Arduino Controlling LEGO Power Functions Servo Motor
A little experiment in controlling the LEGO Technic "Power functions" servo motor (item 88004) using an Arduino. This will totally void your warranty, so do it at your own risk... Also, remember that this motor works on 9V while the Arduino's on 5V.
This servo has 15 fixed positions overall (center, seven to the left and seven to the right). A PWM signal of 0%-100% on the C1 wire controls movement in one direction, while the same signal on the C2 wire controls the other direction.