Wearable Spirometry : Using Integrated Environment Sensor for Breath Measurement

In this work, we present and evaluate a concept for using an integrated environment sensor as a wearable spirometer. Unlike a standard spirometer that by design is fairly bulky, our device can be unobtrusively integrated into various configurations suitable for long-term use in everyday settings (open headset, regular face mask, and professional sports mask). The sensor measures the transient change in air pressure, humidity and temperature in front of wearers’ mouth and nostrils. We present our hardware design and signal analysis methods needed to extract breathing rate information. We compare the results with a standard spirometer. Moreover, a calibration between the BME280 sensor and the spirometer is performed, having both working in parallel. We show that our approach is able to distinguish between normal breaths and deep breaths, as well as to capture the period and magnitude of the breath cycles, with a wearable device that can be used in everyday scenarios, as well as sport activities. The classification accuracy is 96% in face mask settings and 82% in an open headset setting. We also show that the sensor is able to approximate air volume by comparing the sensor’s pressure channel to the spirometer’s flow rate results. Keywords–Wearable technology; Head-mounted sensing; Spirometry; Respiration detection.