Amid the growing trend of research into harnessing kinetic energy, a device has surfaced that can capture energy from a person who is simply walking. Researchers at the Simon Fraser University in Burnaby, British Columbia, have developed a device that generates electrical power from the swing of a person’s knee.

Max Donelan, a researcher on the project, has founded a company to develop the device for commercial use. According to Donelan, the device works on the theory that, with each step a person takes, the leg accelerates and decelerates. He compares it to the way some hybrid-electric cars produce electricity from braking.

With one minute of walking, the device can power a cell phone for 10 minutes. Donelan cited other uses, such as powering a GPS locator, a motorized prosthetic joint or an implanted drug pump. However, according to Donelan, the first use the researchers are aiming for is producing power for artificial limbs.

The device weighs approximately 3.5 pounds. Donelan has noticed users burn energy while using it, but they haven’t noticed when it is turned on or off during tests. With a device on both knees, test subjects were able to produce up to 5 watts of electricity.