If you’ve ever wanted the ability to use some form of hardware-based authentication in your projects then this is the board to do it with. The Parallax RFID (Radio Frequency Identification) reader is super easy to configure. It only takes four wires! It uses the serial protocol to transfer information from RFID cards to the Arduino. This project is a quick introduction on using this RFID reader with the Arduino system.
Using the Parallax RFID Reader with an Arduino – [Link]