Design and Evaluation of a Mobile Sensing Platform for Water Conductivity

Electrical conductivity (EC) is one of the many water quality parameters that provides an indication of total ionic contaminants in water. This is traditionally measured with either lab-based equipment or battery-powered portable meters. These tools are expensive and require expertise to use, hindering their widespread adoption. We aim to address this challenge based on a custom-made electrode and processing unit that can be plugged into a smartphone via the USB port. In this paper, we present the design, development and evaluation of our mobile sensing system that is low cost (< 35 USD), easy-to-use (SUS score of 89.3) and accurate. Our initial testing suggests that the sensor is able to measure EC with < 3% root mean squared percentage error compared to a lab-based instrument. We believe our approach will empower a large group of people to contribute to water quality measurements.