Monday, August 26

UCLA researchers develop device to monitor movement of people in perilous situations


(Courtesy of Dr. Abdelsalam Ahmed/McMaster University) A device created by UCLA researchers  generates electric signals from a person's movement. The device can monitor for signs of stillness that indicate the wearer might be in danger.

(Courtesy of Dr. Abdelsalam Ahmed/McMaster University) A device created by UCLA researchers generates electric signals from a person's movement. The device can monitor for signs of stillness that indicate the wearer might be in danger.


UCLA researchers developed a fire-resistant device that monitors the safety of people working in extreme environments.

Richard Kaner, a distinguished professor of inorganic chemistry who led the research, said the device generates electric signals from a person’s movement to monitor for signs of stillness that indicate the wearer might be in danger.

Maher El-Kady, a graduate student and postdoctoral research fellow in the chemistry and biochemistry department who co-authored the study, said the device, which is about the size of a quarter, can be embedded in the shoes or clothes of people who work in extreme environments, such as firefighters or oil drillers. The device is self-charging and resistant to extreme heat.

“It is basically an all-in-one motion sensor,” El-Kady said. “It converts body motion to electric signals, and we can integrate it into firefighters’ uniforms to monitor their motion and safety.”

El-Kady added that the self-powering device uses a technique called triboelectric charging, during which electrons transfer from a negatively charged object to a positively charged one when the objects are in contact with each other.

“When you rub your feet against the carpet and touch the doorknob, you build off electrons and get shocked from the electricity transfer,” El-Kady said. “In the case of the device, the transfer is between the device and human skin or the floor.”

El-Kady said because motions such as running and jumping create different electric signals in the device, the signals can be used to analyze how someone is moving. He added that the device can send these signals to other people through a Bluetooth transmitter.

“These (provide) important information for the coworkers, because when people are in danger, they usually are not able to ask for help themselves,” he said.

Mit Muni, a graduate student in chemistry and researcher on the study, said unlike previous motion sensors, the device is made from a carbon aerogel. Air makes up 95% of carbon aerogel’s volume, making the material extremely lightweight and easy to use. The material is also what allows the device to tolerate extremely high temperatures, Muni added.

“We tested the device under 200 degrees Celsius for 90 seconds,” Muni said. “The structure of the device was robust and the electric signal it produced was stable.”

Most conventional triboelectric devices stop functioning correctly at this temperature and might even catch on fire, El-Kady added.

El-Kady said the material of the device is safe for the environment and users’ health, which distinguishes it from conventional fire-resistant materials known to have negative health effects.

El-Kady added that triboelectric charging technology can be used to power traveling generators in the future.

“We can integrate such devices into our clothes or shoes,” El-Kady said. “The electricity transfer could be collected and used to charge our phone or computer.”

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