Recently, I visited an Anime and Cosplay convention. Although I rarely watch any Anime, I do enjoy crafting costumes and in particular steampunk-esque things. Of course, I could not let the opportunity pass. So I decided to dress up as a steampunk gentleman.

Nixie Tubes

I always wanted to build something with Nixie tubes. Those are cathode vacuum tubes, which include multiple cathodes in the shape of digits or letters. Essentially, those devices were used to display numbers before the advent of LCD technology – especially in soviet russia.

I got my nixie tubes (IN-12b) from a russian seller on ebay, who apparently sells old stock. Sadly, those tubes are not made anymore nowadays – or only by hand at request for a lot of money. I also bought some driver ICs from the same era, but there are modern equivalents available. Additionally, I picked up a 180V power supply board from a chinese seller.

After some initial testing, the tubes lay unused in a box for almost a year, until I decided they were the perfect match for my steampunk project. I wanted to build something truly awsome. So, naturally, I checked the internet for some inspiration.

A nice arm armour / costume piece. Image credit: “Lost Wax” on YouTube, see https://www.youtube.com/watch?v=sPClbobyLcA

A nixie clock from nixiediy.com, Image credit: NixieDIY.com, see https://www.nixiediy.com/product/in-16-nixie-tube-clock-kit/?v=3a52f3c22ed6

The Idea

In the end I settled on a “Nixie-Wristwatch”. This device would have to be stapped to my upper and lower arm, and display the time or something using Nixie tubes.

My CAD model. The upper piece houses the battery and electronics, the lower one the tubes. Both are connected using two strands of wires.

Leather Patches

To strap the device to my arm, I wanted to mount it to some leather, and secure that using rivets and straps – in true victorian fashion. Although I have quite some experience at several crafts, sewing leather is definitly not my strongest suit (pun intended). Luckily, my girlfried is skilled at sewing and kindly agreed to fabricate the leather parts, saving my project – and probably my fingers. After sourcing some old leather and straps from the basement, we could begin.

All cut, sewn and riveted. That was a lot of work. Thanks again 🙂

The staps fit snugly around my arm.

Final adjustments made.

Structural Parts

All “fake brass” parts I 3D-printed, sanded, sealed and painted to look like metal. All parts were printed in several layers (see CAD model), to allow for wiring etc. to be hidden. The layers were then assembled using screws.

The raw prints. Still pretty rough.

Lower piece test fit. Note the already mounted tubes.

Electronics

To mount the Nixie tubes in their pockets, I glued some tube sockets pins into the bottom of the 3D-printed part. Then I ran a lot of wires to the top piece, where the battery and control logic (Arduino) are housed.

Arduino (left), driver board (middle), buck converter and power supply (right)

These were the parts I used:

IN-12b Nixie Tube * 6 (https://www.ebay.de/itm/281664135380) ~16€

K155ID1 driver IC * 6 (https://www.ebay.de/itm/231527012664) ~10€

74HC595N shift register IC * 3 (https://www.reichelt.de/shift-register-8-bit-2-6-v-dil-16-sn-74hc595n-tex-p217325.html) ~3€

Nixie Tube Socket Pins * a lot (https://www.ebay.de/itm/251173320805) ~10€

Power supply board (https://www.ebay.de/itm/111822987299) ~10€

Arduino Nano (https://store.arduino.cc/arduino-nano) ~5€ Clone

Buck DC-DC Converter (https://www.amazon.de/gp/product/B01GJ0SC2C) ~3€

Each Nixie tube requires ten high voltage inputs. Unfortunately, the Arduino does not have sixty high-voltage pins. So I used thee shift registers which operate on five volts to power the six driver ICs, which can handle the high voltage. This works because each shift register outputs one byte of data, and each driver chip requires only a nibble of data, so one register powers two drivers. The registers are then daisy-chained together, such that the Arduino controls them as one big three-byte register.

Part of the circuit. Note that two tubes are controlled by one two driver ICs, which in turn are controlled by one shift register, which in turn is driven by the Arduino.

After wiring everything up, I wrote a small program for the Arduino, which picked random numbers in 2-sections and then counted up, and also did some more stuff that just “looked cool”. Because I did not have the time to add an RTC module, the watch does in fact not display the current time. However that could be an idea for the future.

Also, I made some kickass plugs to connect the lower and upper piece.

That’s a lot of wires.

Those plugs tho.

Finishing Up

I gave the electronics a coat of black paint, and built a cage from copper pipe so they wont be damaged.

The upper piece, complete with battery pack and electronics.

The lower part, with illuminated tubes.

The full assembly.

Now, all that was left to do, was to wear it! Excuse the low image resolution, but I don’t want to share too many pictures of myself – so I cropped the important parts out.

Side view.

Front view.

This project was great. Even though it took a lot of time and effort, I think it was worth it. We had a blast at the convention and my armpiece cought a lot of looks and interest 🙂

Stay tuned for more steampunk projects, as I am planning on extending my costume.

Downloads

Here you can download the CAD model from the Fusion 360 cloud, and also the schematics as PDF: