Design Overview

This solution relies on a modular voltage divider approach combined with a voltage gating system. For the voltage divider, a low value of 50Ω is selected for the known resistor to minimize the voltage sent to the electrodes. Two adjacent sensors are oppositely powered to create the measured “unknown resistor.” Each pair of sensors are sequentially powered by utilizing Relay8 and Arduino Mega 2560 boards together. The Relay8 is powered via Arduino, and each channel acts as a switch that supplies negative power (i.e. ground) to the associated sensor. The positive power is directly supplied by the Arduino digital output. This efficient polarity switching maximizes the utility of each sensor and enables easy expansion.