Chapter 1: What is a Switch?
A switch is an assistive technology device that provides a simple binary input: ON or OFF. Unlike a keyboard with many keys or a mouse with X/Y coordinates, a switch is the simplest possible input mechanism.
Why Switches Matter
For people with severe physical disabilities, a switch may be the only reliable voluntary movement they can perform. Scanning turns this single binary input into full access.
Real-World Examples
- AAC devices for communication
- Environmental controls (lights, TV, bed)
- Computer access (typing, browsing, coding)
Physical Switch Types
- Button Switches — Large or small buttons activated with any body part
- Joystick Switches — Directional switches activated by tilting
- Pressure Pads — Activated by leaning or pressing
- Puff/Sip Switches — Controlled by breath through a tube
- Muscle Sensors — Detect muscle contraction (e.g., eyebrow raise)
- Beam Switches — Broken by hand movement through infrared beam
Key Insight: For people with severe physical disabilities, a switch may be the ONLY reliable voluntary movement they can perform. Scanning transforms this single binary input into full access to technology.