Co-Located Multimodal Sensing: A Next Generation Solution for Wearable Health

Abstract

A novel physiological sensor which combines electrical and mechanical modalities is introduced. The electrical component behaves as a standard electrode and detects changes in bioelectrical potential, whereas the mechanical component comprises an electret condenser microphone with a thin and light diaphragm, making it sensitive to local mechanical activity but immune to global body movements. A key feature of the proposed sensor is that the microphone is positioned directly on top of the electrode component (co-location). In conjunction with co-located electromechanical sensing, the ability of the electrode to flex allows for motion to be detected at the same location where it corrupts the electrical physiological response. Thus, the output of the mechanical sensor can be used to reject motion-induced artifacts in physiological signals, offering improved recording quality in wearable health applications. We also show that the co-located electrical and mechanical modalities provide derived information beyond unimodal sensing, such as pulse arrival time and breathing, thus enhancing the utility of the proposed device and highlighting its potential as a diagnostic tool.