Simplified Structural Textile Respiration Sensor Based on Capacitive Pressure Sensing Method

We propose a simplified structural textile capacitive respiration sensor (TCRS) for respiration monitoring system. The TCRS is fabricated with conductive textile and Polyester, and it has a simple layered architecture. We derive the respiration by the distance changes between two textile plates in the TCRS, which measures the force from the abdominal diameter changes with the respiratory movement. To evaluate the reliability of TCRS, both linearity test and comparison test were carried out. Three times of tensile experiment were performed to confirm the linearity of change in capacitance by the distance change. The result shows that the coefficient of determination (R-2) of proposed TCRS is 0.9933. For comparative study, 16 subjects were participating in the experiment. As a result, the proposed respiratory rate detection system using TCRS successfully measures respiration compared with nasal airflow detection (R = 0.9846, p < 0.001). In Bland-Altman analysis, the upper limit agreement is 0.5018 respirations per minute and lower limit of the agreement is -0.5049 respirations per minute. From these results, we confirmed that the TCRS could be used for monitoring of unconscious persons, avoiding the uncomfortness of subjects. Monitoring respiration using TCRS offers a promising possibility of convenient measurement of respiration rates. In particular, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products.