Development of a Wearable Measuring System for ‎respiratory Plethysmography

Abstract

Assessment of respiratory volume is widely used in clinical application in order to assess the case of respiratory illness, and the progression of the respiratory syndrome. Respiratory plethysmography is used to determine the changes of chest volume to monitor the breathing. A wearable respiration measuring system has been introduced for detection of volume variations of chest. The system consists of a flexible sensor, stretchable cloth and electrical board. The flexible sensor, whose electrical voltage is produced by body movements, is installed inside the shirt and closely contacts the chest. The low frequency components of body movements recorded by the sensor are mainly generated by respiration. The system can be used at home and be selfapplied by patients. The main features of this system are: low cost, low weight and applicable for athletics and patients. We have tested the system thirty four times for calibration. The curve equation of the flexible sensor output versus the output of spirometer is presented. Finally, this curve equation can be used to determine the changes of chest volume.