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Energy Harvesting (EH) has become a crucial part of self-powered autonomous systems, particularly for Wireless Sensor Network (WSN) nodes and the Internet of Things (IoT) sensors. The main advantages of exploiting Energy Harvesting approach lies on its portability, scalability, and low maintenance, as it reduces the dependency on batteries, therefore offers a sustainable and long-term solution for wireless monitoring over a wide area and a large number of sensor nodes. This paper discusses the use of Thermal Energy Harvesting (TEH) approach to power up a wireless sensor node for IoT applications. Wireless node WSN_1_TEH consists of MEGA328P as the main MCU, nRF24L01 wireless module, and DHT22 sensor. The TEH system consists of two thermoelectric generators with DC-DC boost converter based on MAX757 and an 8200µF storage capacitor. In the experiment, the TEH system was set to function as the only power source for the sensor node; for comparison of its performance with a 7.4 V rechargeable lithium polymer battery-powered counterpart, by operating for 40 hours continuously. In order to reduce power consumption, the WSN_1_TEH node was equipped with an energy-aware EventPriority-Driven Dissemination algorithm. It was developed to manage the WSN_1_TEH operation and to make the sink station able to detect a missing wireless node within the network, which will guarantee the nodes integrity detection. This algorithm will send out data packet based on event or priority, every 20 s of sleeping period. Besides power saving, it also reduces the overall network traffic. Based on the findings, the overall power consumption of this node is 39 mW in “active with transmission” mode, 28-32 mW in “active without transmission” mode, and only 23 mW when operating in “sleep” mode. |
