Design and perceptibility of a wearable haptic device using low-frequency stimulations on the forearm

Upper-limb prosthetics lack the afferent feedback necessary for an amputee to know where the prosthesis is in relation to the rest of the body. To address this problem, haptic feedback devices have been explored. In this work, a prototype device, consisting of five modules, has been developed which has the capability to create touch stimulations on the forearm. Each module of the device is light-weight and compact (7.6 g, 25 × 25 × 11.5 mm) consisting of a wire coil spooled on a non-ferrous core and a neodymium magnet housed in a plastic component which can connect to the other components with Velcro. When a coil is energized, the magnet pushes against the skin creating tactile stimulation normal to the skin. In an experiment with five participants, 20 trials of individual stimulations and 20 trials of pattern stimulations were performed on each participant. Participants reported 86% accuracy in correctly locating a single stimulus and 97% accuracy in distinguishing between the four stimulation patterns.