Measuring Respiration and Heart Rate using Two Acceleration Sensors on a Fully Embedded Platform

We present a novel system which measures the respiration rate using two three-axis accelerometers strapped to the chest and the back of a person. Respiration and heart rate are used as a measurement to determine an athlete’s fitness level during the exercise phase. Common respiration rate measurement methods require devices which are mostly stationary or at least clunky and uncomfortable to wear for an extended period of time. By using techniques such as differential measurement, pre-measurement optimization, adaptive filtering and peak detection we are able to obtain respiration rate even when the athlete is running fast. Our system is low-cost, small, and, by using a digital signal processor, fully capable of processing the data in an online way. Results are compared with a reference spirometer and have shown a very low normalized root mean square error (NRMSE) down to 1.42 %. Additionally, the heart rate of an athlete can be measured with the same sensor setup and similar methods.