摘要伴随着我国经济的迅速发展，汽车的数量也在不断增加，而随之而来的问题便是 愈发频繁德交通事故，在这之中由于倒车引起的交通事故已经是数不胜数。倒车时后 视镜有盲区、驾驶员判断失误、阴雨天视线受影响等因素都会造成倒车事故，会给驾 驶员以及他人带来一系列的麻烦。因此，为了保障汽车倒车时的安全，对汽车倒车雷 达的研究便成为近些年来的一大热点。为此，本论文设计了以单片机为控制核心，借 助超声波测距的原理来实现汽车倒车时的测距。系统通过单片机控制超声波传感器测 距，并将距离通过显示设备显示出来。超声波传感器装在汽车后面用来探测那些驾驶 员难以观察到的障碍物。84916

本设计论文主要详细阐述了基于单片机的汽车倒车测距系统的基本原理和超声 波测距的特性以及 STC 公司生产的 STC89C52 的单片机的性能和特点。本系统将环 境温度引起的测距误差考虑在内并且对其加以温度补偿，设计出了以 STC89C52 单片 机为控制核心的低成本、高精度、具有液晶显示功能的超声波测距系统，测量精度能 够达到使用的要求。

毕业论文关键词：单片机；超声波；倒车测距

Abstract With the quickly development of China's economy, the number of cars is increasing, and then the resulting problem is increasing frequently, traffic accident caused by backing in this traffic accident was already there。 Reversing rearview mirror has a blind spot, the pilot judgment, rainy day back sight affected factors can cause accidents, can bring a series of problems to the driver and others。 Therefore, in order to protect the safety of car when reversing, the study of car reversing radar has become a hot spot in recent years。 To this end, this paper designed with the single chip processor as the core, with the aid of ultrasonic ranging principle to realize the auto reverse range。 Ranging system use single chip microcomputer control ultrasonic sensor, and display the distance through the display device。 Ultrasonic sensor installed at the back of the car used for exploring the drivers are difficult to observe。

This design paper mainly elaborated the basic principle of reverse ranging system based on MCU and ultrasonic ranging features as well as on STC company produces the STC89C52 MCU performance and characteristics。 This system take into consideration of the ranging error caused by the environmental temperature and temperature compensation on it, designed the STC89C52 single-chip microcomputer as the control core of low cost, high precision, the ultrasonic ranging system with liquid crystal display, measurement accuracy can meet the requirements of use。

Keywords : Single chip microcomputer ; Ultrasonic ; Reverse range

目 录

第一章 绪论 1

1。1  本文的研究目的和意义 1

1。2 国内（外）研究状况与发展趋势 1

1。3  本课题的研究内容 2

第二章  测距方案选择 3

2。1 激光测距 3

2。2 红外测距 3

2。3 超声波测距 3

2。4  系统总体方案 4

第三章  单片机概述 6

3。1 STC89C52 简介及主要特性 6

3。2 STC80C52 内部组成 7

3。3 STC89C52 外部引脚：