This was an experiment to design and build a custom Nixie clock with as much of my own PCB as possible. It was a learning experience in high voltage circuitry design and in soldering some of the highest density IC packages up to that point. The clock was designed around Soviet IN-12A and IN-2 tubes that I installed into thru-hole sockets. My code ran on an Arduino development board, and it controlled the high voltage tube inputs using a series of HV5530 shift registers with clamped outputs. While the clock worked perfectly, the Taylor 1363 high-voltage power supply flyback boost converter emitted a headache-inducing audible whine. If I revisit this project, I would try a different power supply or design my own. While I was planning to use a bare ATmega chip on the final board instead of the Arduino dev board, I would instead switch to an ESP32 module that is much more flexible and includes integrated WiFi for network time sync.