An Electret‐Powered Skin‐Attachable Auditory Sensor that Functions in Harsh Acoustic Environments

Abstract

Abstract Auditory sensors have shortcomings with respect to not only personalization with wearability and portability but also detecting a human voice clearly in a noisy environment or when a mask covers the mouth. In this work, an electret‐powered and hole‐patterned polymer diaphragm is exploited into a skin‐attachable auditory sensor. The optimized charged electret diaphragm induces a voltage bias of >400 V against the counter electrode, which reduces the necessity of a bulky power source and enables the capacitive sensor to show high sensitivity (2.2 V Pa −1 ) with incorporation of an elastomer nanodroplet seismic mass. The sophisticated capacitive structure with low mechanical damping enables a flat frequency response (80–3000 Hz) and good linearity (50–80 dB SPL ). The hole‐patterned electret diaphragms help the skin‐attachable sensor detect only neck‐skin vibration rather than dynamic air pressure, enabling a person's voice to be detected in a harsh acoustic environment. The sensor operates reliably even in the presence of surrounding noise and when the user is wearing a gas mask. Therefore, the sensor shows strong potential of a communication tool for disaster response and quarantine activities, and of diagnosis tool for vocal healthcare applications such as cough monitoring and voice dosimetry.