A method and apparatus for use in controlling a device or process. The firststep of the method involves attaching a detector (20) adapted to detectmechanical vibrations to a person's head (22). A second step involvesdetecting mechanical vibrations elicited by sudden contact of upper teeth (24)and lower teeth (26). A third step involves using the mechanical vibrations totrigger a signal to control operation of a device or process (36, 80, 82, 84,86, 88, 90).