摘 要：超声波倒车雷达是当今非常普遍的安全防碰撞辅助系统。超车雷达主要应用在提示司机在障碍物附近保持警惕，用语音提示或更直接的可视方式提醒司机以免发生意外。超声波的频率很高，能够抗干扰，指示性好，所以是倒车雷达测距的最佳选择之一。当今社会下汽车大量普及，出于安全因素的考虑，人们对倒车雷达的需求越来越高。所以，通过对超声波的产生和特性研究以进一步探索与开发高品质超声波能源转换器，对于防止碰撞的倒车雷达设计的发展和改进具有十分重要的现实意义。91669

本设计利用了超声波测距的原理，将精度高、成本低廉作为主要考虑因素，制作出一款以51单片机为关键的汽车停车报警预防装置。在设计中，简单地把该系统分为四个模块，分别是控制子模块、信号发出与接收单元模块、测量距离模块以及显示与声光报警模块，并学习了达到该装置预期效果所需要的核心技术，确定的编程的主要流程与方法;在假设某一安全距离的前提上，对主控制单元系统和信息接收与发出系统进行了软件和硬件的分别调试，能够调整安全距离，当设定值大于被测出来的距离时时二极管闪烁，蜂鸣器报警，真人播报和能及时观测到距离的功能。

毕业论文关键词：超声波传感器，MCU，声光报警

Abstract: Ultrasonic reversing radar is a kind of security collision auxiliary system，which is common, often used in car parking or reverse, by voice or a more intuitive way of LED screen display alerting the driver when reversing car near the obstacles, so as to avoid accidents。Ultrasound used in the back-draft radar as a kind of high frequency sound waves has a lot of good advantages like being susceptible to interference, strong directivity, penetrating good advantages。Therefore it is often used to measure distance。Owning to a lot of popularity of the car occureded in today's society, for reasons of safety factor, people is more and more demand for reversing radar。The further study of ultrasonic generation and propagation law,  developing the high-performance ultrasonic transducer and the transceiver circuit, has very important practical significance,to prevent collision of the development and enhancement of reversing radar design 。

This design based on ultrasonic distance measurement, high accuracy, develop low price as the primary consideration, create a 51 single-chip computer as the key of car parking alarm prevention device。In design, we simply put the system into four modules, respectively is control module, signal and receiving module, distance measuring module, and display and sound and light alarm module, and studied the device desired effect required for the core technology, determined the main process of programming and the method;Under the assumption of a safe distance, on the premise of the main control unit system and information receiving we made the system software and hardware debugging, respectively, to be able to adjust the safe distance。When set value is greater than the measured distance diode constantly flashing, the buzzer alarm, speech and display the on-time distance 。

Keywords: ultrasonic sensor, microcontroller, sound-light alarm

目  录

1 绪论： 5

1。1 选题的目的和意义 5

1。2 超声波传感器的设计现状 5

1。3 设计任务的分析 6

2。系统方案选择与分析 7

2。1 系统方案分析 7

2。1。1 主控芯片方案 7

2。1。2 超声波测距方案