Arduino Controlled Robotic Arm... jk, It's a "hand". Designed and built a proof of concept robot arm prosthetic for fun.
I used stepper motors, and a custom designed robotic hand built with bicycle chain links, elastics and cord to get a similar range of motion as a human hand, It's a simple design we thought of in HighSchool and I finally got around to building it in my free time, there are no schematics since we designed it as kids :), It was a fun project and can be improved a lot since cybernetics/ bionic robots have come a long way now. It uses arduino as the brains of the project and can "Clutch" balls, and other objects mimicking natural human motion.