The BlueCoder model RB20 is an optical incremental encoder that use the benefits of blue LED light. It is housed in a 2″ diameter x 1-3/4″ long enclosure that can be face mounted using three 6-32 x .25″ deep mounting holes on a 1.75″ diameter bolt circle. Short wavelength light, such as blue-light is less diffraction as it interacts with the slots of a code disk. The shorter wavelength light can be taken advantage of by using modern semiconductor processes with small shallow structures. Coupled with the long term temperature-stable modern blue LEDs the result are improved resolution, accuracy and stability.