RFID technology have successfully spread in the industry. So RFID tags are a juicy bite for most embedded developers and hobbyists. So why not to build a RFID tag emulator that could be connected to computer.
This RFID tag emulator simulates a standard 125kHz EM4001 compatible RFID tags. Emulator microcontroller simply receives ID from computer program via RS232 port and emulates it. All you need to connect an antenna coil and start talking to RFID readers. I smell some sort of RFID hacking here!