第二基于單片機的超聲波倒車?yán)走_系統(tǒng)的設(shè)計-全文預(yù)覽

　　

【正文】 性能價格上，這六代產(chǎn)品都各有特點，使用較多的是數(shù)碼顯示、熒屏顯示和魔幻鏡倒車?yán)走_這三種。雖然每輛車都有后視鏡，但不可避免的都存在一個后視盲區(qū)。技術(shù)上向著單芯片功能成靈敏度更高、可視化發(fā)展，設(shè)備趨于小型化、人性化、智能化等方向發(fā)展。Measure Distance Reversing目 錄摘 要 ............................................................................................................................................IABSTRACT...............................................................................................................................II1 緒論 ............................................................................................................................................1 設(shè)計的現(xiàn)狀 ................................................................................................................1 設(shè)計的意義 ................................................................................................................2 目前國內(nèi)倒車?yán)走_的發(fā)展現(xiàn)狀 .....................................................................22 總體設(shè)計方案 ......................................................................................................................3 超聲波測距 ................................................................................................................4 超聲波測距原理 ................................................................................................測量與控制方法 ..............................................................................................理論計算 ............................................................................................................5 影響精度的因素分析 .......................................................................................6 提高精度的方案及系統(tǒng)設(shè)計 .........................................................................7 測量盲區(qū) ..............................................................................................................8 超聲波傳感器 ..........................................................................................................9 超聲波傳感器原理及結(jié)構(gòu) ...............................................................................9 超聲波傳感器的特性 ......................................................................................11 超聲波傳感器的應(yīng)用 .....................................................................................133 硬件設(shè)計 ...............................................................................................................................14 超聲波發(fā)射電路 ...................................................................................................14 超聲波檢測接收電路 ........................................................................................15 集成電路 CX20226A......................................................................................15 超聲波接收電路 ..............................................................................................17 超聲波顯示及控制部分電路 ........................................................................18 AT89C51 單片機的原理及工作特點 ..........................................................18 單片機實現(xiàn)測距原理 ......................................................................................19 壓電陶瓷超聲波傳感器 (TCF4018TR1)................................................19 穩(wěn)壓電源電路 ...................................................................................................20 顯示電路原理 ...................................................................................................21 溫度測量電路 ...................................................................................................23 鍵盤控制電路 ...................................................................................................234 軟件設(shè)計 ................................................................................................................................23 軟件設(shè)計的要求 ...................................................................................................25 超聲波測距的算法設(shè)計 ...................................................................................25 主程序 ........................................................................................................................26 超聲波發(fā)送及接收中斷程序 ..........................................................................28 顯示子程序和蜂鳴報警子程序 ...................................................................305 系統(tǒng)的軟硬件調(diào)試 ..........................................................................................................30結(jié)束語 ..........................................................................................................................................31致 謝 ..........................................................................................................................................32參考文獻 ....................................................................................................................................33附錄 1 超聲波倒車?yán)走_系統(tǒng)的設(shè)計 ........................................................................34附錄 2 程序清單 ...................................................................................................................351 緒論倒車?yán)走_又稱泊車輔助系統(tǒng)，是汽車泊車安全輔助裝置，能以聲音或者更為直觀的顯示告知駕駛員周圍障礙物的情況，解除了駕駛員泊車和起動車輛時前后左右探視所引起的困擾，并幫助駕駛員掃除了視野死角和視線模糊的缺陷，提高了安全性。超聲波接收電路使用 SONY 公司的 CX20226A 紅外檢測專用芯片，該芯片常用于 38kHz 的檢波電路，文中通過對芯片內(nèi)部電路的仔細(xì)分析，設(shè)計出能夠成功對 40kHz 超聲波檢波的硬件電路，距器使用數(shù)碼管顯示目標(biāo)物的距離。最后由信號處理裝置對接收的信號依據(jù)時間差進行處理，自動計算出車與障礙物之間的距離。因此。在公路、街道、停車場、車庫等擁擠、狹窄的地方倒車時，駕駛員既要前瞻，又要后顧，稍微不小心就會發(fā)生追尾事故。工作時，超聲波發(fā)射器不斷發(fā)射出一系列連續(xù)脈沖，給測量邏輯電路提供一個短脈沖。該設(shè)計由超聲波發(fā)射模塊、信號接收模塊、單片機處理模塊、數(shù)碼顯示以及聲光告警顯示模塊等部分組成，文中詳細(xì)介紹了測距器的硬件組成、檢測原理、方法以及軟件結(jié)構(gòu)。 In addition, the ultrasonic energy and the attenuation is directly proportional to the square of the distance, the farther the distance, the lower sensitivity and thus Ultrasonic Ranging way so that only apply to a shorter distance. At present, ultrasonic range finder at home and abroad in general, the ideal distance of the measurement 1~ 5 m, based on AT89C51 ultrasonic rangefinder. Receiving circuit using the SONY pany dedicated CX20226A infrared detecting chip, the chip used in the