Research And Development Of Wireless Intelligent Automobile Key System Based On PIC Microcontroller

With the rapid development of automobile market in recent years in China, more and more families own cars, while automotive safety issue has become hot. Automotive safety has become a key factor in consumers’ choice in the automotive market. More and more car manufacturers will develop automotive safety technology as a priority in the future. The technology associated with automotive safety will increasingly become a growth point of the development of the automotive industry. As a key component of automotive safety, automotive keys into a major research direction. With the development of technology, the automotive key has evolved from the traditional mechanical key to the current wireless intelligent key, become a systematic automotive electronics technology.Existing wireless intelligent automotive key systems is less employed in low allocation models because of the high cost, while the possibility of a larger loss of signal during radio communications. In order to solve these problems, this study designed a wireless car intelligent key system based on PIC microcontroller which enable remote control and the keyless entry function by data communication through the radio frequency signal. The communication process of low frequency radio frequency signal, tri-axial analog front end added in this paper improves the signal reception sensitivity and signal recognition accuracy, and improves the communication quality of low-frequency signal. And radio frequency signal communication theory is introduced in this paper. A keeloq rolling code encryption technology used ensures the safe and reliable of the system, while you can change and extend the key functions for the needs. The hardware design is mature with a sleep mode to ensure the low-power design requirements and lower hardware costs of the automotive keys which is with good marketing value.In this paper, the development principle of wireless automotive intelligent key system will be described in detail and the functional properties of the design scheme used is described. In the part of hardware design, the basic requirements, base station and the transponder key is detailed including main functional circuits and relevant content of PIC microcontroller, especially including PIC microcontroller function characteristic and the pins functions. Circuit wake-up technology reduces power consumption of the device through the sleep mode when a valid signal is not detected.The content in part of software design of this paper include the communication protocol of radio frequency signal and vehicle bus is introduced, the process approach of keeloq rolling code encryption algorithm, the control processes of transponder key and base station, the configuration registers for tri-axial analog front-end and the main functions data stream of the system.In addition, the debugging for wireless automotive intelligent key system is introduced, and software development environment and system physical map is displayed. Test and analysis of function reliability, system power and communication distance is completed. According to the debugging results, herein design and development of intelligent wireless car key system meet the design requirements.Finally, for the future development needs and trends in the automotive safety technology, the future development is discussed of wireless automotive intelligent key system described herein, while experiences harvested and problems encountered in the development process are summarized.