[Carl] has done a lot of work developing a collection of RFID hardware. The two cards you see above are spoofers that can be programmed in the field using the keypad on the left, or the rather intimidating banks of DIP switches on the right. We also enjoyed his look at the Atmel T5557 and ATA5567 on-card chips used for the tags themselves. He shared the schematics for his designs but unfortunately he’s not distributing the firmware. None-the-less, if you’re interested in learning more about RFID this is a wonderful resource as it covers readers, writers, spoofer, and tags.