The Design Of Vehicle Entry System Based On RFID Technology

With the rapid development of social science and technology, RFID technology has been widely applied in various industries. Especially in the car intelligent vehicle entry system, RFID technology, which is an important part of intelligent car, has been paid more and more attention. The access system of traditional car mainly relies on the user’s active operation of keys, with just a simple one-way authentication between the car and the key. Because the communication frequency is fixed and susceptible to interference, the safety factor is not high.The emergence of the RFID technology compensates the deficiency of the old vehicle entry system, and this paper designs a vehicle entry system based on RFID technology, which achieves two-way authentication between the door control module and the identity card for safe and rapid communication. When the user carrying with the identity card enters to the valid communication range of the vehicle entry system the door opening function will be achieved by pressing the touch button on the door handle. and simultaneously the alarm will be releived. When the user leaves the car, he(she) only needs to presses the touch keys to realize the auto lock function, and make the security system in the fortified state. During the whole process, the user doesn’t need to take the identity card out. Experimental results show that the system of remote control key can realize to control the opening of the door in the range of 1.8m. The system has the funcations of fortification, releiving alarm, voice prompting, learning and resetting of identity card. The system is fully functional, and has realized both the entrance controlling functions and the optimization of power consumption.The main work of this paper is listed as follows:1. The hardware design. The Micro Controller Unit(MCU) PIC16F1828 and PIC16F630 are chosen for car door lock control module and identity card module respectively. The LF receiving and sending circuits are designed with the radio frequency chips of TMS37122 and TMS3705 respectively, where the communication frequency of HF and LF are 315 MHZ and 134.2 k Hz, and their digital modulation methods are ASK and FSK respectively.2. The software design. The system software is mainly composed of the MCU initialization program, the key judgment program, the sending program, the receiving program, the memory card handling program, the voice control program, the security control program and the motor control program, the learning and information cleaning of identity card programs etc. The encryption and decryption algorithms of RFID communication are emphatically introduced.3. Experiments. The installation and debugging, parameter measurement, functional testing, antenna testing and the power consumption analysis of the circuit are done for the system., The communication distance of the system is 1.8m when the inductance of the coil antenna is 300 mH. The quiescent current of the car door lock control board is 9.27 mA; The operating current is 80 m A; The quiescent current of the identity card is 5 mA and the operating current is4 m A. The system has full function and low power consumption, which can basically meet the requirements of the keyless entry system.