Chuck Bednar for redOrbit.com – Your Universe Online
A team of German researchers has developed portable, shoe-sized devices that could recharge your gadgets on the go by generating power through the mechanics of walking.
Researchers from the HSG-IMIT – Institute of Micromachining and Information Technology in Villingen-Schwenningen, Germany and the Department of Microsystems Engineering – IMTEK in Freiburg explain that the technology includes two separate power-producing devices.
One device is known as the “shock harvester” and generates power when a person’s heel strikes the ground, according to BBC News reports. The other is called the “swing harvester,” and it produces power when the foot in swinging. They explain the technology of their new on-the-go recharging devices in the latest edition of the journal Smart Materials and Structures.
“We have tried to power a wireless transmitter and to power a simple sensor,” explained Klevis Ylli of HSG-IMIT. “One application we are working on is indoor navigation which means we have sensors within the shoe that measure the acceleration of the foot, the angular velocity – whether you’re turning the foot or not – and the magnetic field.”
“From the data from these sensors, you could calculate how far you have travelled and in which direction. So imagine a rescue unit walking into a building they don’t know,” Ylli added. “They could then track which way they went on their handheld device.”
As the researchers told LiveScience, both the shock harvester and the swing harvester are based on the principle of electromagnetic induction. Both devices contain stacks of magnets and coils of wire, and as the individual wearing them moves, the magnets move past the coils. This causes the magnetic field within those coils to change, creating a charge within the wire.
That voltage can they be used to power whatever electronic devices are embedded in the show, they added. The swing harvester was originally created to power a pair of self-lacing shoes, and it fits at the sole of the shoe’s heel. This device is approximately three inches long, less than one inch wide, half an inch tall and weighs slightly less than one ounce.
The shock harvester, on the other hand, is slightly larger and heavier. It weighs about one-third of a pound and was originally developed to provide power for an indoor navigation systems. These units, LiveScience explained, are touted as alternative to satellite-based GPS systems that don’t always work inside of buildings and are often used by firefighters and military personnel.
“For the indoor navigation system, there are sensors [accelerometers] within the shoe that determine how fast you’re moving, acceleration and the angles that your foot has traveled. And from this data, the system can calculate the path that you have walked,” Ylli told the website, adding that the sensors are powered by an in-shoe battery recharged by the shock harvester.
BBC News notes that the devices generate a relatively small amount of energy. At their peak, they can produce a maximum of three to four millwatts, not nearly enough to charge something like smartphone, which requires approximately 2,000 milliwatts. However, the inventors note that they can power small sensors and transmitters, which could lead to an array of different uses.
Ylli said told the British news organization that the technology represent a trade-off between power generation and limiting factors such as size. He added that his team’s approach is lighter and less intrusive than past attempts to create similar devices.
“Generated power scales with size,” he noted, “but if you want to be able to reasonably integrate such a device within a shoe sole, you have to work with strict constraints, like a small height and limited length of the device. We believe we have built comparatively small devices, considering the power output.”
—–
Follow redOrbit on Twitter, Facebook, Instagram and Pinterest.
Comments