This arm uses turntables for the joints.  It uses motors with rotation sensors to measure the movement.
The turntables are powered through worm-gears.  The claw uses a worm gear powering 16 tooth gears.
Because of the way it closes it is not very good at picking up objects. Most of the wires are routed throught turntables, and are color coded.  I didn't make it to the programing stage, partially because of lack of a very good claw.