Servo motors

Servo motors (or "Hobby serovos") are small motors that can rotate in an arc to position or actuate a mechanism. They do not rotate continuously (unless modified to do so), but instead can be possitioned to a known angle under program control. The servo is not particularly strong or fast, but is very easy to use, and it provides a simple system that can reliably position a mechanical system without the need for additional sensors such as potentiometers or encoders.

Connections

A servo motor requires only three connections to the RoboRio: Power, Ground, and Signal. It is connected to a PWM channel, in the same way an older PWM-based motor controller would be. The power line gives the energy for the movement, and a PWM waveform on the signal line directs the servo to the angle it should move to. The duty cycle of the PWM signal indicates the angle of rotation, and to hold the servo still the RoboRio must keep sending the same PWM signal.

Uses

The servo can actuate a mechanism, such as releasing a spring-loaded device. Or it could be used to push an object, such as to nudge a ball into a lanuncher's spinning wheels.