一種超聲波測距系統(tǒng)

摘  要：超聲波是一種特殊的聲波，為直線傳播方式，頻率越低，繞射能力越弱，反射能力越強，利用超聲波的這種性能就可制成超聲波傳感器。本文介紹了一種以單片機作為微處理器的超聲波測距系統(tǒng), 利用超聲波傳感器的測距原理并配合顯示器,制成了低成本智能超聲波測距系統(tǒng)。本文分析了環(huán)境溫度對波速的影響，介紹了幾種提高測量精度的方法，給出了電路原理圖和軟件設(shè)計流程圖。 實驗結(jié)果驗證了本系統(tǒng)具有成本低、精度高、電路簡單以及抗干擾性好等優(yōu)點,可以廣泛地應(yīng)用于一些中小規(guī)模的測量系統(tǒng)。

關(guān)鍵詞: 超聲波; 測距; 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    錄
摘要…………………………………………………………………………………………1
1 引言…………………………………………………………………………………………3
2 超聲波測距原理……………………………………………………………………………3
2.1 超聲波發(fā)生器……………………………………………………………………………3
2.2 壓電式超聲波發(fā)生器原理………………………………………………………………3
2.3 超聲波測距原理…………………………………………………………………………4
3 硬件電路設(shè)計………………………………………………………………………………5
3.1 超聲波發(fā)送電路…………………………………………………………………………5
3.2 超聲波接收電路…………………………………………………………………………6
3.3 報警電路…………………………………………………………………………………7
3.4 距離顯示與抗干擾電路…………………………………………………………………7
3.5 測量精度的探討…………………………………………………………………………8
3.5.1 測距原理……………………………………………………………………………8
3.5.2 波速的修正……………………………………………………………………………9
3.5.3 隨機誤差修正………………………………………………………………………10
4 軟件設(shè)計…………………………………………………………………………………10
4.1  程序流程圖……………………………………………………………………………10
4.2 程序設(shè)計………………………………………………………………………………12
5 結(jié)束語……………………………………………………………………………………15
參考文獻……………………………………………………………………………………16