Noninvasive Respiratory Analysis using Piezoelectric Sensor Array

Abstract

In this study multiple design approaches have been tried to accurately determine the respiratory rate every 30 seconds of a patient in a hospital bed using six piezoelectric pressure sensors located sand­wiched between the mattress and the bed. After four design iterations using a variety of different methods, a final design using a Least Mean Squares (LMS) filter and peak detection in the frequency domain was implemented. According to the test results, this method determines an accurate respira­tory rate 85% of the time in a controlled, experimental environment with the subject lying completely still. Unfortunately this accuracy is below the set requirements. However, it is believed that multiple improvements can still be made on the algorithm to increase the accuracy.