# SOLVED:Hobby Motors Vs. Continuous rotation servos

What is the difference between one of these:

And a continuous rotation servo like this:

I know a normal servo is controlled by telling it what degree to go to but how do you do that with a continuous rotation servo? Can you make a continuous rotation servo jump to positions? Thanks!

but how do you do that with a continuous rotation servo? Can you make a continuous rotation servo jump to positions?

You canâ€™t and no.

The only real advantage of a modded servo is a compact gearbox, and a small degree of speed and direction control via a single control line.

No, a servo modified for continuous rotation becomes a bidirectional variable speed motor, you cannot command it to go to a specific angle and stop, there is no position feedback available.

The main difference in a modified servo is it still requires one to use servo library PPM commands to tell it to be still or to rotate in one direction or the other and at how fast to turn. A standard DC motor uses PWM analog write commands to tell it how fast to turn or stop and requires extra external circuitry to make it bidirectional rotation if desired (H-bridge drive).

Lefty

(both of the previous replies were posted while I was composing this but here it is anyway)

A continuous rotation (CR) servo has a small motor with a gearbox and controller board that accepts pulses to command the motor speed and direction. Commands of (around) 90 degrees usually stops a CR servo. 0 degrees provides full power in one direction and 180 degrees is full power in the other.

The motor in your picture would need to be connected to an H-Bridge if you want to control speed and direction.

A google search for H-bridge and continuous rotation servo should provide more information if you want .

Have fun!

Thank you everybody. You have all been a great help. So if I were to make a simple robot that bumps into walls, backs up, and turns, like the Arduino Rumble Robot (search it on youtube) I would use continuous rotation with an H bridge for the wheels. Right?

You could use continuous rotation servos or motors with an H-Bridge. The servos are easier but they have limited torque compared to some of the hefter motors. I am sure you can find plenty of examples on the web of both approaches so you can judge which would be more appropriate for the size, weight and performance of robot you want to make.

Have fun!

Thanks! My questions are solved