With the development of China's economic construction, cars are becoming an indispensable part of people's lives. Car theft has become one of the most common crimes in today's society, which has become a serious social problem. With the increase in the number of cars, the number of stolen vehicles has also increased year by year, worrying about the theft of cars has become the first problem that troubles car users. With the advancement of science and technology, in order to cope with the escalation of stolen cars, people have developed anti-theft devices with different structures. Let's talk about the types of car anti-theft devices. 1 Key-controlled anti-theft system The function of the key control type anti-theft system is: when the driver locks the door, the electronic anti-theft system circuit is connected, and at the same time, the electronic anti-theft system begins to enter the working state. Once a thief opened the door illegally, the electronic anti-theft system used a horn to call for help on the one hand, and cut off the ignition system circuit on the other hand, so that the engine could not start, so it played the role of anti-theft alarm. The electronic key code control device relies on the coded ignition key to control the start of the car engine to prevent the car from being stolen. It is mainly composed of an ignition key with an identity code, a controller composed of an encoder, and an engine control unit. The coded ignition key is embedded with a resistance die, and an identification code (resistance value) is provided in the resistance die. A code is stored in the ignition lock cylinder. When the inserted key does not match the stored code, that is, the resistance value does not match the resistance value stored in the ignition lock, the ignition system circuit cannot be connected, thereby playing an anti-theft role. 2 Electronic password anti-theft system The electronic code of the anti-theft device is the key to open the anti-theft device. On the one hand, it records the identity code of the anti-theft device, which distinguishes the differences of each anti-theft device; on the other hand, it also contains the anti-theft function instruction code and data code, which is responsible for turning on or off the anti-theft device, and controlling all functions of the anti-theft device. According to the different ways of password transmission, remote-control car anti-theft devices are mainly divided into fixed-code anti-theft devices and code-hopping anti-theft devices. Earlier anti-theft devices mostly used fixed-code methods, but because they are easily deciphered, they have been gradually replaced by more technically advanced anti-theft devices with better anti-theft effects. The principles and characteristics of two different types of anti-theft devices are introduced below. 1. Fixed code anti-theft device. Early remote control car anti-theft devices have a set of same passwords for the host and the remote control. The remote control transmits the password, and the host receives the password to complete the various functions of the anti-theft device. This password transmission method is called the first generation of fixed code transmission. Mode (referred to as fixed code transmission mode). The application of the fixed code transmission method in automobile anti-theft devices is not popular. When the amount of anti-theft devices is not large, that is, in the initial anti-theft device application market, the security and reliability of the anti-theft devices are still guaranteed. But for a mature market where anti-theft devices are used, the code setting method is unreliable and unsafe. There are three reasons: the amount of passwords is small, and repeated codes are easy to appear, that is, the phenomenon that one remote control controls multiple vehicles; After the device is lost, it is extremely unsafe to replace the remote control alone, unless it is replaced together with the host, but the cost is too high; it is also the biggest danger that the security is poor, the password is easy to be copied or stolen, and the vehicle is stolen. Code skipping anti-theft device. The fixed-code anti-theft device has long had insecure problems such as a small amount of passwords, prone to repeated codes, and passwords that are easily copied and stolen. Therefore, the code-hopping anti-theft device came into being, and its characteristics are as follows: In addition to the identification code and instruction code, the password of the remote control has a code skipping part. The code hopping means that the password depends on a certain coding function. The password changes every time it is transmitted. The password will not be easily copied or stolen, and the security is extremely high. The combination of hundreds of millions of passwords eliminates duplicate codes at all. The host does not have a password. The host learns the password of the remote control to realize mutual recognition between the host and the remote control. If the remote control is lost, the remote control can be replaced safely and at low cost without any worries. 3 Remote electronic anti-theft system At present, this electronic anti-theft system is widely used in many cars equipped with the original anti-theft system. The remote electronic anti-theft system uses the transmitting and receiving equipment to lock or open the vehicle door through electromagnetic waves or infrared rays, that is, to control the anti-theft system to perform anti-theft duty or release. There are many types of remote-controlled electronic anti-theft systems, common ones include electromagnetic wave remote-controlled electronic anti-theft systems and infrared-controlled anti-theft systems. The remote electronic anti-theft system can easily and quickly lock or open the doors at night without the help of lights. Structure and composition. A complete set of remote control car alarm should be composed of the following parts: Host part: It is the core and control center of the anti-theft device. Induction detection part: It can be composed of sensors or probes. At present, oscillation sensors are commonly used. Microwave and infrared probes are rarely used. Door control part: including front cover switch, door switch and luggage compartment switch, etc. Alarm part: Horn. Wiring part. Other parts: Including stickers, screws, relays and other accessories and instructions and installation wiring diagrams.
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