A Self-Powered Wearable Sensor Node for IoT Healthcare Applications

In this paper, a self-powered Internet of Things (IoT) wearable sensor node is proposed for healthcare monitoring. This node enables doctors of measuring the heart rate, blood oxygen saturation (SpO2), and body temperature. This node is based on NodeMCU board that includes a microcontroller with a Wi-Fi chip. A solar energy harvester is developed as power supply to provide a solution for prolonging the lifetime of the node. This harvester is designed of two flexible photovoltaic (PV) panels, a charging controller, and a lithium-ion battery. The harvester is practically tested outdoors under direct sunlight and partly cloudy conditions. Experimentally, the IoT wearable sensor node consumes an average power of 20.23 mW over one hour and the lifetime of the node is 28 hours in a wake-up-sleep mode. Finally, the experimental results show that the monitored physiological data of the node are stored into an Ubidots cloud server.