This board is based on the EM18 RFID Module. Using the board with microcontrollers to read a card's data is very simple and requires 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 reduce prototyping time and effort. An output pin (DET) also indicates the presence of a RFID card. The board can also be used to output data in Wiegand format. It can detect cards in the range of 3-8cms.