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TED Blog: Wireless electricity demo: Eric Giler on

It's been a while since I posted a TED talk. This is not one of those inspiring insights into the human condition. It's just a scientist enthusiastically demonstrating something cool I can't wait to have.

The commercial side of implementing this is as interesting as the science, when you think about it. The devices transmitting and receiving power are on matched frequencies, so other devices would not receive it. What use is that? I want all my devices to be battery-free, picking up power from broadcast transmissions as I walk around. On the other hand, I must be charged for that power, or no-one will invest in the infrastructure to provide it to me. Short of taxing everyone to have the state provide the infrastructure (in which case it will be as unreliable as any service where payment is guaranteed regardless of performance) how could this be done? Will the company transmitting the power have to trust the data from the receiving device? That's not under their control and could easily be rigged.

I am sure someone will figure it out. I hope it's soon. Batteries are much of the weight in our mobile devices and wireless electricity would transform their design as much as their function.


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I did a dissertation, about 20 years ago, concerning the future of road transport in which I suggested an energy transfer system similar to this being installed at junctions, inclines and intermittently on motorways and longer roads.

The fundamental problem with electric cars is the energy density of the batteries, as Mr Giler points out batteries suck. That is why no one has produce an E-car that can compare to an IC powered car, even the Toyota Prius only functions because it stores its energy predominantly in the petrol and not in heavy, expensive, environmentally disasterous batteries.

If you only require enough battery stored energy to get you from one junction to the next an electric car with regenerative braking makes perfect sense. The infrastructure required would be expensive but not prohibitively so compared to the X million pounds per mile that roads cost to lay.

However, it was and is a crap idea because electric cars will never sound or look like this...

...I followed this car for 20 miles today, almost feeling sorry for the driver who couldn't watch his own parade, almost.


Just a thought... but arn't we subject to a magnetic field all the time. The same one that makes a compass point north. It is powerful enough to move a needle. Is that bad for us too?


Rolls her eyes! They are not perfect nor are the folks at the genius bar geniuses since they can't figure it out either. LOL.

To add insult to injury I upgraded to Snow Leopard and everything has slowed down to a crawl. Grumble, grump.


How odd. I astounded the Shanghai office by opening my MacBook Pro and (without any setup) printing wirelessly to their network, which no-one there had been able to do in the years since they installed it. I told them "Macs just work", and now you are telling me you can't get one to do what an ugly PC does?

I guess some people are Mac people and some PC.


Lord T will figure it out.


Well you aren't asking a lot are you? But sounds pretty good to me, says the person who after nine months is still unable to get her mac to print wirelessly through her home network, while all her 3 pcs do it without a hiccough.

Guess who is getting a fancy new wireless network printer for her birthday? If that doesn't work guess who will be getting a fancy new pc? I hope I am kidding.


[Nigel Sedgwick tried to post this comment but had some problems so emailed it to me to post for him. I am happy to oblige and thank him for his input.]

I could not get the video to work, so I have relied on this:

A few excepts are:

Realizing their recent theoretical prediction, they were able to light a 60W light bulb from a power source seven feet (more than two meters) away; there was no physical connection between the source and the appliance.
In the long run, this could reduce our society's dependence on batteries, which are currently heavy and expensive.

I note, firstly, that there are no efficiency figures. Just how much power was 'transmitted' to get the 60W received power?

Secondly, there is nothing new about resonant transformers: they have been widely used in radios in the past, especially in the days of thermionic valves. They are still used, though somewhat less-so, nowadays. The only difference is the separation distance, and then the obvious question of efficiency comes up - and is unanswered. Why is the obvious question not answered?

Thirdly, magnetic fields are vectors: the receiving coil will need its axis aligned with that of the transmitting coil: misalignment will lead to less power being transmitted, and will probably lead to further inefficiency (though that will depend on the separation and the surrounding magnetic environment).

What about the health and safety issues? Especially those arising from chance resonances? Mobile phones with milliWatt transmitted power are one thing; transmitting tens or hundreds of Watts is quite another.

As for the batteryless appliances, I can only draw a parallel with the CT2 telephone:

In the mid-1980s, Ferranti (and subsequently Rabbit) proposed the setting up of a cordless public telephone service that worked within around 50m of public telepoints (which would be sited at railway stations, shopping malls, etc); the service only provided for outgoing calls. Mobile phone technology (of the sort that is now widely prevalent) was, at that time, rapidly advancing: including that of rechargeable batteries (the brick nature of phones being their principal problem). Where now is Rabbit? And the public telepoint concept?
[Even: where is Ferranti? Though that is a somewhat more complicated story.]

It is worth noting that Ferranti's original concept was for a cordless system within offices and factories, with a micro-cellular structure. This was a much more sensible, though the cellular concept of automatic transfer of calls in progress between base-stations was technologically expensive at the time. CT2 technology is now the basis of the DECT standard for digital cordless telephones that are in widespread use residentially.

Why am I writing about CT2 and public telepoints: it was the push of technology well beyond economic benefit, on practical grounds and those of other competing technologies, that should have been obvious at the time (and was to some).

Nigel Sedgwick


I just gotta be a tech nerdette and point out that this tech has practically stood still since 1894.

Tesla was a rival of Edison's and he managed to power incandescent lamps at his New york Labs using "wireless resonant inductive coupling".

Shame poor Tesla didn't have the ruthless business sense of Edison. If he had it might have been utterly common place for a century now... and he might have made fortune off the back of it.


I'm electrical, bombarded by yet more elecro-magnetic polution.

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