Switchmatris

Switchmatris, or switch matrix, is a configuration of switches arranged in a grid of rows and columns that enables detection or routing of multiple signals using a limited number of control lines. In a typical switchmatris, each switch sits at the intersection of a row and a column and closes a connection between those lines when activated.

Operation commonly relies on scanning. A controller sequentially energizes one or more rows (or columns) and reads the state of the corresponding columns (or rows). When a switch closes, its column is observed as active, allowing the controller to determine which switches are pressed or closed. Diodes are often added at each switch to prevent ghosting and ensure reliable multi-switch detection, especially in keyboards or control panels.

Applications of switchmatris span several domains. In keyboards, a matrix reduces wiring while enabling many keys to be scanned with a limited number of I/O lines. In telecommunications and test equipment, switchmatris arrangements route analog or digital signals between inputs and outputs. Crosspoint switches and more complex active matrices are used for higher-density routing and switching in audio, video, and data systems.

Common components and variants include passive switch matrices, diode-augmented matrices for better rollover, and active crosspoint or multiplexed matrices that use transistors or solid-state switches to control signal paths. Advantages of switchmatris include reduced cable complexity, scalable expansion, and lower I/O requirements. Limitations involve ghosting and masking effects without diodes, debounce and switch wear in mechanical implementations, and the need for adequate scan speed to meet responsiveness requirements.

See also: crossbar switch, crosspoint switch, keyboard matrix, debouncing.