摘要：随着时代的发展，汽车越来越多，随之而来的交通事故也逐渐增多。基于超声波测距的汽车倒车雷达系统的设计，主要是利用超声波的特点以及它的优势，将超声波测距系统和AT89S51单片机结合于一体，设计出一种基于AT89S51单片机的汽车倒车雷达系统。本系统采用软硬件结合的方法通过设计出电源模块、单片机及显示模块、报警模块、超声波发射和接收模块来实现其功能，它具有模块化和多功能化的特点。该设计的原理是超声波发射器发射出一连串的超声波，当它遇到障碍物后反射回来再由超声波接收器接收这样只需要能计算出超声波从发射到接收所用的时间，就可以通过计算子程序得出汽车与障碍物的距离，当距离小于报警距离时，发出相应的报警声。因此能够为人们的安全提供保障。78297

毕业论文关键字：测距传感器，AT89S51单片机，LED,蜂鸣器

Abstract： With the development of the times, more and more cars, followed by traffic accidents is gradually increasing。 The content of this article is to design car reversing radar system based on ultrasonic distance measurement, mainly using ultrasound features as well as its advantages, ultrasonic ranging system and combined in one single chip AT89S51, AT89S51 micro controller-based design a car reversing radar system。 The system uses a combination of hardware and software design method by the power module, micro controller and display module, alarm module, ultrasonic transmitter and receiver modules to achieve its function, it is modular and multi-functional features。 The principle of the design is that the ultrasonic transmitter emits a series of ultrasonic rear obstacle when it is reflected back again received by the ultrasonic receiver so that only need to be able to calculate the ultrasonic wave from the transmitter to the receiver by the time they can, through calculation routine come from the car with an obstacle, when the distance is less than the distance alarm, issue the corresponding alarm sound。 It is possible to provide protection for people's safety。

Keywords: distance sensor,AT89S51 MCU,LED,buzzer 

目录

1 前言 4

1。1 课题设计的目的和意义 4

1。2 国内应用现状 4

2 总体方案 4

2。1 本设计的研究方法 4

2。2 系统整体方案的设计 5

2。3 系统整体方案的论证 5

2。4 超声测距原理 5

2。4。1 超声波测距概述 5

2。4。2 超声波传感器介绍 5

2。4。3 超声波测距的原理 7

3 系统硬件设计 8

3。1 AT89S51单片机 8

3。2 超声波测距的系统及其构成 9

3。2。1 超声波测距单片机系统 10

3。2。2 超声波发射、接受电路 10

3。2。3 显示电路 11

3。2。4 供电电路 12

3。2。5 报警输出电路 12

4 系统软件设计 13

4。1 主程序设计 13

4。2 超声波测距子程序