Nixie i2c Clock

Hi fellow Arduino enthusiast and nixie lovers,

i recently started to build my own nixie clock based on an Arduino. Why i wanted to do that? Oh well i like the shiny glow of nixies :P.
Anyway the real reason is that the builds that are available on the internet didn’t fit my needs and i always wanted to programm some sort of µC. I wanted a fully configurable clock including directly driven nixie tubes (no multiplexing).

I know the Arduino project since quiet a while, but i never felt like buying a unit and play with it.
But now i finally got a reason.

I decided to mainly use pre-made modules so i didn’t have to design a pcb.
The following parts were used to build the clock.

6x SmartNixie IN-18 Socket >>>1361-SX<<<
1x SmartNixie IN-12 >>>1328-SX<<<
1x High voltage power supply >>>1364 HVPS-H<<<
1x Real time clock DS3231 >>>DS3231<<<
1x Temperature sensor >>>DS18B20<<<
1x Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board >>>Link<<<
1x Adafruit MPL3115A2 - I2C Barometric Pressure/Altitude/Temperature Sensor>>>Link<<<
1x 5v step down power supply >>>Link<<<
1x 12V wall power supply (old stock)
1x DCF77 reciever (old stock)
Misc. stuff such as resistors, pin headers, cables and mosfets etc.

6x IN-18 Nixie tubes >>>Link<<<
1x IN-19A Nixie tube >>>Link<<<
4x IN-3 Colon Dot

The SmartNixie modules are i2c adressable modules. It’s very simple to drive them. They’re well made and include everything you need such as a nixie socket and the ic logic.

My arduino sketch allows the clock to have quiet a few options such as:

  • 24h time format
  • auto sync time via DCF77 reciever.
  • anti poisoning mode (slot machine + counter)
  • night mode configurable for each day of the week (overrideable with a button for a definable time span)
  • time display (pretty obvious since it’s a clock ^^)
  • temperature display
  • date display
  • humidity display
  • pressure display
  • configurable through serial commands
  • “loop through” digit transition or no transistion configurable
  • operating counter for the nixie tubes, so you know how long they were burning until now.


  • clean up sketch
  • make more stuff configurable
  • build case for the clock
  • make a video of the features and post it here

You need your own website to show your projects :stuck_out_tongue:
Keep on glowing 8)

thank you.

i might open some blog to give more detailed descriptions once i’m done.
The attached picture shows the case that i planned.

we’ll see how it looks painted etc.


i finally got the bare casing done and i could assemble the components for the first time.
Here’s a picture of the clock so far.
It’s still missing the symbol tube, because there are some screws left i need to shorten first.

Here is my Nixie Clock for I2C within schematic, PCB and software GitHub - industral/nixie-clock: I2C Nixie Clock

Looking cool, keep it up!