Wearable displacement sensor system based on elevating tube for measuring breathing pattern

To measure the breathing pattern of a person, a wearable bellows displacement sensor system, based on an elevating tube, is proposed and evaluated. As for the composition of the system, a thermal-flow sensor is mounted on an outlet of a T-joint placed at the end of the elevating tube, and expansion and contraction of the tube due to breathing are detected by the amount of air flowing through the thermal-flow sensor. The sensor is produced and assembled on the basis of MEMS technologies. According to the results of an experimental evaluation of the sensor system, the air-flow volume increases with increasing displacement of the bellows, and the air-flow volume does not depend on the frequency of the displacement.