The Opto Encoder Click Board™ is a linear incremental optical sensor/encoder Click Board™, which can be used for the movement or rotation encoding. Encoders of this type are widely used for many applications which involve precise detection of the position, speed, or rotational angle of an object. Rotary encoders are often used for various types of controllers on many different devices.
Whether it be a rotary encoded knob controller or a rotation encoder on a motor shaft, the principle is the same - it includes an optical sensor, just like the one found on the Opto Encoder Click Board™.