【正文】 畢業(yè)設計 第 I 頁 基于 AT89C2051 單片機控制 的 超聲波 測距 汽車倒車防撞報警器設計 摘要 本設計采用超聲波測距，可用作汽車泊車安全輔助裝置，能以聲音和更為直觀的 LED 顯示告知駕駛員汽車周圍障礙物的情況，解除了駕駛員在泊車和起動車輛時前后左右探視所引起的煩擾，并幫助駕駛員掃除了視野死角和視線模糊的缺陷，提高了泊車安全性。 本設計硬件部分主要由單片機控制電路、超聲波發(fā)射電路、超聲波接收電路、數碼管顯示電路、電源電路和報警電路組成，軟件部分主要由主程序、超聲波發(fā)射接收 子 程序、距離計算子程序及顯示子程序等部分組成。本設計由 AT89C2051 單片機控制時間計數，計算超聲波自發(fā)射至接收的往返時間，利用超聲波在空氣中的傳輸速度，從而得到實測距離。該設計的電路設計合理簡單、工作穩(wěn)定、性能良好、檢測速度快、計算簡單、易于做到實時控制，并且在測量誤差方面能夠達到簡單工業(yè)實用的要求。 關鍵詞 ： AT89C205超聲波、數碼管、汽車倒車 畢業(yè)設計 第 II 頁 Auto reverse bull alarm design Abstract This design uses the ultrasonic ranging, can be used for car parking safety auxiliary devices, to sound and more ocular LED display told the driver of the car around obstacles, lifting the driver in the parking and starting vehicles around when visiting caused the trouble, and help eliminate the vision blind Angle and the driver of sight fuzzy defects, improve the safety car parking. The design of hardware mainly by singlechip microputer control circuit, ultrasound circuit, ultrasonic receiving circuit, digital circuit, the pipe display circuit and alarm circuit position, the software of mainly by the main program, ultrasound receiving interruption program, distance subroutines and display subroutines ponents. This design by single chip microputer AT89C2051 control time count, the calculation to receive from launch ultrasonic roundtrip time, use of ultrasonic transmission speed in the air, so as to get the distance. The design of the circuit design simple, reasonable stable and good performance, test speed, simple calculation, easy to do realtime control, and in the measurement error can achieve simple industrial practical requirement. Key words: AT89C2051 ,Ultrasonic, Digital tube,Automobile reverse 畢業(yè)設計 第 III 頁 目錄 1. 緒論 ..................................................................................................................................... 1 課題研究背景及目的 .................................................................................................. 1 課題國內外研究狀況 .................................................................................................. 2 課題研究方案比較 ...................................................................................................... 3 論文構成及研究內容 .................................................................................................. 4 .................................................................................................... 5 超聲波發(fā)展簡史 .......................................................................................................... 5 超聲波的應用 .............................................................................................................. 6 超生波測距方法 .......................................................................................................... 9 ...................................................................................................................... 10 系統整體設計框圖 .................................................................................................... 10 硬件選型 .................................................................................................................... 11 超聲波探頭的中心頻率及主要參數 ............................................................... 11 單片機的選擇 ................................................................................................... 12 其他元器件的選擇 ........................................................................................... 13 ...................................................................................................................... 13 單片機外圍電路設計 ................................................................................................ 13 超聲波發(fā)射電路設計 ................................................................................................ 14 超聲波接收電路設 .................................................................................................... 15 簡介 .................................................................................................. 15 超聲波接收 電路 ............................................................................................. 16 LED 顯示電路 ...................................................................................................... 17 報警電路設計 ............................................................................................................ 18 ............................................................................................................... 19 程序流程設計 ........................................................................................................... 19 汽車倒車報警器程序的程序清單 ............................................................................ 20 ...................................................................................................................................... 24 附錄 ...........................................................