[Alexander] built an RFID emulator. It uses a wire coil (not pictured here) and an ATmega8 to represent any tag that is EM4001 compliant. This iteration requires connection to a computer to send the tag ID information to the microcontroller. In the video after the break it looks like he’s using a DIY RFID reader to test this. If the two were combined, cutting out the need for a computer, he would have an RFID spoofer on his hands.