Nixie Tube Watch

Around 2017 a friend of mine that is a hardware engineer created a small wristwatch out of 7 segment minitron displays, and I thought it was incredibly cool. What makes them novel is that they are made from incredibly thin tungsten wires inside a tiny vacuum chamber, emitting light by being heated to between 3,100 to 5,400 degrees Fahrenheit.

Despite never having done hardware engineering beyond Arduino and other simple microcontroller project up till this point, I decided to try something similar, but with nixie tubes. Unlike minitron filament displays, nixie tubes are filled with neon gas and function identical to a neon display, but shrunk down to a much smaller scale. There were many challenges and new things I learned along the way; this was my first time ever using any CAD software for routing PCBs.

This design was heavily based on the high voltage power supply circuit created by David Forbes, with many smaller changes to work with a microcontroller of my choice. In the next photo you can see the blank back of the final PCB board design.

Here I am trying on the bare PCB after installing some custom lugs out of scrap metal and some cannibalized pogo pins to hold the strap's lugs in place.

This was my flashing setup. The In-Circuit Serial programmer output has jumper wires plugged into it, and the jumper wires jump to a ribbon cable (left) where each wire of the ribbon cable is soldered to an exposed section of pcb trace that deals with the ISCP functionality.

The back of the watch with programming lines still soldered on. I 3d printed a caseback to shield the components from my skin/sweat. If they directly touched my skin, it would be high enough voltage to shock me.

Here's the first test flashing of the MCU with some test code, I added power to it, and it worked first try!

Here's how the finished result looks on the wrist

And this is the final result!