Servos and how to power them

A servo is a small motor that turns to an exact angle, from 0° to 180°. It has three wires.

How the signal works

The Arduino sends a pulse 50 times a second. A 1 ms pulse means 0°, 1.5 ms means 90°, and 2 ms means 180°. The Servo library does this for you: myServo.write(90);

The most common mistake

One SG90 can pull more than half an amp when it starts moving. Four servos together can pull over 2 A, but the Nano 5V pin is meant for a few hundred mA. The board resets and the arm shakes.

Fix: power the servos from a separate 5V supply (3A for four servos), and connect its GND to the Arduino GND. This is called a common ground.

Check your build with the Servo power checker in Tools.