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Talk-Powered Cell Phones Won't Need Batteries
Posted by
samzenpus
on Wed Dec 03, 2008 06:48 PM
from the talk-charging dept.
from the talk-charging dept.
alphadogg writes "It's possible that in the future conversations on your cell phone could generate enough electrical power to run the phone, without batteries.
That's one possible outcome of recent work by a team of Texas researchers, who appear to have discovered that by building a certain type of piezoelectric material to a specific thickness (about 21 nanometers, compared to a typical human hair of 100,000 nanometers), you can boost its energy production by 100 percent. And the technology could power not just phones, but a whole range of low-power mobile devices and sensors. The breakthrough is an example of 'energy harvesting' that can convert one kind of energy, such as vibrations or solar rays, into electricity."
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Isn't this fairly common already (Score:5, Funny)
Re:Isn't this fairly common already (Score:5, Funny)
I see you've met my sister. She comes through clear as a bell from 8 states away. Next time, I'll have her turn her phone on...
Parent
Re:Isn't this fairly common already (Score:5, Funny)
If she's that loud, her vocalizations could probably power other "battery operated" devices she may use...
Parent
If you can get the power down (Score:5, Insightful)
Current cell phone technology is perhaps four orders of magnitude away from piezo power. At ten times the piezo power level, say 10mW, you may as well use small cheap batteries. One non-rechargable AAA cell would run for approx 700-800 hours at those levels.
Parent
Re:If you can get the power down (Score:5, Informative)
?
Your math. It is very wrong.
A typical AAA battery is 1.5v @ about 900 mAH.
Round that up and you get 1500 mWH.
1500 mWH / 10 mW = 150 hours.
Parent
Re: (Score:3, Interesting)
I don't talk enough on the phone to power it for standby. But what about one powered by motion, much like an automatic watch? Does it generate enough power?
I personally hate batteries, at least the current technology. Perhaps ultra-capacitors one day...
No battery required (Score:5, Funny)
If you assume normal human speech is about 60dB. We know dB = 10 log(I/I0) where I0 is 10^-12 W/m^2. So 60dB works out to about 10^-6 W/m^2 -- that's a microwatt per square meter. With 100% efficiency and a mike of 1 cm^2 collecting area, that's around 10^-10 W -- 0.1 nano-watts. (Thanks phliar [slashdot.org] for the calculations.)
Then utilize this energy using recent advances in String Theory, and you have a workable solution.
Here's a picture of a prototype. [worldofstock.com]
Parent
Re:If you can get the power down (Score:5, Interesting)
Because I rarely talk on my phone more than 10 minutes during the course of a month. And I still like to be able to receive calls on a random basis. Voice powered calling is worthless for people that spend that kind of time carrying the phone around rather than talking on it.
A much better solution would be to put something in that converts the jostling motion that handhelds are constantly subjected to into power. Sort of like the old self winding watches.
Parent
Traffic noises are helpful now! (Score:5, Funny)
Hey, my phone's running low on power, let me find some heavy traffic and big trucks so it'll be loud enough for me to hear you!"
Next thing you know you'll have to shake your phone to get features to work (oh, wait...)
Parent
Re:Isn't this fairly common already (Score:5, Insightful)
Parent
Re:Isn't this fairly common already (Score:5, Insightful)
On the other hand, "funny" can now be used as the mod you give to "epic fail" posts (e.g. dead wrong or missed the joke). It can raise those posts up above the trolls for all to see, and open the authors to public embarrassment, all the while failing to reward them with karma. It's really not an unfair use of the moderation system. Who said funny has to mean laughing with the author - can't it mean laughing at the author?
Parent
Re:Isn't this fairly common already (Score:5, Insightful)
Talk to CmdrTaco. Of course, it's been this way for about 8 years, so don't expect anything to change. Of course, that doesn't stop them from the Web 2.0 paradigm of replacing a perfectly usable and nice home page design with something eye-gougingly ugly and much harder to use.
Parent
Re:Isn't this fairly common already (Score:4, Interesting)
Hmm, what sort of consequences?
Moderations often affect the tone of a message. A misplaced 'Insightful' mod can turn a joke into perceived ignorance. That can lead to negative moderations and a flood of comments trying to dispute it. It's not the most common thing in the world, but I've seen it happen several times.
That's not to say I'm against the idea of a funny comment being modded informative. I do, however, have a preference that people don't use Insightful mods solely to give funny comments karma. And yes, I've softened my stance a bit. Heh.
Parent
Re:Isn't this fairly common already (Score:5, Insightful)
The reason funny gets modded insightful is because negative mods hurt karma, but funny doesn't add karma. Funny can draw just as much rebuttal as insightful. So if someone says something witty that holds an issue to the light of reason I'll go for the insightful mod.
Sometimes I'll mod something I regard as particularly dense as funny rather than a negative mod. But I laugh at stupid stuff in RL too.
If you don't agree, metamod.
Parent
a return to Pyramid Power (Score:5, Funny)
Just set it in a Pyramid and use pyramid power to keep it topped off. That is what they ancient Egyptians did.
Don't forget to call your Mummy.
not enough energy to power a modern cell phone (Score:5, Insightful)
Most modern phones are probably much too power hungry to be get enough energy from audio vibrations, even you manage to ramp up the efficiency close to 100%, which is unlikely to ever be practical.
Where this could be useful is in specialized low-power devices that get bundled into emergency survival [ready.gov]
kits.
OTOH, future cellular devices might incorporate enough improvements into power efficiency (e.g., e-ink displays [wikipedia.org]), such that you could significantly extend battery life and perhaps even power a very basic subset of the phone when the battery runs out.
Also, harnessing vibrations efficiently might be very useful in surgically implanted medical devices where replacing the battery can be rather inconvenient [wikipedia.org].
Re:not enough energy to power a modern cell phone (Score:5, Funny)
Mmmm, I dunno. If this turns out to be true my wife could talk on the phone enough to power the whole grid.
Parent
Re: (Score:2, Informative)
Re:not enough energy to power a modern cell phone (Score:5, Funny)
His heart implant is failing hand me a vibrator stat!
Parent
That's just great. (Score:5, Funny)
Wonderful. I can just imagine being in a restaurant or an elevator with a group of people with phones all saying "Low Power - please speak louder."
Re: (Score:2)
CAN YOU HEAR ME NOW!!!!!!!!!
GOOD!!! OUCH!!!! (as a fist-powered brickbat comes crashing down on his head)
Re: (Score:2)
Why don't they use body heat? (Score:4, Informative)
And, no I am not talking about the Matrix...ok...it crossed my mind.
I remember there was also a digital watch that worked on body heat. I could not find that one, but I found another, non-digital. http://www.roachman.com/thermic [roachman.com] .
Re:Why don't they use body heat? (Score:5, Insightful)
Why would you want one? We have watches working off the constant motion of our body/arm/wrist/whatever. Mine takes a few days before it winds down. I think that anyone that stays immobile for that long will not be doing so great in respect of body heat, either.
Parent
Re: (Score:2)
The harvesting of heat energy always depends on the temperature differential between two materials. The temperature differential between your body and ambient air is so low that it can only be used to produce very, very, very little power. It just so happens that a watch can be designed to run on very, very, very little power--way less than required by a cell phone, you know with its little transmitter and all that kind of stuff ;-)
Physics might say otherwise (Score:5, Informative)
Re: (Score:2)
"Won't need batteries" may be a bit of an exageration, but even if the new tech only increases time between required charges a bit, it seems like a win to me.
Technology not for some married men (Score:5, Funny)
Yes, honey. Ok, honey. Will do, honey.
Re: (Score:2)
Ya, I was thinking the same thing. It would only work for woman to woman calls were they are able to fully duplex the conversation without pause.
I don't think you can power any think on uh-hu, yes, maybe, ok, and goodbye.
Re: (Score:3, Insightful)
I don't know if this would work for me, because I usually just end up listening on my phone. Yes, honey. Ok, honey. Will do, honey.
Yeah, but you could sell the excess power your wife generates to the utility.
I think women talking on cell phones will solve our future energy needs.
Texas (Score:3, Funny)
However Olivetti is working on a cellphone powered like a self-winding watch, by arm-motion.
Supply energy to the world! (Score:5, Funny)
Just hand these out to teenage girls and we'll have enough power to supply the entire world for all its needs.
Re: (Score:3, Funny)
Nah, for that you need a tiny dynamo underneath each button...
Re:Supply energy to the world! (Score:5, Funny)
Nah, for that you need a tiny dynamo underneath each button...
Bad girls have that under their zipper.
Parent
One HUNDRED Per Cent?? (Score:4, Insightful)
Wow, that is amazing!!!
Now if someone could tell me what the baseline of this increase is, we might actually learn something...
(seriously, does anyone know what the efficiency of current nano-piezoelectric power generators are?)
bspower (Score:2)
New idea, meet old idea? (Score:3, Interesting)
Yet for some reason we don't all have those...
Of course, very few people do much typing on their laptops now, but there are some people who presumably could have found it quite useful.
Music! (Score:2)
Re: (Score:2, Funny)
Just hold one of the headphones up to it once in a while.
I'm not yelling.... (Score:4, Funny)
...I'm just charging my batteries.
"battery's almost dying, I need to talk some more, let me call AOL and try to cancel."
What are they "powering"? (Score:2)
The mW needed to transmit the cell signal? Or the power needed to illuminate the 2x2" full color screen with real-time GPS positioning, speakerphone, and fluid game play?
The former.. possible. The latter.. only if you put the phone in a paint mixer.
Won't they still need batteries? (Score:2, Insightful)
Bullshit (Score:2, Insightful)
Uh oh. Piezo-electric butterflies? (Score:2)
Now every phone conversation can start a tornado or hurricane somewhere!
Do the math, Barbie (Score:5, Insightful)
It does not matter if they improve the microphone efficiency to exactly 100% The amount of power in any reasonable voice is miniscule at best. And most of the power is in the lower part of the register, where the sound wavelengths are several meters long. And to get even a fraction of the power out of a wave, you need a microphone at least a quarter wavelength across.
So even if cell phone microphones were a foot in diameter, they'd only capture a few milliwatts on voice peaks. And cell phones need a couple watts of power full-time to output a watt or so to the antenna. No way, Jose, and by at least three zeros after the "1".
Re:Do the math, Barbie (Score:5, Informative)
A little help for those too lazy to do the math:
Power per area transmitted by a sound wave:
F = p^2 / (rho0 c)
where
p = rms pressure variations in the sound wave (.01-.05 Pa or so for human voice)
rho0 = density of air (1.3 kg/m3 typ.)
c = speed of sound in air (330 m/s)
I get 1 microwatt per square meter. So for a 20-cm2 cell phone, 2 nanowatts, ignoring the receiver-coupling issues mentioned by the parent post.
No way, Jose, and by at least three zeros after the "1".
Let's make that nine.
Parent
I feel a great disturbance in the force (Score:5, Funny)
Not enough energy (Score:4, Insightful)
Some back-of-the-envelope calculations: normal human speech is about 60dB. We know dB = 10 log(I/I0) where I0 is 10^-12 W/m^2. So 60dB works out to about 10^-6 W/m^2 -- that's a microwatt per square meter. With 100% efficiency and a mike of 1 cm^2 collecting area, that's around 10^-10 W -- 0.1 nano-watts.
Color me skeptical.
Re: (Score:2)
YEAH NO I AM AT THE MOVIES WHAT? NO, WE'RE IN THAT NEW FILM, YEAH IT'S GREAT (really shouting) HANG ON I CAN BARELY HEAR YOU YEAH THE GUY DIES AT THE END I'VE SEEN IT
please god no
Re: (Score:3, Funny)
These could be wall panel in loud factories and make the electric meters run slower....someday, maybe even backwards...wait....that darn 2nd law of Thermodynamics, again! Okay, slower.
I'm sure you could come up with noise sources that don't draw from the grid to get the meter to run backwards without violating entropy. It all depends on not keeping the system closed.
One way would be to regularly feed humans to the machinery. They don't consume power off of your grid, but they sure do make a lot of noise, especially when inserted feet first.