Adafruit ST25DV16K I2C RFID EEPROM Breakout - STEMMA QT / Qwiic

The RFID tag operates seamlessly with mobile phones, allowing dynamic reprogramming via I2C. It appears as an ISO/IEC 15693 chip, readable by phones and tablets, suitable for dynamic data-writing projects.

In one test, a microcontroller wrote different URLs at intervals, and a mobile phone detected each sequentially. Note that common RFID reader/writer chips like the PN532 do not support ISO15693, so they cannot read the programmed ST25DV tag.

This tag can potentially serve as an I2C-to-RFID transfer system, wirelessly sending and receiving data from mobile devices, requiring a custom app. ST offers a library to write NFC URLs via I2C, not compatible with Arduino UNO due to RAM limitations. A Metro M0 or equivalent SAMD chip is recommended for communication.

The breakout includes an ST25DV04 chip with support circuitry and a PCB trace antenna. Standard 0.100"/2.54mm pitch headers enable breadboard use. Stemma QT connectors (compatible with SparkFun Qwiic) are available for easy connections, though the QT cable is sold separately.