Optical fuel gauging system is an optical sensor measuring level of fluid system which uses optical refraction principle.
In air, light coming out from illuminators goes back to receiver because of complete reflection of prism.
In liquid, the light passes the prism and does not reach to receiver.
Photocells including illuminator, receiver and prism are put vertically to generate signal depending on liquid level.
Thanks to the technology developed by Tamagawa it is possible to connect up to 10 sensors each other.