How does the breathing detection work?
The expansion and contraction of the thoracic cavity generates a size differential as measured by the strap under the wearer’s right arm. This differential is picked up by the strap sensor and sent to the BioHarness module on the strap. Signal processing in the BioHarness module produces a waveform and breathing rate in Breaths per Minute. This is subsequently transmitted via an ISM protocol to the RF dongle antenna. In the case of the Zephyr solution the data is imported into Zephyr ‘s PC application. This software application also performs additional filtering to improve the respiration quality. When viewing the Zephyr PC application, inhilation is denoted by a downward trend in the breathing waveform. This is because the distance between the sensors in the strap is decreased (compressed) due to thoracic expansion. Commensurately, exhalation (sensor expansion) causes an upswing in the waveform. Respiration at rest should appear as a sine wave; respiration under activity should appear
