As part of my research into RFID security I came across the “EM4100 RFID Cloner kit” by KBEmbedded which outside of having a terrible name is an amazing low-frequency (125 kHz) self-contained RFID cloner that can store and replay 16 cards.
I was lucky enough to be in the Portland area this week and be able to have dinner with Kris Bahnsen who designed the board and he said the that he thinks he could rewrite the software to read and replay HID proximity cards which would make this a must have gadget for all security professionals.
As it stands now this is an awesome $25 tool that is amazingly fun to play with and you should order one!