Arduino has launched its next generation of UNO boards, introducing a 32-bit Renesas microcontroller and Espressif ESP32-S3 module, one-click cloud connectivity and plenty of I/O plus a 12×8 red LED ...

Looking to improve on this simplistic interface, [Sören Beye] tacked an ESP8266 to the board so it can broadcast sensor readings out over MQTT. Just three wires link the ESP8266 to the PCB.