Low Power Multimode Electrochemical Gas Sensor Array System for Wearable Health and Safety Monitoring

This paper presents an electrochemical gas sensor array system for health and safety monitoring. The system incorporates a custom room temperature ionic-liquid gas sensor array, a custom multimode electrochemical sensor readout board, and a commercial low power microcontroller board. Sensors for multiple gas targets were implemented in a miniaturized 2 x 2 array where each sensor consumes <3.2 mu W and occupies a sensing area volume of 350 mm(3). A novel resource-sharing circuit architecture tailored to the gas sensor array was utilized to significantly decrease power, cost, and size. The system supports multiple electrochemical measurement modes to provide orthogonal data to in-module sensor array algorithms for better prediction accuracy. The system achieves a resolution as high as 0.01 vol% in amperometry mode and 0.06 vol% in ac impedance mode for oxygen as an example target gas.