Wearable Device Monitoring Cough with Piezoelectric Energy Harvester as a Simultaneous Sensor and Battery Life Extender

Cough is the most common symptom for which individuals seek medical advice. However, wireless and autonomous tools and standards for cough monitoring are lacking, possibly due to issues of measurement reliability and device lifespan. This work utilizes the piezoelectric energy harvesting concept to sense coughing signals. Different from conventional sensing techniques, the piezoelectric harvester here converts energy of muscle movement triggered by cough into electricity which then charges a capacitor, rather than being directly read by the microcontroller. The capacitor will accumulate energy for a certain period and then the capacitor voltage will be read by the microcontroller. This simple change of data collection mechanism magnificently reduces the duty cycle of the entire electronic system whilst maintaining high accuracy of recording the history of coughs. Proven in clinical trials, the battery life of the device has been significantly extended to longer than a week compared to approximately only overnight where conventional sensing techniques are implemented, even if using the same piezoelectric harvester (sensor). The newly developed system can then be used to autonomously monitor and analyze cough data of in-/outpatients for daily, research and clinical purposes and thus to improve prediction and management of severe respiratory diseases.