【正文】 1998. 3 [13] PVDF film Transmitter and Receivers for Air trans Ultrasonic? Ferroelect.， ， 2020 [14] Design for Portable Ultrasound Enhanced TransdermalDrugDelivery Ferroelect. ，.， 2020 [15] Hongjiang He Jianyi Design of Ultrasonic Distance Measurement System Based on S3C2410[C].2020 International Conference on Intelligent Computation Technology and Automation [16] W Kappes, B Rockstroh, F Walte. Ultrasonic Testing Station for WheelSets of Passenger Trains of the Deutshe Bahn ,43(11):751 753 [17] M. Parrilia, J: J. Anaya, C. Fritsch. Digital signal processing techniques for high accuracy Ultrasonic range measurements[J], IEEE Trans on Instrumentation and Measurement, Aug. 2020:759763 4．進(jìn)度安排 超聲測距 — 汽車倒車?yán)走_(dá)的設(shè)計 IV 設(shè)計（論文）各階段名稱 起 止 日 期 1 超聲波測距的基本理論及測量方案 ~ 2 超聲波測距系統(tǒng)的硬件設(shè)計 ~ 3 超聲波測距系統(tǒng)的軟件設(shè)計 ~ 4 測距系統(tǒng)實驗與誤差分析 ~ 5 結(jié)論與展望 ~ 太原工業(yè)學(xué)院畢業(yè)設(shè)計 (論文 ) V 超聲波測距汽車倒車 雷達(dá)的 設(shè)計 摘要 本設(shè)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(shè)計由 AT89C2051 單片機(jī)控制時間計數(shù)，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。 關(guān)鍵詞： AT89C2051，超聲波，數(shù)碼管，汽車倒車 超聲測距 — 汽車倒車?yán)走_(dá)的設(shè)計 VI Car reversing radar 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 太原工業(yè)學(xué)院畢業(yè)設(shè)計 (論文 ) VII 目 錄 1. 緒論 ..................................................................................................................................... 1 課題研究背景及目的 .................................................................................................. 1 課題國內(nèi)外研究 狀況 .................................................................................................. 1 系統(tǒng)整體方案的設(shè)計與論證 ...................................................................................... 3 ..................................................................................................... 5 超聲波發(fā)展簡史 .......................................................................................................... 5 超聲波的應(yīng)用 .............................................................................................................. 6 超生波測距方法 .......................................................................................................... 9 ....................................................................................................................... 11 系統(tǒng)整體設(shè)計框圖 .................................................................................................... 11 硬件選型 .................................................................................................................... 11 超聲波探頭的中心頻率及主要參數(shù) ............................................................. 11 單片機(jī)的選擇 ................................................................................................. 13 其他元器件的選擇 ......................................................................................... 14 ....................................................................................................................... 15 單片機(jī)外圍電路設(shè)計 ................................................................................................ 15 超聲波發(fā)射電路設(shè)計 ................................................................................................ 15 超聲波接收電路設(shè) 計 ................................................................................................ 16 簡介 ................................................................................................. 16 超聲波接收 電路 ............................................................................................. 16 LED顯示電路 ............................................................................................................ 19 報警電路設(shè)計 ............................................................................................................ 20 ....................................................................................................................... 22 程 序完成的功能 ....................................................................................................... 22 編程語言的選擇 ....................................................................................................... 22 主要部分程序流程圖 ................................................................................................23 實現(xiàn)重要功能的程序的分析 …………………………………………………… ....23 實現(xiàn)溫度讀取功能 ………………………………………………………… ..23 超聲測距 — 汽車倒車?yán)走_(dá)的設(shè)計 VIII 實現(xiàn)根據(jù)溫度轉(zhuǎn)化聲速 …………………………………………………… ..25 實現(xiàn)距離計算 ……………………………………………………………… ..25 主函數(shù)的結(jié)構(gòu)與內(nèi)容 …………………………………………………… .....25 .