Source: McMaster UniversityResearchers at Canada’s McMaster University in collaboration with other universities have developed a motion-powered and fire-proof sensor capable of tracking the movements of those working in high-risk professions including firefighting, mining and steel working.

The inexpensive sensor, which is roughly the size of a button-cell watch battery, can fit easily into the sole of a boot or under the arm of a jacket — any location where motion produces a pattern of consistent contact and release to power the sensor. In other words, the sensor relies on triboelectric (or friction-generated) charging, taking electricity from movement the way one might when moving over a carpeted surface wearing socks and picking up static electricity. Without needing to be powered from an external power source, the sensor can be used to track the movement of workers as they navigate a mineshaft, a burning building or other dangerous environments where their location would be unknown to others. In the event that movement stops, the sensor would alert others outside.

Although similar self-powered sensors already exist, their material would break down at high temperatures and they would become useless. However, the McMaster-led team used a fireproof carbon aerogel nanocomposite to create the sensor to prevent such failures. According to the team, the sensor successfully performed at temperatures as high as 300° C without losing function.

"If somebody is unconscious and you are unable to find them, this could be very useful," said Ravi Selvaganapathy, a professor of mechanical engineering who oversaw the project. "The nice thing is that because it is self-powered, you don't have to do anything. It scavenges power from the environment."

The research appears in the journal Nano Energy.