Mini Beta: A robot arm made with LEGO Mindstorms

This 2 DOF robot arm features a base that concentrates the three motors, this allows the superstructure to be compact, light, fast and precise. All the motion is transmitted mechanically to the joints, and perhaps the greatest highlight here is the use of two concentrical axles that go trough the turntable. The rotating superstucture consists of an arm and the smallest claw I could make. This configuration allows it to sort small objects (such as balls) quickly. If you build it, note that if you want the superstructure to rotate, all three motors must coordinate in order to keep the arm&height and the claw&position. This is achieved in the program provided below.