Flexible pressure sensor with a tunable pressure-detecting range for various human motions

Abstract

Various human motions yield stimuli from low-pressure (0–10 kPa) to high-pressure level (100–300 kPa). However, previous flexible pressure sensors are unable to detect various human motions from low to high-pressure stimuli, thus are unfavorable for the facile and integrated design of sensing system. Herein a novel flexible pressure sensor with a tunable and large pressure-detecting range is produced by simply infusing magnetic carboxyl iron particle (CIP)/silicone resin into carbon sponge (CS). Attributed to the magnetorheological effect, the upper pressure-detecting limit of the CS/CIP/silicone sensor in a frequency of 0.01–5 Hz is significantly increased from 180 to 330 kPa in the presence of magnetic field, while a lower pressure-detecting limit of 70 Pa is obtained in the absence of magnetic field, thus covering the whole pressure-detecting range for various human activities. The CS/CIP/silicone sensor in monitoring various human motions with low to high-pressure stimuli is demonstrated by recording breathing, arm movement, walking, lifting and grasping, consecutively. Characterized by high flexibility, low cost and easy manufacturing, the current strategy is highly provoking for the development of pressure sensors adapted to human motions of different pressure levels in a wide range.