Robotic arms — the original robot

Before wheeled robots, before drones, before humanoids — there were robotic arms. The first industrial robot arm, Unimate, started working at a GM plant in 1961. Today you'll find them welding car frames, assembling iPhones, performing keyhole surgery (da Vinci surgical robot), and packing your Amazon parcels.

You're going to build a 3-DOF arm using three SG90 servo motors and an Arduino. It won't weld car frames — but it will pick up small objects and place them somewhere else, which is the exact same fundamental challenge.

DOF stands for Degrees of Freedom. Each joint adds one degree of freedom. Your arm has:

• Base — rotates the whole arm left and right (yaw)
• Shoulder — raises and lowers the upper arm (pitch)
• Elbow — bends the forearm (pitch)

3 joints. 3 DOF. 3 servos. Let's build it.