Wirelessly-powered phones on sale within four years, says Nokia Nokia has claimed that by 2013 it could become possible to recharge your phone from the ambient electromagnetic radiation (AER) emitted by Wi-Fi transmitters, mobile phone antennae and TV masts. The Finnish phone firm has developed a prototype AER phone able to suck up 3-5mW of power, but said it’s working towards a prototype …
Coverage elsewhere says this technology includes a wideband (relatively untuned) microwave antenna and a receiver circuit.
Coverage elsewhere does not explain what's powering the receiver circuit, or how a relatively untuned antenna followed by an amplifier extracts more power than it uses.
The thing about both crystal sets and RFID is that they work using *tuned* (not untuned) circuits to extract a narrowband signal from a wideband RF smog.
How does that work with *untuned* antennae which need amplifiers (that's what a receiver is, an RF amplifier followed by a signal extractor; in this case the signal extractor isn't needed)?
Still, there's one born every minute.
Hands up who knew before today that Nokia had a Cambridge Research Laboratory?
Now that's more like it.
In my house, with the huge amount of Wireless gadgets, WiFi signals, mobile traffic, and not to mention that electricity pylon just down the road zapping me with radiation, I should be able to charge hundreds of Nokias!
Maybe I can store the energy and flog it back to the grid :-)
Worrying thing is what all this is doing for my health though.
I seem vaguely to remember I've got a calculator at the back of a drawer gathering dust somewhere that used to recharge itself using a solar panel. The problem is that if too many consumer electronic device designers latch onto this idea too efficiently they will suck all the power out of the mobile signal, resulting in increased shadow the further away from the transmitter you get.
Then the mobile phone companies will have to double and quadruple their masts, and eventually they'll be providing free electrical power to all and sundry for any application. I kind of suspect different departments within Nokia might have a conflict of interest here.
Since (if I remember from my schooldays correctly) it's a cornerstone of physics that energy/matter is neither created nor destroyed but merely changes form, where does all the power that's pumped out by transmitters end up currently?
I guess it mostly ends up as heat in various places. Hmmm maybe carbon emissions aren't the only thing heating the planet up!
"2. Is it physically possible for a phone to absorb more energy than a similarly sized piece of copper, painted black?"
That is a very interesting question. At microwave frequencies I'm not sure the black paint is relevant, but I'd love to hear a definitive and well explained answer to the question.
So far, I'm thinking the phone can't absorb more than the metallic absorber. I'm thinking the answer might change a bit if there was some kind of tuned coupling between a narrowband signal and a tuned aerial, but that's *not* wot Nokia are proposing, they have wideband RF and a wideband aerial.
But I'm willing to be persuaded otherwise.
At 5mW 24/7 your phone will harvest enough energy to make 1 cup of tea every 217 days.
During the life time of the phone it will harvest significantly less energy than it took to manufacture the electronics required to do the harvesting.
Complete and utter greenwash garbage.
Harvesting energy from the 'ether' only makes sense for ultra low power equipment where it can completely remove the need for a battery (and the sometimes high cost of replacing it) and even then it is marginal.
If all you are going to do is convert RF energy to DC power, you don't need a tuner; indeed, using one would be counter-productive. All you need is an antenna of some sort, a rectifier, and possibly a capacitor to smooth out the current flow.
The biggest drawback to this idea is that it would only trickle-charge the phone when it was turned off. In my case, I leave the phone turned on nearly all of the time, including when charging, so that I will receive any incoming calls instead of having them roll over to voice mail.
Maybe it's not a green solution. However it might be the answer to the "Universal Charger". i.e. phone manufacturers do away with a mains charger entirely, meaning no complications over different connectors etc, and a cost saving in manufacturing the charger plus the packaging required.
And after all, they've (all?) signed up to make a universal charger for all phone brands (except I assume Apple will refuse on the basis they can't flog a sexy Apple branded charger that's unique to them).
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