Posting in Energy
Korean scientists create a nanowire panel that generates electricity from sound waves.
Korean scientists see (or hear) a possible energy source being wasted all around us. Noise.
Their hope is that someday your chattering voice could help charge your phone, or possibly highway walls could absorb the honking and drone of traffic to supplement the electric grid during rush hour.
Sound far-fetched? Well, at this point it pretty much is. But in their study in the journal Advanced Materials, the scientists created a piezoelectric material from zinc oxide that transforms sound waves into electricity.
Piezoelectric materials generate electricity from mechanical stress. The scientists sandwiched a bed of zinc oxide nanowires between two electrodes and exposed the device to 100 decibels. As the sound waves hit the electrode, it vibrated, causing the nanowires to compress and release. The piezoelectric nanowires generated around 50 millivolts. This is not enough to power a cell phone. And though some phone talkers seem like they are speaking at 100 decibels, humans typically converse at around 60 or 70 decibels.
Eric Bland writes for Discover:
Over the last few years, however, scientists have made dramatic advances in getting electricity out of piezoelectric devices. Most of these devices, which are not yet available for consumer purchase, would generate power as a person walks, runs or, in this case, talks. The U.S. Army is even looking at partially powering some vehicles by channeling the physical impact of a bullet into a small electrical current.
A bullet strike seems like a high price to pay for a modicum of power, but the world is a noisy place. If the technology develops, we might as well make use of all the clatter. That is, as long as it doesn't encourage people to talk even louder into their phones.
Related on SmartPlanet:
- Charge! Outfitting the military with clothing that serves as a battery pack
- Researchers investigate turning clothing into electrical chargers
- The future of cell phone charging
Sep 16, 2010
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I don't want o break anyone's bubble, but most US Navy shipboard telephones have been sound-powered (with simple voice coils) since at least the 1930's.
MrEddie: Still not even close - even if you could convert all of that energy into electricity, which is physically impossible. Converting even a small percentage of it would be very difficult.
prof@... yes, the laws of nature and what we imagine don't often agree! But, as a mind exercise, I do wonder if you could capture all the energy of 1) The sound waves of your voice 2) The air you push against the phone as you speak and 3) The energy it takes your jaw to produce the words, would you then have enough energy to power the phone?
There are some serious misunderstandings of the nature of energy in this report and, it appears, in the original paper. While the piezoelectric effect can indeed produce voltages, that is not power. The 100 decibel sound means a power of 1/100 watt on a square meter of surface. The 70 decibels of ordinary conversation is 1000 times smaller. A cell phone uses several watts during a call. It is highly unlikely that a human voice can power a cell phone - power available is at least 100,000 times too small. P.S. I am a physicist and recently taught this material.
If this could be used to generate large amounts of power; what about using these at airports to help support their power consumption? Or how much power do the digital billboards use? These are usually near high traffic areas. If we really think about it. The possibilities go on and on. I do wonder though if these are generators or batteries. Generators are cool but batteries just mean more stuff in landfills.
@FiOS-Dave You were in the U.S. Navy, weren't you? The Navy had sound-powered phones about that time. They didn't stop using them until recently.
Also, I remember back over 50 years ago, using sound powered headsets, with no external power source.
I think a better method would be like the old self wind watches, where a pendulum would wind the spring. The modern version would use the mech to charge a battery. This could be worn strapped to your arm or leg, or maybe integrated into a bluetooth headset.
If anyone's interested in more information on the science behind this story, we've set the original research article free to access for the next few weeks; you can find it here: http://www.materialsviews.com/details/news/843529/Self-Powered_Cell_Phones_Piezoelectrics_in_Action.html Adrian Miller Advanced Materials