I have a similar question, and this topic is less than a month old, so I'll stick it here.
I scrapped a couple DC motors from a dual cassette player and am trying to find a way to use them in place of permanently modifying a couple servos (snipping the mechanical stop) for the $50 robot. Is this possible? How much more difficult, electronics wise, would it be to do this and wire up an h-bridge? (I'm not that concerned about the coding aspect). Can anyone suggest a good h-bridge to buy?
Secondly, the DC motors are a little strange, I think. They have four wires coming out of them, labeled -, +, A and B. + and - are obvious, and the motor works fine if I just hook up those two to a power supply, but I have no idea what A and B are, or what I'd do as far as the PWM signal goes. Thanks!