Michigan State University (MSU) scientists have developed a new self-powered, alarm system for detecting forest fires and monitoring the environment.
The device – a multilayered cylindrical triboelectric nanogenerator (MC-TENG) – generates electrical power by harvesting energy from the sporadic movement of the tree branches from which it hangs.
“As far as we know, this is the first demonstration of such a novel MC-TENG as a forest fire detection system,” says lead author and assistant professor Changyong Cao.
The recent tragic forest fires across the American West, Brazil and Australia were what propelled Cao and his team to create their new device.
He believes that 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 and watch towers, which have high labor and financial costs in return for low efficiency.
The new device converts external mechanical energy – such as the movement of a tree branch – into electricity by way of the triboelectric effect, a phenomenon where certain materials become electrically charged after they separate from a second material with which they were previously in contact.
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.
MC-TENGs – like the one utilized by the MSU team – are equipped with several hierarchical triboelectric layers to increase electrical output.
The Michigan system stores its sporadically generated electrical current in a carbon-nanotube-based micro supercapacitor.
The researchers selected this technology for its rapid charge and discharge times, allowing the device to charge in less than three minutes with only short, but sustained gusts of wind.
Cao’s team has also outfitted the initial prototype with both carbon monoxide (CO) and temperature sensors.
According to the scientists, the addition of a temperature sensor helps reduce the likelihood of a false positive carbon dioxide reading.
Image and content: Pixabay/Michigan State University