Nick is an open source nixie clock based on ESP8266 designed to be as simple as possible and as compact as possible. There are three versions of Nick you can make, one is direct driven IN-12, second version is duplexed IN-12 and finally a tiny duplexed IN-16 version. The clock uses NTP to sync with internet time.
Check out wiki: https://github.com/mcer12/Nick-ESP8266/wiki
3d printed case here:
https://www.thingiverse.com/thing:4014357
If don't like the stock firmware and want to have more options in the clock configuration portal, see https://github.com/nullstalgia/Nick-ESP8266 fork of this repository :)
UPDATE 14/4/2020: ESP8266 can occasionaly stutter in multiplex, especially if the wifi signal is bad, so I can't recommend it. If you want to use ESP8266, choose the direct-drive version with 4 x 74141 IC which will always be flawless. Or use separate microcontroller for the multiplexing.
UPDATE 11/12/2020: Firmware rewrite for duplexed IN-12 version is done, others will follow. With this firmware, the duplexed version runs smoothly at ~70hz. Little to no stutter can be observed only at the lowest brightness (low duty cycle). The firmware contains simple config portal, check out screenshot below.
UPDATE 11/23/2020: New firmware was added for all clock variants. It uses HW interrupts so there's no stutter anymore even when wifi is used.
