Demonstrating How to Increase the Dexterity of Electrical Muscle Stimulation using Back of the Hand Actuation

We demonstrate a technique that allows an unprecedented level of dexterity in electrical muscle stimulation (EMS), i.e., it allows interactive EMS-based devices to flex the user's fingers independently of each other. EMS is a promising technique for force feedback because of its small form factor when compared to mechanical actuators. However, the current EMS approach to flexing the user's fingers (i.e., attaching electrodes to the base of the forearm, where finger muscles anchor) cannot flex one finger alone at the metacarpophalangeal (MCP) joint, they always induce unwanted actuation to adjacent fingers. To tackle the lack of dexterity, we propose a new electrode layout that places the electrodes on the back of the hand, where they stimulate the interossei/lumbricals muscles in the palm, which have never received attention with regards to EMS. We demonstrate the improved dexterity with a series of EMS-assisted music applications for playing piano, drums, and guitar.