Coil in wall could wirelessly power multiple electronic devices

February 12, 2010 By Lisa Zyga feature
Coil in wall could wirelessly power multiple electronic devices

Enlarge

As the figure shows, the overall power transfer efficiency of the wireless system can be increased by powering multiple devices simultaneously, rather than each device individually. Using more than one device increases the coupling resonance. Reprinted with permission from Kurs, et al. Copyright 2010, American Institute of Physics.

(PhysOrg.com) -- A team of MIT physicists has developed a system that can wirelessly transfer power to multiple electronic devices simultaneously with high efficiency. The system takes advantage of electromagnetic resonance coupling, and could be implemented by embedding a large copper coil in the wall or ceiling of a room. Somewhat surprisingly, the physicists found that the overall efficiency of powering multiple devices can be significantly higher than the efficiency of powering each device by itself, as long as the system is properly tuned.

Physicists André Kurs, Robert Moffatt, and Marin Soljačić of MIT have published their study on the new wireless power transfer approach in a recent issue of .

As the scientists explained, the new wireless power transfer system could satisfy mid-range applications by filling the gap between short-range inductive systems (such as wireless power mats) and long-range radiative systems, which are sensitive to obstructions, require complex tracking mechanisms, and pose safety risks.

“The main goal of our research was to show that it is possible to transfer power between a source, which could be embedded in a wall, and receivers, which could potentially be embedded in actual devices, over distances comparable to the size of a room and with efficiencies that may be good enough for many real-life applications,” Kurs told PhysOrg.com.

To demonstrate their new system, the physicists built a large self-resonant copper that resonated at an optimal frequency of 6.5 MHz. The helix-shaped coil spans an area of about one square meter, and could be embedded in the walls or ceiling of a room. The large coil, which serves as the resonant source for two smaller coils, could wirelessly transmit power to located a few meters away, although efficiency decreases with distance.

The system works on the principle of electromagnetic , in which all devices are resonating at the same frequency. When this happens, the devices can transfer energy between themselves while interacting weakly with other off-resonant objects. The researchers also showed that the cross-coupling between electronic devices is about 15 times smaller than the coupling between each device and the source coil, which is necessary for efficient power transfer.

Experimentally, the scientists showed that the system could supply more than 25 watts of power to each of two electronic devices located two meters or more from the source coil. In addition, the researchers found that powering multiple devices simultaneously could increase the overall efficiency. For example, the system could achieve power efficiencies greater than 50% for multiple devices, whereas the power efficiency for a single device was less than 20%. Having multiple devices increases the coupling resonance, which leads to greater efficiency.

“Before it is widely used, we need to embed the receivers in a seamless way into devices,” Kurz said. “We would also like to make further improvements to the performance. Perhaps someday it will find its way into many consumer applications.”

More information: André Kurs, Robert Moffatt, and Marin Soljačić. “Simultaneous mid-range power transfer to multiple devices.” Applied Physics Letters 96, 044102 (2010). doi:10.1063/1.3284651

Copyright 2010 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

TheBigYin
Feb 12, 2010

Rank: 3.6 / 5 (5)
I'll be sure to sleep with a tinfoil hat on.
Doug_Huffman
Feb 12, 2010

Rank: 3 / 5 (5)
Hah! Wait 'til the anti-cellphone EMF radiation crackpots get hold of this!
holoman
Feb 12, 2010

Rank: 4.5 / 5 (2)
Be able to charge my toothbrush while in the backyard.

the energy efficency is poor, energy loss into
heat into the wall.

we need a Q factor greater than one from this concept and not less than 1.

Energy is important and wasting it to make
a concept seem revolutionary isn't impressive.

SmartK8
Feb 12, 2010

Rank: 1.5 / 5 (2)
I hope this will be implemented soon. All the computer cables, under my table, created sort of a gordic knot over the time, and must be moved as one piece since. The distance is short, so at least in this particular case it'd be a relieve.
El_Nose
Feb 12, 2010

Rank: 2.5 / 5 (4)
Speaking to the gordic knot of cables Smart k8 mentioned

Why is it we have cables now anyway??? the throughput of my wireless router FAR outdoes my internet connection so why do we need to physically connect the monitor to the case?? We did away with it for key boards and mice...

Also why don't keyboards come with a super small usb device that goes unobtrusively in a usb port on the back of your computer comparible to tiny thing i get with wireless mice intended for laptops. I buy laptop mice and use them for my desktop because its cheaper and you need a battery either way,, but that way I don;t need that clucky signalling station.

I am all for this technology -- but the EM freaks are partially right we are ever increasing the amount of EM radiation we are exposed to from cell phones to radiowaves to wrieless routers in every apartment ( I can get 7 strong signals) will energy transmission push us over the edge ... I hope not
mauro48it
Feb 12, 2010

Rank: 3 / 5 (7)
Are you sure you wish live for the rest of your life in a low frequency owen?
Are you sure that a part of your body or a part of your appliances do not resonate on that frequency?
antialias_physorg
Feb 12, 2010

Rank: 4.8 / 5 (6)
Why is it we have cables now anyway??? the throughput of my wireless router FAR outdoes my internet connection so why do we need to physically connect the monitor to the case??

Because one transmit information (your router) while the other transmits power (and information depending on what your cable looks like)

I'll stick to cables when it comes to transmitting power - it's MUCH more efficient. As someone already noted: Needlessly outfitting a place with an energy wasting infrastructure is stupid when today we shgould be saving energy.

C'mon - How much effort is it really to plug in a cable? And how often do you move them once you have plugged a new appliabce in? Every blue moon.

That's not to say I couldn't envision special applications for his. But certainly not in the home.
Objectivist
Feb 12, 2010

Rank: 3.8 / 5 (4)
A giant coil in the wall doesn't seem very practical. Wouldn't it be better if you'd install smaller coils in tables, with a much more directed effect, to power whatever is placed on it? Such as a TV, lamp, laptop, etc. Perhaps even a big cluster of small coils inside such a table that may increase and decrease the throughput of each coil separately on demand (from the device, which the table would seemlessly communicate with via a built in positioning system). Then wherever a device is put it would create a "hotspot" with more active coils.
Quantum_Conundrum
Feb 12, 2010

Rank: 4 / 5 (2)
antialias_physorg:

I agree. Mostly, I think this is a stupid idea, especially in the home or even in most business or industrial applications.

There is no good reason to have electricity or other forms of energy just arcing through the air "just for the hell of it".
Skeptic_Heretic
Feb 12, 2010

Rank: 3 / 5 (3)
Why is it we have cables now anyway??? the throughput of my wireless router FAR outdoes my internet connection so why do we need to physically connect the monitor to the case??

For the longest time all TV was wireless. Then we decided it wasn't good enough and laid cable across the world. It wasn't until recently that wireless became both powerful enough, and safe enough for home use.

I'm a fan of the coil electricity distribution system. Too bad Tesla isn't around to see his brainchild become manifest.
Caliban
Feb 12, 2010

Rank: 1.5 / 5 (2)
Kind of a sidebar- but here's link to story a few days ago that seems to me like the way to go:

http://www.physor...481.html

This would make it possible to avoid all the troubling issues voiced above. The idea of all that EMR in the air where I live is disturbing.
I'll stick to cabling for now.
Quantum_Conundrum
Feb 12, 2010

Rank: 3.7 / 5 (3)

For the longest time all TV was wireless. Then we decided it wasn't good enough and laid cable across the world. It wasn't until recently that wireless became both powerful enough, and safe enough for home use.


Wireless antenas WEREN'T good enough, AT ALL.

Constant static and interference from EVERYTHING, and complete loss of signals from literally a cloud or a gust of wind, have to go outside and spin the antena to get it aligned right again, every day or two, etc.

Of course, the only benefit of wireless television was that you didn't pay for the service! Once you had an antena, only the advertising companies paid, and the consumer paid nothing!!

Still, I would not want my television or internet done on a wireless system unless it was at least 10 times more reliable than existing cell phones, which still suck, BTW...

CAn you imagine "static" or "snow" on an internet connection with modern internet sites? You'd never be able to do anything really...
Quantum_Conundrum
Feb 12, 2010

Rank: 3.3 / 5 (3)
I'm a fan of the coil electricity distribution system. Too bad Tesla isn't around to see his brainchild become manifest.


I don't think this is what Tesla had in mind.

He intended to create a system of large scale energy transfer, say from city to city, or power plant to city using wireless, but from what I've seen on the subject, I don't think he intended people to have appliance-strength energy beams bouncing around inside the home...
Skeptic_Heretic
Feb 12, 2010

Rank: 4.8 / 5 (4)
Still, I would not want my television or internet done on a wireless system unless it was at least 10 times more reliable than existing cell phones, which still suck, BTW...

The majority of data traffic in the world is sent wirelessly for the majority of it's transit now a days.

As I said, wireless got better. Back then it was good enough, (when compared to the cost of running cable across the planet).

Tesla's dream was completely wireless energy. In the home and outside of the home.

He insisted that the most dangerous thing about electricity was all the wiring on more than one occasion.
dirk_bruere
Feb 12, 2010

Rank: 2 / 5 (1)
Just wrap the coil around your house.
xstos
Feb 12, 2010

Rank: 4.3 / 5 (4)
can't wait to order my magneto magnetic underwear and float through my house like an x-man
tkjtkj
Feb 12, 2010

Rank: 2.7 / 5 (3)
It's not surprising that 'techie buffs' such as most of us are here seem to ignore any details of the physiological effects of EMR! Fortunately, the FCC is supposed to care .. there are many regulatory items already . Unfortunately, these were written/enacted years and years ago and just cant reflect the plethora of radiation sources now bathing us all.
The 'cellphone-braincancer' debate isnt even over, and that's a milliwatt issue!

I believe that this problem and the problem of toxic consequences of nanotechnologies represent the most dangerous combo we've ever imagined: (excuse me while i turn off my electric blanket ... brbbbb........

jon
tkjtkj@gmail.com
fixer
Feb 12, 2010

Rank: 5 / 5 (3)
Great for high density housing though, no need to put the power on or pay the bill.
Just tap everyone elses power.
Another point, YOU may choose not to have this radiation in your house, but if your neighbour has it then so do you.
A bit like second hand cigarette smoke!
Mercury_01
Feb 12, 2010

Rank: 1.7 / 5 (3)
Yeah, just what I want. A giant EM coil in my house thats connected to the new smart grid. Oh, and sure Mr census man, go ahead and record the exact GPS coordinates of my home. Im a good citizen. I have nothing to hide, and why would anyone on earth want to cause me any ill?
http://www.satweapons.com/ -click "more information"
antialias_physorg
Feb 12, 2010

Rank: 5 / 5 (6)
There's a bit of a misunterstanding here:

We're not talking about wireless INFORMATION transmission (which requires very low power and is biologically (probably) of no importance).

The article, however, talks about wireless POWER transmission. We are talking about sizeable amounts of energy here (orders of magnitude larger than used for information transmission!).

Even in the days of antenna-TV the TV was plugged in to get POWER. No way could the antenna signal power a TV set.

Transmitting power like this in your home engenders a bit of a questionmark when it comes to biological effects.
Ulg
Feb 12, 2010

Rank: 4.7 / 5 (3)
I'm a fan of the coil electricity distribution system. Too bad Tesla isn't around to see his brainchild become manifest.


I don't think he intended people to have appliance-strength energy beams bouncing around inside the home...


His attempts to globalize electricity through the atmosphere was different- he was going to use the upper atmosphere as an actual conductor (low pressure atmosphere is highly conductive) If you are talking about Wardenclyffe tower anyway.

But he also did work on portable wireless/batteryless power devices:

"I mean the transmission of power to any distance without the use of wires" - Tesla 1893 Ben Franklin Institute

There is a famous picture of his from the cover of Electrical Experimenter 1919, he is sitting in a chair holding a light bulb that is wireless and without any type of battery, he not only had his house, but a large field in the back where you could bring any of combination of his devices and they would work.
mosahlah
Feb 12, 2010

Rank: 4.8 / 5 (4)
If this is capable of powering my electric lawn mower, I'd be concerned. However, we are already close to the threshold of being able to power many electronics off of ambient EM radiation. It would seem to be a step forward if we could bridge the gap with a supplemental source of energy. The benefit could be a revolution in energy saving technology if we can adapt common electronic applicances such as cell phone, clocks, computers, security systems, lamps, etc. to operate at milliwatts without the need for disposable batteries, wasteful transformers and heavy grids.
Mercury_01
Feb 12, 2010

Rank: 5 / 5 (1)
There's a bit of a misunterstanding here:
We're not talking about wireless INFORMATION transmission (which requires very low power and is biologically (probably) of no importance).
The article, however, talks about wireless POWER transmission. We are talking about sizeable amounts of energy here (orders of magnitude larger than used for information transmission!).
Even in the days of antenna-TV the TV was plugged in to get POWER. No way could the antenna signal power a TV set.
Transmitting power like this in your home engenders a bit of a questionmark when it comes to biological effects.

Power transmission wires, or coils, can do more than transmit power. Any type of wave can be made to act as a carrier wave for other frequencies. ELFs in particular. http://www.raven1.net/elf.htm
zekesphysorg
Feb 12, 2010

Rank: 5 / 5 (4)
Antialias wrote:

C'mon - How much effort is it really to plug in a cable? And how often do you move them once you have plugged a new appliabce in? Every blue moon.

You seem to be forgetting the reason why you have spent your whole life only moving appliances "once in a blue moon".....it was because they had cords! We've been limited by cords and proximity to outlets all our lives, of course we aren't going to move things often.

I can't wait for the day when cords are obsolete, and I can put any appliance, computer, or gadget anywhere in my house and it...just...works.
Bob_Kob
Feb 13, 2010

Rank: 3.4 / 5 (5)
This is not using electromagnetic waves, its using magnetic induction. And from all knowledge, magnetic fields do not interact negatively with the human body despite its energy level.
mauro48it
Feb 13, 2010

Rank: 5 / 5 (2)
Some small additional doubts. Perhaps this grandiosity seems exaggerated. How to solve the problem to charge the cost of energy used in a great condominium? I do not think it is easy to confine the magnetic field within a single apartment. If someone comes who underwent surgery with sensitive electronic equipment plant? If in the apartment there is a large structure that is equivalent to a resistive coil, how much energy could absorb? It seems that the application of this principle could be much less straightforward than assumed.
Bob_Kob
Feb 13, 2010

Rank: 4.7 / 5 (3)
One assumes you don't have a huge sheet of metal at resonant frequency in your average home.
Ant
Feb 13, 2010

Rank: 1 / 5 (4)
you could call this a cancer initiator, rather like living near power transmission overhead cables
Bob_Kob
Feb 13, 2010

Rank: 5 / 5 (3)
Again magnetic fields don't harm humans. Look at MRIs, they operate at many times the teslas that this device would be able to produce.
Quantum_Conundrum
Feb 13, 2010

Rank: 3 / 5 (2)
One assumes you don't have a huge sheet of metal at resonant frequency in your average home.


You're joking right?

The "average home" has huge amounts of metals, including, usually, a metal sheet behind the oven and microwave ovens.

Let's see, there's foundation wiring and re-bar, there's the nails and staples througout the house, as well as the hurricane straps, and don't forget the copper plumbing and the faucets.

It was already mentioned, but medical implants would be endangered, and anyone with metallic fillings, implants, or braces in their teeth would be endangered, particularly in cases where they have more than one type of metal fillings.

Additionally, and MRI scan lasts for a few minutes, while exposure to coil power would last a life time.
rethinker
Feb 13, 2010

Rank: 1 / 5 (1)

I think a coil in every apartment wall may be just what people want,or need, or don't need.

When the baby crib is near the coil and it can send power to his or her auto bottle feed, that makes it so we wont have to go into the room and manually do it. More time for TV.
seneca
Feb 13, 2010

Rank: 2 / 5 (2)
I'll be sure to sleep with a tinfoil hat on.

This technology was proposed by freaky Tesla before many years, but it was controversial from its very beginning - not only with respect to its apparent inefficiency, interference with another electronic devices (it could destroy your computer of wifi tower easily at distance) and negligible impact to human health.

For example, high intensity of high frequency field could cause uncontrolled formation of electric sparks between conductive objects, whenever they appear at proximity accidentally. It means, you should invest into your fire pull alarms well, if you're planning to change your bedroom into microwave oven.
seneca
Feb 13, 2010

Rank: 3.7 / 5 (3)
Again magnetic fields don't harm humans. Look at MRIs, they operate at many times the teslas that this device would be able to produce.

Steady state magnetic field (like those in MRIs) cannot transfer energy at distance - no matter how intensive it could be. Stop watching TV and learn some physics.
seneca
Feb 13, 2010

Rank: 2.3 / 5 (3)
Even electromagnetic waves of radiofrequency range could be unpredictable and dangerous. In 2007 retired radio-engineer John Kanzius developed an apparatus for cancer treatment by polarized radiowaves in 13 MHz frequency range (which is pretty close to 6 MHz, used in the disputed article).

During desalination tests of his device with tube filled by marine watter (~ 3% solution of NaCl, very close to concentration of salt in body fluids) he observed an evolution of hydrogen peroxide and gaseous hydrogen, which can be ignited by lighter (video http://tinyurl.com/yjr8dlw ). Experiments were confirmed and replicated by material scientists at Pennsylvania State University.

http://tinyurl.com/l3flvv

Do you want to evolve hydrogen and peroxide in your bedroom, while sleeping or listening music? Frankly, me not...
seneca
Feb 13, 2010

Rank: 3 / 5 (2)
..All the computer cables, under my table, created sort of a gordic knot over the time, and must be moved as one piece since...
You'll save only one cable from this knot - the power line one. The other cables will just become thicker due the need of better shielding. In addition, you'll need a much complex & better power sources in your computer & other electronic devices, capable of handling changes in input power. It's not so easy and simple, how it appears at the first look.
otto1923
Feb 13, 2010

Rank: 3.3 / 5 (3)
increasing the amount of EM radiation we are exposed to from cell phones to radiowaves to wrieless routers in every apartment
Which is inevitable and unavoidable, and will only increase as we look to implant telemetry and 'telepathic' communication via embedded devices. I suppose 'natural' selection would begin to adapt the species but treatments will be devised until favorable genetics can be identifed and the general population re-engineered to compensate. Artificial EM is now a permanent part of the human condition.
Mercury_01
Feb 13, 2010

Rank: 5 / 5 (2)
Again magnetic fields don't harm humans. Look at MRIs, they operate at many times the teslas that this device would be able to produce.


What makes you think that? Moving EM fields have been proven to induce mental states in test subjects. I thought that was common knowledge. this device operates at 6.5 Mhz. What would stop someone from sending 7.8 Hz ELF waves into our homes, ridden on the guise of a Mhz carrier wave? We would be oblivious. glued to our TVs and drooling in a highly suggestible theta state.

And dont say its not a wave. Induction IMPLIES that the field from the coil is moving at a given rate.
Bob_Kob
Feb 13, 2010

Rank: 3 / 5 (1)
Hmm that is disconcerting. I was always under the impression that magnetic fields, even if alternating did not interact with our molecules with any dramatic effect.
JacobA
Feb 14, 2010

Rank: 2.3 / 5 (3)
This technology seems quite practical in a sense but it also seems very dangerous. I know this type of technology has been around for a long time. I was under the impression that it didn't catch because sending high amounts of energy around could destroy DNA structure and cause cancer and tumors.

Speaking from experience I know of way too many people who are either fighting or have died from cancer. The last thing we need is to turn our living room into a microwave oven because we can't be bothered to plug in a chord. I really hope this does not become common place in the home or any residential area. Also, it seems like a gross waste of energy seeing as most of the energy would be lost to ambience.

I am only a layman not a physicist so correct me if I am wrong.
Skeptic_Heretic
Feb 14, 2010

Rank: 5 / 5 (1)
I am only a layman not a physicist so correct me if I am wrong.
It's a matter of whether we're talking ionizing energy or energy of a significant amount of force required to "remove" pieces of DNA.

If we can use energy more efficiently then the broadcast strength need not be much.

Think of lighting. You can briefly illuminate a CFL by dragging your feet on a shag carpet. Energies at that level are hardly deleterious, unless you're highly suceptible to static shock induced death.
antialias_physorg
Feb 14, 2010

Rank: 5 / 5 (1)
Again magnetic fields don't harm humans. Look at MRIs, they operate at many times the teslas that this device would be able to produce.


1) MRIs work with a static field (the variable field used for reading the signal is much lower powered). A static field does not induce any electrical current in a conductor (unless you move the conductor which you don't in an MRI)

2) You don't live 24/7 in an MRI

The propsed system would bathe you constantly in a shifting magnetic field. The body is not a perfect insulator so you'd constantly have low powered currents induced in your body.

Now I don't know about you, but I don't think our bodies were designed for this (and anything they weren't designed for tends to have harmful side effects if it is experienced for too long)

Additionally you would have to ban all passive metal objects from your appartment since they would constantly draw power.
Mercury_01
Feb 14, 2010

Rank: 4 / 5 (1)
Hmm that is disconcerting. I was always under the impression that magnetic fields, even if alternating did not interact with our molecules with any dramatic effect.


Im not too sure about DNA and cancer risks, Im just speaking of the effect certain waves can have on electrical brain activity.
RETT
Feb 15, 2010

Rank: 5 / 5 (1)
An MRI is a pulsed magnetic field in a superconducting coil. It is the pulses that produce the image slice. In any case, a magnetic field from anything other than a permanent magnet is also pulsing continuously, which is the only way that it can induce current flow in anything. Permanent magnet motors must still have induced variable fields to create motion. This may be by mechanical motion, but it is still variable. In the case of these charging coils, we are hoping that a very high percentage of the energy is transferred at the resonant frequencies and that other formations that can resonate do not extract the energy by "accident". This would be your pacemaker or the pen or keys in your pocket, or maybe even your cell phone that was not designed to charge itself this way. This whole idea sounds completely half-baked as could be the humans exposed to the wrong type of resonance. I think that I and most sensible people will pass.
seneca
Feb 15, 2010

Rank: 5 / 5 (2)
Im not too sure about DNA and cancer risks

DNA disintegrates in electromagnetic field, but the required frequencies reported are somewhat higher..

http://arxiv.org/abs/0910.5294

Of course, if salt water can be electrolyzed in 12 MHz field, then one could be never sure by anything...

http://tinyurl.com/yjr8dlw

We simply need more experiments in this area - it seems for me, most of physicists are pursuing Higgs bosons and black holes at LHC and no one cares about boundary phenomena of classical physics.
seneca
Feb 15, 2010

Rank: 3 / 5 (3)
It seems, microwaved watter isn't very healthy for some plants..

http://www.intern...rch.html
Mercury_01
Feb 15, 2010

Rank: 3 / 5 (2)
Well, yes, obviously higher frequencies mike microwaves can damage our biology.
It seems, microwaved water isn't very healthy for some plants..

http://www.intern...rch.html

Yeah, I havent used a microwave in 5 years for that reason (also, having one just promotes unhealthy eating). Someone needs to do a large scale experiment with that.

Water's weak bonds form a type of lattice in the liquid state that plays a role in biology. In fact, our cytoplasm is polarized in a manner that facilitates the movement of cellular mechanisms.

Consider this: The very first cells arranged themselves into spheres by way of polar attraction and repulsion.

Our biology rests on electrical activity. Its obvious that we need more studies before we let some enterprising geeks bring this 100 year old resonance experiment into our homes.
fixer
Feb 15, 2010

Rank: 5 / 5 (1)
An entire medical industry is based on the interaction of magnetic fields and the human body.
Unless you are prepared to denounce this industry as fraud write this article off as a "techie" joke.
Let's move on to something sensible.
antialias_physorg
Feb 15, 2010

Rank: 5 / 5 (1)
An entire medical industry is based on the interaction of magnetic fields and the human body.


Have you ever seen any of these applications in the hospital (besides MRI)? No. Me neither.

These 'magnetic healers' _are_ a fraud. There are no studies to support them and your medical insurance certinaly on't cover them.
fixer
Feb 16, 2010

Rank: 4 / 5 (1)
They may be a fraud, but it is proven that a magnetic coil will polarise iron in the blood.
Incidently, cancer contains a lot of iron and an inductive field is used to cook it in situ, so I wouldn't be too quick to dismiss it all as fraud.
Skeptic_Heretic
Feb 16, 2010

Rank: 3 / 5 (4)
Have you ever seen any of these applications in the hospital (besides MRI)? No. Me neither.

PET scanners, Full body scanners, Bariatric imaging is done via magnetic resonance.

We use EM fields for almost 80% of non-physical diagnostics and it's involved in 3% of treatments, (mostly for cancer).
to_be_2718281828459
Feb 16, 2010

Rank: 4 / 5 (2)
And can you imagine a Vacuum cleaner using these coils? Damn, that would be so sweet. The biggest problem a Roomba has is it's battery life, this would get around that!

If an entire house where wired with the coils, then an 'active' room could resonate with an 'inactive' room with no current, that might get around the need for many devices active at once to create a resonance!

Resonance happens almost everywhere you go, but you're never aware of it, because we don't have the needed sensory organs, which is why no one understand electric currents are not a all like water, even if we call it a "current".

At the moment, if my cell phone rings, my headset will resonate with it. Both have small coils, so when one emits, the other can receive that frequency, and I get static, the other is ready to catch it. So even with my headphones, I can hear my cell. Electricity is not like water, at all.
seneca
Feb 16, 2010

Rank: 5 / 5 (2)
Roomba has is it's battery life, this would get around that
Not quite, resonant coupling mechanism proposed in wireless power requires, both source, both charged object should remain at rest in well tuned distance, or the efficiency falls down. Such device could be powered by directed microwave or IR beam from floor reflector (a quite viable technology, in fact) And Roomba is able to clean whole room during single charging cycle.
antialias_physorg
Feb 16, 2010

Rank: 5 / 5 (1)
PET scanners, Full body scanners, Bariatric imaging is done via magnetic resonance.


PET = Positron Emission Scan. This is a scan that uses beta decay of an introduced substance (no magnetic fields are involved, though many scanners are delieverd today as double systems with MRI)

Full body scanner - this is either an MRI (which I already mentioned) or a CT (which does not use magnetic fields)

Bariatric imaging - I don't know what you mean here. Bariatric surgery is a discipline that deals with surgical applications in relation to obesity. Postoperative imaging is sometimes done via MRI.

You are right, however: There is a tratment application for cancer using magentic fields. But that treatment does not use the effect of the magnetic field on the patient. The EM field heats up a specific substance that bonds to cancer cells (basically a substance that contains metal and the EM waves are short circuited via the metal - creating a heat locus that denaturates the proteins)
to_be_2718281828459
Feb 16, 2010

Rank: 5 / 5 (1)
And Roomba is able to clean whole room during single charging cycle.


How dare you presume the size of my room!!!

But I'm sure there are many places where large cabling can be removed for an important advantage.

And if my radio can tune to a radio station as I walk, why not this? What we would get is a fluctuating in the power of the moving device, which means the emitter has to lower/raise whatever it's doing to match that.

It means two vacuum cleaners, moving randomly in a room, on a fixed x-y plan, with a resonant emitter somewhere, have to receive constant power in any position they may go to. I can see how that would be tricky...

But that's where the magic of batteries come in: we don't need the electric field to be constantly resonating in the devices, as long as our batteries get charged sometimes! =)
seneca
Feb 16, 2010

Rank: 5 / 5 (2)
And if my radio can tune to a radio station as I walk, why not this?
I'm sure, whenever such technology appears in the market, many people like you will buy it just from curiosity reasons...;-) In radio broadcasting the efficiency of energy transmission is of low significance, because signal is amplified in three to four orders of magnitude range and radio-signal becomes quite homogeneous at sufficient distance from transmitter.

Nevertheless it brings an idea of self-tuned coupling by using of varicaps or transducers in circuit, which could improve the effective range of wireless power technology. Of course such circuit could work only for single coupled pair charged.
to_be_2718281828459
Feb 16, 2010

Rank: 4 / 5 (1)
Buy it? I wanna try and help create it!

If I could only figure out Coulomb's law so that the Biot-Savard law is obvious in such situations.

What really surprises is how the efficiency falls off in a 1/r fashion with distance, instead of 1/r^2, the way you expect charge over distance to behave. I wonder why?

Oh, intro to electrodynamics, why must you hurt so good?
broglia
Feb 17, 2010

Rank: 5 / 5 (2)
... the efficiency falls off in a 1/r fashion with distance, instead of 1/r^2...
From where did you got such information? Such dependence is extremelly nonlinear due the inductive coupling. It's evident, at low distance, comparable to diameter of Helmholtz coil the efficiency of energy transfer is inductive and it doesn't depend on distance too much, whereas at the larger distance is radiative by inverse square law.

http://www.wirele...ure2.jpg
Javinator
Feb 18, 2010

Rank: not rated yet
It seems, microwaved watter isn't very healthy for some plants..

http://www.intern...rch.html


Microwaves make water molecules move around. It's the movement of the molecules that makes them hot. These moving water molecules impart energy into neighbouring "food" molecules which makes them hot. It cooks things faster because the microwaves penetrate the food and move the water molecules throughout a substance more evenly than a conventional oven.

Conventional ovens/stovetops heat from the outside in or heat from the element on the stove. The heat causes the molecules on the outside to "shake" and bounce into its neighbouring water molecules and "food" molecules. And so heat is propagated throughout the food.

The water molecules aren't altered, they're simply "moved" in different ways.

There are just as many sources debunking this toxic microwaved water claim there are proving it out there.
Javinator
Feb 18, 2010

Rank: not rated yet
Nice source by the way:

From http://www.intern...rch.html :

"Dr. Emoto and his team study water from different sources of the world and also water that was effected by music, image, television, thoughts of a single person and a group of people, prayers, words typed or pronounced in different languages etc. Emoto discovered that there was a significant difference between crystals that listened to Beethoven and heavy-metal. Words "angel" and "devil" form structures that are similar and completely opposite at the same time."
Skeptic_Heretic
Feb 18, 2010

Rank: 5 / 5 (1)
This is the best part:
Words "angel" and "devil" form structures that are similar and completely opposite at the same time."


Because water naturally speaks english.
Mercury_01
Feb 19, 2010

Rank: 1 / 5 (2)
This is the best part:
Words "angel" and "devil" form structures that are similar and completely opposite at the same time."


Because water naturally speaks english.

typical "skeptic" straw man logic. Its not language, smart guy, its large scale entanglement. prove me wrong, then talk like you know everything.
Skeptic_Heretic
Feb 19, 2010

Rank: 3 / 5 (2)
typical "skeptic" straw man logic. Its not language, smart guy, its large scale entanglement. prove me wrong, then talk like you know everything.

Distant intention is not entanglement.

Distant intention would be if I thought about killing you and my thoughts killed you.

Thinking about water does not make water do things, what sort of pseudo scientific garbage are you reading?
The Institute of Noetic Sciences conducted a double-blind test of the effects of distant intention on water crystal formation. This was done with Dr. Masaru Emoto and the participants of the International Water Festival in Tokyo, Japan sending blessings of love and gratitude to water in a remote location.
That type.
Mercury_01
Feb 23, 2010

Rank: not rated yet

What makes you think you know anything about it? Got any first hand experience? Read any good books on large scale entanglement? There are none, so keep your thoughts to yourself on matters in which you have NO experience.

"Distant intention is not entanglement."

Just because you say something doesnt make it real. Hundreds of well conducted studies, all with a statistical significance greater than p.o5 speak to a different story. Your skepticism is of the NON- SCIENTIFIC variety.

Causation between seemingly unrelated events, when consciousness is an intentional factor, consistently displays a significant level of system continuity. If people like you weren't so damned PHOBIC, we could already have a full functioning hypothesis, but for those of us in the know, it's already fully apparent that consciousness is capable of large scale system entanglement, affecting at least a few properties of matter.

John_Doe
Mar 06, 2010

Rank: 1 / 5 (1)
"the overall efficiency of powering multiple devices can be significantly higher than the efficiency of powering each device by itself"

Guess what, the efficiency of creating brain tumors is going to be higher too.
Rank 4 /5 (28 votes)
Relevant PhysicsForums posts
  • Physical laws .... are they material?!!
    created52 minutes ago
  • increasing time of daylight
    created1 hour ago
  • Light & Sight
    created1 hour ago
  • Wind Turbine Power
    created4 hours ago
  • Steam Table issues
    created6 hours ago
  • electrostatic induction in a conductor should be immpossible
    created10 hours ago
  • More from Physics Forums - General Physics

More news stories

Hovering not hard if you're top-heavy, researchers find

Top-heavy structures are more likely to maintain their balance while hovering in the air than are those that bear a lower center of gravity, researchers at New York University's Courant Institute of Mathematical Sciences ...

Physics / General Physics

created 1 hour ago | popularity 5 / 5 (1) | comments 1 | with audio podcast

SLAC, Stanford team focuses on high-energy electrons to treat cancer

Accelerator physicists at SLAC and cancer specialists from Stanford are working on a new technology that could dramatically reduce the time needed for cancer radiation treatments. The team ran an initial experiment ...

Physics / General Physics

created 4 hours ago | popularity 5 / 5 (1) | comments 0

Measurements from high-energy collisions lead to better understanding of why meson particles disappear

For several years, physicists at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), USA, have studied an unusual state of matter called the quark–gluon plasma, which they ...

Physics / General Physics

created 4 hours ago | popularity not rated yet | comments 0

Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible

(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...

Physics / Quantum Physics

created Feb 08, 2012 | popularity 4.1 / 5 (11) | comments 32 | with audio podcast weblog

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (14) | comments 34


Grass to gas: Researchers' genome map speeds biofuel development

Researchers at the University of Georgia have taken a major step in the ongoing effort to find sources of cleaner, renewable energy by mapping the genomes of two originator cells of Miscanthus x giganteus, a large perenn ...

Researchers develop new method for creating tissue engineering scaffolds

Researchers at Northwestern University have developed a new method for creating scaffolds for tissue engineering applications, providing an alternative that is more flexible and less time-intensive than current technology.

Molecular profiling reveals differences between primary and recurrent ovarian cancers

There is a need to analyze tumor specimens at the time of ovarian cancer recurrence, according to a new study published in Molecular Cancer Therapeutics. Researchers used a diagnostic technology called molecular profiling to examine ...

C-sections linked to breathing problems in preterm infants

Research conducted at Yale School of Medicine shows that a cesarean (C-section) delivery, which was thought to be harmless, is associated with breathing problems in preterm babies who are small for gestational age.

Review: Netflix and Hulu's new scripted originals

Within just over a week, Netflix and Hulu are both debuting their first stabs at original scripted programming.

India probes Google over 'forex transactions'

Indian authorities are probing whether online giant Google broke domestic foreign-exchange transactions rules while shifting funds abroad, the Press Trust of India reported on Friday.