Skip to content

SciTech

Power to the people - how a walk could charge your cell phone

by Martin Leggett 23 Aug 2011
Power to the people - how a walk could charge your cell phone
etadshow468 -->

It's the ultimate dream in green power on-the-go - having cellphones, flash-lights and laptops that power themselves, just from their owner's day-to-day movements. But for two scientists, from the University of Wisconsin-Madison, this eco-dream is anything but that. Instead it's a fast-approaching reality - thanks to their newly demonstrated energy-harvesting technique. Called 'reverse electro-wetting', this innovative technology could make battery-juggling and phone-charger blues a thing of the past, say the duo - Tom Krupenkin and J. Ashley Taylor - in this week's Nature Communications.

"Humans, generally speaking, are very powerful energy-producing machines," said Krupenkin 'What has been lacking is a mechanical-to-electrical energy conversion technology that would work well for this type of application." But they believe that this gap may now have been filled by their recent work. And not only could their suggested technology help to un-tether mobile devices from power cords - it could revolutionize the use of devices like cellphones in developing countries, where access to power can be a real issue.

Electro-wetting has been a hot research topic for the last few years. It involves making tiny liquid dots to move across surfaces, by applying varying electrical currents - in essence gaining mechanical energy from electrical energy. It has a number of hi-tech uses, from making fiber-optic switches and adjustable micro-lenses, to e-paper and the liquid 'lab-on-a-chip' applications favored by the bio-tech industry.

Filling the gap with foot-power

Reversing the process, however, opens a very different possibility - the production of electricity, from the natural movement of those same tiny liquid dots. The team's 'micro-fluidic device', stuck into the user's shoe, takes full advantage of this amazing property. It contains a nano-structured surface, mixed up with a countless number of liquid micro-droplets. As the user walks, and strikes the ground, these droplets interact with the specially-shaped surface, so producing the electrical charge.

Although only a fraction of the energy produced by walking is captured - typically up to 20 watts - that matches the power needs of many mobile devices. They are poorly served, at the moment, by energy from the grid, needing frequent recharging of clunky batteries. Solar and other 'traditional' renewable approaches are also rarely practical for those on the move. "What's been missing is the power in the watts range," said the reports co-author, Taylor. "That's the power range needed for portable electronics."

After proving the practicality of the 'reverse electro-wetting' concept, through a National Science Foundation Small Business Innovation Research grant, they are now looking to commercialize the technology. Two applications stand out as good candidates for walking-power. First, a new generation of devices could be powered directly from the shoe-to-gadget. That could cover smart-phones, radios, GPS units, flash-lights and and laptops; but these would require a lead to supply power from the foot.

Faster, lighter, fitter?

An alternative use would be for the shoe-borne energy-harvester to power just the WiFi component of wireless devices like cellphones. The WiFi component would be placed alongside energy-harvester. Connecting to the network is a massive power-drain for cellphones and the like. If the energy-harvester is handling that, by providing the connection itself, cellphones would be able to become much more light-touch in their energy use. Battery life could be massively lengthened. "You cut the power requirements of your cellphone dramatically by doing this," says Krupenkin. "Your cellphone battery will last 10 times longer."

All told, the technology promises to reduce power-use, free-up electrical gadgets and cut back on the pollution and waste problems burdening the disposal of millions of dead batteries. And, just maybe, the fitness of the 'smart-phone generation' could soar too - especially when a quick jog round the block will help to keep your vital little device fully charged.

Top Image Credit: Copyright Yanc


Trending Eco-Friendly Clothing

Love My Planet Women's Relaxed Fit Hoodie
Earth
Quick Add
Close
Notify me
Notify me
Love My Planet Women's Relaxed Fit Hoodie
Love My Planet women's eco-friendly relaxed fit hoodieSize Guide Centimeters 8 10 12 14 16 18 Bust 84 88 92 97 103 108 Waist 66 70 75 80 85 91 Hips 91 95 99 104 109 116 Bust: Measure around the fullest part of...
£38.00
£38.00
Close
Notify me
Notify me
Penguins Hate Push-Ups Men's Pullover Hoodie
Earth
Quick Add
Close
Notify me
Notify me
Penguins Hate Push-Ups Men's Pullover Hoodie
Penguins Hate Push-Ups men's eco-friendly pullover HoodieSize Guide Centimeters XS S M L XL XXL Height 171 175 179 183 189 195 Chest 86 93 99 104 116 129 Waist 71 76 81 89 99 112 Chest: Measure all round your chest just below...
£38.00
£38.00
Close
Notify me
Notify me
Lightning Bolt Kids Long Sleeve T-Shirt
Earth
Quick Add
Close
Notify me
Notify me
Notify me
Lightning Bolt Kids Long Sleeve T-Shirt
Lightning Bolt kids eco-friendly long sleeve t-shirtSize Guide Centimeters 3-4yrs 5-6yrs 7-8yrs 9-10yrs 11-12yrs Height 98 112 125 136 147 Chest 60 66 70 75 84 Chest: Measure all around your chest just below your armpits. Height: Your natural height If you fall between...
£18.00
£18.00
Close
Notify me
Notify me
Notify me
Union Jack Tote Bag
Earth
Quick Add
Close
Notify me
Notify me
Union Jack Tote Bag
Union Jack eco-friendly colour tote bagProduct Specification Organic Cotton Tote Bag. Twill Weave (170gsm). 37 x 42 cm (7cm gusset.) Made in India / Designed on the Isle of Wight. Wash Cool, Hang Dry.
£16.00
£16.00
Close
Notify me
Notify me
Prev Post
Next Post

Eco-Friendly Shop

Women's Clothing

Eco-Friendly Clothing for Women Our online shop offers a wide range of sustainable women’s clothing products, including t-shirts, hoodies, vests, sweaters, shorts, and...
Shop Now

Men's Clothing

Eco-Friendly Clothing for Men Our online shop offers a wide range of sustainable men’s clothing products, including t-shirts, hoodies, vests, sweaters, shorts, and...
Shop Now

Kids Clothing

Eco-Friendly Clothes for Kids Our online shop offers a wide range of sustainable kids clothing products, including t-shirts, hoodies and jumpers. Our garments...
Shop Now
Someone recently bought a
[time] ago, from [location]

Thanks for subscribing!

This email has been registered!

Shop the look

Choose Options

Earth Times
Sign up for exclusive updates, new arrivals & insider only discounts

Recently Viewed

Edit Option
Back In Stock Notification
this is just a warning
Login
Shopping Cart
0 items

Before you leave...

Take 20% off your first order

20% off

Enter the code below at checkout to get 20% off your first order

CODESALE20

Continue Shopping