An IoT Device for Determining the Level of Chlorine Present in Water, Based on Electrochemical Reactions

This work describes the design and construction of an IoT device to determine the level of free residual chlorine present in drinking water. The device measures the level of free residual chlorine through the correlation of the signals from three sensors (ORP, pH and temperature), the signals obtained by these sensors are processed and stored in the device, later this information is taken to the cloud through a mobile phone network. The work begins with the characterization of the response of the electrical signal of the ORP and pH sensors to contact with water with different concentrations of chlorine and different temperatures. The design of the circuit for amplification and filtering of the electrical signals obtained by the ORP and pH sensors is described, as well as the design of the digital and communication circuit, and the printed circuit, considering the immunity to possible electromagnetic interference. An analysis of the operating limits of the device is carried out by performing contrast tests with conventional measurement systems. The designed device is part of the research project “Automatic telemonitoring system of the level of chlorine present in drinking water in treatment plants belonging to small rural communities located in Ecuadorian territory”, carried out by the GIHP4C research group of the Salesian Polytechnic University.