A High‐Fidelity Skin‐Attachable Acoustic Sensor for Realizing Auditory Electronic Skin

Abstract Wearable auditory sensors are critical in user‐friendly sound‐recognition systems for smart human–machine interaction and the Internet of Things. However, previously reported wearable sensors have limited sound‐sensing quality as a consequence of a poor frequency response and a narrow acoustic‐pressure range. Here, a skin‐attachable acoustic sensor is presented that has higher sensing accuracy in wider auditory field than human ears, with flat frequency response (15–10 000 Hz) and a good range of linearity (29–134 dB _SPL ) as well as high conformality to flexible surfaces and human skin. This high sound‐sensing quality is achieved by exploiting the low residual stress and high processability of polymer materials in a diaphragm structure designed using acousto‐mechano‐electric modeling. Thus, this acoustic sensor shows high acoustic fidelity by sensing human‐audible sounds, even loud sounds and low‐frequency sounds that human ears cannot detect without distorting them. The polymer‐based ultrasmall (<9 mm ² ) and thin sensor maintains sound‐detection quality on flexible substrates and in a wide temperature range (25 to 90 °C). The acoustic sensor shows a significant potential of auditory electronic skin, by recognizing voice successfully when the sensor attached on human skin is connected to a commercial mobile device running the latest artificial intelligence assistant.