Respiration and Heartbeat Signal Measurement with A Highly Sensitive PVDF Piezoelectric Film Sensor

A highly sensitive sensor for monitoring the respiration status of subjects using artificial respiration devices and screening tests for sleep apnea syndrome (SAS) of public transportation drivers was developed using a very simple poly-vinylidene difluoride (PVDF) piezoelectric film. A charge amplifier and a band elimination filter which were required for accurate respiration sensing were also developed. By using the sensor developed, it was also possible to measure the heartbeat signals due to its excellent sensitivity. The respiration and heartbeat signals could be separated cleanly by applying low-pass and band-pass digital filters with the appropriate cut-off frequencies. Furthermore, a wireless monitoring system was also developed so that the respiration and the heartbeat activities could be monitored from mobile devices such as smartphones, tablets or laptop computers.