Developing a Low-Cost Salinity Sensor Using Locally Sourced Materials

We report the design and construction of a locally constructed hydro-meteorological sensor for surface and underwater vehicles. This salinity sensor consists of four electronics units: the power, input (sensor), gain (amplifies the output signal), and output units. Each unit/block utilizes various low-power integrated circuits. The calibration equation of the salinity sensor was 1055.6exp -1.062 ml/mg/volt (correlation coefficient r = 0.9897). The performance and the coefficient of efficiency of the constructed sensor were compared with a standard sensor, showing the Mean Bias Error (MBE), Root Mean Square Error, and Standard Deviation of -0.5535, 1.3825, and 3.4839 ml/mg, the error margins were relatively small, indicating an excellent performance by the sensor. However, the negative MBE suggests a slight underestimation of the standard. Conclusively, the sensor is efficient in hydro-meteorological studies, capable of monitoring solution conductivity and measuring salinity (and total dissolved salt) in the ocean or brackish water.