Here’s an open source RFID cloner design that is about the same size as a standard RFID key card. It doesn’t need a battery to capture key codes, just the magnetic field generated by an RFID ...
a chip used for RFID tags. Minimally, all that is needed is the AVR and a coil, but he recommends some filtering capacitors. Depending on the size of the coil, different frequencies and ranges can ...