【正文】 為光導(dǎo)效應(yīng)。通常將光電效應(yīng)分三類:其一，光照在光電材料上，材料表面的電子吸收能量，若電子吸收的能量足夠大時(shí)，電子會(huì)克服束縛脫離材料表面而進(jìn)入外界空間，從而改變光電子材料的導(dǎo)電性，這種現(xiàn)象稱為外光電效應(yīng)。它首先把被測(cè)量的變化轉(zhuǎn)換成光信號(hào)的變化，然后借助光電元件進(jìn)一步將光信號(hào)轉(zhuǎn)換成電信號(hào)。光電傳感器是以光電效應(yīng)為基礎(chǔ)，將光信號(hào)轉(zhuǎn)換為電信號(hào)的傳感器。利用這種性質(zhì)，可對(duì)檢測(cè)物體的顏色進(jìn)行檢測(cè)。因此，傳感器能長(zhǎng)期使用。也可進(jìn)行微小物體的檢測(cè)和高精度的位置檢測(cè)。響應(yīng)時(shí)間短：光本身為高速，并且傳感器的電路都由電子零件構(gòu)成，所以不包含機(jī)械性工作時(shí)間，響應(yīng)時(shí)間非常短。已經(jīng)成熟的測(cè)速方式中，光電式傳感器較其他的具有有以下優(yōu)點(diǎn)：檢測(cè)距離長(zhǎng)：如在對(duì)射型中保留10m以上的檢測(cè)距離，便能實(shí)現(xiàn)其他檢測(cè)手段(磁性、超聲波等)無(wú)法檢測(cè)的距離。據(jù)調(diào)查，每100例交通事故中，由于超速行駛造成的占60％以上，正所謂十次事故九次快！而且凡是由于超速所導(dǎo)致的交通事故，大部分都是惡性事故，對(duì)司乘人員造成嚴(yán)重傷害。但是，在追求省時(shí)、舒適的同時(shí)，安全也日益成為人們關(guān)注的焦點(diǎn)?，F(xiàn)代社會(huì)的快速發(fā)展，中國(guó)經(jīng)濟(jì)的快速增長(zhǎng)，社會(huì)上機(jī)動(dòng)車擁有量也急速增多。 設(shè)計(jì)背景隨著人們生活水平的逐漸提高，人們對(duì)于生活質(zhì)量的要求也日益增加，尤其是對(duì)出行的要求。 Single chip microputer。 the program is designed in the mode of modules. The system has simple hardware, mon subprogram, and meets the demand of design.KEY WORDS: Mileage / speed。該系統(tǒng)硬件電路簡(jiǎn)單，子程序具有通用性，完全符合設(shè)計(jì)要求。硬件部分利用光電傳感器組件將汽車每轉(zhuǎn)一圈的脈沖數(shù)傳入單片機(jī)系統(tǒng)，然后單片機(jī)系統(tǒng)將信號(hào)經(jīng)過(guò)處理送顯示。以 AT89C52 單片機(jī)為核心，OPTC 光斷續(xù)器測(cè)轉(zhuǎn)數(shù)，實(shí)現(xiàn)對(duì)汽車速度、時(shí)間的測(cè)量統(tǒng)計(jì)，并能將汽車的里程數(shù)及速度信息送單片機(jī)，并通過(guò)單片機(jī)輸出驅(qū)動(dòng)信號(hào)，用LCD實(shí)時(shí)顯示。一個(gè)性能良好、測(cè)量精確、穩(wěn)定的測(cè)速系統(tǒng)，從某種意義上說(shuō)，直接影響著汽車乃至司乘人員的生命安全。以便做出判斷和采取必要的措施，以防止交通事故的發(fā)生?；贏T89C51的LCD數(shù)字測(cè)速儀的設(shè)計(jì)——測(cè)量汽車車速基于AT89C51的數(shù)字測(cè)速儀 內(nèi)容摘要隨著居民生活水平的不斷提高，家用轎車開(kāi)始普及為人們娛樂(lè)、休閑代步的工具。汽車測(cè)速儀能夠滿足人們最基本的需求，讓人們能清楚地知道當(dāng)前的速度、里程、時(shí)間等物理量。測(cè)速儀作為汽車最基本、最重要的部件之一，在汽車的運(yùn)行過(guò)程中起著至關(guān)重要的作用。本論文主要闡述一種基于光電傳感器的汽車測(cè)速儀的設(shè)計(jì)。文章詳細(xì)介紹了汽車測(cè)速儀的硬件電路和軟件設(shè)計(jì)。軟件部分用C語(yǔ)言進(jìn)行編程，采用模塊化設(shè)計(jì)思想。關(guān)鍵詞：速度；時(shí)間；光斷續(xù)器；單片機(jī)；LCD顯示The car speedometer design based on the AT89C51ABSTRACTWith the developing of people’s life, the car is being the universal tool of transportation and substitute for walking and being the first choice of entertainment and exercising. The car speedometer can fulfill the basic need of people’s life, so that they can learn the speed、 the mileage 、the time of the car. For that people could take some necessary measures in case of any accident happened by a dangerous speed. As one of the most basic and important part of a car, speedometer is taking an important role during the car’s running. To some extent, an accurate and stable speedometer has a effect on the driver’s life directly.In this paper, the car speedometer design based on the photoelectric sensor element is elaborated. By AT89C52 as kernel, using photoelectric sensor element to measure revolution, the measure and statistic are achieved. The car speed can be displayed on LCD. In this article, the hardware circuit and software design of car speedometer instrument are introduced in detail. About the hardware, the pulse number is transmitted of one cycle of the car into Single Chip Microputer system. Then the signal processed by Single Chip Microputer system is sent to display scream. About the software, in C language。 Time；temperature；photoelectric sensor element。 LCD目 錄設(shè)計(jì)背景 1欲實(shí)現(xiàn)功能 3系統(tǒng)硬件設(shè)計(jì) 4 4 5 OPTC光電斷續(xù)器 6 液晶顯示LM016L 7 三端穩(wěn)壓集成器LM7805....................................8 84 、軟件設(shè)計(jì).....................................................9 程序流程圖............................................... 9 C語(yǔ)言編程............................................... 9 5 、系統(tǒng)仿真及調(diào)試...............................................10 6 、元器件清單...................................................11 7 、結(jié)語(yǔ).........................................................11 8 、附錄.........................................................13附錄1 實(shí)驗(yàn)仿真電路...........................................13 附錄2 源程序.................................................14 9 、參考文獻(xiàn)......................................................2310 、致謝........................................................