UHF RFID for Intelligent Access Control System and Indoor Tracking

Abstract

Radio Frequency Identification (RFID) is identification of objects or people by incorporating the use of radio frequency waves to transmit data, without any line-of- sight alignment or physical contact between the tag and the reader. In this project, a UHF RFID-based intelligent access control system at a frequency range of 902MHz to 928MHz is developed by integrating the UHF RFID reader, Arduino, electromagnetic lock and PIR sensor. To trigger the electromagnetic lock, the PIR sensor monitors the immediate environs of the door solidly. It also has a contribution to energy conservation since the electromagnetic lock does not need to be energized the whole time if there is nobody walking by. Only people with authenticated tag can access. Our proposed system can converse up to 50% of the energy in contrast to the traditional access control system. Also, the recovery time of the PIR sensor is greatly decreased from 5.5s to 0.2s after the hacking, which means the door can be locked promptly whenever a visitor comes up. This ensures the security of the system. Another feature of the system is contactless communication between the reader and the tag that is realized by backscatter coupling mechanism. It facilitates the process of entering a locked room without even taking out the tag and placing it on the reader. Although the read range of the system is 1m, it can be expanded with a higher power antenna rather than the one used in our prototype. Apart from the access control system, the characteristic of RFID is called into play to implement testing of indoor tracking. RSSI is the core of the indoor tracking. After the comparison with the most popular formula, a model describing the relationship between the RSSI and the distance is constructed. Results show an average error of 0.20%.