【正文】 use C language for conducive to the program structure and easy to calculate the distance. I plete hardware and software design of the ultrasonic range finder, and achieve measured results display. According to system debugging, LED digital display clear and measuring results are stable and reliable and the range finder error is less than 5cm. KEY WORDS: ultrasonic range finder SCM 前 言 隨著科技的迅猛發(fā)展越來(lái)越多科技成果被廣泛的運(yùn)用到人們的日常生活當(dāng)中 ， 給我們的生活帶來(lái)了諸多方便。 人們能聽(tīng)到聲音是由于物體振動(dòng)產(chǎn)生的，它的頻率在 20Hz20kHz 范圍內(nèi)，超過(guò)20kHZ 稱為超聲波。超聲波有兩個(gè)特點(diǎn)，一個(gè)是能量大，一個(gè)是沿直線傳播，它的應(yīng)用就是按照這 兩個(gè)特點(diǎn)展開(kāi)的。本設(shè)計(jì)采用超聲波傳感器工作于發(fā)射和接收 ,利用聲波在空氣中的傳播速度和發(fā)射脈沖到接收反射脈沖的時(shí)間間隔計(jì)算出障礙物到超聲波測(cè)距器之間的距離 ， 并實(shí)時(shí)顯示出來(lái)。 目 錄 1 緒 論 .................................................................................................................................... 1 課題設(shè)計(jì)的研究現(xiàn)狀 ........................................................................................................ 1 課題設(shè)計(jì)的任務(wù)和要求 .................................................................................................... 2 課題設(shè)計(jì)的任務(wù) .......................................................................................................... 2 課題設(shè)計(jì)的要求 .......................................................................................................... 2 選題的意義 ........................................................................................................................ 3 研究?jī)?nèi)容及論文構(gòu)成 ........................................................................................................ 3 2 超聲波測(cè)距原理 .................................................................................................................... 5 超聲波簡(jiǎn)介 ........................................................................................................................ 5 超聲波的聲學(xué)特性 ...................................................................................................... 5 超聲波的發(fā)生原理 ...................................................................................................... 6 超聲波傳感器的原理與特性 ............................................................................................ 7 原理 .............................................................................................................................. 7 特性 .............................................................................................................................. 9 超聲波測(cè)距儀的測(cè)距原理 ................................................................................................ 9 單片機(jī)最小系統(tǒng) ........................................................................................................ 11 超聲波發(fā)射電路 ........................................................................................................ 12 超聲波接收電路 ........................................................................................................ 13 超聲波測(cè)距儀顯示電路 ............................................................................................ 15 本章小結(jié) .......................................................................................................................... 15 3 超聲波測(cè)距系統(tǒng)軟件設(shè)計(jì) .................................................................................................... 17 超聲波設(shè)計(jì)概述 .............................................................................................................. 17 主程序流程圖 .................................................................................................................. 18 定時(shí) /計(jì)數(shù)器 T0/T1 定時(shí)程序流程圖 ............................................................................. 20 方式控制寄存器 TMOD.......................................................................................... 20 控制寄存器 TCON .................................................................................................. 21 定時(shí)器 T0 流程圖 ...................................................................................................... 21 定時(shí)器 T1 中斷服務(wù)程序流程圖 .............................................................................. 22 外部中斷服務(wù)程序流程圖 .............................................................................................. 23 顯示程序流程圖 .............................................................................................................. 23 計(jì)算程序流程圖 .............................................................................................................. 24 4 電路調(diào)試及誤差分析 .......................................................................................................... 26 系統(tǒng)軟件的調(diào)試 .............................................................................................................. 26 系統(tǒng)的軟硬件串聯(lián)調(diào)試 .................................................................................................. 28 系統(tǒng)的誤差分析 .............................................................................................................. 30 聲速引起的誤差 ........................................................................................................ 31 單片機(jī)時(shí)間分辨率的影響 ........................................................................................ 31 隨機(jī)誤差 .................................................................................................................... 32 提高測(cè)距精度的方法 ...................................................................................................... 32 本章小結(jié) .......................................................................................................................... 33 結(jié) 論 ........................................................................................................................................ 34 致 謝 ........................................................................................................................................ 35 參考文獻(xiàn) :.....................................................................................................