Abstract: An optical potentiometer comprised of a specialized circuit board and a movable reflector device capable of traveling left and right stably on the specialized circuit board. The movable reflector device has a reflecting mirror suitably disposed in alignment with a light wave transmitter on the specialized circuit board that enables the reflection of light waves emitted by the light wave transmitter to the area of a point detecting light wave receiver. The light waves are thereafter amplified and filtered to predetermined settings by an amplifier and a filter on the specialized circuit board and, furthermore, stored in an memory bank as reference values that facilitate a controller to calculate the actual distance traveled by the movable reflector device through a comparison of the predetermined settings with the standard excursion range in the controller, which then drives an digital variable resistor to output a resistance value that corresponds to the distance traveled.