While continuous heart rate monitoring has found its way into our fitness trackers and smart watches, the optimal way to measure real-time variations in breathing is still largely an unsolved problem, albeit with potential for clinically significant impact. A-spiro is a single-point wearable sensing technique to estimate respiratory flow and volume, in addition to respiratory rate. The A-spiro prototype consists of a wearable sensor that is integrated into a belt worn around the chest. We show that when coupled with an inertial measurement unit, our system can accurately measure breathing parameters, even when the user is ambulatory. A-spiro can model lung hysteresis to separately predict increasing and decreasing trends of breathing flow. Existing techniques either monitor breathing rate only, or estimate volume and flow when the user is immobile, for example, sleeping. A-spiro incorporates techniques for motion correction to provide accurate estimates even when the user is non-static.
