Thumb robotics.

A set of students in Singapore have developed an aluminum gadget. It acts as a substitute for a missing thumb without any batteries. Mimic, is a small, lightweight device that traps on back of the hand and wraps around index finger to hold a movable metal thumb. It moves whenever the forefinger moves. With 2 small pulleys and a fine steel cable the movements of the metal thumb were synchronized forefinger. It allows a person to write and to pick up small objects. But each piece needs to be custom made to fit the wearer’s hand.