Step 12: Done(?)
Well, it works now and looks very cool -- but the photos can't show what it really looks like in operation. I'll try to add some video clips..... Some of the chase patterns are really hypnotic. For example, at one point, as the wires spiral up, the lit wires shift downwards at about the same apparent speed, so that it looks like a single wire flashing through the whole range of colors while remaining motionless.
Watching the "drain" end of the tube is also interesting.... the angle of the wires decreases (with respect to the tube end) near the ends, so there is sort of a (difficult to describe) "trailing" effect as the glowing wires reach the end of the spinning tube. It might also be an optical illusion; I can't tell for sure.
The tube wobbles substantially while spinning up to speed, but then settles down to a tolerable level. I don't think I can eliminate all wobble.
One possible direction for future development would be to add a magnet to the motor and a magnetic pickup to the top support rod, so that I can time the sequencer changes to the rotation of the pipe. Any suggestions?
The sequencer itself could be improved by adding a serial port so that it could be programmed without having to remove the Basic Stamp from the board.....
There are a few quicktime videos attached that give some idea of how this looks.