This invention can be embodied in a wearable device or system for measuring finger motion and recognizing hand gestures comprising a distal loop which encircles the intermediate phalanx of a finger, a proximal loop which encircles the proximal phalanx of the finger, a joint-spanning strip which connects these two loops, and a bend sensor which is part of the joint-spanning strip. Changes in energy transmitted through, or generated by, the bend sensor are used to measure the motion and/or configuration of the proximal interphalangeal joint.