Quantcast

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

Business

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

EcoWatch Daily Newsletter

A glacier is seen in the Kenai Mountains on Sept. 6, near Primrose, Alaska. Scientists from the U.S. Geological Survey have been studying the glaciers in the area since 1966 and their studies show that the warming climate has resulted in sustained glacial mass loss as melting outpaced the accumulation of new snow and ice. Joe Raedle / Getty Images

By Mark Mancini

On Aug. 18, Iceland held a funeral for the first glacier lost to climate change. The deceased party was Okjökull, a historic body of ice that covered 14.6 square miles (38 square kilometers) in the Icelandic Highlands at the turn of the 20th century. But its glory days are long gone. In 2014, having dwindled to less than 1/15 its former size, Okjökull lost its status as an official glacier.

Read More Show Less
Members of Chicago Democratic Socialists of America table at the Logan Square Farmers Market on Aug. 18. Alex Schwartz

By Alex Schwartz

Among the many vendors at the Logan Square Farmers Market on Aug. 18 sat three young people peddling neither organic vegetables, gourmet cheese nor handmade crafts. Instead, they offered liberation from capitalism.

Read More Show Less
Sponsored
StephanieFrey / iStock / Getty Images

By Lauren Panoff, MPH, RD

Muffins are a popular, sweet treat.

Read More Show Less
Hackney primary school students went to the Town Hall on May 24 in London after school to protest about the climate emergency. Jenny Matthews / In Pictures / Getty Images

By Caroline Hickman

Eco-anxiety is likely to affect more and more people as the climate destabilizes. Already, studies have found that 45 percent of children suffer lasting depression after surviving extreme weather and natural disasters. Some of that emotional turmoil must stem from confusion — why aren't adults doing more to stop climate change?

Read More Show Less
Myrtle warbler. Gillfoto / Flickr / CC BY-SA 2.0

Bird watching in the U.S. may be a lot harder than it once was, since bird populations are dropping off in droves, according to a new study.

Read More Show Less
Sponsored
Amazon CEO Jeff Bezos announces the co-founding of The Climate Pledge at the National Press Club on Sept. 19 in Washington, DC. Paul Morigi / Getty Images for Amazon

The day before over 1,500 Amazon.com employees planned a walkout to participate in today's global climate strike, CEO Jeff Bezos unveiled a sweeping plan for the retail and media giant to be carbon neutral by 2040, 10 years ahead of the Paris agreement schedule.

Read More Show Less

By Winona LaDuke

For the past seven years, the Anishinaabe people have been facing the largest tar sands pipeline project in North America. We still are. In these dying moments of the fossil fuel industry, Water Protectors stand, prepared for yet another battle for the water, wild rice and future of all. We face Enbridge, the largest pipeline company in North America, and the third largest corporation in Canada. We face it unafraid and eyes wide open, for indeed we see the future.

Read More Show Less
The climate crisis often intensifies systems of oppression. Rieko Honma / Stone / Getty Images Plus

By Mara Dolan

We see the effects of the climate crisis all around us in hurricanes, droughts, wildfires, and rising sea levels, but our proximity to these things, and how deeply our lives are changed by them, are not the same for everyone. Frontline groups have been leading the fight for environmental and climate justice for centuries and understand the critical connections between the climate crisis and racial justice, economic justice, migrant justice, and gender justice. Our personal experiences with climate change are shaped by our experiences with race, gender, and class, as the climate crisis often intensifies these systems of oppression.

Read More Show Less