Nowadays most prosthetic hands cost dozens of thousands of USD. The OpenBionics initiative (www.openbionics.org) presents a new open-source design for highly functional prosthetic hands. The proposed hands cost less than 200$, weigh less than 300 gr and can be easily fabricated with off-the-shelf materials and rapid prototyping techniques (3D Printing).

A novel differential mechanism (based on the whiffletree) allows the user to block the motion of each finger independently and facilitates the execution of 144 different grasps with only 1 actuator. The design is based on parametric models of hand anthropometry studies, so it can easily be personalized to specific patients.