Servo Motors

Hobby servos, such as those found in remote-controlled vehicles, are essentially DC motors with a gear box and control circuitry already built-in. In order to use a servo as a drive motor it must be modified for continuous rotation (you can find information about this on the Internet). The result, however, is a small and strong motor that is good for driving small robots. Another advantage is that these motors come with several attachments that will aid in mounting a wheel. If you decide to use servos, buy a good quality motor with ball bearings so that it will support the weight of your robot without breaking down.

Servos have three connections: +5 volts, ground, and signal. The signal is a pulse between 1 and 2 milliseconds long, at a rate of about 50 pulses per second. By controlling the width of the pulses to the servo, the microcontroller will determine whether the wheel spins forward or backward and how fast it spins.

Another option is to remove all of the control circuits within the servo and to use it as a regular gearhead motor. This option is still cheaper than buying most gearhead motors and you still have the advantage of the wheel attachments.

 

Summary

Because of the gear ratio, mice built around servo motors will not be very fast. But if you want an easy way to mount a motor and wheels, then a servo might be the way to go.