I want to implement an steering mechanism for my battle bot. I'm thinking of using rack and pinion arrangement for it rather than a servo steering mechanism. For the rack and pinion arrangement, a motor is needed for attaching it to the pinion. I've seen in small rc cars, But i exactly dont know what type of a motor is it? If it is normal dc motor, how to use it to give just few rotations like 5 or 6 rotations?