Next I had to come up with some Arduino methods that would take a number and make a series of 0s and 1s out of it and then output those through the pins of my chip to the shift registers that are switching the Nixie digits on and off.
This is the Arduino sketch I made. Without a lot of help of my dear friend O. I wouldn’t have made it. If you want to have a look, you can download the sketch.
I then attached some LEDs instead of the first Nixie Tube so I could check the functionality without getting involved into that horrid 160V business just yet.