A Flexible Capacitive Pressure Sensor for Wearable Respiration Monitoring System

This paper presents the design, fabrication, and characterization of a wearable capacitive pressure sensor for respiration-monitoring systems. For the dielectric layer of the proposed capacitive sensor, Porous Ecoflex with a porosity of ~36% was prepared from a manually made sugar cube via a simple melting process. A polydimethylsiloxane-based silver nanowire and carbon fibers thin films were used for the sensor electrodes. The fabricated flexible pressure sensor exhibited a high sensitivity of 0.161 kPa ^-1 for low pressure regime (<;10 kPa), a wide working pressure range of <;200 kPa, and a high durability over 6000 cycles. Since the proposed sensor is flexible and resizable, it can be integrated into clothes and easily placed at any location of the human body. Finally, the practicality of the sensor was successfully demonstrated by integrating the sensor into a waist belt to monitor the real-time respiration signal of the human being. The finding is highly useful to monitor respiration signal for the detection of diseases, such as sleep apnea, asthma, and others.