EM18 RFID Working Mechanism

HOW DOES RFID WORKS?

RFID EM18 working mechanism is quite simple. RFID Reader module has a transceiver (which can transmit and receives data) which generates a radio signal and transmits it through an 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 an RFID tag comes in the range of signal transmitted by the reader (10 cm for EM18), the transponder of the tag is hit by this signal.
  • RFID tag induced power from the electromagnetic field which is generated by the reader.
  • Then, the transponder converts that radio signal into the usable power and after getting power, the transponder sends all the data/information it has stored in the chip, such as a 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.

RFID WORKING

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 the module to display. Next power the system. When a tag is brought near the MODULE it reads the ID and sends the information to the 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 interfaces. 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 the 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 the bit rate of the controller mismatches then the system will not work correctly.


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