Researchers at Michigan State University have built a battery-free remote forest fire detection and alarm system powered by the movement of the trees in the wind.
The alarm is based around a multilayered cylindrical triboelectric nanogenerator (MC-TENG) that generates power by harvesting energy from the sporadic movement of the tree branches.
"As far as we know, this is the first demonstration of such a novel MC-TENG as a forest fire detection system," said Changyong Cao, directors of the Laboratory of Soft Machines and Electronics in MSU's School of Packaging and is an assistant professor in the Packaging School and Departments of Mechanical Engineering, and Electrical and Computer Engineering.
"The self-powered sensing system could continuously monitor the fire and environmental conditions without requiring maintenance after deployment," he said.
Early and quick response to forest fires will make the task of extinguishing them easier, significantly reducing the damage and loss of property and life. Traditional forest fire detection methods include satellite monitoring, ground patrols, watch towers, among others, which have high labour and financial costs in return for low efficiency.
Current remote sensor technologies are becoming more common, but primarily rely on battery technology for power. "Although solar cells have been widely used for portable electronics or self-powered systems, it is challenging to install these in a forest because of the shading or covering of lush foliage," said Yaokun Pang, co-author and postdoc associate at Cao's lab.
The simplest version of the TENG device consists of two cylindrical sleeves of unique material that fit within one another. The core sleeve is anchored from above while the bottom sleeve is free to slide up and down and move side to side, constrained only by an elastic connective band or spring. As the two sleeves move out of sync, the intermittent loss of contact generates electricity. The MC-TENG are equipped with several hierarchical triboelectric layers, increasing the electrical output.
The MC-TENG stores its sporadically generated