Complete File Update 7/26/19
Hands, Fingers and Whipple update 6/30/19
Cleaned and updated files for hand, forearm and gauntlet 3/21/19.
This an analog prosthetic arm device in a digital world. Instead of a myosensor, Arduino, motor controller, and individual finger motors, it uses one linear actuator (geared for both torque and speed at 63:1) closing four fingers toward a fixed thumb. It is actuated by a simple DPDT on-off-on switch placed on the body side of the forearm. The switch position determines open/hold/close commands. Simplicity allows long battery life (rechargeable via an external port) and easy operation. The total cost currently is appx. $125 per unit.
There are only 9 printed parts per complete arm (palm, 4 fingers, forearm, whippletree, palm cover and outer cover). Other hardware is minimal which means that assembly is quite straight forward as well. Not necessarily easy, but no more complex than a typical Phoenix hand.
PolyMax PLA or PETG
These parts require accurate printing for best results. You should know your own machine and materials settings as well as preferred strengths (walls and infill). The forearm needs inner supports and the fingers print best upon a raft. Everything else is pretty straight forward.