Hemi is a therapeutic toy that motivates children with arm-hand motor disabilities to continue exercising at home. It consists of physical controllers and a digital platform with therapeutic games. By interacting with the controllers, kids can improve their hand motor skills while playing different digital games that facilitate the repetition of hand movements for therapeutic effect. The main component is a motion sensor ball. By attaching different handles and knobs to it and placing the ball into different cases, children can build different controllers to exercise various hand grips and hand movements.