Non-invasive piezoelectric detection of heartbeat rate and blood pressure

A non-invasive piezoelectric-based sheet sensor is utilised for the deliberate measurement of heartbeat rate and blood pressure. It may consist of a single sheet to capture various temporal signals or it can be formed as an array of small piezoelectric sensors to capture the temporal and spatial cardiac signals over the chest to give an added spatial granularity on top of the localised temporal signal. The mechanical activity of the heart will cause the piezoelectric sheet to deform, and thus produce a voltage signal. To count the heartbeat rate, a mechanical model has been developed using the corresponding electric waveform; a compression ratio is defined due to the delay as a result of the physical coupling mechanism. Validation of the obtained results has been performed using conventional techniques and apparatus. The quantitative assessment shows low errors when compared with other conventional meters.