Quantcast

Kinetic Energy-Harvesting Shoes Could Charge Your Smartphone or Be Wi-Fi Hot Spot

Mechanical engineers at the University of Wisconsin-Madison have developed electricity-generating footwear that lets you charge mobile electronic devices simply by walking.

As it turns out, “human walking carries a lot of energy,” as UW-Madison mechanical engineering associate professor Tom Krupenkin said in a university news release.

Researchers say this shoe could directly power mobile devices through a charging cable or act as a Wi-Fi hot spot. Photo credit: University of Wisconsin-Madison, College of Engineering

“Theoretical estimates show that it can produce up to 10 watts per shoe, and that energy is just wasted as heat," Krupenkin continued. "A total of 20 watts from walking is not a small thing, especially compared to the power requirements of the majority of modern mobile devices.” A typical smartphone, for instance, requires less than two watts.

As the news release points out, the shoes could be especially useful for the military as soldiers have to carry heavy electronics such as flashlights, night vision devices, GPS and many pounds of batteries on top of that.

The shoes could also be a source of electricity to people living in developing countries where access to reliable power sources can be difficult.

In the video below, Krupenkin uses the shoes to directly power an LED flashlight.

There are already many other power-generating-shoe concepts, but successfully pulling it off for the market is quite the difficult task. That's because "traditional approaches to energy harvesting and conversion don’t work well for the relatively small displacements and large forces of footfalls," according to the researchers.

However, by using a process called “reverse electrowetting,” a phenomenon that Krupenkin and senior scientist J. Ashley Taylor pioneered in 2011, a conductive liquid interacts with a nanofilm-coated surface and the mechanical energy is directly converted into electrical energy.

This method can generate an electrical charge but it requires a high-frequency energy source such as a quickly vibrating or rotating motor.

To solve this problem, the researchers came up with the so-called “bubbler” method which combines reverse electrowetting with the growth and pop of, yes, bubbles.

According to the news release:

The researchers’ bubbler device—which contains no moving mechanical parts—consists of two flat plates separated by a small gap filled with a conductive liquid. The bottom plate is covered with tiny holes through which pressurized gas forms bubbles. The bubbles grow until they’re large enough to touch the top plate, which causes the bubble to collapse.

The speedy, repetitive growth and collapse of bubbles pushes the conductive fluid back and forth, generating electrical charge.

An energy harvester, battery and electronics suite are integrated into each sole. Photo credit: University of Wisconsin-Madison

“The high frequency that you need for efficient energy conversion isn’t coming from your mechanical energy source but instead, it’s an internal property of this bubbler approach,” Krupenkin said.

“The bubbler really shines at producing high power densities. For this type of mechanical energy harvesting, the bubbler has a promise to achieve by far the highest power density ever demonstrated.”

According to the engineers, their harvester can be integrated with a broad range of electronic devices embedded in a shoe, such as a Wi-Fi hot spot that acts as a “middleman” between mobile devices and a wireless network. This process "requires no cables, dramatically cuts the power requirements of wireless mobile devices and can make a cellphone battery last 10 times longer between charges," they noted.

Krupenkin and Taylor and their startup company, InStep NanoPower, is currently seeking to partner with industry and commercialize a footwear-embedded energy harvester.

The research team published their findings in a paper on Nov. 16, 2015 in the journal Scientific Reports. Additional authors on the s paper include UW-Madison mechanical engineering graduate students Tsung-Hsing Hsu and Supone Manakasettharn.

Learn more about the footwear in the video below.

YOU MIGHT ALSO LIKE

Check Out These Super Cool Lamps Literally Made From Mushrooms

Leonardo DiCaprio Joins Carbon Capture Technology Company to ‘Bring About a More Sustainable Future for Our Planet’

Kelly Slater: World’s ‘Best Man-Made Wave’ Is Powered 100% by the Sun

Health Scare Led This Woman to Launch an Organic Tampon Company

Show Comments ()

EcoWatch Daily Newsletter

Bernie Sanders holds his first presidential campaign rally at Brooklyn College on March 02 in Brooklyn, New York. Kena Betancur / VIEWpress / Corbis. Getty Images

Bernie Sanders has become the first contender in the crowded 2020 Democratic presidential primary field to pledge to offset all of the greenhouse gas emissions released by campaign travel, The Huffington Post reported Thursday.

Read More Show Less
An aerial view of the flooding at the Camp Ashland, Nebraska on March 17. Nebraska National Guard / Staff Sgt. Herschel Talley / Flickr / CC BY 2.0

The record flooding in the Midwest that has now been blamed for four deaths could also have lasting consequences for the region's many farmers.

Read More Show Less
Sponsored

In tea, food, or just on your windowsill, embrace the fragrance and fantastic healing potential of herbs.

Read More Show Less

By Ana Santos Rutschman

The world of food and drug regulation was rocked earlier this month by the news of a change in leadership at the Food and Drug Administration. Commissioner Scott Gottlieb resigned and will step down in early April. His temporary replacement is Dr. Ned Sharpless, director of the National Cancer Institute.

Read More Show Less
MartinPrescott / iStock / Getty Images

On Wednesday the U.S. Environmental Protection Agency (EPA) announced the first 20 chemicals it plans to prioritize as "high priority" for assessment under the Toxic Substances Control Act. Given the EPA's record of malfeasance on chemicals policy over the past two years, it is clear that these are chemicals that EPA is prioritizing to ensure that they are not properly evaluated or regulated.

Read More Show Less
Sponsored
Strawberries top the Environmental Working Group's "Dirty Dozen" list of U.S. produce most contaminated with pesticides. DANIEL LEAL-OLIVAS / AFP / Getty Images

Which conventionally-grown fruits and vegetables in the U.S. are most contaminated with pesticides? That's the question that the Environmental Working Group answers every year with its "Dirty Dozen" list of produce with the highest concentration of pesticides after being washed or peeled.

Read More Show Less
A drilling rig in a Wyoming natural gas field. William Campbell / Corbis via Getty Images

A U.S. federal judge temporarily blocked oil and gas drilling on 300,000 acres of federal leases in Wyoming Tuesday, arguing that the Bureau of Land Management (BLM) "did not sufficiently consider climate change" when auctioning off the land, The Washington Post reported.

Read More Show Less
Mizina / iStock / Getty Images

By Ryan Raman, MS, RD

Oats are widely regarded as one of the healthiest grains you can eat, as they're packed with many important vitamins, minerals, and fiber.

Read More Show Less