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Author Topic: Wireless Power is it possible?  (Read 6569 times)

Offline ScientificSorcerer

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Wireless Power is it possible?
« on: 28/04/2015 23:06:53 »
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                                                            idea Posted by Scientificsorcerer
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I Have presently been researching radio technology, I've been searching for a method to make wireless energy   possible.  through my research I Have come up with an experimental set up which in theory could make a type of "wireless power device" which could be used much like a wireless internet router to supply a healthy amount of wirless energy into an area the size of a room or house.

The Idea works works like a conventional microwave oven, which involves reflecting the microwaves in a "mirror box configuration" in-order to "enclose" the waves and concentrate them inside the box.

My Idea Is similar to A microwave oven in that respect.  My Idea involves painting the interior of a room/house with a conductive paint and have a powerful radio transmitter somewhere inside the room/house throwing out large amounts of radio energy, the radio waves should be mostly trapped inside the house, the paint on all the walls, floors and ceiling acting like a Faraday cage allowing the most of the radio energy to be trapped and concentrated in a small area.

The high powered radio waves can be used by devices like computers, cellphones, tvs and other utilities to supply electrical energy witlessly by inducing a current into an antenna.

Imagine this being your house.


You could imagine the whole house being coated with conductive ink, it's everywhere, on the ceiling under the floors and on every inch of the walls,  heck you might even be able to coat the windows with conductive indium tin oxide.
you can think of this "conductive shell" much like the thermal insulation of a house.  The better your house is coated in conductivity the more efficient your wireless power transfer system will work.  It might even be possible to recapture some unused radio energy in a feed back loop system were some energy can be absorbed by a radio antenna and fed back-into the wireless power system.


I would also like to note that making the conductive shell can be done in a variety of ways which might prove to be cheaper and more efficient at containing the radio waves in the room or house, for example during construction of a house  conductive sheets of aluminum wire can be placed behind drywall or you could install conductive wallpapers made of mylar all over the place,  the point is that as long as your contained inside a conductive box you should do fine, heck you could put up a conductive dome over your house and get the same effect.

The safety hazards of high radio are a concern though, there can be health risks associated with being exposed to high powered radio fields but I don't know much about what will happen to a guy if he lives inside a radio-wave oven.  [|)]

I Want to create a system like this so that in the future all of your wireless devices can always remain powered up when inside of your house or inside a restaurant or store.


That's this Idea of mine in a nut shell, what are your thoughts on this Idea, do you think it could work?
« Last Edit: 30/04/2015 05:06:35 by ScientificSorcerer »


 

Offline alancalverd

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Re: Wireless Power is it possible?
« Reply #1 on: 28/04/2015 23:13:04 »
The word "healthy" is wrong. The idea of your finger beng fried by a wedding ring is a bit offputting.
 

Offline RD

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Re: Wireless Power is it possible?
« Reply #2 on: 29/04/2015 02:28:38 »
Even the best mirrors absorb some of the energy incident upon them, which means the vast amount of energy in your microwave house will not be used by wireless appliances, but absorbed by the walls, i.e. wireless transmission of energy is grossly inefficient.

Tesla had a similar idea : wireless transmission of electrical power over large distances. He died bankrupt ...

Quote from: wikipedia.org/wiki/Wireless_power#Tesla
The inductive and capacitive coupling used in Tesla's experiments is a "near-field" effect, so it is not able to transmit power long distances. However, Tesla was obsessed with developing a wireless power distribution system that could transmit power directly into homes and factories, as proposed in a visionary 1900 article in Century magazine. and believed that resonance was the key. He claimed to be able to transmit power on a worldwide scale, using a method that involved conduction through the Earth and atmosphere. Tesla was vague about his methods ... 
http://en.wikipedia.org/wiki/Wireless_power#Tesla.27s_experiments
« Last Edit: 29/04/2015 02:38:22 by RD »
 

Offline Colin2B

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Re: Wireless Power is it possible?
« Reply #3 on: 29/04/2015 17:56:29 »
The word "healthy" is wrong. The idea of your finger beng fried by a wedding ring is a bit offputting.
Unfortunately there are a lot of loops in the average house. Scissor handles, egg whisk, skewers, also in electronic equipment eg radios, computers and phones, and pacemakers.
Could be of use in some low power short range eg chargers. A lot of toothbrushes use inductive charging but need the transmitter and receiver coils to be very close.
 

Offline ScientificSorcerer

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Re: Wireless Power is it possible?
« Reply #4 on: 30/04/2015 05:02:47 »
The walls do absorb energy but perhaps that energy can be fed back into the transmitter.  Think of the walls as radio receivers that feed it's signal back into the transmitter.

Also I think your finger ring should be safe, I should have also mentioned that the maximum power output would not be very high, maybe less then 5 watts

you have to remember that radio towers do induce power into objects from a fast distance away. don't believe me then look at this

 
 

Offline Colin2B

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Re: Wireless Power is it possible?
« Reply #5 on: 30/04/2015 06:18:34 »
Also I think your finger ring should be safe, I should have also mentioned that the maximum power output would not be very high, maybe less then 5 watts
Ok, I was misled by your comment:
"The high powered radio waves can be used by devices like computers, cellphones, tvs and other utilities to supply electrical energy witlessly by inducing a current into an antenna."

Obviously 5w won't power computers or TVs.

you have to remember that radio towers do induce power into objects from a fast distance away. don't believe me then look at this
I did know, I used to work in telecoms and have seen fluorescent tubes lit, and interference caused, by radio waves some distance from the radio tower. It is worth remembering that these towers can have an effective radiating power of 500kW, that's a 100,000 times the power you are using.

The walls do absorb energy but perhaps that energy can be fed back into the transmitter.  Think of the walls as radio receivers that feed it's signal back into the transmitter.
The absorbed energy will be lost as heat. You would need to find a way of tapping it off before absorption.
Reflection as in a microwave might put some energy back.
To be honest, at 5W it really isn't worth worrying about the expense of shielding the building or recovering the power. Remember, you power will drop off as inverse square law.
« Last Edit: 30/04/2015 06:23:18 by Colin2B »
 

Offline diethyl

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Re: Wireless Power is it possible?
« Reply #6 on: 30/04/2015 07:02:34 »
At least, it has been realized in small electrical appliances such as mobile phone. We can believe it will be used in more areas.
 

Online evan_au

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Re: Wireless Power is it possible?
« Reply #7 on: 30/04/2015 12:45:34 »
Quote from: ScientificSorcerer
https://www.youtube.com/watch?v=gfUuwnD2-fg
It is not clear from this video (or the descriptive text) whether:
  • the loudspeaker is being powered directly from the coil, or
  • the loudspeaker box has an internal amplifier and batteries, and an audio signal is being fed into the amplifier audio input.
I think probably (2), and it is a demonstration of induction, rather than a demonstration of wireless power transmission.

Old (vacuum tube) amplifiers used a transformer to power the speakers, but these required an iron-cored transformer, closely coupled coils and a closed magnetic path to achieve significant power transfer. An air-cored transformer loses on all 3 counts.

Wireless charging is certainly possible, but place the appliance to be charged as close as possible within the coil, and don't make the coil any larger than necessary.
 

Offline wolfekeeper

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Re: Wireless Power is it possible?
« Reply #8 on: 30/04/2015 15:09:59 »
It's perfectly possible to flood your house with RF fields to enable you to charge everywhere.

There's a couple of catches though:

a) running the field costs energy, and the bigger the field is, the more energy it costs
b) you're sitting in the field as well, and the field strengths are likely to be above the guidelines

There is another way to do this though. If you set up directional aerials you can beam radio waves directly at the things that need charging. The fields are much more concentrated and the safety issues aren't so bad- you're only charging things that need charging, and multiple beams would be hitting it from different angles, so there's much less field strength everywhere else.
 

Offline Colin2B

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Re: Wireless Power is it possible?
« Reply #9 on: 30/04/2015 15:44:54 »
. If you set up directional aerials you can beam radio waves directly at the things that need charging.
Sourcerer, look up yagi array and dipole with reflector. Remember the lower the frequency, the larger the metalwork!

 

Offline alancalverd

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Re: Wireless Power is it possible?
« Reply #10 on: 01/05/2015 08:41:36 »

you have to remember that radio towers do induce power into objects from a fast distance away. don't believe me then look at this


Yeah, that's, like, how radio works, man. Some dude called Helmholtz did it. It won't catch on, though.
 

Online evan_au

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Re: Wireless Power is it possible?
« Reply #11 on: 02/05/2015 03:17:30 »
Quote
If you set up directional aerials you can beam radio waves directly at the things that need charging.
Some of the research currently being done for "5G cellular networks" is demonstrating phased array antennas that could be made the size of your hand, containing perhaps 128 tiny antennas which produce very directional beams at 60GHz or so. They don't tend to go so well through walls or rain, but they are OK within a room.

Electronics at these frequencies is rather inefficient today, but I expect that this will improve over time.

An in-home transmitter probably should have no more than 0.1W of power for communication purposes, but if wireless charging were a requirement, you may need to bump this up to (say) 10W, at probably 10 times the cost for the electronics.
 

Offline wolfekeeper

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Re: Wireless Power is it possible?
« Reply #12 on: 07/05/2015 02:02:47 »
The word "healthy" is wrong. The idea of your finger beng fried by a wedding ring is a bit offputting.
Unfortunately there are a lot of loops in the average house. Scissor handles, egg whisk, skewers, also in electronic equipment eg radios, computers and phones, and pacemakers.
The mid-distance schemes rely on resonance, but wedding rings are not resonant; so although they will absorb some power, it won't be a lot.
 

Offline alancalverd

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Re: Wireless Power is it possible?
« Reply #13 on: 07/05/2015 07:56:00 »
"Estimate the resonant frequency of a wedding ring" used to be a regular interview question, but clearly the laws of physics have changed. Anyway, should you be magically transported back to the 1960's and seeking a career in RF engineering, or a degree in electronics, the answer IIRC was around 200 MHz. A wire coathanger still makes a reasonable receiver coil for low-field MRI machines at about 20 MHz. The parallel capacitance required for resonance is provided by the person inside either device.

Not that resonance is required. It will optimise power transfer but any shortcircuited turn will generate heat in an RF field, so beware of wire-rimmed spectacles, scissors, washers.....   
 

Offline wolfekeeper

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Re: Wireless Power is it possible?
« Reply #14 on: 07/05/2015 15:00:46 »
The amount of heat generated matters here. Sure, they'll generate some heat, but still virtually none.

It's not enough for it to be simply resonant, it has to have stupidly high Q at the transmitter's frequency.

With all of these schemes, they struggle to get significant power to a carefully designed, very high Q receiver, never mind something that just happens to be lying around that's only roughly the right shape; you get essentially no power transfer in that situation.

Some of the systems for charging electric cars and induction hobs have to have things to prevent heating other objects, but they're using very high powers, and even then it's not as big an issue as you would expect.
« Last Edit: 07/05/2015 15:02:31 by wolfekeeper »
 

Offline alancalverd

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Re: Wireless Power is it possible?
« Reply #15 on: 07/05/2015 18:15:16 »
It's as big an issue as you want it to be. I've designed inductive coupling to power underwater x-ray machines (like a toothbrush charger, but somewhat bigger) and to recharge artificial hearts (ditto but smaller) and suchlike, but the key is always to keep your keys away!

To see what effect a 500W RF field can have on an untuned circuit, try putting a gold- or silver-rimmed plate or cup in a microwave oven. Or even try picking up a salt-glazed or metal-decorated earthenware pot after cooking in it.

Wireless power is good fun at trivial levels, but there's a good reason why walkie-talkies and mobile phones are banned from cardiac operating theatres and even dental x-ray facilities - the damn stuff gets to places you really don't want it.
 

Offline wolfekeeper

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Re: Wireless Power is it possible?
« Reply #16 on: 07/05/2015 19:09:45 »
It's not a complete non issue; it's potentially a problem for things right next to the transmitter. If the transmitter finds that there's a lot of power being dissipated at frequencies other than the resonant one, then it needs to shutdown.
 

Offline syhprum

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Re: Wireless Power is it possible?
« Reply #17 on: 08/05/2015 13:28:16 »
In pre war days armature radio transmitter enthusiast used to have loops of wire laying around with miniature light bulbs soldered into them to impress the uninitiated
 

Offline SciencyGummyWorms

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Re: Wireless Power is it possible?
« Reply #18 on: 19/05/2015 20:42:46 »
there is a type of conductive paint called electric paint. This is water based. It acts like a wire, so I think you can use it for the application you want. I recommend finding itemized cost and making a chart. This paint cost  $24.95 per ml. You can calculate the surface area and then buy accordingly. To see the product. newbielink:https://www.sparkfun.com/products/10994 [nonactive]
 

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Re: Wireless Power is it possible?
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