[robzyb]

> It has run for years and years without stopping, charging or winding.

A small point of note - it has been wound. But not by hand. It has a rotor (i.e. weight) in it that spins when you move, and this winds the watch.

http://i.imgur.com/VWvlDgH.jpg

> I wonder if something similar would suffice for energy needs of a device like this with no screen to power?

When I looked into it this was not possible. But of course, now that I've said that, someone's going to figure out how to do it.

I think that the trick would be customized silicon so it would be as lower power as possible. You'd also want to use super-low-power wireless technology to link it to your phone, and I think that the speed would be the tradeoff.