This project aimed to develop a wireless system to detect and allow only the authorized persons. The system was based on Radio Frequency Identification (RFID) Technology and consists of a passive RFID tag. The passive micro transponder tag collects power from the 125 KHz magnetic field generated by the base station, gathers information about the Tag ID and sends this information to the base station. The base station receives, decodes and checks the information available in its Database and Manchester code was used to send those information. The system performed as desired with a 10cm diameter antenna attached to the transponder. The Base Station is built by using the Popular 8051 family Microcontroller. It gets the tag ID and if the tag ID is stored in its memory then the microcontroller will allow the person inside.
RFID Reader Module, are also called as interrogators. They convert radio waves returned from the RFID tag into a form that can be passed on to Controllers, which can make use of it. RFID tags and readers have to be tuned to the same frequency in order to communicate. RFID systems use many different frequencies, but the most common and widely used Reader frequency is 125 KHz.