A Wireless Sensor System Supplied by a Solar Energy Harvester toward IoT Environmental Monitoring

Abstract Harmful environments can cause seriously health problems to humans. Thus, it is should be develop a generation of wireless sensor systems that are energy self-powered to monitor physical parameters of an ambient environment in real-time and sending these parameters remotely to an IoT cloud service. In this paper, a wireless sensor system is proposed for an environmental monitoring. This system is based on two sensors and a NodeMCU board that includes a microcontroller with a Wi-Fi chip. This system is built to measure the ambient temperature, relative humidity, atmospheric pressure, and ultraviolet (UV) index. The power supply of the sensor system is a solar energy harvester, which consists of a solar cell, a DC-DC converter, and a rechargeable battery. This harvester is practically tested outdoors under direct sunlight. The wireless sensor system experimentally consumes an average power of 40 mW over one hour and the life-time of this system is 123 hours in active-sleep mode. The results demonstrate that the wireless sensor system has long-term and sustainable operation of the monitoring of an environmental data.