Aiming at the problem of high noise interference and low signal-to-noise ratio that flexible piezoelectric sensors have in signal acquisition

a human pulse acquisition and heart rate evaluation system is proposed using flexible piezoelectric sensor as core device

combined with wavelet transform algorithms.Firstly

a sensitivity experiment for polyvinylidene fluoride(PVDF)flexible piezoelectric thin film is constructed

and a charge amplifier conditioning circuit is designed to complete the material characteristic verification of the flexible piezoelectric sensor and to achieve amplification output of sensor signal.The upper computer of the system performs wavelet analysis on acquired signal at different scales

and a high signal-to-noise ratio pulse signal is obtained after wavelet reconstruction based on the threshold method.The subject’s pulse characteristics are marked using a peak-finding algorithm

and the heart rate is ultimately calculated for evaluation.Pulse analysis experiments are conducted on 10 test subjects

and the results show that 9 test subjects have heart rates within the range of 57~65 beats/min

which falls within the healthy heart rate range for humans.One test subject’s heart rate is approximately 54 beats/min

which is relatively slow and indicates a risk of developing cardiovascular disease.