HOW DOES RFID WORKS?
RFID EM18 working mechanism is quite simple. RFID Reader module has transceiver (which can transmit and receives data) which generates a radio signal and transmits it through antenna. This signal itself is the form of energy which is used to activate and power up the RFID tag.
EM18 RFID WORKING MECHANISM
- When RFID tag comes in the range of signal transmitted by the reader (10 cm for EM18), transponder of the tag is hit by this signal.
- RFID tag induced power from the electromagnetic field which is generated by reader.
- Then, the transponder converts that radio signal into the usable power and after getting power, transponder sends all the data/information it has stored in the chip, such as unique ID to the RFID reader in the form of radio waves or RF signal.
- Then, RFID reader reads the data/unique ID (in the form of byte) & transmits it through serial Tx (transmit) pin from reader to Rx of microcontroller serially using UART communication.
There are various RFID readers available according to their frequency
HOW TO USE EM-18 RFID MODULE
EM-18 is used like any other sensor module. First we choose the mode of communication between MODULE and CONTROLLER. Next we will program the controller to receive data from module to display. Next power the system. When a tag is brought near the MODULE it reads the ID and sends the information to controller. The controller receives the information and performs action programmed by us.
Step1: Establishing a mode of communication. EM-18 can provide output through two communication interface. One is RS232 and another is WEIGAND.
The form of communication is selected by SEL pin. If SEL pin is selected HIGH then form of communication is RS232 and if SEL pin is pulled LOW then form of communication is WEIGAND.
Usually the RS232 (default) is selected because it’s popular so SEL pin is pulled HIGH.
Step2: The output baud rate is 9600 bps (bit per second) of MODULE . The controller should be programmed to receive information from MODULE at this baud rate. If bit rate of controller mismatches then the system will not work correctly.
Also Read: INTERFACING RFID READER WITH ARDUINO