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.

[Marc] and [Xavi] just wrote up a quick tutorial on how to turn the ESP8266 into a WiFi sensor platform that will relay the state of a GPIO pin to the Internet. If you’re going to replicate this ...

At its core, it is just an ESP8266, a cheap simple Wi-Fi chip that is in tons of tech. If you have Wi-Fi light bulbs, you probably have several of these chips in your home right now. Devices like ...