As a big enthusiast of glowing neon, I had to do something with the INS-1 (ИНC-1) tubes. Disclaimer: this project is inefficient in many aspects, fortunately plenty of time was available during the 2020 lock-down.
Fortunately, these single dot tubes are still easy to find in large quantity and rather cheap. Made by Gazotron, it seems they buildup a large stock at that time. The INS-1 has the advantage to be small and produce a nice dot due to the lens-style front. Plus its striking voltage is maximum 100V, lower than regular Nixies.
At first I imagined 5×7 dot character modules, such as the TIL305, but bigger. While playing and trying to make a tiny and simple 5V to 100V step-up power supply, I realized how simple it can be. Here we just need to reach the striking voltage and only 0.5mA. As there is yet non uniformity in brightness between tubes, no strong voltage accuracy is needed. Without the signal generator, it is a diode and a coil, shorted to ground with a transistor at high frequency.
Then comes the idea to mimic the popular serial cascading LEDs, such as the WS2812 or SK6812, the so called Adafruit ‘NeoPixel’.