Prototype Nokia phone recharges without wires

[preppiechick]

Prototype Nokia phone recharges without wires

Christopher Null: The Working Guy

Tue Jun 16, 2009 1:06PM EDT


Pardon the cliche, but it's one of the holiest of Holy Grails of technology: Wireless power. And while early lab experiments have been able to "beam" electricity a few feet to power a light bulb, the day when our laptops and cell phones can charge without having to plug them in to a wall socket still seems decades in the future.

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.

While "traditional" (if there is such a thing) wireless power systems are specifically designed with a transmitter and receiver in mind, Nokia's system isn't finicky about where it gets its wireless waves. TV, radio, other mobile phone systems -- all of this stuff just bounces around the air and most of it is wasted, absorbed into the environment or scattered into the ether. Nokia picks up all the bits and pieces of these waves and uses the collected electromagnetic energy to create electrical current, then uses that to recharge the phone's battery. A huge range of frequencies can be utilized by the system (there's no other way, really, as the energy in any given wave is infinitesimal). It's the same idea that Tesla was exploring 100 years ago, just on a tiny scale.

Mind you, harvesting ambient electromagnetic energy is never going to offer enough electricity to power your whole house or office, but it just might be enough to keep a cell phone alive and kicking. Currently Nokia is able to harvest all of 5 milliwatts from the air; the goal is to increase that to 20 milliwatts in the short term and 50 milliwatts down the line. That wouldn't be enough to keep the phone alive during an active call, but would be enough to slowly recharge the cell phone battery while it's in standby mode, theoretically offering infinite power -- provided you're not stuck deep underground where radio waves can't penetrate.

Nokia says it hopes to commercialize the technology in three to five years.

[Potemkin]

Tesla did it!



OK, not exactly but he did come up with the wireless power transfer idea.

[US Blues]

My Oral B toothbrush has been doing that for years

[afljafa]

Originally Posted by US Blues

My Oral B toothbrush has been doing that for years

I was thinking the exact same thing. LOL.

[Potemkin]

OK, this is a little different. Your Oral B and my Sonicare use the plugless recharching but this is a little different.

This will use the EMF "in the air" to give the phone a low power charge. If you think about all the EMF flying through the air from radios, electrical lines, etc. it is a wonder someone hasn't done this before.

It is amazing how much is there. I rented a house with some high power line. A PC CRT I had in the house glowed all night from the EMF. Good thing it was in the den and not the master bedroom. (BTW, did you know if you take a fluorescent tube, stand under high power line, and turn it 90degrees to the line it will light up?)

[afljafa]

Of course - but it was the first thing that popped into my head.

[Susie]

If they can do it with phones, can they please do it with houses?

[Old Hawk]

Over 50 years ago Popular Electronics published a project for a crystal radio that harvested broadcast emf to power a one transistor audio amplifier for itself.

There is way more broadcast power in the environment now than there was then.

http://en.wikipedia.org/wiki/Crystal_radio
Attempts at recovering RF carrier power

A crystal radio tuned to a strong local transmitter can be used just as a power source for a second amplified (often a power-efficient regenerative) receiver for distant stations that cannot be heard with a plain crystal radio.[4]
There is long history of less successful attempts and unverified claims to recover the power in the carrier of the received signal itself. Traditional crystal sets use half-wave rectifiers. As AM signals have a modulation factor of only 30% by voltage at peaks[citation needed], no more than 9% of received signal power (P = U2 / R) is actual audio information, and 91% is just rectified DC voltage. Given that the audio signal is unlikely to be at peak all the time, the ratio of energy is, in practice, even greater. Considerable effort was made to convert this DC voltage into sound energy. Some earlier attempts include a one-transistor[5] amplifier in 1966. Sometimes efforts to recover this power are confused with other efforts to produce a more efficient detection.[6]. This history continues now with designs as elaborate as "inverted two-wave switching power unit"[4] and bridge amplifiers[citation needed].

http://www.newscientist.com/article/...y-special.html
Energy-harvesting antennae

Plenty of RFID tags do not need a battery. Instead, each tag has an antenna connected to a circuit that converts an AC signal to a DC voltage when zapped with radio waves from a tag reader. The tag then uses this voltage to transmit a signal of its own. Essentially, the tags harvest energy from ambient radio waves.
But, since there is no shortage of radio signals on the airwaves, might it be possible to harvest a little of this too?
Marlin Mickle, an electrical engineer at the University of Pittsburgh, thinks so. His idea is to make tags with numerous antenna circuits, each tuned to absorb energy from a different radio frequency.
The antenna should thus harvest juice from commercial radio stations, public service transmitters, and anything else on the airwaves, producing clean and free energy from an as-yet untapped source. This method could be used to power other devices than RFID tags too.
See the full energy harvesting antennae patent application.

OH

[afljafa]

Sure - Cats Whisker. My father used to make them as a boy.

[Potemkin]

Originally Posted by Susie

If they can do it with phones, can they please do it with houses?

With a large enough antenna, yes.

However to run everything a modern house uses you would needs tons of copper wire.

Modestly you could get away with a light and some trickle charging.

[Old Hawk]

Sure - Cats Whisker. My father used to make them as a boy.

I can't remember how many crystal radios I made but it was a bunch and launched me on a lifetime career in electronics.When the germanium diode came along the cat whisker was no longer needed.

Originally Posted by Potemkin

With a large enough antenna, yes.

However to run everything a modern house uses you would needs tons of copper wire.

Modestly you could get away with a light and some trickle charging.

Pote, such a device might have several applications for preppers including radio receivers and low power transceivers. Any possibility of a DIY project?

OH

[Potemkin]

Originally Posted by Old Hawk

Pote, such a device might have several applications for preppers including radio receivers and low power transceivers. Any possibility of a DIY project?

OH

The concept is simple as you know it is nothing more than induction of a current in a wire by a magnetic field.

Most times, you build the coil, and push a magnet through the center and watch the voltage. Simple school experiment.

The bigger the coil, the greater voltage. Instead of moving a magnet through the coil the AC voltage would create the field.

Maybe a frame about 3'-6' in dia., out to a 110v? AC (or whatever, unclear here, haven't figured that out) to 12v converter to batteries.

Maybe tune the coil size/winds to hit an easy voltage like 220v, 110, or something close to 12v?

I thought of this after hearing a story from my Father who talked about hobos doing something similar when camping along the tracks.

They could toss loops of wire over the power lines and bring it down to a incandescent light. They didn't get full wattage but it would glow enough to see in the dark after your eyes got accustomed to it. I also remember he said they used it for a small radio.

Capturing EMF was radio waves? Probably a little beyond me, I am just a hacker.

DIY project? I do have a buried high power line behind my house but I think any project would have to wait until I get out of Graduate school.

[Old Hawk]

EMF is Electromotive Force or simply voltage.

Ordinarily one would want to capture a given frequency with a tuned parallel circuit and just detect the AM signal with a rectifying diode. That's easy, I cut my teeth on that.

But in this case we want to capture the energy in all available signals, or perhaps to identify and harvest the richest frequencies. It will still be in the low millivolt range. The voltage produced would have to be electronically multiplied on the order of 10,000 times to get high enough to trickle charge at 9 volts.

Pretty sure it could be done (Nokia is doing it) but I haven't the foggiest exactly how.

BTW, there is much prepper enthusiam for crystal radios for am reception with no power required. I once made one inside a fountain pen, then all you need is a long wire antenna and a ground.

OH