This board uses the EM18 RFID Module. It can be used to read our RFID cards. Using the board with microcontrollers to read a card's data is very simple and required just a serial connection. The board should be powered at 5V, and it requires a direct connection to the microcontroller's Serial Rx pin. The card data is transmitted over the serial line when the card is brought near the module.
The board has an onboard power indication LED, a LED and Buzzer to indicate the presence of a RFID Card. All the IO pins are brought out to standard clearly labeled header pins, which simplify prototyping time and effort. An output pin (DET) also indicates the presence of a RFID card.. It can detect cards in the range of 8-10cm.