Research on photoelectric pulse monitoring system

Abstract

Aiming at the shortcomings of the existing photoelectric pulse wave acquisition and analysis chip with large volume or no data processing and analysis function in the prior art, this paper proposes a small and highly integrated heart rate blood oxygen monitoring system solution with a built-in pulse wave algorithm. Its internal data acquisition and analysis module is as small as 3 × 3mm2 . The position of each module on the PCB is reasonably distributed, and the overall structure of the heart rate and blood oxygen monitoring system is miniaturized. The integrated monitoring system can be as small as 7 × 15mm2 , which makes the heart rate oximetry system can be embedded in more portable products. The software algorithm first performs an average filtering process on the original signal. Then, the differential threshold method is used to extract the characteristic points of the pulse wave signal, that is, the maximum value and the minimum value, so as to obtain the positions of the peaks and troughs. The heart rate value is calculated based on the time difference t between two adjacent peaks of the light signal reflected by the red light source during the period. The experimental results show that the heart rate error of the integrated system can reach ±2% + 1 times / minute, and the blood oxygen error can reach ±2% within the range of 70-100.