Waist-wearable wireless respiration sensor based on triboelectric effect

Highlights: • A waist-wearable wireless respiration sensor based on TENG is proposed. • Feasibility of the device is verified by mechanical tests and theoretical analyses. • Practicability for real-time monitoring in different daily activities is validated -- Abstract: Obstructive sleep apnea syndrome (OASA) is a respiratory disease caused by upper airway obstruction that is harmful to sleep quality and human health. Real-time monitoring of the respiration status may help to detect the symptoms of apnea and provide accordance to early warning, diagnosis, and proper treatment. As a solution, we here propose a waist-wearable wireless respiration monitoring device based on triboelectric nanogenerator (TENG) that is designed to monitor the breathing status by sensing the variation of the abdomen circumference. The breathing information is transmitted to a mobile phone via a wireless transmission chip. A theoretical electromechanical analysis is performed to predict the output performance of the TENG with two different sizes. The results agree very well with measured data, thus addressing the feasibility of the TENG sensor for monitoring respiration of different modes (thoracic and abdominal respiration) and various daily activities (lying, standing and sitting). A series of real-time tests on two volunteers with different waistlines and various breathing rhythms have been carried out. It is demonstrated that the current TENG sensor have high accuracy and sensitivity in real-time monitoring of respiratory status. The results may provide a new alternative for real-time monitoring respiration related diseases especially the obstructive sleep apnea syndrome.