Hardware

Limit Switch

A limit switch is an electromechanical or contactless sensor that triggers when a moving axis reaches a defined position, used to bound travel and to establish a repeatable reference during homing. Mechanical lever, optical interrupter, and Hall-effect variants are common. On robots and CNC-style axes, limit switches provide hard end-of-travel protection independent of software and let incremental-encoder systems recover absolute position after power-up.

Why it matters for physical AI

Cheap, deterministic hardware interlocks remain a bedrock safety layer beneath learned controllers, guaranteeing that policy errors or estimator faults cannot drive an axis past its mechanical limits.