Is Nokia's Cell Phone Recharging via Radio Waves Really Possible?

In summary, Nokia has invented a phone that recharges itself using ambient radio waves. This is good news because it means that cell phones will not run out of juice as often. It is not clear if this technology is only useful in major cities, but if it is, it would be a valuable addition to the arsenal of cellphone users.
  • #1
OAQfirst
23
3
I'm not knowledgeable about these things, with all the free energy nonsense I frequently see. So what do you think?

http://tech.yahoo.com/blogs/null/143945
Nokia, however, has taken another baby step in that direction with the invention of a cell phone that recharges itself using a unique system: It harvest ambient radio waves from the air, and turns that energy into usable power. Enough, at least, to keep a cell phone from running out of juice.
Does this sound right? If so, it looks like exciting news. Even for stand-by charging, that's still a good thing.
 
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  • #2
You have to assume Nokia have done their sums.
But assuming the signal is a couple of milliwatts and you leave it on continually.
My phone battery is 700mAh x 3.6V so stores around 2.5Wh, charging with 1mW would take 3months! It's difficult to believe it's even enough to overcome the leakage in the charging circuit.
 
  • #3
It reports their goal is 50 milliwatts. Would that be substantial enough?
 
  • #4
My phone lasts a week on standby with a 2500mWh battery so around 15-20mW - if they can pull 50mW out of the air that would certainly help.
I suppose if they didn't just use the phone antenna they could also use the power form lots of other transmitter sources, TV/radio/wifi etc.
 
  • #5
Hmm. Well, here's to hoping!

Thanks.
 
  • #7
Presumably. I wonder if anyone has actually calculated how dense the radio energy is in various places.

[edit] calculation deleted. I guess you'd want to do a calculation based on surface area...
 
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  • #8
...and over what range of frequencies?
 
  • #9
russ_watters said:
Presumably. I wonder if anyone has actually calculated how dense the radio energy is in various places.

[edit] calculation deleted. I guess you'd want to do a calculation based on surface area...

I immagine you would want to make your windings as large as possible to contain the maximum amount of magnetic flux. Probabilly the entire surface area of the phone. Also, if the phone wasn't sitting in the correct orientation with the source, you wouldn't get anything.
 
  • #10
The surface area of a 1"x2"x4" phone is 8 square inches. At 50mw, that's 900 mw/sq ft. The side surface area of my 19x14x8' living room is 528 square feet, which would mean if I wrapped it with antennas, could generate 475 w. My house is 20'x40'x20', or 2400 square feet side surface area. That's 2.1 kW, which (with storage), would be more than enough to supply all my energy needs.

I find that hard to swallow.
 
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  • #11
OAQfirst said:
It reports their goal is 50 milliwatts. Would that be substantial enough?

Over what time frame?

When would this be most useful? I'd think if you were stranded out in the wilderness without a charger is when you'd need something like this...one would hope the charge would happen fast enough to call for help before you die of dehydration or exposure to the elements. Otherwise, it's nothing more than a gimmick.
 
  • #12
miliwatts is power, Moonbear - it's got a timeframe in it (seconds).
 
  • #13
Isnt it illegal to 'harvest' energy from radio waves? I could imagine those who live near the transmitters putting up huge coils on their houses to sap up the free kilowatts.
 
  • #14
russ_watters said:
miliwatts is power, Moonbear - it's got a timeframe in it (seconds).

D'oh. Sorry, I made the classic mistake of mixing up power and energy. Thanks for the correction.
 
  • #15
Blenton said:
Isnt it illegal to 'harvest' energy from radio waves? I could imagine those who live near the transmitters putting up huge coils on their houses to sap up the free kilowatts.

What transmitter?
 
  • #16
Radio station transmitters.
 
  • #17
Blenton said:
Radio station transmitters.

I would think that's somtehing you could do right now. I was thinking he meant that Nokia was planning on building transmitters specifically for recharging cell phones.
 
  • #18
No I believe they meant radio waves currently in the air.
 
  • #19
Before I read the Yahoo! article, I assumed induction, like the contact-free charger for my Braun toothbrush, or the ones used to recharge cardiac pacemakers and ICDs (implanted defibrillators). It doesn't look like that's what they meant.

My immediate image was of holding a four-foot fluorescent tube under an HT power transmission line and seeing it glow dimly. Kinda neat, but not a lot of oomph for being so close to the EM source (albeit 60Hz, not RF). I aint' doin' the math for that, so I'd like to see a white paper or something before I throw away my chargers.

Neat topic
 

What is recharging via radio waves?

Recharging via radio waves is a wireless technology that allows devices to be charged through the air using radio frequency waves instead of traditional charging methods such as cords or cables.

How does recharging via radio waves work?

Recharging via radio waves works through a process called electromagnetic induction. This involves a transmitter emitting radio frequency waves, which are then received by a receiver coil in the device being charged. The receiver coil then converts the radio waves into electricity, which is used to charge the device.

Is recharging via radio waves safe?

Recharging via radio waves is generally considered safe. The radio frequency waves used are non-ionizing, meaning they do not have enough energy to cause harm to human cells. However, it is important to follow proper safety guidelines and use certified products to minimize any potential risks.

What are the benefits of recharging via radio waves?

Recharging via radio waves offers several benefits, including convenience, efficiency, and versatility. It eliminates the need for cords and cables, making charging more convenient and reducing clutter. It is also more efficient as it can charge multiple devices at once and can be used with a variety of devices, from smartphones to electric vehicles.

Are there any limitations to recharging via radio waves?

While recharging via radio waves has many advantages, it also has some limitations. The distance between the transmitter and receiver must be relatively close for efficient charging. Additionally, the technology is still in its early stages and may not be as widely available as traditional charging methods.

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