Nokia Developed Wireless Power-Harvesting Phones 246
Al writes "An engineer from Nokia's UK research labs says that the company is developing technology that can harvest ambient electromagnetic radiation to keep a cellphone going. The researcher says that his group is working towards a prototype that could harvest up to 50 milliwatts of power — enough to slowly recharge a phone that is switched off. He says current prototypes can harvest 3 to 5 milliwatts. It will require a wideband receiver capable of capturing signals from between 500 megahertz and 10 gigahertz — a range that encompasses many different radio communication signals. Other researchers have developed devices that can harvest more modest power from select frequencies. A team from Intel previously developed a compact sensor capable of drawing 6 microwatts from a 1.0-megawatt TV antenna 4.1 kilometers away."
Crazy Idea - during his time... (Score:3, Insightful)
Another great example as to how Tesla has shaped our future. Truly ahead of his time by leaps and bounds.
Re:Crystal radio (Score:3, Insightful)
They also reduce the power of the signal for everyone else further away from the transmitter, reducing the range of the signals. If deployed widespread into cellphones, this could result in a non-trivial reduction in signal range for broadcasters in the harvested frequency range.
But if they sequester a range of frequencies specifically for wireless power usages....
Re:Why not solar? (Score:5, Insightful)
Where do you put your mobile phone when not in use?
Exactly.
Re:Crystal radio (Score:3, Insightful)
But if they sequester a range of frequencies specifically for wireless power usages....
No one would use them for broadcast, and thus, no "free" energy to suck up.
Re:Cellphone Range (Score:3, Insightful)
Which leads to more power to harvest.
Which leads to more devices developed to harvest it.
Which leads to more powerful signals.
Which leads to Tesla's dream of sufficient power being broadcast wirelessly to run all of our electric devices. For free! Woohoo!
(Well, either that, or the amount it takes from the signal is so tiny as to not make any practical difference...)
Re:Crystal radio (Score:3, Insightful)
But if they sequester a range of frequencies specifically for wireless power usages....
No one would use them for broadcast, and thus, no "free" energy to suck up.
Someone would: the people using it for power for their wireless communication devices. They could just have it broadcast dead air (silence) or white noise, though they'd likely figure out a suitable signal that maximizes the power that can be harnessed most efficiently.
Re:Why not solar? (Score:5, Insightful)
I'll stop putting my phone in my pocket the moment someone proves that this "possible harm" is anything more than luddite hysteria.
Re:Crystal radio (Score:4, Insightful)
Do you know how incredibly inefficient a power broadcast system would be?
Do you know the rate at which said power broadcast would drop off with regards to range?
Simple physics.
Re:What is the CEO of Nokia doing? (Score:3, Insightful)
Presumably, they're relying on the fact that you're very rarely within range of just ONE transmitter. I'm going to assume that the following maths are bad, but if 1Megawatt gives you 6miliwatts from 4.1Km away, then is it unreasonable to assume that if you're 2.05Km from that same transmitter, you could get 12millwatts?
And getting back to the first point, what if there's more than one transmitter nearby? Cellphone stations, radio towers, TV transmitters and so on - it's bound to all add up in some way. No doubt this technology would be completely useless for those who are in the country or less "dense" areas, but for the people who live in or near the City, it could probably reach that figure with ease.
Or a different way to look at it - right now, there's a lot of "potential" energy floating around that's just going to waste. Technology like this could make use of it and when distributed on a large scale could feasibly save the economy a hell of a lot of money.
Microwatts, not milliwatts (Score:4, Insightful)
The Nokia press release says they are expecting almost 10,000 times 6 microwatts, all received inside a tiny cell phone that is covered with metal.
Re:Need More (Score:3, Insightful)
is left as an exercise for the reader.
What, I must have cheated when I watch this documentary about time travel several years ago.
Re:Crystal radio (Score:4, Insightful)
What you suggest is deliberately sending out EM energy for these devices to pick up and recharge. The EM waves don't travel directly to phones; they travel in all directions from the tower. I don't know the exact equations, but for a cell phone a couple of miles from a tower you can count the zeros in the efficiency numbers. Tesla experimented with this idea, but found that the efficiency made it not feasible over any worthwhile distance.
To respond to grandparent's post, there is the possibility it could result in a non-trivial reduction in signal strength. However, I'll bet our use of aluminum and steel in large quantities for buildings, roads, and bridges have a larger effect today (as one constraint is the size of the device).
Re:Why not solar? (Score:3, Insightful)
Re:Huh? (Score:4, Insightful)
That's insane.
What do you think they're going to do, block the entire airways between the buildings with cellphones? Most of the radiation is going to miss the phones *and* the buildings.
Re:Microwatts, not milliwatts (Score:3, Insightful)
Comment removed (Score:3, Insightful)
Solar cell (Score:4, Insightful)
wrong (Score:3, Insightful)
So? What does it matter whether it's "an actual stream of electrons moving along like wires"? Electrical signals in biological systems get generated and transmitted by tiny local movements of ions across membranes in order to change local electrical fields, fields that then change the shape of charged molecules slightly. The process is very sensitive to electrical fields, and it can be affected by radio waves.
Re:Crystal radio (Score:3, Insightful)
This would be plain crazy, they usually shut down the transmitter during maintenance. Are they still doing it today ?
I wouldn't like being kept warm in a microwave oven, would you?
Re:wrong again (Score:2, Insightful)
While the voltages involved are small (up to a hundred millivolts), it's the strength of the electrical field that is important ant this is more on the order of thousands of volts per metre, more then an order of magnitude stronger then you would find near even the strongest transmitters.