Ultrasonic Power Transfer Investigated Using Data From uBeam Patent Filings (hackaday.com)

szczys writes: Transmitting power through the air using sound above the range of human hearing: that's the gist of ultrasonic power transfer. The promise is that you can sit in a coffee shop and use your phone like normal while it's recharged by invisible waves of energy. That's a future we all want — and one that uBeam has been promoting, but hasn't backed it up with proof. Physics is a cruel mistress, and this is no exception. Using the data found in uBeam's patent filings you can see that ultrasonic power transfer is a brutal engineering challenge. It's probably not impossible, but looking at what it would take for a widespread rollout of the tech makes it highly improbable.

Comments

My Phone is Charging!

[DumbSwede]

...But my EYES and EARS are bleeding.

Re:My Phone is Charging!

[rrohbeck]

But it'll clean your glasses and dentures at the same time.

Re:My Phone is Charging!

[Locke2005]

And every dog with 10 blocks is howling!

Re:My Phone is Charging!

[davester666]

As a bonus, it keeps those pesky teenagers away!

Ugh

[grimmjeeper]

When are people going to learn that pushing power through air, in any form, is horribly inefficient and impractical for anything more than a science experiment?

Re:Ugh

[ralphsiegler]

oh? I think winding two or more sets of insulated wires around an inductor might be a way to push power through the air while altering EMF level for devices that need it at a different level, in a very efficient manner. We could call such a device a pusherformer.

Re:Ugh

[sims 2]

100W of power to get 10W to charge my phone is acceptable if my phone will charge when placed anywhere in a 20x20ft room.

As long as I still have to place my phone in a 0.5x0.5ft area to use a wireless charger i'll just stick with a cable.

Re:Ugh

[U2xhc2hkb3QgU3Vja3M]

The whole planet is struggling to keep up with energy demands and you think it's acceptable to waste 90% of the energy you use?

Re:Ugh

[Locke2005]

What percentage of the energy in sunlight striking the Earth do you think gets wasted?

Re:Ugh

[Aaden42]

Not so much: https://en.wikipedia.org/wiki/...

In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet network. ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, and later the IEEE 802.11 protocols, respectively.

Re:Ugh

[NatasRevol]

Exactly. If I can't have charging as useful & accessible as wifi, then what's the point?

Re:Ugh

[Anonymous Coward]

What kind of a stupid rhetorical response is this?

It's like asking "How much water does Niagra Falls waste?" in response to someone pointing out the stupidity of hosing down your pickup truck during a drought.

Re:Ugh

[sims 2]

If I am the one that is paying for it why should you even care?
There are hundreds of thousands of outdated computers still in use today that have much worse power efficiency ratings compared to today's equipment. Their was a /. article about that a short while ago. http://hardware.slashdot.org/s...

Energy demand problems in this country tend to be related to NIMBY. We need a new power plant but no one wants it in their backyard.

I like energy efficient appliances up to the point that they no longer function as they should. Incandescents bulbs are lights, led bulbs are lights but CFL bulbs are an abomination of energy policy and optimistic manufacturing that never should have happened.

Re:Ugh

[NatasRevol]

Outside of plants, about 95% of it.

With plants, about 90% of it.

Re:Ugh

[ShanghaiBill]

The whole planet is struggling to keep up with energy demands and you think it's acceptable to waste 90% of the energy you use?

The amount of power used to charge cell phones is negligible. So it doesn't really matter if it is inefficient. It is still negligible.

I get into a similar argument with co-workers about water here in California. They wanted to save dishwater and use it to flush the toilet. Then I pointed out that we can flush the toilet twice a day for a year with the amount of water saved by eating tofu for lunch instead of beef ONE TIME.

Keep some perspective.

Re:Ugh

[angel'o'sphere]

Actually: none.

It hits the earth, so it has an effect ... what exactly did you want to say?

Re:Ugh

[grimmjeeper]

There's a reason transformers don't have coils across the room from each other. Maybe someone smart already figured out how fast the energy drops off the further away you get... ;)

Re:Ugh

[U2xhc2hkb3QgU3Vja3M]

I already eat tofu, you insensitive clod!

Re:Ugh

[sims 2]

Which Is slightly more convenient but it's not worth the extra cost and loss of efficiency imho. Maybe if it was standard but not as an extra.

Re:Ugh

[sims 2]

Meh 20x20 is big enough that if I need it in every room I can buy a couple more and never have to worry about it.

As for laziness just having to have my phone in a 20x20 room a few hours every day would completely eliminate ever having to remember or think about charging my phone. That would easily be worth the loss in efficiency and extra cost of the setup.

Think about how much time wifi saves you sure it's insecure slow and unreliable. But having wireless web access on your devices is so awesome people use it anyway. At least I think so but then again I had wifi when I was still using dialup. sharing a 56k connection among 3 computers and a nintendo ds with 802.11b now that's some fun!

Re: Ugh

[AntronArgaiv]

And the data rate was...9600 bits per second, over the air.

Re:Ugh

[Tyrannosaur]

The whole planet is struggling to keep up with energy demands and you think it's acceptable to waste 90% of the energy you use?

Yes

Re:Ugh

[U2xhc2hkb3QgU3Vja3M]

I also live here and I still think it's a waste. We could be selling that surplus to the U.S.A.!

Re:Ugh

[WinstonWolfIT]

I like this. With the exception of Tesla, pushing anything through the resistance of air tends to look like lightning with all of the downsides.

Re:Ugh

[KGIII]

I thought we bought some? I'm in Maine. Well, not technically, but my home is in Maine. I also don't buy power but make enough to push some back into the grid but I think other Mainers buy power from Quebec. At least I'm pretty sure I've read such a few times in the paper.

If it was easy ...

[tommeke100]

it would already have been done. Obviously did not RTFA, but this probably has very bad efficiency and a lot of the power gets lost.

'Wireless charging' is for fools

[Anonymous Coward]

People who think that you can run your entire house off a generator connected to a bicycle, or that putting a propeller connected to a generator on the hood of your car is 'free energy', are the same idiots who believe that 'wireless charging' is a good idea. The Inverse Square Law fully applies to any sort of wireless charging because physics works, and no amount of wishful thinking or marketing bullshit is going to change that. Sitting there saying 'But it works, we have it right now' means Jack Shit because it's all so wasteful of energy as to be worse than useless. Just plug your gods-be-damned phone into a USB port, let it charge, and fucking get over it already. Oh, and memo to those of you who want 'wireless charging' because you keep annihilating the USB connector on your phone: Try being a little more careful instead of looking for a workaround for how clumsy and careless you are with your expensive electronics, and stop encouraging retarded marketing people who keep pushing for this rediculous and unnecessary technology, it's just distracting developers and engineers from working on things that actually matter.

Re:'Wireless charging' is for fools

[U2xhc2hkb3QgU3Vja3M]

What people need are docking stations. No cable to handle and yet it's not wireless.

Re:'Wireless charging' is for fools

[Knee Patch]

The Inverse Square Law fully applies to any sort of wireless charging because physics works.

I'm pretty sure the fact that most wireless charging systems operate in the near field and rely and near field effects means that the inverse square law doesn't "fully apply". Even if it does in a technical sense, the distance between transmitter and receiver is very small.

Re: 'Wireless charging' is for fools

[Locke2005]

If you have to use a highly directional transmitter and receiver, might as well use an infrared laser beam. If you're making it omnidirectional, than power drops off as the cube of distance, so extremely inefficient. I'm not seeing an up side here.

Re: 'Wireless charging' is for fools

[ColdWetDog]

You can use beam forming to change the virtual distance used for the calculation of the power transmission efficiency. Examples if you use an ideal parabolic reflector behind a point source the distance used for that computation should be measured from the focal point

This. At Starbucks (who apparently is investing in this thing), you can do two things at once - keep your coffee hot and charge your laptop. Three things - keep your coffee hot, charge laptops and fry the brain of everyone in the establishment.

Sounds like a winner to me.

Re:'Wireless charging' is for fools

[Khyber]

"Even if it does in a technical sense, the distance between transmitter and receiver is very small."

Induction charging, even at its best, is only about 40% efficient and that's practically touching coils together.

Re: 'Wireless charging' is for fools

[angel'o'sphere]

Again: power drops of with the square of distance. As this is the increase of surface it is illuminating.

You should have learned that in school.

Re:'Wireless charging' is for fools

[Knee Patch]

Induction charging, even at its best, is only about 40% efficient and that's practically touching coils together.

Sure, but that loss isn't due to any inverse square law, is it? Like you said, the coils are practically touching. The op was implying that all wireless charging is stupid because loss increases with the square of the distance. I'm saying (with no research and little expertise in the area) that all of the wireless charging I've seen operates in the near field; and while I don't know how much that 40% efficiency number you gave could be improved upon, I doubt that the dominating factor in the loss is distance in this specific case.

Re:'Wireless charging' is for fools

[Hussman32]

For linear attenuation of sound, Stoke's Law is more appropriate for a back of the envelope estimate. More searching will yield more refined models. That being said, no planar transducer propagates only linearly, and there is decay in the x and y directions (considering z as the normal vector).

I was scratching my head when I read about this idea because I work with ultrasonics a bit and we have a heck of a time with maintaining energy density over short distances.

Re:'Wireless charging' is for fools

[Khyber]

"Sure, but that loss isn't due to any inverse square law, is it?"

A good deal of that loss is inverse square (or inverse cube in the case of omnidirectional transmission.) Doesn't matter if you're doing millimeters, centimeters, inches, whatever. Whatever you're getting at 2mm distance is half (or less) what you'd get at 1m distance. That's how great the inverse dropoff effect is.

Re:'Wireless charging' is for fools

[Knee Patch]

Cool, does that mean I can get infinite power out of it as long as I can get the receiver and transmitter arbitrarily close to each other? Sounds like each time I cut the distance in half I get twice the power. Zeno saves the day!

If distance=0 represents a theoretical "full power", then how do you double that distance to get the half (or quarter) power according to the inverse law? If some distance > 0 represents "full power", then getting the TX and RX that close ought to be free of this nasty inverse square business.

Re:'Wireless charging' is for fools

[kheldan]

If distance=0 represents a theoretical "full power", then how do you double that distance to get the half (or quarter) power according to the inverse law?

You're halfway across the bridge.
You're three quarters of the way across the bridge.
You're seven eighths of the way across the bridge.
You're fifteen sixteenths of the way across the bridge.
You're thirty-one thirty-seconds of the way across the bridge.
You're sixty-three sixty-fourths of the way across the bridge.
You're one hundred twenty-seven one hundred twenty-eighths of the way across the bridge.
You're two hundred fifty-five two hundred fifty-sixths of the way across the bridge.
(and so on, and so on..)

A transformer, which has tightly wound coils over a metal core, is something like 99.99% efficient. Loosening things up with distance, the efficiency starts dropping off quickly, as previously stated by others.

Re:'Wireless charging' is for fools

[sims 2]

After you get so close the wires touch and then its not wireless power anymore. :P

Re: 'Wireless charging' is for fools

[CanadianMacFan]

If they're at Starbucks then frying their brain is a bit redundant.

Re:'Wireless charging' is for fools

[KGIII]

Yup. In fact, you can already do that. You just plug it in and contact is made. Tada! You now have wireless power - except for still having the wires, of course. But you get much greater efficiency. (Reduction starts immediately - as soon as you have even the smallest of gaps.)

Re:'Wireless charging' is for fools

[Khyber]

"and you seem to have no idea what people mean when they talk about the near field"

You're not paying any fucking attention to the conversation. Near-Field in this context means radio and I am ENTIRELY CORRECT - https://en.wikipedia.org/wiki/...

Try again when you can actually comprehend the fucking conversation taking place, nimrod.

No, No, No, No..... This will not work

[bobbied]

Any technology which attempts to push power though a transmission medium where you have to worry about the "Inverse of the Square" of the distance is going to fail on it's face. Sound though air is such a problem. Magnetic and electric fields though air/vacuum is another. Power transfer may be possible, but the amount of losses means it will never be practical unless you have HUGE amounts of power to waste.

In this case you may not be able to hear ultra sonic frequencies, but that does NOT mean it cannot harm your hearing at the SPL's required to get any kind of power transferred.

Re:No, No, No, No..... This will not work

[sims 2]

For the small amount of power required I feel 10% efficiency is acceptable. I doubt any wireless charging tech will ever be energy star certified. Wireless charging tech will always be less efficient than wired. But I think you will find most people are willing to pay for convenience.

Re:No, No, No, No..... This will not work

[Locke2005]

It 3 dimensional, therefore inverse cube, not inverse square. But agreed, losses are phenomenal over even short distance with an omnidirectional point source. an array of transmitters in the ceiling would be slightly more efficient, but in that case, why not use infrared transmitters and photovoltaics? Or, here's a twist: use sunlight?

Re:No, No, No, No..... This will not work

[Khyber]

"For the small amount of power required I feel 10% efficiency is acceptable."

When it comes to SPL, your efficiency means nothing. We're still dealing with sonic ranges, here. For you to get enough sound energy to charge your wireless phone in an hour inside of a room, the ultrasonic energy would be such that it would fuck with you if you spent more than ten minutes in proximity to it.

How acceptable is it when your brain and hearing is getting turned to shit? 7 watts at audible ranges is enough to make you deaf from SPL.

Re:No, No, No, No..... This will not work

[angel'o'sphere]

It is inverse square, not cube.
We are talking about the area the beam is hitting, not the volume of space it is occupying.

Re:No, No, No, No..... This will not work

[sims 2]

That would be a unacceptable sacrifice in safety.

If that were acceptable we would have microwave based.. http://www.thinkgeek.com/stuff... wireless charging today.

Wifi is only safe because it is so low power even though it operates at the same frequency as your microwave.

Re:No, No, No, No..... This will not work

[JoeDuncan]

Magnetic and electric fields though air/vacuum is another. Power transfer may be possible, but the amount of losses means it will never be practical unless you have HUGE amounts of power to waste.

Not true. Microwave power transfer with rectennas can have efficiencies up to 90% or so...

https://en.wikipedia.org/wiki/... https://en.wikipedia.org/wiki/...

Re:No, No, No, No..... This will not work

[bobbied]

Consider this..

You won't get 10% unless you are within a very short distance, lets say 1 foot is that distance, lets also say that the collection surface is 1 square foot, which is big for a phone, but is about right for a large tablet. Charging takes 1 hour. If you assume an isotropic radiation pattern from the emitter, a 1 foot sphere has a surface area of 4*Pi*(square of (1)) or about 12 square feet. My phone has a 12 Watt/Hour battery, so assume 1 square foot generates 12 watts, and my huge phone will charge in an hour.

Double the distance to two feet from the emitter and you have a sphere of (4*Pi*(Square 2)) = 50 square feet, so moving your phone ONE FOOT further away from the emitter takes the time to charge from 1 hour to 50.

Halfway across the room at say 5 feet the power available will be drastically reduced (4*Pi*(Square of 5)) = 314 Square Feet, which means now, with the same power input as before it's going to take 314 hours to charge that same phone.

Do you see how this doesn't work? Even if you have a directional radiation pattern, the power density you can get will suffer from the square of the distance being on the bottom of the ratios here.

Re:No, No, No, No..... This will not work

[bobbied]

Which is NOT practical approach, even for what is intended.

Microwave power transfer requires very high frequencies amd very large transmission antennas which can successfully keep all the energy from the transmitter in a narrow beam. Even then, the receiving end of this arrangement requires a receiving array kilometers in size because no antenna can perfectly produce a beam of energy and going though the ionosphere, atmosphere, clouds, dust, wind and rain causes a drop off on the cohesiveness of the beam and quickly degrades the efficiency to a formula that has the square of the distance in the denominator.

You see this is a geometry problem. You have to get all that energy though some transmission medium by making the energy stay narrowly confined and not refracting away and spreading out. Any amount of spreading and you end up with the distance squared in the bottom of the power in to power out ratio. It's really really hard to keep that ratio from going to absurd fractions (for a power system). Unless you can construct an antenna that only radiates in a single direction, has a zero degree beam width AND can put useable amounts of power out, get said antenna into space, pointing exactly at the right spot which is moving all the time without wreaking it, warping it or having it deform due to uneven heating in orbit, this technically possible feat, becomes practically impossible to accomplish.

So, Yes, what I said is true. It won't work. Nor will this idea of using microwaves to transfer power to earth ever work. The equipment require is too heavy to get into space, too difficult to assemble once it's there and impossible to get and keep aligned. Even a minor variation from the idea will quickly kill any efficiency and because the distance is SO large and the alignment required so exacting it's not going to be possible on an industrial scale. It won't work unless you have lots of power to waste and even then it's going to be darn hard and expensive to do and even more expensive to maintin.

Re:No, No, No, No..... This will not work

[bobbied]

The issue is not about the volume, but the energy passing though the surface of what ever geometry the radiator emits energy into. Of course the "isotropic" radiator is the theoretical device that puts out equal amounts of energy in all directions and makes the math simple because we can use a sphere. The surface area of a sphere is (4*Pi* Radius Squared).

I've run the numbers elsewhere, but if you have a 1 foot collection area about 1 foot away from an isotropic radiator, you will get about 1/10th of the radiated power at best. 2 Feet gives you about 1/50th of the power and 5 feet lowers the available power to 1/300.

Re:No, No, No, No..... This will not work

[khchung]

Power transfer may be possible, but the amount of losses means it will never be practical unless you have HUGE amounts of power to waste.

Waste itself is not the biggest problem, if you are rich enough, waste becomes unimportant.

*Unintended absorption* will be the killer. Whatever means you use to send energy, "wasting" 90% means 90% of the energy would be absorbed by *something else*.

Probably something that is near the phone you want to charge, such as your body. Tinfoil hat should be provided to all customers.

Re:No, No, No, No..... This will not work

[citizenr]

Hearing is one thing, I dont want my cornea to get unglued

Re:No, No, No, No..... This will not work

[JoeDuncan]

Not practical NOW, no. But your statement was that this type of thing would NEVER be practical, and as far as I can see, all of your objections are simply engineering problems, the concept and theory is solid and has been proven in the lab and experimental implementations.

The only issue is in refinement of methods and equipment, which as I said, is just an engineering issue, so your NEVER modal qualifier is simply false.

Re:No, No, No, No..... This will not work

[bobbied]

This isn't an engineering problem it's a physics problem, and it's the physics that make it impossible. Technology and engineering cannot change the physics, but must work within the rules that physics provides.

All lab experiments aside, the physics of the problem mean it will not work on an industrial scale at any reasonable distance for a price anybody can afford. Why? The structures required are HUGE, literally kilometers in size, both in space and on the ground and this size is driven by the physics. Building such structures, while conceivable and possible, is VERY expensive and VER"Y time consuming, especially in space. (Lots of money) X (Lots of time) = Never going to happen.

So "NEVER going to happen" is accurate enough for a rule of thumb in this case.

Some things just are never going to be practical, I don't care how much you wish it was different. Sometimes the physics of a problem require a solution that simply cannot ever be implemented. Where the theoretical solution is beyond what can be successfully engineered to a theoretically possible cost and schedule. This is such a problem/solution.

Re:No, No, No, No..... This will not work

[JoeDuncan]

...will not work on an industrial scale at any reasonable distance for a price anybody can afford. Why? The structures required are HUGE, literally kilometers in size, both in space and on the ground and this size is driven by the physics.

"reasonable distance for a price anybody can afford"? You keep watering down your definition of practical. So it's only practical if you can have one today, in your garage? You know that we build structures of this magnitude already, right? Space telescopes, particle accelerators... etc

Building such structures, while conceivable and possible, is VERY expensive and VER"Y time consuming, especially in space. (Lots of money) X (Lots of time) = Never going to happen.

The building of these structures, in terms of materials and time, is precisely the engineering problem I was referring to, so this just confirms what I already said. Sure, it may be time consuming and expensive NOW, but reducing the material costs and construction time isn't a physics problem, it's entirely an engineering one. The physics are already proven.

Re:No, No, No, No..... This will not work

[bobbied]

You are engaged in wishful thinking. It will NEVER be economically possible to put structures together in orbit that are measured in kilometers, espically ones that will need to be aligned to tolerances in the micrometers. It's too expensive to get the materials into orbit that would be required to build the transmitting array and it would take too long to assemble and align an array for any useful amount of power to get transferred to the surface. You cannot make smaller arrays because of the physics involved and no amount of engineering or technology can change this.

Don't you see, it's like saying the entire text of "War and Peace" could be written by monkeys hitting random keys on a typewriter if we use enough monkey typewriter pairs or wait long enough. Sure, it's *possible* in that we could assign a possibility that the a series of random selections just happened to match the text we are looking for, but it doesn't mean it will ever happen. One could never buy enough typewriters, obtain enough monkeys or create a workable schedule for this project yet you want to hang your hat on that "it's possible" part and just ignore the rest.

The lab demos of this amount to getting a group of monkeys to type "War" as their first word on the first page. They transferred a few watts over a very short distance and achieved fairly good efficiency. But, they used a LOT of time and Resources to create their transmission and receiving arrays for the power levels achieved, used very short distances compared to what would be required in an industrial application and then scaled up their engineered solution mathematically to simulate how it might work on an industrial scale. I implore you to scale up their costs and multiply by a few orders of magnitude to account for the difficulty of getting all this into space and assembled. The costs are HUGE and the payoff is nowhere near enough to justify it, and that will never change. Just like buying monkeys and typewriters will never get you "War and Peace" even though it's *possible* it could happen.

The "Use microwaves to send power back to earth from space" idea is NOT practical and that will never change because the physics of the problem require structures which are simply too large to build and maintain for the benefit they could possibly provide. No amount of engineering is going to change that, unless you are suggesting we can change the laws of physics if we simply try hard enough... It's never going to happen because the rules of physics don't change...

Re:No, No, No, No..... This will not work

[JoeDuncan]

You are engaged in wishful thinking.

Maybe, but you keep repeatedly missing the point.

It will NEVER be economically possible to put structures together in orbit that are measured in kilometers,...

I disagree, this is nothing but speculation on your part.

...espically ones that will need to be aligned to tolerances in the micrometers. It's too expensive to get the materials into orbit that would be required to build the transmitting array and it would take too long to assemble and align an array for any useful amount of power to get transferred to the surface.

Every single one of these objections are engineering problems. Tolerances? Find better sync algorithms, better materials with less "give" in the relevant properties etc... Too expensive to get materials into orbit? Work on more efficient transport mechanisms, more efficient use of materials, or develop better/lighter materials to use, or use material from the moon, asteroids or comets etc... that you don't need to lift up a well. Assembly and alignment issues? Again, just a matter of better engineering, better assembly methods, better tools for more accurate alignment etc... ALL of your relevant objections are only obstacles to our CURRENT technology and can be addressed via innovation and engineering.

Saying these issues can NEVER be addressed is pure hubris.

You cannot make smaller arrays because of the physics involved and no amount of engineering or technology can change this.

So what? We don't need to make them smaller. The size of the arrays are only an obstacle because of current engineering constraints.

The costs are HUGE and the payoff is nowhere near enough to justify it, and that will never change.

Costs and payoffs change *all the time*! Saying these things are fixed and "that's that" is just plain silly. History is full of ideas that were once deemed "impossible" for reasons of costs and payoffs, yet became practical later with better methods and materials. Airplanes and the analytical engine; just to name two.

Re:No, No, No, No..... This will not work

[bobbied]

LOL... I think you are missing the point. These theoretical things are sized by the physics and they are literally too big to fly. This isn't hubris on my part it's wide eyed practicality that's driving my preannouncements on this. These devices are KILOMETERS in size and anything that size is going to be pretty heavy. Big and heavy are the two things which are very difficult and thus expensive when you want to throw them into space, even in LEO. The amount of energy required to lift this stuff into orbit will exceed what it can return as power. This fails the practical test on it's face.

Physics dictate the size of this thing. Physics will dictate how much power it can transfer, how much it will loose and how much it will have to collect. Physics will dictate how much solar collection area you will need, engineering may be able to approach that someday. Physics will mandate how much energy it will take to get everything necessary into the proper locations. You will be able to engineer lighter structures, but not smaller ones. There is a lower limit on the weight of this structure, regardless of the properties of the materials we can engineer. You might be able to engineer cheaper ways of getting something into orbit, but you cannot change the minimum energy required by physics.

Physics is your problem. It defines a system that is so massive that there is no way it ever gets to be cost effective to build because by my calculations, it will take more energy to create and operate this thing than you can ever hope to recover. That makes it uneconomical too.

Believe what you want though. Personally I think there are much better uses for our time and resources spent on developing new energy sources. Things which are way more cost effective and promising than this nutty idea of throwing solar panels into space and beaming the energy home. Can we say fusion? That's a much better and more effective way to produce energy that we know is theoretically possible too. The remaining engineering problems of fusion are close to workable solutions and the physics, while daunting, do not mandate that we build engineering solutions which are massive in size and complexity. Seems very likely to me we can master these problems and if we did, there would be no need for your pet energy solution where the laws of physics demand massive structures in very harsh environments and equally massive development and deployment costs.

Re:No, No, No, No..... This will not work

[JoeDuncan]

Big and heavy are the two things which are very difficult and thus expensive when you want to throw them into space, even in LEO. The amount of energy required to lift this stuff into orbit will exceed what it can return as power.

...and completely ignoring the idea of building using materials already outside the gravity well, or development of alternative lift methods that are more efficient. Rockets are at best like 70% efficient for lifting loads into orbit (under ideal circumstances, in practice it's lower). You're saying it's *impossible* to *ever* do better? I won't deny it might be difficult to do better, but claiming it's impossible is short-sighted.

Big is irrelevant, heavy is the issue. If you think it will NEVER be possible to build a structure of the appropriate size using less material or lighter material, then we'll just have to disagree. Personally, I think you're ignoring the fact that we can build much larger structures in micro-gravity with much less material because they are under a lot less stress. Just look at how thin and light solar sails are, they cover huge areas with a tiny amount of material.

Physics dictate the size of this thing. Physics will dictate how much power it can transfer, how much it will loose and how much it will have to collect. Physics will dictate how much solar collection area you will need, engineering may be able to approach that someday. Physics will mandate how much energy it will take to get everything necessary into the proper locations.

I don't dispute any of this. I agree.

You will be able to engineer lighter structures, but not smaller ones.

At the risk of repeating myself, size is irrelevant in space. You have all the room you need. Between size and weight, the only relevant issue here is weight, and you've just agreed that we can likely engineer lighter structures.

There is a lower limit on the weight of this structure, regardless of the properties of the materials we can engineer.

Agreed, but neither you nor I are in any position to say what that lower limit is, or assert that that lower limit is absolutely too high to ever be practical.

You might be able to engineer cheaper ways of getting something into orbit, but you cannot change the minimum energy required by physics.

Obviously. I've never claimed you could change the energy requirements for a given mass, but like I've said already, there are ways around that. Like using material which is already up the well, using lighter materials or better construction that uses less material. Using better lift efficiencies, lighter or less material, or eliminating the need to lift stuff out of the well altogether could all go a long way to making it more practical. I'm not saying it IS possible, even with these improvements it might not be; but I AM saying that declaring it impossible now and forever is unwarranted.

Physics is your problem. It defines a system that is so massive that there is no way it ever gets to be cost effective to build...

No, physics is not the problem, it's just one of the constraints on the problem. You can't possibly *know* that the lower limit on mass is too massive to be practical. Unless you can predict the future, new developments in material science could change that in a heartbeat.

...because by my calculations, it will take more energy to create and operate this thing than you can ever hope to recover. That makes it uneconomical too.

Calculations which are based on the constraints of current materials, structural engineering techniques, lift efficiency and the necessity of lifting resources out of a gravity well. Change any one of those things and your calculations are no longer valid. You seem mighty confident that it's impossible to change ANY of them. Me, I'm not so much of an absolutist.

With

A solution in search of a problem & likely fr

[dfenstrate]

Assuming the project isn't essentially fraudulent, and is technically feasible- why? It would have worse performance than inductive charging and would require a specific alignment of an extra peripheral towards the sound source.

Anyway, there's another link in the article to a take-down of the product that goes over basic physics and sound level safety requirements that suggest this project is fraudulent. One thing you do see in there, however, is talk about Ubeam's 25 year old CEO, Meredith Perry. A google search quickly reveals she's an attractive young lady.

Quite frankly I think she's a huckster, and is using her charisma, beauty, and the latest 'women in tech' craze to bilk a few investors who have money to blow. Sure, there might be a few engineers performing 'research'- fiddling with components and actually transmitting power with ultrasound in a carefully controlled and isolated environment. Their function is to provide Ms. Perry with legal cover. They'll do work obstinately in the relevant line of investigation, while knowing full well that the final finished product can never be delivered for a variety of reasons. They'll issue reports saying 'the next obstacle to overcome is....' knowing that obstacle is insurmountable. And the entire time, Ms. Perry will be collecting an excellent salary for a 25 year old, and may even get bought out by some fool.

why not user ultra low frequency instead?

[Ionized]

i feel like the obvious question is, why use ultrasonic frequencies that lose half their power in a meter of air, when we could be using ultra low frequencies that travel much further before losing power - and are also much better at penetrating obstacles? something like 5hz or 10hz?

anyone care to dig into the physics or biology of why that wouldn't work either?

Re:why not user ultra low frequency instead?

[angel'o'sphere]

Because a device as small as a cell phone can not pick up a wave that is several meters long?

(facepalm)

Re:why not user ultra low frequency instead?

[Ionized]

antenna? we are talking sound waves, not radio waves - they need a speaker, not an antenna. i'm not a sound geek but my understanding is that relatively standard subwoofers can put out sound below 20hz, approaching as low as 10hz, so i wouldn't expect size to be an issue.

Re:why not user ultra low frequency instead?

[GuB-42]

Low frequencies carry less energy per unit of amplitude.
So to charge a phone with a 5-10 Hz frequency, you need something really loud. Loud enough for you to feel it through your body and to rattle things.

Additionally, because of impedance mismatch, low frequencies are hard to transmit through air, that's why subwoofers are so big and powerful.

Re:highly improbable?

[Locke2005]

Not to mention the flying cars and hoverboards! Seriously, we've had 30 years to work on this... where is my fricken' hoverboard (the liquid-nitrogen cooled superconducting magnet on a specialized track doesn't count!)

Re: A solution in search of a problem & likely

[dfenstrate]

I realize I used 'obstinately' when I meant 'ostensibly.' oops

Pet-friendly?

[Dark Fire]

Doesn't "sound" very pet-friendly to me. Perhaps some evil genius is looking for a way to fund the development of his doomsday device.

This sounds like a great idea!

[ilsaloving]

I'd love to see this implemented. Then I'd get some popcorn and stay the heck away from the area cause once the soundwaves bounce off enough surfaces, they'll lose enough energy to fall into hearing range, and suddenly you feel like you're back in the 80s, surrounded by TVs with failing transformers.

oops. yeah i suppose that explains it

[Ionized]

n/t

Re:highly improbable?

[angel'o'sphere]

There is no hoverboard, and there never will be one: deal with it.

actually, are you sure about that?

[Ionized]

looking at the size of various sound waves, it looks like for instance a 50hz soundwave has a wavelength somewhere around 30 feet. yet that is within the range of human hearing - somehow our tiny eardrums are able to hear 30ft soundwaves? so its a little more complicated than you make it out to be

Re:actually, are you sure about that?

[angel'o'sphere]

Of course it is ... closer to 25 feet actually ... but that does not change the fact that small devices are bad with long wavelengths.

E.g. you mainly hear low frequency sound because your body is picking it up and transports it to your head. That is the reason why your ears are not able to detect the origin(direction) of low frequency sounds.

Re:highly improbable?

[Hussman32]

I'm guessing this hoverboard doesn't meet your criteria either.

Some of their tech might have uses

[mhkohne]

If their beam-steering is actually something new and quick, then it might have applications elsewhere - medical ultrasound is a pain in the ass partly because the tech has to fool around a lot to get a good image. If you could steer the beam and do the ultrasound equivalent of auto-focus, you could make some ultrasound studies quite a bit faster and therefore easier on the patient.

But in a Starbucks? Forget it. Install 5V USB outlets on every table and call it a day instead.

Re:Some of their tech might have uses

[sims 2]

Is there a reason why they can't use the same autofocus algorithms on ultrasound? Other than the fact that the autofocus in cameras has the bad habit of picking everything but what you want to take a picture of to focus on. What's worse is most cameras today don't even have a manual focus option.

Definitely Possible, not Practical

[chesterw]

Of course it will work; this is exactly what an ultrasound transducer does; it converts electrical energy to acoustic energy via mechanical strain in response to said electrical energy, then converts acoustic energy back to electrical energy via mechanical strain when impacted by the returning acoustic bounceback. Well and truly settled issue. The problem is the power loss over distance, as has already been pointed out. So while it will work, it will work poorly, be expensive, and is overly complicated. It is an idea backed by a fundamentally sound theory, but like so many the practical application is unworkable.

Tesla

[KermodeBear]

Isn't this similar to what Nikola Tesla wanted to do in order to provide free electricity to the masses?

How can this be patented? Prior art must be all over the place.