Rabbit processor with rc servo

This is my first attempt at playing with motors. I am using an rc servo and want to be able to control its position and be able to read its current position and hence have a point of reference on the servo. A couple of questions i need help with:
The servo ordered is the Hitec HS-422.

  1. If the rabbit processor (connected to my pc via serial) has pwm ports available do i need a controller chip (motor driver chip). And what is the main purpose of a controller chip?

  2. To get feedback on the positioning of the servo can i simply use a potentiometer?


You’re mixing up regular dc motors and rc servos. RC servos have internal control electronics, and you only have to send them the correct signals to get them to move. However, you could still use a “controller chip” to generate the necessary pulses since controlling more than a few servos at a time gets very time-intensive for a primary microcontroller.

DC motors are entirely different (just one part of what’s in an RC servo), and you need a “motor driver chip” to provide the high current that the motor draws.

A potentiometer is an easy way to get position feedback.

For more information, you can take a look at our servo controller and motor controller manuals, and do some more searches online. There are many examples out there for controlling both RC servos and straight DC motors.

- Jan