A few years ago i discovered Nixies and bought myself a 4 digit Nixie clock, it didn't take long before i also wanted to make a wristwatch with a Nixie.
After a long time browsing the internet for a simple clock design i came up with this page. This is a very simple design and a drives the Nixie directly from the main without the hassle of a complicated power supply, it also uses probably the most popular PIC there is, the PIC16F628A. I decided to build this clock as a practice run and ended up using most of the design and controls in the final product.
Step 1: The Components
The tube i've used is a IN-2, The high voltage supply I bought from eBay since it was already a very small size and i didn't think i could easily make a smaller one on my own. It converts 3-28 VDC to 180 VDC. the power comes from 2 LiPo battery's that can be charged with a built in USB charger bought from Adafruit.
To show the time you have to touch the aluminum part of the case. this functions as a big touch sensor controlled by a TS02N chip I had lying around.
As I tried to keep the clock as small as possible, almost all the parts used are SMD. The High voltage transisors used are BFN24.
The case is made from 2 separate pieces that fit together; a scrap piece of plastic that i drilled out and milled and a aluminum tube i shaped on the lathe and mill. A piece of clear acrylic shows and protects the IN-2 tube. The strap i've bought online.
Step 2: The Controls
In the first movie you can see how the time is set, the second one shows the finished watch (the time is 22:59)