What is an optical encoder?

An optical encoder is an electromechanical device that uses a light source, light detectors and an optical grating to convert angular position or motion to an electrical signal.

What is an optical encoder

With optical encoders, a light source shines light onto or through a grating (usually a glass or plastic disk) which is marked so that the light passes through or is blocked. The optical detector(s) sense the light’s passage and generate a corresponding electrical pulse.

Strengths and weaknesses of an optical encoder

StrengthsWeaknesses
High resolution, high accuracy, widely availableDelicate, Susceptibly to foreign matter