| The meter of automobile is the main interface. The driver can get message from it. And these message is important to the safety and economy of the running automobile. With the development of Computer Technology and Microelectronics Technology, more and more new technologies have been widely used in automobile. Stepping automobile combined meter displays and records the related information. Compared with traditional motive magnetic and motive coil meter core, new automobile meter has many advantages, such as, small size, light weight, high reliability, strong anti-disturbance and so on. It has become a development trend of automobile meter nowadays in the world.The principle of how to measure the main automobile running parameters is first discussed in this paper and the correlative math model is given. According to the status in our country, a low cost, high reliability meter solution project based on the microprocessors need to be found. This project can not only overcome those disadvantages of mechanical meter, but also it has some others advantages (beauty appearance, simple structure, high design degree, small size, good real-time, high sensitivity, high precision, clear and direct display, more information, easily function extended capacity).In the paper, working principle of stepping motor, the interface technology of MC68HC908LJ12 and its control technology was analyzed firstly. Then, according to the demand of displaying information such as car speed, rotate speed, water temperature, remaining fuel the paper analyze the key point and difficulty and get the solution project. A new automobile meter based on MC68HC908LJ12 and stepping motor was designed and realized. There are LCD, LED and stepper motors display in this system. And the system is able to measure and display all kinds of parameter (vehicle speed, running mileage, engine speed, water temperature, remaining fuel etc).In order to expand system function, there are more Switching modules and stepping motor modules to be set.
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