The robot's shoulder joint must allow rotation, flexion and extension.

Parts list for building the arms

• Rectangular moulding (pvc or wood)
• Hinge
• Windshield wiper motor
• Plywood
• Standoff
• Rubber bands, surgical tubing, or bungee cord

Shoulder

Elbow

The elbow joint is represented as hinge joints connecting the upper arm and the forearm. The joint allows for 180 degrees of flexion and extension and must prevent hyperextension.