Dekatron Clock #1 in action

Here's a quick video clip of my first Dekatron Clock, in an incomplete state. It's basically just showing a test pattern, but one advantage is that this pattern repeats every 2 seconds - thus allowing a short, smoothly looping movie. You'll need QuickTime to view it: I'm not sure of the minimum version required, but I think the necessary Cinepak codec has been around since version 1.5.

<A HREF="Dekatron1.mov">[Click to view/download movie - your browser doesn't seem to be capable of inline movies]</A>
Some differences between what is shown here and the final clock:

The front panel wasn't built at the time this movie was recorded. The panel is made of clear plastic, so the tubes are still fully visible.
The firmware for the clock isn't complete: what you see running here is just a test of three variations of a pendulum effect that I wanted to try. These and other options will be available for the bottom (seconds) tube in the finished clock. The top tube is simply spinning around, for lack of anything better to do with it during this test: the clock has no provision for turning off individual tubes, and it isn't good for a Dekatron tube to leave it sitting in one position for long periods of time. Yes, it is spinning at an uneven rate.
My old video camera has problems with small, intense light sources - the dots of light in the tubes are smaller and better defined than the movie shows. Also, the reflections of the room lights in the tubes aren't nearly this noticeable on the actual clock.
The movie was recorded at 30 frames per second, however the clock updates its display 120 times per second. Therefore, the movie doesn't capture every state of the tubes, especially the top one which is changing the fastest. This is only really noticeable if you single-step through the movie's frames. The top tube has 36 display positions (the others have 30), and a complete revolution involves all of those positions - skipping around isn't possible.

Contact

Any questions or comments about this page can be directed to Jason Harper.