RFID Emulator Built Around AVR

The project creates a RFID tag emulator that can be connected to a computer through the RS232 port for emulation.

A standard 125kHz EM4001 compatible RFID tags are being simulated by this RFID tag emulator. The 64 bit long ID from the computer program using the EM4001 is being received via RS232 by the emulator microcontroller. To start communicating with the RFID readers, the only thing required is to connect an antenna coil. The baud rate during the sending of calculated ID over the RS232 connection is 9600bd.

For the Atmega8 microcontroller running at 8MHz and the computer, a C program was used to write the software and compile it with AVR-GCC. Other components used include the MAX232 level converter, 8MHz 7805 crystal stabilizer, power & control LEDs, ISP & coil connection, and reset button.

In the middle of bit period, there is always a transition from ON to OFF or from OFF to ON. The change of phase occurs at the transition from logic bit 1 to logic bit 0 or vice versa. When the modular switch is OFF, it represent high value of data stream and low value when switch ON.

Rest of the project