You’d need an ESP8266 to run the clock code, or if you’d rather sit and admire the rainbow light show unabated by the passing of time, just use an Arduino Uno or something similar.

Inside the jar there’s six 8×8 MAX7219 LED matrix modules tacked together to create one long strip, with a NodeMCU board stuck to the back with double-sided tape.

Nick is a small Nixie clock has been made available via Tindie priced at $129 and providing everything you need to build. The open source nixie clock based on ESP8266 designed to be as simple as ...