Artificial arms have become far more advanced, common and cheaper over the last few years but the Handii Bionic Arm stands out both from a design and cost point of view. The arm called the Coyote ended up costing less that $300 by re-using parts from other items and by 3D printing.
The arm works by sensing EMG activity in the users upper arm and then transmitting that data wirelessly to a smartphone. The smartphone processes the data and then sends commands back to the arm as to how to move. This allows a minimum of processing power in the arm itself which keeps costs and battery usage to a minimum. In addition there are a number of pre-programmed grips and hand configurations that can be selected via a button on the arm or with the smartphone.
Each arm is 26custom-made to fit the user using mainly 3d printed structures