WASHINGTON — Call it the ultimate power walk.
Researchers have developed a device that generates electrical power from the swing of a walking person’s knee. With each stride the leg accelerates and then decelerates, using energy both for moving and braking.
Max Donelan and colleagues reasoned that a device that helps the leg decelerate could generate power without requiring much additional energy from the person.
It’s sort of like the way that some hybrid-electric cars produce electricity from braking.
With the device, a minute of walking can power a cellphone for 10 minutes, said Donelan, of Simon Fraser University in Burnaby, British Columbia. Other potential uses include powering a portable GPS locator, a motorized prosthetic joint or implanted drug pumps.
Donelan and colleagues report on the device in today’s edition of the journal Science.
The generator weighs about 3.5 pounds, so users burn energy carrying it on their knee, he said. But they miss it when it’s removed because they get used to its braking action, he added.
