一种超声波测距系统.doc

一种超声波测距系统

摘  要：超声波是一种特殊的声波，为直线传播方式，频率越低，绕射能力越弱，反射能力越强，利用超声波的这种性能就可制成超声波传感器。本文介绍了一种以单片机作为微处理器的超声波测距系统, 利用超声波传感器的测距原理并配合显示器,制成了低成本智能超声波测距系统。本文分析了环境温度对波速的影响，介绍了几种提高测量精度的方法，给出了电路原理图和软件设计流程图。 实验结果验证了本系统具有成本低、精度高、电路简单以及抗干扰性好等优点,可以广泛地应用于一些中小规模的测量系统。

关键词: 超声波; 测距; AT89C51

An Ultrasonic Distance Measurement System

Abstract: Ultrasonic is a kind of special sound waves which transmitted in straight lines. The lower the frequency is , the worse its diffraction ability and the better its reflection ability will be. Such performance of ultrasonic can be used to make ultrasonic sensor. This paper presents an ultrasonic distance measurement system which take use of the distance measurement principle of ultrasonic sensor provided with monitor to make a lower-cost intelligent ultrasonic distance measurement system. It analyzes the interference of environmental temperature towards wave speed, introduces several methods to improve measurement precision and also presents the flow chart of circuit principle and software design. The experimental result shows that this system processes many advantages, such as low cost, high precision, simpleness,  anti-jamming etc. It can be widely applied to some medium and small scale measurement system.
Key words : ultrasonic; distance measurement ; AT89C51

目    录
摘要…………………………………………………………………………………………1
1 引言…………………………………………………………………………………………3
2 超声波测距原理……………………………………………………………………………3
2.1 超声波发生器……………………………………………………………………………3
2.2 压电式超声波发生器原理………………………………………………………………3
2.3 超声波测距原理…………………………………………………………………………4
3 硬件电路设计………………………………………………………………………………5
3.1 超声波发送电路…………………………………………………………………………5
3.2 超声波接收电路…………………………………………………………………………6
3.3 报警电路…………………………………………………………………………………7
3.4 距离显示与抗干扰电路…………………………………………………………………7
3.5 测量精度的探讨…………………………………………………………………………8
3.5.1 测距原理……………………………………………………………………………8
3.5.2 波速的修正……………………………………………………………………………9
3.5.3 随机误差修正………………………………………………………………………10
4 软件设计…………………………………………………………………………………10
4.1  程序流程图……………………………………………………………………………10
4.2 程序设计………………………………………………………………………………12
5 结束语……………………………………………………………………………………15
参考文献……………………………………………………………………………………16