Each speaker has its own device which consists of a NodeMCU ESP8266 and X9C104 digital potentiometer inside of a 3D printed case.

As usual I’ll be using a NodeMCU board (I really did order a lot of them) which uses an ESP8266, but there’s no reason this would be difficult to achieve on an Arduino-based device.

Damien George has created a new programming language with standard API to make creating Internet Of Things projects more enjoyable and easier when using the ESP8266 WiFi chip.