Monitoring of breathing rate by a piezofilm sensor using pyroelectric effect

This paper presents a piezo film based headphone system for respiratory rate monitoring. The proposed system attaches a flexible piezo film sensor to a headphone to sense the respiratory airflow. During breathing, the temperature of respiratory airflow varies in inspiration and expiration phases. This temperature variation could be detected by the pyroelectricity of the piezoelectric film sensor. Monitoring the sensor output variation therefore could monitor the subject's respiratory rate with high accuracy. Experimental result also indicates that the pyroelectric response is faster than temperature-sensitive device thermistors. In addition, the headphone type of the proposed system makes it easy to be used for subjects' respiratory rate monitoring during sleep. The advantages of this respiratory rate monitoring system are rapid response time, low cost, and ease of implementation.