A switch is a simple device with two states - on and off - like a light switch.
Many people with severe physical or cognitive impairment use one or more switches to access computers and other devices.
A switch is an assistive technology device that replaces the need to use a computer keyboard or a mouse. It may allow users to control a computer, power wheelchair, video game console, tablet, smartphone, toy, and a variety of other electronic devices.
Switch access is a way to interact with a computer or mobile device, AAC device, toys and environmental controls using a switch. Switches can access computers, mobile devices, toys and environmental activities of daily living. A switch user navigating a website would have an onscreen keyboard that would include buttons for common browser actions like Back, Home, Bookmarks.
It would also include a mouse emulator. Different techniques of mouse emulation are used, some as simple as four arrows and a button for click, right click and double click.
Other more effective approaches are horizontal/vertical scanning and Radar scanning. A person who may only have one or two reliable physical movements may be able to use switches if the switches are placed in the correct place.
Switches come in an extensive range of sizes, can be placed almost anywhere, and accommodate most types of movement. The largest group of switches is for limb or head operation. These include simple lever or pressure switches that can be used with a single movement of any part of the body.
Grip and thumb switches, pneumatic pressure switches, tilt or posture switches, touch and proximity switches and even ‘wobble’ sticks also exist.