to the processing of time lag, automatic calculation of the car and the distance between the obstacles. At present, the domestic and foreign general ultrasonic range finder, the ideal measuring distance of 1 m ~ 5 m, so mostly used in the close distance such as car reversing radar. Design accord