Remote monitoring of water salinity by using side-polished fiber-optic U-shaped sensor

In this paper, a remote water salinity measurement system based on a simple and low-cost intensity based side-polished fiber-optic U-shaped sensor is presented. The sensor system utilizes a side-polished U-shaped configuration in order to maximize the sensitivity and expand the measurement range. The implemented salinity sensor is made of a multimode plastic optical fiber, and sensor determines the salinity by measuring the refractive index. Measurement resolution and uncertainty of proposed salinity sensor are 0.001 and 0.002, respectively. Wireless electronics based on ZigBee protocol is also implemented. Therefore, the sensor has the possibility of wireless measurements. The main advantages of this sensor are simplicity, lightness and flexibility. This sensor is also electrically safe and immune to electromagnetic interferences. In LabVIEW software package client and server applications are implemented, which gives a possibility of remote monitoring of water salinity over the internet.