~e; electromagnetic body-power
Sun, 30 Dec 2001 20:11:04 -0600
Unlocking the Power of the Body Electric
December 27 2001
Scientists are working on tiny batteries that capture energy derived
from motion and heat for military and civilian uses.
By Dave Wilson
American soldiers slogging though Afghanistan use constant radio
communication, satellite navigation and night vision goggles. Today,
a single grunt has capabilities and powers a battalion couldn't call
on just a couple of decades ago.
But the gizmos that give a commando godlike abilities devour power.
There was a time not so long ago when all an infantryman had to carry
were a weapon and ammo. Now he's got to drag around a couple of
pounds of batteries for stuff like his range finder.
Some servicemen have to lug a pack that tops 100 pounds, depending on
the mission. When gear gets that heavy, the choice comes down to
packing an extra AA battery or another couple of rounds for the
rifle. There's only so much weight a man can carry before he looses
his effectiveness as a soldier--and in many cases, a battery can be
more important than a bullet. That is one reason so many researchers
are trying to capture electricity derived directly from human bodies
to power portable devices. Although much of the research has been
aimed at military applications, low-end civilian uses for this
technology will appear soon, perhaps even next year. And someday, the
ability to self-generate power might help dramatically redesign many
For decades, the normal movements of the human body have powered some
smaller gadgets. The best example is a self-winding watch, which uses
the frequent motion of the human arm to wind a spring and keep the
clock mechanism moving.
Several researchers, such as Joe Paradiso, head of the responsive
environments group at the Massachusetts Institute of Technology's
Media Lab, have installed tiny power generation equipment in shoes.
Every step generates a burst of electricity. Properly controlled,
that's the sort of thing that could power a radio.
"The trick here is storing the electricity in some kind of battery,
so that the power doesn't stop if you're not walking around,"
Other researchers are thinking about other ways to tap the energy
created by the human body. One of the most common methods is based on
a well-understood principle that the difference in temperature
between two objects can be converted into electricity. Advanced Power
Solutions Inc. of Palm Beach, Fla., said its tiny thermoelectric
generator will be used in a wristwatch that may be on the market next
year. The generator creates electricity based on the difference in
temperature between skin and air.
Why should anybody care about this?
"Beyond the life-and-death decisions on the battlefield, which is the
focus of much of the research today, many people think this kind of
technology will help us conserve energy in the future," said Henry W.
Brandhorst, director of the Center for Space Power and Advanced
Electronics at Auburn University. NASA is funding the center's power
research for use on space missions.
Look for the technology eventually to filter down to consumer devices
such as mobile phones and electronic organizers. "We depend on
batteries, and they always seem to fail us at the worst possible
time," he said. "I just tried to turn on my Palm Pilot yesterday and
Tapping into the power human bodies produce holds out the possibility
of making medical devices largely self-contained. Someday, a cardiac
patient may not need to get his chest cracked open every few years to
replace the pacemaker battery.
But the technology's most profound effect may be in the way people
design and interact with portable devices.
Battery power dictates the size and shape of just about every
electronic gizmo. Part of the reason pagers clip to a belt instead of
being worn as rings or shirt buttons is the size of the batteries
needed to power them.
Someday, however, with clothing that collects and stores electricity,
and gadgets designed to draw power from that system, form really will
follow function. Gadgets will be no bigger than they need to be to do
the job. Which means soldiers will be able to carry more of the
lifesaving gear they need to do their jobs.
But Paradiso of MIT said that day won't arrive soon.
"People love this idea, but there's a lot of work that needs to be
done. Making all this work at that level is going to be pretty hard."
Dave Wilson is The Times' personal technology columnist. He can be
reached at dave.wilson @latimes.com.
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electromagnetism / infrastructure / civilization