[sdiy] motors (was Embedded micros)

[Tavys Ashcroft]

>Actually, I've been toying with a "mechanical" module the last few days.  I
>have a motor from an old Laser Disc Player that conveniently works as a DC
>generator.  It has a 3.5" diameter wheel attached to the top that I'm
>planning to weight with lead-free solder for a little more inertia.

I've been wanting to do something like this for a while now.  Anybody 
know if there's an easy way to tell if a particular DC motor will 
also work as a generator?  How about AC motors?  And I mean besides 
using a voltmeter (like if I'm rummaging through trash or in a 
surplus or junk store).  Is there any particular kind of motor which 
does/does not function both ways?

I haven't messed much with DC ones, but I know a lot of the AC motors 
I've tried will not generate.  I wanted to take an old turntable of 
mine and mount a bunch of AC motors on it so the turntable would turn 
their shafts.  By varying the turning speed of the turntable and 
position of the motors, I could get them to emit tones in and out of 
harmony with each other.  I think it would make a nice sine wave 
generator.  Is this feasable with any existing AC motors?

-Tavys