This RFID project is the second iteration of the RFID board for DEF CON's DarkNet game. This project is based on the OPEN RFID tag with resources pulled from t4f.org and kukata86.com. Envelope detector credit to multiple people listed here: http://playground.arduino.cc/Main/DIYRFIDReader
This project is to create a battery powered RFID cloner that is compatible with LF 125kHz RFID tags, a.k.a. EM4100. There are 16 slots each able to store a 5 ID. This device does not clone a tag and reprogram another, it is able to read and clone a tag and then turn around to emulate it to a proper transponder. There is also a mechanism to manually program an ID to the device via the button and DIP switch. Any of the 16 slots can have a cloned ID saved, a manually input ID saved, and an ID replayed from.
2023-05-06: I've discovered that Microchip has radically changed their assembler system. This will not compile under current MPLAB X IDEs, but should work on the older v3.50 or v3.55 (I think is what was originally used). They can still be found here: https://www.microchip.com/en-us/tools-resources/archives/mplab-ecosystem#MPLAB%20XC%20Compiler%20Archives If that link ever goes stale, well, good luck.