IoT EM4305 RFID Reader

RFID tags come in various forms and sizes, from standard plastic cards to chips that can be implanted in one's hand. I got particularly interested in RFID rings, which can be purchased online for less than USD 20$. Those are based on EM4305 chips, which require a compatible reader. Thus, I designed an IoT EM4305 reader that can exchange data over MQTT with other devices.

Hardware

The reader is built around an ESP8266 Wifi microcontroller and an unnamed EM4305 reader module.

User feedback is provided using an OLED display and a Piezzo buzzer. Those component are laid out according to this schematic:

A PCB has been design based on the schematic. Its layout is as follows:

More details about the hardware can be found on OSHWLab.

Software

The device runs an Arduino sketch which handles the EM4305 chip and communicates with other IoT devices via MQTT. The sketch can be found on GitHub.