Low-Cost Multipoint Liquid-Level Sensor With Plastic Optical Fiber

A simple and low-cost discrete liquid-level measurement system is present in this letter. It consists of a group of plastic optical fiber segments, which are aligned coaxially and spaced equally. When the spacing between every two adjacent fiber segments is filled with liquid, the light power will be easier to couple from one segment to the next as compared with the situation that the fibers are exposed in air. Based on this point, we design this intensity-based sensor and investigate its working properties theoretically by using the ray-tracing method. The performance of this sensor is demonstrated in detail where different liquids are utilized as specimens.