Slashdot Mirror
Magnets To Replace Bluetooth?
aceat64 writes "News.com is carrying a story that suggests magnets could eventually replace Bluetooth as a cheaper and more energy effiect wireless solution. The concept of magnetic induction isn't new, but Aura has managed to shrink the technology onto a single chip. The first device to be made using the technology is a wireless headset that will cost between $60 and $80."
Talk about lack of ambition.
This is JUST what we need! A bunch of wild magnetic fields around our electrical equipment! I can't wait to get an adapter for my computer, there's space in the case right next to my hard drive...
-- Dr. Eldarion --
Correct me if i'm wrong but dont most Radio transmission technologies use some form of magnetic induction in order to achieve their goal. Last i heard passing electricity through a coil produces a magnetic field. Whats new here?
Electronic Music Made Using Linux http://soundcloud.com/polyp
All my credit cards seem to be erased.
Expect carrier pigeons crashing into your cell phone.
Magnets... the geek's natural enemy, even more so than fresh air and natural light.
Be you Admins? nay, we are but lusers!
Bad news for Iron Man.
"If you want to improve, be content to be thought foolish and stupid." - Epictetus
The magnetic approach also consumes very little power when compared with notorious battery-draining RF techniques like Bluetooth. According to a description on the Aura Web site, Fonegear's headset can keep going for up to three months on a single AA battery, as opposed to only a number of hours for equipment outfitted with Bluetooth.
I looking forward to see this technology and hearing more about it, as always I'm very open to new tech due to my principle and goal of life... However magnetics and magnetic storage doesn't math up, I remeber when we formatted HDD the hardcore way by using string magnets around attached to it!
I'm positively repelled by this, flux you very much.
Just another day in Paradise
So the hapless doofi who've spent years thinking a) magnets can heal them and b) phones can give them cancer must be delighted with this new headset; it'll fix those brain tumours right up.
D'you think it's coincidence that the company who came up with this is called Aura?
How can you replace a technology that nobody actually *uses*?
I can just now see the new line of infomercials talking about combining the freedom of a wireless headset and the 'healing power' of magnets! Sweet Jesus...
Docker uses a single AA primary cell battery to get up to 1500 minutes - 25 hours! - of talk time and 3 months of standby. What's more, Docker has no on-off or stand-by button, so you never need to remember to turn it off.
it'll automatically turn off when the battery runs out though, so you'll have to remember to change the battery.
OK I RTFAd and unless there has been a change in the fundamental laws of physics and the properties of electrical and magnetic fields then this whole thing is just BS.
You can NOT get a varying magnetic field without also getting a varying electrical field. That is the way the physical universe works. If you can not vary the magnetic field... how are you going to send a signal from the transmitter to the receiver?
-DU-...etc...
"Don't sweat the technique."
finally using wireless technology will bring some holistic benefits, instead of just causing brain tumor ;)
Consensus is good, but informed dictatorship is better
'At the heart of the new interest in what's known as "magnetic induction" is Aura, or so claims the nine-year-old chipmaker'
quick, somebody stop these fiends!
I'm a rabbit startled by the headlights of life
Developed in the late 1950s, magnetic induction never really caught on
Gee, silly me, and I always thought Faraday developed "magnetic induction" and that it was in wide use. But, hey, it has turned out that, contrary to my own silly ideas, Gates actually invented the Internet and that BT invented the hyperlink, so I must be wrong on Faraday as well.
I'm wearing metal braces, you insensitive clod!
well why go here?
Be you Admins? nay, we are but lusers!
This cell phone has been certified by the Association of Alternative Medicines as an evvective communications/healing device.
Yeah, I guess I never really knew what an Inductor actually did in a circuit... I guess Physics II and Circuits were a waste of time...
Integrate Keynote and LaTeX
also in news, segways could eventually replace cars on commuting, rocket packs could eventually replace aeroplanes, slashdotter could eventually get laid..
you get it, anything could eventually do anything.
(and bluetooth is not useless, obsolote tech. it's pretty useful, and if you're bitchin that you don't need a cellular then it really doesn't make much sense to bitch about not needing bluetooth fo r it)
world was created 5 seconds before this post as it is.
then: Bu-Bye! (And take your annoying little dog with you, too...)
I installed one at my home yesterday, and today my hard drive isn't working and my monitor's got all sorts of funny colors on it. I'm posting this from work... I think I'll install one here to trouble shoot.
Just a se
--
RumorsDaily
A broadcast antenna is a magnet, an electromagnet, one that changes polarity many times per second, and that varying electromagnetic field is what induces a response in the receiving antenna. This is called radio transmission (see Marconi, or better yet look up Heinrich Hertz or James Clerk Maxwell.) If this so-called technology is claiming to transmit information using a static magnetic field they are full of little red ants. Phooey.
The higher the technology, the sharper that two-edged sword.
In other news, the letter "B" is replacing Shakespeares "Hamlet"... For some reason, that's what it sounds like to me :)
"Hey, look over there it's bluetooth!"
"What, where?"
"Oh, sorry, you missed it."
Dacels Jewelers can't be trusted.
Well it'll really bug you that I just modded you down then ;)
Ho ho ho.
After reading the article and the aura site i still have absolutely no idea how this works, can someone please explain? Articles that talk about rippling pond water and secure bubbles are usually marketing crap.
This comment does not represent the views or opinions of the user.
Internet was invented by Al Gore ;)
Like many here, I was very skeptical when I read this article -- the reporter is clearly a total sci/tech ignoramus (you gotta love the totally redundant "cordless cell phone").
So I went to Aura's website for more info. Here's their blurb:
While the concepts behind magnetic induction communication have been around for decades, Aura's engineers are the first to develop and implement practical solutions capturing the benefits of this technology.
Conventional radio frequency (RF) wireless communication systems are optimal for sending large amounts of information and communicating over long distances. However, this consumes power, creates information security issues, and results in interference and "crowding" among devices. A good example is in the 2.4 GHz band where simultaneous operation of a cordless phone, WiFi network and Bluetooth headset is frequently not possible without severe degradation of Quality of Service. In sharp contrast, LibertyLink's magnetic communication operates in a "bubble" that envelops the personal space of each user and is - by the laws of physics - inherently private and secure. The result is an easier to use, lower-cost system that makes far more efficient use of power and bandwidth than conventional RF solutions. By selecting a technology that limits the range and bandwidth to only what the application requires, Aura achieves a very substantial savings in power with all of the simplicity advantages of LibertyLink: dedicated communication channels, no bandwidth sharing, complete frequency re-use between bubbles, worldwide regulatory flexibility, and reliable coexistence with WiFi, CDMA, TDMA. and GSM transmissions.
Still pretty vague -- how the hell do they handle interference issues in this "magnetic bubble"? Do they supply Faraday cages for your PC/monitor?
I just got Bluetooth!
Stupid technology...
-Waldo Jaquith
Did we even _start_ using Bluetooth yet?
Assuming this isn't all complete bollocks, about which I'm going to hold an open mind, as I'm not entirely sure how this thing would work near computers or pylons, or electrified rail tracks, or power mains, unless it has some AMAZINGLY good filtering in it.
Anyway, assuming that, does that mean we get a chip on a usb stick (say), that would allow Van Eck Phreaking to be done at home? I mean, if you can send useful amounts of data through this technology, it must be good enough to pick up clock signals and keyboard presses?
I know this post is amazingly vague, but so is the technology.
I know how magnets heal people! you take a large magnet and beat a pseudo-spiritual idiot over the head with it, thus you healed the world of one less germ! I read this headline and saw "magnets" and first thing that came to mind was "erased hard drive" so, replacing a technology that no one uses with a technology no one will use.. smart idea! I think I'll start selling AOL cd's instead of music cd's to get my business flourishing!
...but doesn't every form of wireless transmission that exists use magnets for transmission? Temporary magnets, electromagnets, but how could anything be done fixed magnets, which are, well, fixed? I'd be impressed if something cool were to replace EM transmission, like gravity, or the strong nuclear force, or midgets on scooters. Yeah, that last one would be cool.
Actually, I have to wear a hearing aid in one ear due to mid-ear damage, and I'm expecting before long to have an inductive loop for my cell phone that means handsfree use without any kind of additional earpiece. Apart from convincing people that I'm completely mad and talking to myself in the street, it should be a considerable improvement over bluetooth headsets, which, compared to either of my hearing aids, are heavy and have poor frequency response.
Panurge has posted for the last time. Thanks for the positive moderations.
I don't believe that the magnetic fields would need to be so strong that they would cause a problem for magnetic media, but there are probably too many variables to generalize. Think "speakers" here. These generally use magentic coupling too to send information wirelessly (albeit at acoustic frequencies).
rat-a-tat-tat...
Not only can magnets give you lighter wireless communication, but also eternal life!
If you open any shortwave radio, you'll find ferrite antena inside-antenna which reacts on the magnetic part of EM radiation...
There is no magnetic radiation without electric field radiation, which means that all that is really EM radiation as well. One implies another.
Ehhh, slashdot science...
It could be said that "new" comm way doesn't use resonant prioperties of its antenna, but even that is hardly novel.
Antenna resonance might be a bad thing for modern high bandwidth communication, but without it environmental noise becomes bigger problem...
> Magnetic fields also create waves, but the waves
> form a kind of bubble, which stops growing after
> four feet, making them more secure than waves
> wafting endlessly in every direction, Cui said.
Doesn't anybody study physics any more?
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
In Soviet Russia, Overlords welcome You!
Escher was the first MC and Giger invented the HR department.
A single manufacturer is selling a "cordless cell phone headsets" which no mobile currently supports, yet somehow it's the death knell for Bluetooth, purely because it's technically superior. Does this strike anyone as a pointless product?
Betamax was better then VHS, but it's even deader than my favourite OS. So I'm still going not going to hold my breath.
Do you mind, your karma has just run over my dogma.
1 - They complement each other, yes, and they are intimately interrelated.. but they are not the same thing (for practical purposes). If you have a bar magnet in front of you, is their an electric field around it? no, there isn't.
2 - A cruise of the whitepapers indicates that the magnetic field strength is related to distance via 1/d^6, as opposed to radiated power, where it's relatd to 1/d^2. This means a much sharper dropoff in power... meaning the point beyond which there is a negligible power level is much sharper.
3 - A magnetic field and RF radiation are not the same thing.. one transmits energy over distance (RF).. the other puts that energy into sustaining a field (Magnetic)
4 - What you are saying about frequencies applies to RF. This is not about RF. The mention of a high frequency, relatively unused ISM band probably refers to the EM side effects of the devices. (a 10Ghz oscillator, even if it's used via induction, sitll creates a 10Ghz EM signal)
5 - "Used by Industrial, Scientific, and Medical" as they said in the article, is most likely just the reporter trying to sound smart.. but that's usually abbreviated as "ISM", and covers the fun 900Mhz and 2.4Ghz bands we already love and know, as well as others....
6 - interference is not an issue for practical purposes because this thing has a high field strength within the bubble, and virtually none outside. Any inteferer would have to be really strong, or really close.
No one else has touched on this precursor to radio, but the above post is so close (since it mentions the only remaining application of the technology) that I thought I'd give a reference to Nathan B. Stubblefield, from my Dad's hometown of Murray, Kentucky, credited with wireless transmission of a voice in 1892: his system used magnetic induction at voice frequency instead of a modulated carrier.
http://www.nathanstubblefield.com/
Don't knock this too hard... it has been used in the past. Back in college when I designed web pages I used to use a Wacom tablet, which for those of you that have never used one, is a large tablet that lets you control the mouse with a pen. The pens had magnets built into them, and the tablet sensed the position, orientation, and button presses by a change in the magnetic field. The biggest advantage of this was a pen that was lightweight and didn't need either a cord or batteries to operate.
Unfortunately (or possibly, by design), the pens only functioned up to about 1 inch above the surface of the tablet, however considering how well it functioned, it would not surprise me if this technology could be improved to the point where accurate communication could take place over several feet, i.e. Bluetooth range.
Children in the backseats don't cause accidents. Accidents in the back seats cause children.
Did *no* one read the pdf entitled Near Field Magnetic Communtication Properties??
It is a quasi-static magnetic field (READ: electro-magnet creates magnetic field with small variation in magnetic field with most of that 'variation' energy around the 24MHz ISM band)
The idea has two-fold benefit over using RF-coupling..
The energy falls off as 1/R^6 instead of what they claim is RF's 1/R^2 (I could have sworn my Emag classes said RF signals die as 1/R^3)
The majority of the coupled energy is used for a static field and the signal uses very little energy. This is better than RF in the sense that the EM energy is proportional to the freq, and RF uses HIGH freq RF for the transmission/ coupling benefits of using high-freq RF but the signal is a low(er) freq signal riding withing the RF energy.
Interesting that you need coil loop orientation diversity rather than RF's antenna diversity (in space).
What interests me is how this can be used for low-power sensing applications (like RFID tags) (BTW I'm claiming the first use of MIID tag for magnetic induction)
If I recall correctly from my Calculus-based Physics 110 course, an electric field cannot exist without a magnetic field which is why we call them ELECTROMAGNETIC FIELDS.
everyone here is making stupid jokes because they don't understand what the product is. i was skeptical at first, but i looked around at some of the documents on the site and did some googling and found this is actually kind of interesting.
here is a relevant article that explains the technology a little better.
If someone is using one of these and it knocks out your laptop, etc., who do you sue? The manufacturer for producing a damaging product, or the user, who probably didn't know any better?
GL
Now, I'm no physicist, but I was under the impression that all radio waves were based on electromagnetic induction. So this article doesn't really make sense at all.
Now, I know there are some devices that use magnetic induction to 'charge' and then blast out information, like RFID. But the key here is the RF -- radio frequency (ID = identification, of course).
So it would make some sense if these guys said they wanted to carry power using Magnetic induction, rather then using power cables or batteries, but it doesn't make sense for them to say they want to replace 'blue tooth' with it, because blue tooth and all radios use Magnetic induction to communicate...
My guess, yet another reporter with absolutely no idea wft they're talking about.
autopr0n is like, down and stuff.
I really hope you're just trying to be funny and doing a poor job of it, but in case you're serious...
I keep waiting for a gas pump that "recognizes" my gasoline credit card device and waits for me to "fill it up."
Uh, hate to break it to you, but those have been around since the mid to late 90's, when Mobil introduced the SpeedPass. I've had one since long before I ever heard of Bluetooth. Now they are used at Exxon and Mobil stations all over the place. I think McDonald's even did testing a while back in California, IIRC, where people could pay for their drive-thru purchases via SpeedPass-- dunno if that's going to go national. When they launched it, it came in two varieties-- a small cylinder for your keyring that must be waved in front of a spot on the pump, and a transponder meant to be stuck inside your car's window that is "read" by an overhanging antenna when the car first pulls up to the pump (sort of like the E-Z Pass system some states have for toll roads). I think the stick-on transponder SpeedPass has been phased out, because I see no reference to it on the website.
Have a hard time getting a paper receipt, though. Keep getting a message saying "Your receipt is inside."
Where I live, gas pumps have been accepting credit cards right at the pump for at least 10 years, and have been printing their own receipts right at the pump as well. My SpeedPass account is even configured to assume I want a receipt when I gas up, so the pump just spits one out without asking when I'm done filling my tank.
I won't even tell you what I can do with my Macs running OS X and my Bluetooth phone, it may make your head explode. No flying cars yet, though.
I suggest you move to a state where people aren't too busy dating their relatives to embrace technological advances. By the way, the North won.
So if you are using a headset on your cell phone with one of these gizmos and you step away from your desk you lose your call? No sale. I'll keep Bluetooth and it's 10 meter range.
Correct me if i'm wrong but dont most Radio transmission technologies use some form of magnetic induction in order to achieve their goal. Last i heard passing electricity through a coil produces a magnetic field. Whats new here?
What's new is that they've goofed.
At any given frequency you can launch an electromagnetic wave by using:
- And electric dipole. (Essentially impossible at anything above DC due to the current from the moving charges.)
- A permanent magnet or a current loop (producing a virtual magnetic dipole).
- A combination of the two, to produce the electric and magnetic fields simultaneously.
With a current loop the field very near the loop is essentially pure magnetic and falls off as the first power of distance (as more of the wire's length becomes signficant to the observer).
Moving out a bit more, in the first two the field moderately NEAR the antenna is essentially pure electric or magnetic (respectively) and falls off as a dipole field - with the cube of the distance. (Inverse square for each "pole" of the dipole, times inverse first-power for the smaller angular separation of the poles as viewed by the distant observer.) In the third you get the same effect with both the electric and magnetic field, typical of ordinary antennas.
But the changes to the electric field produce a magnetic field, and vice-versa. By the time you're a wavelength or so away from a simple driven element an electromagnetic field - a "radio wave" - has peeled off. This weakens at inverse-square rate (once you're far enough from the emitter that local additions and cancelations from different parts of it don't confound the issue.)
For signals in the tens of kilohertz and less (audio, for instance), a wavelength is very long. So a coil acts like more like a dipole than an antenna for a long way. Inverse-cube attenuates the signal rapidly with distance (though a strong amplifier can pull it back up - along with any competing noise).
But for computers you'll probably want this to operate at high speed - for images, disk access, etc. Now you're talking megahertz - with coding schemes that end up putting essentially all the informaiton at high frequencies. So the radio-wave effect takes over quickly, and the signal propagates without serious attenuation, regardless of whether the emitter is a magnetic loop (B-field) or electric dipole (E-field) emitter.
The guys operating the TEMPEST equipment will LOVE this system, thanks to the unjustified feeling of security it will give the user.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Methinks this is viscious plot hatched by the optical media industry to bury the magnetic media industry once and for all.
In the meantime don't keep your PDA anywhere near your credit cards...
------ The best brain training is now totally free : )
N&V covered this in the June 2003 issue along with RFID and UWB. Page 22 for those who can get access to a backissue (say at the library or somewhere like that)
One problem (that's easily fixed) with the magnetic system is that both transmitting and receiving coils have to be parallel. If they're at 90 degrees little or no signal gets through. The fix for it happens to be using 3 coils, each one 90 degrees from each other on the receiver. The transmitter only needs one, but no matter how that one is oriented one of the 3 coils in the receiver can pick it up. I haven't heard of any other chips, but the LibertyLink chip from Aura Communications can automatically select the coils on it's own.
Very short range, but it works for something like a wireless headset where range doesn't matter anyways.
Hopefully, manufacturers will race to put this in their products and wont bother securing links with pesky things like "encryption" because the "bubble" provides security.. then i can have my fun intercepting stuff by standing behind people ;)
But if done properly this could be useful - you could control your phone, notebook, or mp3 player using your watch or some sort of mini-handheld touchscreen, rocking
This comment does not represent the views or opinions of the user.
Does this mean I get the day off when there are severe solar flares?
Isn't the range of Bluetoth like 25". This 4" has so few uses it is mindnumbing. I can overcome the 4" holding the 2 objects in my hands. They should just keep selling to the DoD.
you jackasses. Al Gore claimed responisibility for ARPANET becoming the internet because it was a bill he backed in Congress. Get it? It was a perfectly reasonable claim. And that joke is an entirely too old repetition of Republican propaganda making him out to be a liar. Despite the fact that all the things they claimed he lied about were true!
Dear God! I don't think the aluminum foil in my deflector beanie is thick enough to handle all that! Quick, get me some sheet metal!
"I'll just plug in my new magnetic WLAN card and... oh shit, now my laptop doesn't work. Dammit."
So no, this isn't Firewire, or quite even Bluetooth - it's Almost Appletalk, but very low power cordless. However, unlike Bluetooth with works with 2.4GHz radio, this is working down at 13MHz where there's not much interference. I'm not convinced about its security claims, except that they can apparently do some modulation things to keep nearby sets of equipment from interfering, and the range is short enough that there's not much risk of it.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Even if the magnetic feild falls off like 1/r^6, that doesn't mean you can't "hear" what's going on inside the field from farther away.
As the field modulates it will, generate electromagnetic radiation. And while the Aura recievers won't pick up anything outside the feild. A good RF reciever operating at the same frequecies could easily pick up the signal from the "bubble".
Correct me if I'm wrong. I'm not quite sure what kind of amplitude the EM radiation would have. I think it would be pretty substantial, but I could be wrong.
The data rate is 204.8 kilobits/sec - I can't tell if that's bidirectional or shared unidirectional like Ethernet? However, you're wrong about your use of Nyquist's formula - that tells you that your pulse sampling rate has to be twice the frequency of a continuous wavelength you're trying to send (so your data rate needs to be N*2 samples/sec for a N Hz audio signal). This is the other side - Shannon's formula is that if you want to carry a given bit rate using an analog signal, the bit rate you can get is (IIRC)
Bandwidth * log (1+Signal/Noise)
which means that if your signal/noise ratio is arbitrarily good, you can get an arbitrarily high data rate
The place that Nyquist bites them is that with only a 204.8 kbps data rate, it limits their audio capabilities. They're actually using 64kbps CVSD for their audio, which is kind of an odd choice of codecs - maybe they're sampling at a higher rate than telephony, or maybe they're figuring it will do less or different damage to the signal than the GSM or G.723 codecs used by the phone? In either case, CVSD is a simple codec that doesn't need much CPU horsepower, and a little better than ADPCM at that speed.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Magnetic induction differs from Bluetooth and just about every other wireless technique now available, most of which use what's known as radio frequency, or RF, signals--bursts of electrical energy that waft out like ripples in a pond until they reach an antenna.
Why is it a wafting signal? Why not a propogat[ing/ed] signal?
Magnetic fields also create waves, but the waves form a kind of bubble, which stops growing after four feet, making them more secure than waves wafting endlessly in every direction, Cui said.
Hot damn! Wafting again! Wafting without permission from the FCC! The editor who wrote this must be remeniscing his co-worker or himself after a bad lunch? I know beans are the leading cause of wafting.
What's the difference between this and other forms of EM transmission?
Repeal the DMCA!
Perhaps the easiest way to explain this technology is that it's simply a type of transformer.
:-)
One coil creates a varying magnetic flux that induces a current in a matching coil -- and thus an electrical signal is passed through the ether.
Those who claim that it's no different to a radio link are almost right -- the only real difference is that with such a system there's no need to use a carrier wave (RF) -- the information can be dumped (raw) into the transmitting side of the coil and received by the other coil.
There's no rocket science here -- all that's happened is that some crowd has figured out that by using three coils instead of one, they can effectively adjust the direction of the strongest flux lobe to give the maximum transfer of energy.
Of course, the marketing droids would never simplify things by simply telling us it was a "clever transformer" because then they couldn't charge so much for it eh?
I attended DemoMobile and talked with these guys one on one. Their product is real and works pretty well. I also own a Bluetooth unit that I paid over $150 for and while they both provide communications to my cell phone, these guys give over 25 hours of use. I'm always looking for a charger with my Bluetooth unit and if sales guy would have told me before I bought it that I'd realistically only get an hour or so of use, I wouldn't have bothered. As the say, " the proof is in the pudding," and these magnetic guys have something that meets my taste buds!!! I've also gone through their web site. They use near field communications and claim that they suppress the electrical field and use the magnetic field for the communications. That would explain the short distance. But at .2 microwatts output power, that's good enough for me. I don't need to walk 30 feet away from my cell phone. Also, I can't use my Bluetooth unit near my 2.4Ghz phone or my 802.11 network. This new headset can be used with all of that. They were offering a show price of $49 and that's a no brainer for me....especially after trying the unit out!
Arnt magnetic fields meant to have severe effects on the way your brain works? Those healing magnets are meant to be very specifically designed, etc to be healing magnets. Something like this could easily trigger a whole bunch of non healing emotions. Who wants to see the wallstreet business man (already on the edge) even more stressed out because of his new phone+headset.
--
The last digit of pi is four.
http://www.auracomm.com/Downloads/llcondenseddatas heet.pdf
64 kbps CVSD decoding
64 kbps is plenty for voice and input devices. Added to the lack of interference with wifi and you've got me sold.
So how is that different from practically every word a republican makes being taken out of context and similarily ridiculed? I'm sure YOU of course, haeve never uttered an ill word against them. But there are others that do so.
If Al Gore can joke about it, then you should as well.
You CAN have a static magnetic or electric field without the presence of the other. Case in point - motors and generators. A generator will not generate electricity (and a corresponding electric field) unless the wires are moving relative to the magnetic core. Even motors with brush magnets are simply magnets until you apply current to the motor coils. Until then, the motors/generator are at best regular magnets, and most large motors don't use magnets but metal cores with proper magnetic permeability.
Only a changing electric field produces a changing magnetic field, which produces a changing electric field, and so on.
Someone care to comment on the possible health effects of having a headset that creates a magnetic field next to your head? When people are concerned about having a cellphone's radiation near their head for a few minutes to perhaps an hour or so a day, I'm sure there is more of a concern with a headset that might be worn for several hours a day. Is the field strong enough to cause health problems?
Losers choose to abuse the use of "loose".
Well, while I could not find a "near-field for dummies" link anywhere, let me explain it to you myself.
Far-field and Near-field are just two simplified formulas, describing one electromagnetic field in different regions. But as we can use what we can describe, these notions are now routinely refered to as objects.
Basically the term comes from the approach to a problem of a wave propagation equation with constraints (e.g. difraction on a piston for Maxwell equation, but not limited to). Often the solution is much easier to formulate if one wants to know the field properties quite far from the source. Quite far means more than couple of wavelenghs. For most practical cases it holds true. (e.g. broadcasting radiowaves). This is "far-field".
But what happens in the immediate vicinity of the source? There is analytical solution as well, and it is called "near-field". It dissapears very quickly with the distance from the source, that is why we do not have to take it into account while dealing with "common" far-field waves.
Recently there were found application of this field in Microscopy, and it seems Data Transmission is following. The whole thing about this field is that it does not propagate far, so the energy is contained in a limited volume. In Microscopy one can get better resolution. For the data transfer it means that field density in that volume is relatively higher compared to the "far-field" mode of radiation.
But once again, this are mathematical objects to describe (electromagnetical) field. These objects came into existance because of the particular structure of the field equation.
...a stunned silence fell upon the hall.
My electrodynamics is *very* rusty, but perhaps whey they mean by a 'bubble' is that the field (which AFAIK is electro-magnetic, despite what the product hype says) is not your usual electric field which falls off as 1/r^2, but perhaps a dipole or quadrapole field which falls off as 1/r^3 or 1/r^4. And there are higher order fields which drop of even more quickly.
In brief here are examples of the different kinds of fields.
Think about what kind of effects this could have on devices much more sensitive to magnetism. Like in a plane:
"This is your captain speaking. As you can see on the aisle TV screen, we're currently flying through a purple and green blob, and according to our compass we're spinning at approximately 90 revolutions per second."
Regards,
--
*Art