摘要：本设计以单片机为基础利用超声波技术来实现倒车时对后方物体实时距离的测量与报警。根据超声波不易变向，在空气中传播距离远,我们设计了在单片机上处理发射和接收的超声波信号，并在液晶显示器上显示结果。基于STC89C52的超声波测距报警系统是依靠超声波在空气中传播反射的原理，依靠超声波在空气中来回所需时间来计算距离,依据公式S=T×V／2，T即为超声波往返时间，V为超声波实时速度,由STC89C52运行计算得到距离S，并由液晶显示器显示结果。除此外系统还能显示系统的实时时间，当距离少于一定值的时候，系统会不断播报出当前到障碍物的距离。35052
毕业论文关键词：独立键盘 STC89C52 蜂鸣器 LCD显示管 语音播报
Ultrasonic Ranging reversing radar warning device based on microcontroller
Abstract: A kind of ultrasonic distance measurement system controlled by MCU is introduced in this paper. It is a set of assistant installation applied on auto back-up that can informs driver of obstacles. Because the direction of the ultrasonic is impossible to change, and it can propagate a long distance in air, we used MCU for transmitting and receiving ultrasonic signals, and display the results on the LCD monitor. STC89C52 ultrasonic distance measurement relies on the principle of reflection of ultrasonic wave propagation in air. Rely on ultrasound in the air back and forth needed time to calculate the distance. According to the formula S = T × V / 2, where T is the round-trip time ultrasound, V is the real-time speed ultrasonic. STC89C52 run according with the calculated distance S. The results were shown on a liquid crystal display. Thus obtains from the launch to receiving signal ultrasonic lag between driving, and then calculating the distance between the obstacles to instruct driver safety reverse.
Keywords：Independent keyboard   STC89C52   Buzzer    LCD display tube Voice broadcast
目 录
1 绪论    1
1.1 目的和意义    1
1.2 研究概况及发展趋势综述    1
1.3 本系统主要研究内容    1
2. 总体方案的设计与选型    2
2.1主要控制模块的选型    2
2.2总体设计概述    3
3.系统硬件模块设计    4
3.1主要控制模块    4
3.1.1 STC89C52单片机简介    4
3.1.2 单片机最小系统设计    6
3.2 LCD液晶显示器简介    7
3.2.1液晶原理介绍    7
3.2.2液晶模块简介    7
3.2.3液晶显示部分与STC89C52的接口    7
3.3键盘模块设计    8
3.4时钟模块的设计    8
3.4.1 DS1302概述    9
3.4.2 DS1302内部RTC 和RAM 地址分配    10
3.4.3 DS1302时钟和日历    12
3.4.4 DS1302时钟电路设计    13
3.5.超声波模块设计    13
3.5.1 超声波的基本理论    13
3.5.2 超声波对声场产生的作用    14
3.5.3 超声波传感器介绍    14
3.5.4 收发分立集成超声波探头HC-SR04    15
3.5.5 温度矫正电路    17
3.6语音模块设计    17
4.系统软件设计    19
4.1系统软件总体设计    19
4.2程序设计原理    19
5.系统调试    21
5.1硬件调试    21
5.2软件调试    21
5.3调试结果    21
6.结论    22
7.致谢    23
8.参考文献    24 STC89C52单片机超声波测距倒车报警雷达装置设计:http://www.youerw.com/zidonghua/lunwen_32832.html