Switch Keyboard

A switch keyboard is a virtual keyboard interface designed for people with severe motor disabilities who cannot use a standard keyboard or pointing device. It works through a scanning mechanism: a cursor automatically moves across rows and columns of the keyboard, and the user triggers a binary switch at the right moment to select first a row and then an individual key. The switch can be activated by any reliable voluntary movement the user can produce — an eye blink, a puff of air (sip-and-puff), a head movement, or a muscle twitch. Because typing requires multiple switch activations per character, speed is extremely slow (often measured in characters per minute), making the layout and scanning pattern of the keyboard critical for efficiency. Switch keyboards are a key AAC tool for people with conditions like locked-in syndrome, severe cerebral palsy, or advanced ALS.