A Low-Cost Virtual Sensor for Underwater pH Monitoring in Coastal Waters

In coastal water monitoring, abrupt pH changes might indicate different pollution sources. Existing sensors for monitoring in waters at low cost are mainly based on a glass membrane and reference electrode. Virtual elements capable of measuring certain parameters data from other or variables. The aim this paper is to propose the use virtual sensor physical effects H+ electromagnetic field generated by an inductor. Double inductors two solenoids 40 80 spires used as sensing elements. Samples with 4 11 used, effect temperature evaluated using samples 10 °C. induced voltage delay signal measured powering frequencies 100 500 kHz. These delay, voltage, frequency, included probabilistic neural network classify these according pH. results accuracy 11. A second analysis, excluding data, offered correctly classified cases 88.9%. system can achieve considerable high (87.5%) gathered single 246 248 predicted versus observed correlated linear model characterized R2 0.69, which similar ones sensors.