Let's Make Robots!

Clock movement as lightweight gearbox

Anyone ever try to modify one of those cheap battery operated analog clock mechanisms as gear train?  It would make an extremely lightweight gearbox for small bot.

Some quick research on the web provided some insight on how these things work:

http://www.explainthatstuff.com/quartzclockwatch.html

Then I tore open a broken clockwork that's been sitting around for ages. OK, I tore it open first, then did the research. ; j

The result? I was able to disassemble the mechanism, remove the coil, crystal and battery contacts, drill one small hole in the case, and I had a working lightweight gearbox. I inserted the cut off end of an electric toothbrush to propel the driven gear.

The exterior thumb wheel (originally used for settting the time) turned a bit slowly, but that was with a 3v motor. I tried stopping the thumb wheel with moderate pressure from my finger, and I couldn't do it.

I did notice the clock hands (OK, just one hand. This is from a broken clock, remember?) didn't move with the motor. It turns when I move the thumb wheel by hand, so I'm not sure what's going on there. However, I think I proved to myself this is a workable approach.

I took video, which I will post as soon as my camera battery recharges. 

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Here's video of my clock movement modification.

http://www.youtube.com/watch?v=GP_4oVzAb2U&feature=player_embedded