PossessedHand, being developed jointly by the University of Tokyo, Japan, and Sony Computer Science Laboratories, electrically stimulates the muscles in the forearm that move your fingers.
A belt worn around that part of the subject’s arm contains 28 electrode pads that flex the joints between the three bones of each finger and the two bones of the thumb, and provide two wrist movements. Users were able to sense the movement of their hands that this produced, even with their eyes closed.
Having successfully hijacked a hand, the researchers tried to teach it how to play the koto, a traditional Japanese stringed instrument. Koto players wear different picks on three fingers, but pluck the strings with all five fingertips, so each finger produces a distinctive sound.
PossessedHand does not generate enough force to pluck the koto strings, but it could help novice players by teaching them the correct finger movements.