Talk-Powered Cell Phones Won't Need Batteries 197
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."
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].
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?)
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.
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.
Won't they still need batteries? (Score:2, Insightful)
Re:Technology not for some married men (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.
Bullshit (Score:2, Insightful)
Re:Isn't this fairly common already (Score:5, Insightful)
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: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.
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?
Re:Isn't this fairly common already (Score:2, Insightful)
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.
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.