基于单片机的汽车防盗报警系统设计中英文参考资料Word文档下载推荐.docx

1、 Decodes the automobile security system using them on litchis integrated circuit interior resources realization jump code, it each time uses the remote control password all is changing, both enhanced the system security, and greatly reduced the cost.Keyword: Monolithic integrated circuit, Automobile

2、 security system , Code/decodeIntroductionIs unceasingly progressive along with the social economy and the high tech rapid development, in the routine work and the life, the automobile has become the people ideal transportation vehicle. But the following motor vehicle the case which robbed gradually

3、 is also in creased has created the pilot economical property loss. In order tore duce the automobile to rob the event the formation rate, for has the automobile the user to provide the safety control, simply develops one kind to be reliable, the ease of operation, can send out in the discovery norm

4、al condition to the pilot reports to the police the reminder and the security warning safety system has the practical significance. This article based on to the existing automobile security alarm system generalized analysis, develops one kind of brand-new security alarm system. This system has mainl

5、y used the jump code code/decoding principle, causes the overall system to be safer, greatly reduces password explaining rate.1. System principle of workThe automobile security alarm system the remote control which carries by the driver and installs in the automobile the controller two parts compose

6、s. The remote control and the controller all use eight CMOS which American AT-MEL Corporation produces the AVR monolithic integrated circuit, this series monolithic integrated circuit based on new simplifies instruction R the ISC structure, includes the service life most to be few is 1,000 time writ

7、es/scratches the circulation the Flash program memory, as well as the service life at least is 100,000time writes/scratches the circulation E the EPROM data-carrier storage, some 2 only have when the entire piece cleaning can clean the programming encryption locks the localization.1.1 System designT

8、he automobile security examination uses the ultrasonic sensor. The ultrasonic sensor is composed by the ultrasonic wave transmission circuit and the supersonic reception electric circuit, in the automobile cab appropriate position, installs the ultrasonic wave launch/receiver, as well as switch elec

9、tric circuit T1. When the automobile parks the vehicle owner person must leave the automobile, with remote control closed switch T1, the automobile alarm system sat garrisons the condition, around the system use ultrasonic wave examination vehicle obstacle. Launches the partial electric circuits lik

10、es chart 1 to show. When its P1 mouth P1.1, P1.2 to the D trig , the P1.0 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. Simulta

11、neously 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 computation. The reflection signal causes the D trigger

12、 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 comparison with the datum distance, if examines when the actual distance is bigger than reference value 80cm, does not carry on

13、 the accustom-optics to report to the police; 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 P2.2 and the P2.3 port, actuates the indicating lamp display circuit

14、 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 circuit1.2 Code/decoding principleThe present automobile remote control security system are many is usesVD5026/27, PT2262/72

15、, HT12E/D and so on the general code/decodes the electric circuit, its password decided by the component 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 interce

16、pt this fixed password, moreover general arranges the decoding address to lose the person to carry the component 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, th

17、is 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 n

18、o 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 system resistance illegal scanning the ability. The remote control coding altogether has 12 bytes, separately by 3 bytes codes channel

19、s code, 3 bytes codes forewords number, 5 bytes jumps codes, 1 byte pressed key operation code is composed. Encoded front adds on logic in each byte 0 to take the outset position, encoded behind adds on a logical 1 achievement in each byte to stop the position, and in most front adds on several logi

20、c 1 to take the guidance signal, this constituted the serial coded signal which uses in to transmit. The code channel code uses in to express the remote control status; each set of systems use a fixed channel code. The code foreword number uses in to record the encoded order, its starting value is 0

21、, the monolithic integrated circuit every time codes a time, the code foreword number upwardly counts time. The code channel code and the code foreword number deposits in monolithic integrated circuit EEPROM, guarantees them power cut the influence. The jump code is the systematic true password, it

22、passes through the complex special algorithm by the code channel code and the code foreword number to extract, this special algorithm foreign security. The pressed key operation code by the pressed key which presses was decided, when the hypothesis the key is pressed down, its code decides as 0 1H;

23、When relieves the key presses down, its code decides as 00H. Whether is the decoding confirms receive the code legitimate a series of operating process. Was confirmed the legitimate code needs to satisfy three conditions; （1） codes the channel code and the decoding channel code is same; （2） coded th

24、e foreword number to be bigger than the decoding foreword number （decoding foreword number to record on legitimately has used code foreword number, this condition might guarantee before has used code was invalid）; （3） jumps the code to be equal to reuses the special algorithm to extract changes the

25、code. After the monolithic integrated circuit confirmed receives is the legitimate code, writes the code foreword number in the decoding foreword number, and completes corresponding operation processing according to the operation code. The decoding channel code and the decoding foreword number also

26、deposits in monolithic integrated circuit EEPROM, guards against because of power cut loses.1.3 Security reports to the police realizationIf will have robber Chen ZheRu the room, starts the automobile, after wrong password, then the automobile storage battery +12V voltage, the ignition electric curr

27、ent way ignition lock, the ignition outage, the engine extinguishes, again starts, will duplicate the above process, like this, the bandits and thieves always will not be able to start the automobile, will not be able to achieve its anticipated goal. The alarm circuit mainly is composed by the integ

28、rated block and the speaker and electronic switching SCR. Triode or the multiple-unit tube, are for enhance the electric circuit measure which the power but often uses, it has composed a current amplification factor very big equivalent transistor, total enlargement factor for these two enlargement f

29、actor product. SCR is the electronic switching which constitutes by the silicon-controlled rectifier, the electric capacity and the resistance constitution negative booster concurrently filter, provides +3 +4V to IC the voltage, IC is traces Draws up sound reports to the police the integrated circui

30、t, the alarm apparatus by the SCR control, robs the vehicle thief once after the wrong password, then the storage battery electric current enters the security system besides a group, another group is started in the engine, after leads the engine work, natural contact output voltage, after the differ

31、entiating circuit, silicon-controlled rectifier SCR is triggered, also passes through the resistance to fall the pressure, the voltage adds in the IC power source input end, IC obtains the voltage output alarm, enlarges after the multiple-unit tube, Destroys moves the speaker to send out resoundingl

32、y reports to the police the sound. when static state, entire electric circuit does not consume the electricity.2. Software designThe alarm apparatus software design mainly divides into: Master routine （alarm apparatus initialization, key modulation and decoding）; Alarm apparatus interrupt handling routine. This alarm apparatus installs on the automobile steering wheel. After installs, starts the alarm apparatus, the alarm apparatus automatically retards2030s to start to work, in order to lets use the person to have the enough time to lock the ga