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    • CommentAuthorKosmopolit
    • CommentTimeFeb 14th 2008 edited
    First we had the power-generating knee brace.

    Now we have the power-generating tee-shirt.

    A piezoelectric fabric that generates power through the bending of its component threads could harvest useful amounts of power from a wearer's body motions.

    In 2007 Zhong Lin Wang, a materials scientist at the Georgia Institute of Technology in Atlanta, US, developed a generator composed of a forest of piezoelectric zinc oxide nanowires topped by a flat conductive plate. As the plate is pushed down, the wires bend, producing a voltage that induces current to flow into the plate.

    Now Wang has turned this idea into an electricity-generating thread, which he plans to weave into a fabric. His team figured out how to grow the nanowires on a strand of Kevlar fibre instead of a flat surface, so that the wires stick out from the fibre like the bristles on a pipe-cleaner.

    When two of the bristly fibres rub against one another, the nanowires deform, causing a current to flow through a thin layer of metal coating on one of the fibres.
    No prickles

    In tests with just two short fibres, Wang's team was able to generate a few picowatts of power, but they found that the power output increased 50-fold when three pairs of fibres are twined together into a yarn, increasing the area of contact.

    Wang estimates that the fabric should be capable of generating about 80 milliwatts of electricity per square metre, enough to charge a cellphone battery or other personal electronics from the ordinary motions of a shirt or a curtain blowing in the wind.

    If I were less tired at the moment I could probably think of a ton of fun stuff to do with this.

    Piezoelectric materials have been around for ages and there are a zillion harebrained ideas about how to use them. The interesting thing here is that Wang has found a way to increase the effective charge you can get from the materials.

    Just for starters, this could form the basis for a whole new form of wind power with close to zero moving parts. Just hang a length of the material somewhere where the wind will catch it and cause it to move.

    Found another article about this:

    By allowing nanowire growth to take place at temperatures as low as 80 degrees Celsius, the new fabrication technique would allow the nanostructures to be grown on virtually any shape or substrate.

    As a next step, the researchers want to combine multiple fiber pairs to increase the current and voltage levels. They also plan to improve conductance of their fibers.

    However, one significant challenge lies head for the power shirt -- washing it. Zinc oxide is sensitive to moisture, so in real shirts or jackets, the nanowires would have to be protected from the effects of the washing machine, Wang noted.
    • CommentTimeFeb 14th 2008
    They're not the only ones - Australia's CSIRO are working on the same idea, and all the lovely military applications that go with it. Because you might be dreaming of charging your ipod, but there are people who move more and need their electronics to work a lot more.
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    I think we've all seen where this is headed.

    • CommentTimeFeb 14th 2008
    And yet, I can't help but giggle at "Wang's team."
    • CommentTimeFeb 14th 2008
    "Power Shirt"? For those who just couldn't get cancer fast enough between cigarettes, TV, phones, microwaves and The Sun. Now you can just WEAR the "Cancer Shirt"! Great work, humanity. Never cease to amaze me.
    • CommentAuthorzacharius
    • CommentTimeFeb 14th 2008
    I suspect it's one of those energy return-on-energy invested kind of things. sure, power from the suit is harvested for free, but once you factor in the energy costs to make it, you probably get less out of it during it's useful life, then you put in to make it.
    • CommentTimeFeb 14th 2008
    Hey, weave a towel out of that stuff and you can power up your HHGTTG and Galactic Thumb anywhere!

    Or string a ribbon or ten of that across a canyon.. if Christo starts using some of that stuff, he'll be a millionaire in a fortnight.
    • CommentAuthorKosmopolit
    • CommentTimeFeb 14th 2008

    It's a reasonable question. The main material used is zinc oxide which shoudd be pretty cheap and easy to make and not very energy-intensive. It also uses a small amount of gold. The material is created at low temperature (ca. 80 degrees Celsius) so I don't see any reason why it should require a big power input.
    • CommentTimeFeb 16th 2008
    It's all beginning to come together. As nanotech improves such piezo-power systems will become more efficient - hook them up to powered exoskeleton, and then we'll really be talking.

    A slight issue of conversion efficiency to keep such a power hungry device charged, but at the very least it'll extend the battery life.
    • CommentAuthorPooka
    • CommentTimeFeb 16th 2008
    i agree with the cancer shirt line above...:P