Interface RFID With AVR


Radio-frequency identification (RFID) uses electromagnetic fields to transfer data through wireless.

  • RFID Devices consist of two parts
  • Tag contain electronically stored information.
  • Information read by the reader.


  • An RFID system uses a tag, attached to the objects for identification.
  • Readers send a signal to the tag and read its response.
  • Tag is read-only the tag uses the radio energy transmitted by the reader.
  • Each tag has a unique serial number, by using this tag number it is easy to identify product details.

RFID Reader

  • There are different types of reader available in the market
    1. Passive Reader Active Tag.
    2. Active Reader Passive Tag.
    3. Active Reader Active Tag.

Passive Reader Active Tag

  • The system has a passive reader which only receives radio signals from active tags (battery operated, transmit only).

Active Reader Passive Tag

  • The system has an active reader, which transmits interrogator signals and also receives authentication replies from passive tags.

Active Reader Active Tag

  • The system uses active tags awoken with an interrogator signal from the active reader.


  • Transportation payments.
  • Transportation and logistics.
  • Public transport.
  • Libraries.
  • Hospitals and healthcare.

Hardware Required

  • RFID reader.
  • RFID Tag.
  • Atmega16 MicroController.

RFID Pinout

  • Vin= +5V.
  • Tx= Rx of Microcontroller.
  • Gnd= Ground.


Virtual Circuit