For the last year and a half, designers Richard Van As and Ivan Owen have collaborated remotely on a reasonably priced prosthesis to assist people with missing fingers. Commercially available prosthetics exist, but can run $10,000 per digit or more for externally powered designs. The fruit of Van As and Owen's labors is now posted on Thingaverse, an online repository of downloadable open-source files that can be used to build designs with 3D printers, lasercutters, CNC, and more.
Billed the Robohand, Van As and Owen's prosthesis is a simple cable-operated assembly of 3D-printed linkages, bolts, cords, bungees, and rubber finger cots from the "Sorting Aid" section of any OfficeMax. In short, the mechanical design's cables — which travel wrist cuff to fingertips — trace a more curved arch during wrist or finger-stub curls. Therefore, the prosthesis fingers bend to grasp objects when the wearer flexes inward.
Several versions, including one built for a South-African tyke, are already in use. Watch little Liam master his prosthesis with heartwarming tenacity.