摘  要：近年来，伴随着工业化及现代化的不断推进，我国的经济得到快速发展，人民生活生平不断提高。我国家庭轿车的数量增长迅速，但部分驾驶员的倒车水平却有限，导致倒车事故发生频率极高，引起了全社会的关注和相关部门的重视。本文以单片机为控制核心，以超声波传感器为超声波发射与接收的器件，设计了测距与预警系统。给出了系统硬件与软件的设计方法与设计过程，并进行了安装与调试，结果表明，该系统能够作为汽车泊车安全的辅助装置，以语音提示和更为直观的LCD1602数字显示让驾驶员及时了解汽车后方障碍物的情况，提高了泊车安全性。56878

毕业论文关键词：汽车倒车，单片机，报警电路，超声波测距

Abstract: In recent years, with the development of industrialization and modernization, China's rapid economic development, people's living life continuously improve. The growth in the number of family cars in China rapidly, reversing level with some drivers Co., led to high frequency reversing accidents, which caused the concern of the whole society and the relevant departments of the attention. In this design, the ultrasonic ranging can be used as auxiliary device for automobile parking safety, to achieve sound and more intuitive LCD1602 display allows the driver to understand the automobile rear obstacles, improve the parking safety. The design of hardware is composed of MCU as the control core, using ultrasonic transmitting and receiving module as the main test component, at the same time, the buzzer and the LCD1602 measurement of obstacle distance as the output part. Provides real-time and visual prompts for the driver, and has the advantages of reasonable design, good performance, fast detection speed and many other advantages, meet the design requirements.

Keywords: reversing car, SCM,warning circuit,ultrasonic ranging

目  录

1前言 4

1.1研究背景 4

1.2国内外研究现状 4

2系统总体方案设计 5

2.1超声波测距原理 5

2.2系统总体框图 6

3 系统硬件设计 6

3.1超声波模块 6

3.1.1超声波传感器原理 6

3.1.2超声波传感器的选择 8

3.2单片机最小系统 10

3.2.1 AT89C51单片机引脚 11

3.2.2 AT89C51的并行I/O口 13

3.2.3单片机最小系统连接图 13

3.2.4单片机最小系统的晶振和复位电路 14

3.3 报警电路设计 15

3.4 液晶显示模块 15

4 软件设计 17

4.1 51系列单片机定时器 17

4.2 总体软件设计 19

4.3 发射模块软件设计 20

4.4 接收模块软件设计 20

5 测试及结果分析 21

5.1 硬件设计原理图 21

5.2 实物测试 21

结  论 23

参考文献 24

致  谢