Radio-frequency identification (RFID) is the wireless non-contact use of radio-frequency electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects. The tags contain electronically stored information. This EM-18 RFID Reader is a Tiny, simple to use RFID reader module. With a built in antenna, the only holdup is the 2mm pin spacing. Power the module, hold up a card, and get a serial string output containing the unique ID of the card. It has TTL output. Application of EM-18 RFID Reader Module:- Smart Access Control System. Card Based Entry System. Attendance System. DIY projects requiring need for RFID based System