In-Depth: What is RFID? How It Works? Interface RC522 with Arduino

Radio Frequency Identification (RFID) technology allows contactless communication between a reader and a tag using electromagnetic fields. In this project, the core components are an Arduino board, an RC522 RFID reader/writer module, and an RFID card or key fob. The RC522 module generates a high-frequency electromagnetic field via its integrated antenna. When an RFID tag containing an embedded microchip and antenna is brought within range of this field, the tag draws power inductively from the signal. Once powered, the tag transmits its unique identification data back to the reader by modulating the radio frequency field. The RC522 module captures this transmitted data and communicates it to the Arduino board using the Serial Peripheral Interface (SPI) communication protocol. Using the Arduino IDE and the MFRC522 software library, the Arduino processes these incoming digital signals, allowing the maker to read the unique tag identifier, verify authorized users, or even write new data back to compatible MIFARE tags. This wireless interaction forms the foundational mechanism behind modern contactless security and tracking systems.