Development on Low Temperature Protecting Device with Theft proof Function for Cars
Development on Low Temperature Protecting Device with Theft proof Function for Cars You Bo Ding Liang Xu Jiazhong （Harbin University of Science and Technology, Harbin 150080 China） Abstract: In this paper, a kind of intelligent low temperature protecting device with theft proof function for cars is presented from the aspects of both hardware structure and software design. By keeping the environment temperature suitable for the engine to run, it solves a good many problems for cars when cars are kept under low temperature circumstances. The temperature collecting circuit with DS1820 digital sensor, running lamp control circuit with a 555 integrated timer, flow chart of main control program and so on, are all introduced particularly. Keywords: DS1820 sensor; 555 oscillating circuit; Low temperature protecting device; Watchdog. 1 Introduction If cars are remained off for a long while under cold circumstances, the lubricant viscosity of engine’s drive system and electrolyte viscosity of battery will become larger, volatility of gas will be weaker and oil film will fall off, so that a lot of problems may be brought on because of low temperature, such as the car is difficult to start and hard to run quickly at the beginning, its assembly especially the engine wears out severely, the battery’s voltage is lower. The intelligent low temperature protecting device with theft proof function for cars is developed to solve the problems brought forward above. Not only can it resolve the problems by keeping the environment temperature suitable for the engine to run, but also it can guard against theft independently and can be compatible with additional theft proof device installed by users themselves. The devices have been used on cars of some cities in China, and they are proved to be convenient, economical and useful. 2 Hardware Structure The hardware structure diagram of low temperature protecting device for cars is shown in Fig.1, which is mainly composed of CPU, external interface circuit, voltage stabilization module, display module, auxiliary control circuit, 555 oscillating circuit, watch dog circuit, key input module, etc.
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