Mon Aug 25, 2008 11:45AM EDT
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Tesla coils notwithstanding, the transmission of electricity wirelessly is a challenge that has flummoxed researchers for a century. Is it possible those challenges could be coming to an end? Last week, Intel showed off a working system that powered a 60-watt light bulb remotely, sans wires.
In simple terms, the technology uses magnetic fields to do the job. A field is created in one disc (about the size of a pizza pan) of copper wire, and that magnetic field causes electrons to move in another disc, stationed a few feet away (but within the range of operation of the magnetic effect). This is a similar theory to the one that allows electric toothbrushes to recharge, but those devices usually have to be so close together that they touch. The basic process for the new system, known as resonant induction, was developed in 2006. The ultimate range for the technology is predicted to be about 15 feet.
Power is great, but safety is better. Critically, Intel notes that this magnetic induction system (officially known as resonant induction) is non-hazardous to humans, since we aren't affected by magnetic fields. In other words, you can walk through the transmission area and not be zapped, an insurmountable problem with some current high-power wireless transmission solutions like lasers and microwaves.
Commercialization of the technology is likely years away, but given the intense interest in wireless power I'd say it's extremely likely we'll see it come to pass before long. The challenges, of course, are myriad: Increasing range, increasing efficiency (lots of power is lost in the induction process), and decreasing the size of the units needed to transmit and receive the power. Still, for anyone who grew up watching fluorescent bulbs light up next to eight-foot-tall Tesla coils at their local science fair, this is some very cool tech.
WATCH: The system in action (first video on the page)
Join in the discussion. Here you'll see the comments in the order they were posted.
Heh - they better replace hard drives with something not affected by these magnetic fields before then - and TVs and game units and HDMI cabling and so on...
How strong are these magnetic fields? If they get very strong at all the complications could be disastrous. To go any distance with this technology I would imagine that there would need to be very strong magnetic fields which can't be good for a lot of sensitive electronic equipment (pacemakers included).
As an EE, I've seen this tried before, and it's a great high school science experiment but it's never worked in the commercial world. My biggest worry would be, what happens if you walk over such a coil with a set of keys in your pocket? I think your charging coil could too easily turn into an inductive cooktop coil and fry a hole in your leg. That's in addition to de-magnetizing all the credit cards in your other pocket. I read in their article that they're saying "magnetic fields are less dangerous than electric fields", but any first-year Physics student knows you can't have one without the other. I agree that wireless power would be a good thing, but I don't think this is going to work. Just too many potential pitfalls.
@middlenamefrank - I'm not an engineer, but there are tons of examples of magnetic fields that don't involve electricity. Look at the magnets on your fridge, for starters. @jirojas - This is an evolution of the toothbrush charging tech, as noted in the story.
Chris, The magnet on your fridge is a permanent magnet, which is to say its field never varies. True it has no electric field associated with it, but the only way you'll extract any power from it is with a moving loop ala an alternator (which is a moving loop inside a steady magnetic field). Any CHANGING magnetic field (which is what an induction coil creates) also, by law of nature, also creates an electric field. Don't get me wrong, induction is great, but it does have its limits.
@middlenamefrank - I realize the technology is hugely different, but that's not what you said... ;) Check out some of the research on resonant induction, which is tuned to a specific frequency... it's way beyond what is currently on the market.
Chris, I am familiar with the technology...I'm an EE and I've been following it. They're hoping that by using a resonant circuit, which only really responds at a very narrow range of frequencies, it won't couple energy into anything else very well. That's why I said a set of keys might be a problem...its variable geometry just might assume the right shape to couple energy really well. I do believe it would easily erase magnetic media too. It certainly is intriguing though, and I do hope they make it work. I'm just a born skeptic. :)
We'd have to add this to the list of potential cancer-inducing EM fields, in your "mobile phone" study. Sure the frequency is probably a lot lower, but the field itself would be WAY stronger. Inefficient ? You bet - that's due to the huge field it's producing. Better off restricting this to low power devices- like toothbrushes.
I am not an expert about magnetics and electric fields but I know that a lot of scientist, teachers and hobbist made a lot of experiments. I remenber ones where my teacher puts 2 coils and one connect to the power and other to a bulb. The second ones was mounted over wheels and he moved away and we could see how the light bulb change intensity. It has a limitations, first the coils were same direction, works no more than 6 feet, create interferences with electric and electronic devices around it, like radio. All of it was a demostration about relationship between electric and magnetic fields. Of course it wasn't harmfull for us.
1 Posted by jirojas on Thu Sep 3, 2009 4:35PM EDT Report Abuse
I think Sonicare has been doing this with the electric toothbrush, charging it by induction. Now, if they could do this for other rechargeable devices like laptops and cell phones, that would be extremely cool.