Invention from MIT, revisited

Interesting physics. I have seen the product and it's amazingly convenient. Problem is getting CE companies to standardize and adopt it.

--Waikit Lau

I remain skeptical

This is very old technology, that is well understood and it is being repackaged and hyped.

Tails of energy indeed! A blatant attempt to hype it as new and unusual.

The idea of a universal charger is good - hyping it as "green" is questionable. So you don't buy a new charger when you change phones, but run the transmitter even when you aren't using it.

And where does the 16 foot distance come in? If it works at that distance it is probably putting out significant RF radiation.

The splash site looks good they aren't over hyping its usefulness - the BBC site with its 16 foot range, implying that the power magically goes where it is needed, etc. looks more like the IPO BS one sees in the Wall Street Journal.

Is not! It's the kind of styling which would complement even the most sophisticated of home or office interiors, and you'll never want to use tangled traditional chargers again.

John

snip

Well, The Chink Govt has apparently decreed that all new mobile phones must be fitted with a mini USB connector for charging.

Bet the US or EU couldn't have organised that!

martin

I have a razor that's inductively charged, and some beard clippers that must make connection to contacts.

I'm perpetually having to clean the contacts (with an eraser) to keep the clippers working.

The inductively charger razor just keeps on working no matter how much bathroom steam crud accumulates ;-)

...Jim Thompson

On a sunny day (Tue, 06 Feb 2007 08:20:54 -0800) it happened John Larkin wrote in :

It looks so ugly that if I got one for free, including the energy payed for, plus the modified cellphone and mp3 player etc.. I would not want it in the house.

The phantom must be sitting back laughing at all these comments, most of which are confused of which technology we are referring to. Inductance is a radiative near field phenomenon that most of us somewhat understand and is commonly used in transformers. Splashpower uses such a technique to charge batteries placed on it. The MIT group is referring to "Non-Radiative Energy Transfer" Their scheme involve Hi Q (>2000) resonate transmitter and receivers that couple energy between themselves but not to other nearby objects that are not in tune, therefore this is a more efficient energy transfer than inductive coupling which spews flux lines in an omni-directional manner. I understand little of this physics but do believe that it is not normal inductive coupling as most of you folks infer. Cheers, Harry

No reason the electronics and coil need to be that bulky. They probably make it thick so as to avoid having it placed on a conductive surface and driving energy into a shorted turn - solid metal surface.

Restrict the mounting to non-conductive and away from sensitive electronics and it could probably be thin and more aesthetically pleasing.

"Harry Dellamano" schrieb im Newsbeitrag news:dL2yh.3503$384.2497@trnddc05... | The MIT group is referring to "Non-Radiative Energy Transfer" Their scheme | involve Hi Q (>2000) resonate transmitter and receivers that couple energy | between themselves but not to other nearby objects that are not in tune, | therefore this is a more efficient energy transfer than inductive coupling | which spews flux lines in an omni-directional manner. | I understand little of this physics but do believe that it is not normal | inductive coupling as most of you folks infer.

It sounds like inductive-coupling - that means near-field with at least r^4 attenuation. The high Q is to get the thing working by high circulating current in the coil. "Field" energy loss is near nothing, as there is no EM field.

Nothing new. Much hype.

- Henry

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On a sunny day (Tue, 06 Feb 2007 12:19:58 -0500) it happened default wrote in :

Yes that could be the reason.

I build a HF transmitter many many many years ago with a big 1kV 250mA penthode, and it was around that frequency.... You could put a screwdriver in the tank-coil and it would heat up. I put a neon in it, it glowed bright, then REAL bright. That night I dreamt of lasers.... That setup put out about 250W CW, and you could do all sort of funny things with it, it also was picked up by my rather expensive tape recorder (early transistor one with Ge transistors) that went immediatley up in smoke. With an antenna connected you could walk around in the garden with a lit neon. I had to swith it off when I noticed the guys in the black car making bearings. I never had the guts to try to stick a finger in the tank coil.... I still have 10.

My Tesla coils would wipe out electronics. They would eat ram inside a computer and write to cmos resetting the date and other user adjustable parameters.

I built an AM jammer outside the US. None of us had air conditioning so windows stayed open. One of my neighbors would crank up the volume when I was trying to sleep . . . I got into my junk box and wound a

I worked at the HFDF site and knew the government ops. I also knew they could only get one bearing at that frequency so there was no triangulating my signal. I guess the plan was to run along the bearing with the van and try to see where it peaked. There was no DF loop on the truck. The neighbor never did turn up his stereo after that, so I really don't know what happened. I asked as many questions at work that I could without giving away my involvement, but only found that they had a strong carrier with 60 HZ on it (my transmitter had no filters on the power supply so I had 100% modulation with 60 HZ).

All the hype the MIT guys are spinning - that really sounds like some bunk to me. And they are making all these claims because a computer model tells them it is so? They haven't built anything to test the theory. These folks are less believable than the "cold fusion" guys some years ago.

The energy "tunnels" to the resonant circuit? From what I see with Tesla coils a second resonant circuit just sucks up some of the field around it and the radiator coil may send more energy towards the area where it is being absorbed. But the radiator is just blanketing the area with energy otherwise.

I'd like to know more about the circular tank circuits the drawings on the BBC site show. Due those coils do something to polarization that changes the game?

On a sunny day (Tue, 06 Feb 2007 15:04:58 -0500) it happened default wrote in :

I had two of these:

I dunno, I look at that picture, the number of turns of the coil, and yes perhaps that will tune to 6 MHz with those small capacitor plates. But what is the core material? It cannot be very high permeability with that many turns.... But indeed C is very very small. You could build one from the picture I guess, and beat them to a practical test. If they are right then a few watt should arrive at the other side in a similar coil..... But I find that a bit hard to believe -magnetically- at a meter or so...

I found this

The solution, according to Soljacic, is "nonradiative resonant energy transfer," which he says can harness omnidirectional energy beacons without wasting energy, without requiring a clear line of sight and without damaging obstacles in the process. Power from such energy beacons would pass harmlessly through everything but their intended targets, by virtue of resonant power antennas that would be tuned to the power beacon's frequency in a lock-and-key approach.

"We are proposing the use of evanescent tails of oscillatory electromagnetic energy resonan- ces to transfer power wirelessly and nonradiatively over distances of a few meters," said Soljacic, who worked on the design with professor John Joannopoulos, the Francis Wright Davis professor of physics at MIT, and electrical engineer Aristeidis Karalis, a doctoral candidate in MIT's department of electrical engineering and computer science.

Well "non radiatively" implies it ain't radio waves.

"Evanescent" interesting choice there. Evanescent means something like ephemeral, wispy, or vanishing like smoke . . . like this guy?

"We are proposing the use of evanescent tails of oscillatory electromagnetic energy resonan- ces to transfer power wirelessly and nonradiatively over distances of a few meters,"

And he's got a bridge for sale in Brooklyn

He also implies in the article that the cap is larger than usual for the tank (not usually good for high Q) and using ceramic disk caps? (not noted for low dissipation factors - high loss)

The BBC article didn't help any either. Junk journalism more usual with the Fox network than BBC. The writer did a quick search on Google and found some devices that he thinks are similar and lumps them all together implying that practical applications of a wonderful new discovery are around the corner.

Notice the good professor has it ramped up to powering buses and trolleys in his application ideas?

Sounds like a scam artist to me.

That would be "radio", and nobody has yet figured out how to do it with better than maybe 0.0001% efficiency.

Good Luck! Rich

That was before he discovered "evanescent tails of oscillatory electromagnetic energy resonan- ces" One doesn't take evanescent tails of oscillatory electromagnetic energy resonan- ces lightly you know. . . .

He got a grant of my tax money for this.

Do they do these experiments at the plane arium?

Cheers! Rich

Just the thing to heat Win's stale coffee from yesterday. Stick a metal cup on there and it's off ;)

Nah, they sold the business on as OTC shares after taking millions in fees - probably to some small'ish pension fund providing insurance for widowers and orphaned children. Orange County, perhaps?? (Citron means, appropriately, Lemon in Danish ;-)

I'm fairly sure it means Car in French...... A logical language after all.

DNA

Aw S*IT! Almost lost my coffee again ;-)

...Jim Thompson