A Wearable Device with Triboelectric Nanogenerator Sensing for Respiration and Spirometry Monitoring

Wearable devices have been developed for the continuous and long-term monitoring of respiration. Although current wearable devices are able to measure the respiration rate, extracting breathing volume has been challenging. In this paper, we propose a wearable respiration monitoring sensor based on triboelectric nanogenerator (TENG) technology. The proposed device successfully measures both respiration rate and volume in real-time. The device is tested with seven participants for respiration and spirometry studies. The results show that the proposed TENG sensor is able to capture the respiration waveform with high accuracy. All breathing patterns mentioned in this study give a mean absolute error (MAE) within 0.2 breaths per minute and a mean percentage absolute (MPAE) error within 2%. The results of the spirometry study show that the TENG sensor can measure the airflow and volume during exhalation. The flow time graph gives an average correlation of 0.88 compared with that of the reference spirometer. The reconstructed volume time plot from the TENG sensor results in an MAE of 2.43% for the ratio of the forced expiratory volume in 1 s to the forced vital capacity (FEV₁/FVC). The proposed device provides a low-cost solution for real-time and wearable monitoring for respiration parameter measurement.