The Study Of Tire Pressure Monitoring System Based On Enbedded System

With the increase of the number of auto, the security of auto is becoming more and more concerned by the customers and the government. Tire Pressure Monitoring System (TPMS) is a newly auto electronic technique for improving the security of auto. TPMS mainly is used to do real-time monitor automatically for the temperature and pressure of tires and to warn for leakage and low pressure when cars are driving so that protecting driving safety. It is a safety control system for drivers and riders. With the TPMS issued,the research of the field is coming into a new phase.First of all, the paper analyzes the technical standards of TPMS, and researches into the impact of the performance of tires on pressure and temperature of it. Basing on discussing the common technical programs at home and abroad, put forward a new method: namely, makes use of surface acoustic wave sensors as sensitive elements, combined with embedded technologies, builds up monitoring system. Besides, analyzes the structure of resonance style, module and characteristics, then it makes analysis and simulation for the equivalent circuit.Secondly, the key technology of TPMS basing on SAW sensor is researched . The principle of the system of detection is analyzed deeply, and the paper researches into the response under incentive and puts forward how to collect and deal with the echo signal. By varying the structure of the SAW, it can be used to measure pressure and temperature. Meanwhile, the sensor has the ability of encoding.According to the character of the system, the paper combines with the embedded technology,analyzes the function of hardware module and designs the central control module, the radio-frequency module, power circuit, network interface, touch-screen interface and etc. Meanwhile, it analyzes the problem should be noticed when designing hardware, PCB. In the part of software, the paper focuses on the principles of theμC/OS-Ⅱ,transplants theμC/OS-Ⅱinto the LPC2148. The OS realizes the network communication. Besides, the paper designes the software of the signal acquisition and the touch-screen control.On the base of it, the paper designes the prototype for the system of tire pressure monitoring, and according to the situation of experiment, makes up the plan of experiment: namely, adjustes the temperature by air-conditioning, and used the pressure container whose pressure is adjustable simulated the alternation of tires, then puts the module of the SAW sensor into pressure container, the main module receives the feedback from , upload the signal to PC by serial ports, and the main module has ability to sent out data by network interface. Finally, all the modules available are debugged, including the central control module, radio-frequency module, and network module, furthermore.Above all, the following conclusion can be drew: SAW sensors can be sensitive to temperature and pressure, the whole embedded systems meets well in Tire Pressure Monitoring System.