This BEAMbot is different in three ways.
1) It doesn't use a motor but the lens-positioning system for a CD-ROM drive,
2) It looks pretty pretty,
3) Errr... It doesn't work as it should. As in: not at all...
Quick and dirty, since it doesn't work, heh:
Two bigger and two smaller discarded electrolytic capacitors, glued together after I stripped them bare of the plastic casing, and copper legs from electrical wire (also stripped of the insulator, obviously.)
As I said, from a CD-ROM drive. basically it is a bunch of magnets, surrounded with fine copper-wire wound around it with a gap where you apply current, so it moves up or down. The purplish thingy I got from a toy, glued it on the system for a reason I completely forgot.
A basic, free formed solar engine with L.E.D. The rubber sleeve is again from a discarded CD-ROM drive, it was a shock mount. It is there because in full sunlight, the L.E.D. tends to otherwise oversaturate and stuff then doesn't work.
And it worked, honest, for one split second. I wired it on a breadboard, and the L.E.D. blinked, the lens mount twitched once and then it was dead.
So why didn't I troubleshoot it? Because it was dead, Jim. I obviously fried something I didn't use a solar-cell to power it but a regular battery, an accu, actually, and these pack a lot of oomph these days, so I figured I somehow burned its poor brain out. Desoldering the transistors showed that yeah, one was dead.
I didn't have a spare transitor lying handy (booh! hiss! revoking geek membership!) so the thing just lay there forlornly for quite some time. And I kind of forgot about it.
Then my girlfriend saw it and she thought it was cute, so I 'finished' it as a glorified stand-in-the-way-on-the-coffeetable
it looks kinda nice, but I don't feel very good about it, because it is just standing there, doing nothing.
Nice looking failure.