【正文】 kes chart 1 to show. When its P1 mouth , to the D trig , the control ultrasonic wave launch, are 0, the photo electricity coupler outputs the TP1 end is 1, the permission ultrasonic wave launch, launches/the receive ultrasonic wave in turn, the circulation repeatedly carries on. Simultaneously the monolithic integrated circuit interior counter starts to count. The steam distance between vehicles obstacle distance is the time which sends out through the sound navigation and ranging reflects spends determines and carries on the putation. The reflection signal causes the D trigger to produce interrupt request signal INT1,simultaneously stops counting, reads takes counts the value, calculates the actual distance after the formula, then carries on the parison with the datum distance, if examines when the actual distance is bigger than reference value 80cm, does not carry on the accustomoptics to report to the police。超聲波傳感器由超聲波發(fā)射電路和超聲波接收電路組成，在汽車駕駛室的適當(dāng)位置，裝設(shè)超聲波發(fā)射/接收器，以及遙控開關(guān)電路T1。編碼通道碼和編碼序號(hào)碼存放在單片機(jī)的 EEPROM中，確保它們不受停電影響。延時(shí)的目的是使汽車的主人在開門進(jìn)入車內(nèi)能關(guān)閉報(bào)警器,以免誤報(bào)警。安裝好后，啟動(dòng)報(bào)警器，報(bào)警器自動(dòng)延遲20~30s開始工作，以便讓使用人有足夠的時(shí)間鎖好門離開汽車。編碼通道用于表示遙控器的身份，每套系統(tǒng)使用一個(gè)固定的通道碼。遙控器和控制器都用美國(guó)ATMEL 公司生產(chǎn)的八位C MOS 型 AVR 單片機(jī)，該系列單片機(jī)基于新的精簡(jiǎn)指令R ISC 結(jié)構(gòu)，含有使用壽命最少為1000 次寫/擦循環(huán)的 Flash 程序存儲(chǔ)器，以及使用壽命至少為 10萬 次寫/擦循環(huán)的E EPROM 數(shù)據(jù)存儲(chǔ)器，有 2 位只有在整片擦除時(shí)才能擦除的編程加密鎖定位。 If some people approach the automobile to enter the cab, the examination actual distance is smaller than or was equal to when reference value 80cm, through monolithic integrated circuit and the port, actuates the indicating lamp display circuit and the sound alarm circuit, sends out three two flash. And triggers a high level, the actuation is wire less signal transmission circuit.Chart 1 Ultrasonic wave transmission circuit Code/decoding principleThe present automobile remote control security system are many is usesVD5026/27, PT2262/72, HT12E/D and so on the general code/decodes the electric circuit, its password decided by the ponent address, each set of security systems use a fixed invariable password. Along with the micro processing technology development, through the receiver emote control transmitting message, may intercept this fixed password, moreover general arranges the decoding address to lose the person to carry the ponent size limit, its quantity is impossible too much, can obtain not repeatedly codes very is also limited, also can very quickly explain the password with the automatic scanner. Therefore, this kind of password fixed invariable automobile security system has received the serious threat. Decodes the automobile security system using the monolithic integrated circuit interior resources realization jump code, it each time uses the remote control password all is changing, with the password no longer duplicates uses, causes the interception password also is makes a futile effort, in addition, it may increase the enough many passwords figure, enhances the sys