Fundamental research on human interface devices for physically handicapped persons

The mouse for a personal computer is now replacing the keyboard for computer input devices, due to it's ease of use and the progress of operation systems. A mouse is easy for a nondisabled person to operate, however not so easy for a handicapped person. In particular, a cerebral paralyzed person and a proximal spine injured person often have much difficulty in dealing with a mouse or can't use it at all. However, a person with a C4 injured spinal nerve is able to bend, stretch and rotate his neck and also able to raise his shoulders because the functions of his sternodeidomastoid and trapezius muscles remain. For those people, the authors have developed an input system using neck and shoulder motions instead of manual input by a mouse. In this study, two kinds of devices using limit switches and linear potentiometers were developed and both of the results were compared. As operability has to be improved, practical usefulness for the handicapped person was confirmed. Finally, the feasibility of such systems being used for the driving wheel-chairs was examined.