Hobby Servo Tutorial
Servo motors are an easy way to add motion to your electronics projects. Originally used in remote-controlled cars and airplanes, they now crop up in all sorts of other applications. They’re useful because you can instruct these small motors how far to turn, and they do it for you.
A typical hobby servo
You ordinary, small DC motor has two hookup wires and simply turns continuously when power is applied. If you want it to spin in the opposite direction, you reverse the power. If you want to know how far it has turned, you’ll need to devise a way to measure that.
DC motor (left) and hobby servo
In contrast, you instruct a servomotor where to turn using a command protocol. The servo has three wires – power and ground, plus a third wire, to carry those commands.