At first I felt awful because I was thinking like part of the establishment: there's no way she came up with something that will replace power cords. I've got a degree in physics, and have always been interested in acoustics, and sound in air has some amazing properties, including the ability to transfer non-trivial amounts of power, especially at nodes, and especially when focused with, say, a parabolic reflector.. The best case would be a tracking parabola that follows your device through space beaming concentrated ultrasound at it, and even then the power transfer is going to be a handful of milliwatts. The power draw of modern laptops is around 10 watts (although it varies somewhat). This, of course, is the bet case ignoring inefficiency to transfer that mechanical energy back into electricity (piezo is probably really efficient, but coupling the sound to the piezo won't be).
I was feeling really bad about myself, but then I realized: without such skepticism the surprise and delight of proving others wrong (not to mention being proved wrong) would be lessened, and so my skepticism does serve a useful purpose, and I could go on living with myself again. This is one skeptic who's hoping that he's wrong and that the inventor is right!
I think that the reason this new idea came from someone outside of Physics or Electrical Engineering is because its poor efficiency is obvious to people with a background in those fields.
Sometimes it takes an outsider to challenge assumptions and achieve a breakthrough, but I don't think thats going to happen in this particular case.
Reminds me of sitting in a Larry Smith [1] lecture 14 years ago, where he mentioned the real key to innovating is for people who can look outside their discipline and find links or problems in another discipline that could use their experience, knowledge and fresh take on solving it.
Train everyone in a discipline that everything must be green. This idea of turning perhaps 99 watts into heat and 1 watt into battery charge is terribly non-green. "Everything must be green" is the cognitive filter which had to be overcome.
In cold climates, especially if you have electric heating, turning electricity mostly into heat is not as much of a loss as you'd think, anyway. In areas of Canada with cheap hydro and electric baseboard heating, its probably a great idea.
It's kind of like the common mistake people make just getting into saving and investing. This is where they are calculating everything on a 'per month' basis, not realising that the interest rate is done annually.
> I was feeling really bad about myself, but then I realized: without such skepticism the surprise and delight of proving others wrong (not to mention being proved wrong) would be lessened, and so my skepticism does serve a useful purpose, and I could go on living with myself again. This is one skeptic who's hoping that he's wrong and that the inventor is right!
/song
The world needs people like you and me
who've been knocked around by fate.
'Cuz when people see us, they don't want to be us,
And that makes them feel great!
We provide a vital service to society
You and me!
Funny, I was thinking that most people with an engineering/physics background would dismiss the though that spurred her to investigate the matter in the first place ("why in this day and age should I plug my "wireless" device to charge it") as just absurd, and drop the issue without a second thought...
Wireless power is something that has been researched for years I believe, the fact that to this day there is not a feasible solution (that I know of) means that it's a really hard problem, I guess.
I've had the same thought she had - that we shouldn't necessarily need to plug stuff in to charge it. My preferred solution - not an original idea - is to find a way to free-ride off existing broadcast signals. Right now, the world is full of radio-frequency devices pumping energy into the air. Find a way to convert some of that energy - the energy of the strongest available broadcast source in your area, whatever it happens to be - back into power. An old-fashioned crystal radio would tune into one strong radio station and use the power from that to amplify the broadcast of a weaker station with no battery required - that's our proof-of-concept. It's not a LOT of power, but if you were charging even a tiny drip all the time you wouldn't necessarily need very much.
One of the answers has the following math:
For a large radio tower (100kW), you'd get roughly 80 W per square meter of receiving antenna area at 100m distance.
Since the typical distance to a nearby radio tower is probably more like 5 miles, we can reduce that to ~12mW for a 1m^2 antenna. For the size of a phone, we're talking more like 0.10mW, which is about 10,000 times less than a typical phone needs (assuming it was charging 24/7 with 100% efficiency).
Although, the answer gives the formula as 100kW/(4 * pi * r^2), which seems to give 0.80 W/m^2 instead of 80 W/m^2, so perhaps divide my other answers by 100 (and make that 1 million times lower than the power necessary to power a phone)
EDIT: I previously stated the formula gave the wrong units which was a mistake.
As an off the cuff engineering estimate an AM crystal radio is pretty efficient internally and just barely converts a multi kilowatt transmitter output into barely audible sound inside an earphone, given a substantial antenna and grounding system. So for multiple closer antennas, and something much more electrically demanding than a crystal radio, like a smartphone, its believable.
The biggest problem is going to be PR. So wifi milliwatts of microwave power tens of feet away make hypochondriacs and conspiracy theorists think the government is controlling their thoughts using radio waves... I'm guessing "tens of watts in a ISM diathermy band" is going to substantially encourage them.
I think the equation given does give units in watts/m^2? Unless I'm missing something, power has the units of W, and the only dimensions on the bottom of the equation are the radius, which is meters. Because it's r^2, the result is in W/m^2.
For a non-directional beam, it would be P/(4.pi.r^2).
It just occurred to me that the / (4 pi r^2) factor may not be relevant here. The reason is that the acoustic wave could be steered (http://en.wikipedia.org/wiki/Beam_steering) so it does not propagate evenly over all the solid angle.
Perhaps the steering could be done cooperatively with the device(s) being charged. I.e., devices announce their location to the charger, and the charger steers the beam towards them.
Maybe that would bring the power required down to a reasonable range.
Did anyone else read this and immediately wonder, "how many watts?" 1.5 pages of prose and no hard numbers. Years in the industry reading marketing white papers and such cause things like this to really set off the bullshit detector. I'm not saying it's not possible, but, just give me the power (in watts) that is being transmitted by a prototype device. If you don't put that number as a feature bullet, I automatically assume you've got something to hide.
I was wondering about the watts for a different reason...
From Wikipedia:
"Although the long term effects due to ultrasound exposure at diagnostic intensity are still unknown,[24] currently most doctors feel that the benefits to patients outweigh the risks.[25] The ALARA (As Low As Reasonably Achievable) principle has been advocated for an ultrasound examination — that is, keeping the scanning time and power settings as low as possible but consistent with diagnostic imaging — and that by that principle non-medical uses, which by definition are not necessary, are actively discouraged."
I would imagine the doppler effects of beaming a couple watts at a low freq thru a ceiling fan would be humorous.
Another interesting one is phase noise and distortion and crossover distortion (if you use a simple class-B amp) means you can send a sine wave into a high power amp, but the amplified noise level at audible range might be icky. As a personal anecdote I've noticed this with commercial ultrasonic cleaners. Sure... noise level might be 30 dB down at audible range, but pump a 100 watts at 40 KHz into it and I'm listening to 0.1 watts of noise at audible freqs which is quite loud indeed. Theoretically ultrasonic cleaners should be inaudible, but high powered ones are not. Much as intermod distortion is hilarious with high power RF, noisy/corroded/semi-faulty ultrasound could be loud as heck acoustically thru no fault of the generator, amp, or transducer.
Did not consider this. Intermodulation and other distortion by-products are going to be difficult to control although I have no experience with the performance of modern amps for sub-MHz frequency ranges.
Building a working prototype that can beam ~1W (or even 100mW) a few feet would be very interesting and would do a lot to lessen my skepticism.
The design in that video involves transmitting ultrasound from a central charging station to an ultrasound receiver and that receiver is then plugged into a cell phone using a normal cable. The claim in that video is that it takes 3.3 hours to charge the receiver but she doesn't actually mention the watts or joules involved. Given that most claims of technology that can charge a device from across the room have turned out to be bullshit, I'm going to lump this claim of into the same bucket until there is more evidence to show otherwise.
I'd be curious to see a graph of transmission efficiency vs. distance. The technology here is almost certainly acoustic beamforming, and that large square under wraps in the image is an array of small ultrasonic piezo speakers. Beamforming will give you better than 1/R^2 relationship between power and distance, but probably nowhere close to linear.
I'd be hard pressed to imagine this working over distances larger than the 3 feet demonstrated, which suggests constraints on the use case, like charging your laptop while its on a desk, for which there would seem to be easier methods of wireless charging (inductive coupling, conductive pads, etc).
Very interesting in concept, I'd like to see numbers before I believe anything.
Seriously. Given the existing levels of waste in our society and the associated environmental consequences, do we have any business switching to less efficient methods of power transmission?
Unless this transmits as well as a cable, I'm not interested.
The other thing is that this is probably still transmitting sound when there is nothing to charge? Which would be probably even more of a waste than any transmission efficiency
The simplest method would be to add a short range transmitter to the charging device. You don't have to limit yourself to using the charging technology for that.
I wonder about the health aspect of this. It seems there is very little known about long-term exposure to high intensity ultrasound.
Also, there could be a risk of ear damage if a non-linear material came into the sound field, and producing distortion artifacts in the audible frequency range - given that about 1W/m^2 can be enough to cause damage.
My dentist's ultrasonic dental plaque removing tool produces audible squeals reminiscent of analog tuning of an AM radio. That's one possible example of probable nonlinearities (in my gums an teeth) producing detectible audible power from ultrasonic energy transmission. No reference -- it's just what I hear every time I have my teeth cleaned.
Granted an ultrasonic water stream (dental application) has different physical characteristics than an ultrasonic air pressure wave (ultrasound).
It doesn't even have to be nonlinearities, could also be sidelobes of the fundamental ultrasound frequency. There's no reason to filter those out if it's not harmful, which I'd like to think was carefully verified.
It can't actually harm your hearing, by definition. Hearing damage caused by high intensity sound is the result of mechanical transduction of sound waves to hair cells in your inner ear. When the amplitude of a certain frequency is too high, the cells responsible for turning those mechanical vibrations into electrical signals are physically damaged.
Ultrasound is mechanically filtered, so it can't propagate into your cochlea and damage the hair cells. This is in contrast to something like photons, where UV or infrared light can absolutely damage your photoreceptors in your eye.
No filter has an infinitely steep cutoff slope, it's a question of the 'degree' of attenuation. It may or may not be safe in practice, but if it is it's not "by definition".
50KHz is just two octaves above our normal range of hearing. She's claiming "charge laptop in 3.5 hours" levels of power transferred to a transducer "the size of a flash drive" a useful distance away.
Now apply the inverse square law to estimate the necessary output power or assume a focused beam.
Now imagine that flash drive is your ear, your eyeballs, or a pregnant lady.
Did she have a hard time finding investors because it was a hardware business, or because she was a woman?
Did she ultimately get investment because she was a woman, in spite of the hardware business?
According to a friend's college thesis, there are lots of concrete reasons VCs don't invest in women.[0] In summary, VCs don't take a girl very seriously. The thesis makes the case though that there's real opportunity for women founders, not the least because they're so undervalued for reasons under than business fundamentals.
So maybe Meredith got investment precisely because she was a woman. The collection of investors is curious. According to CrunchBase, Marissa Mayer invested in 8 companies over the last 2 years (+Square in 2009), 7 of which have women founders or co-founders. Lady Gaga's manager, who I thought was not a professional investor, in fact makes a lot of investments. According to CrunchBase, 4 of 16 of his investments have women founders or co-founders. By comparison, VentureSource shows about 1 in 14 startups with funding have women founders or co-founders in 2010—more details in Alisha's paper.
Still, it would be wrong to accuse of sexism the "hundreds" of the investors who declined her project. She's an astrobiologist who wants to run a mass-manufacturing business. I'm not a venture capitalist, but I can see aversion to hardware manufacturing risk generally being the biggest factor here.
"Still, it would be wrong to accuse of sexism the "hundreds" of the investors who declined her project. She's an astrobiologist who wants to run a mass-manufacturing business. I'm not a venture capitalist, but I can see aversion to hardware manufacturing risk generally being the biggest factor here."
As physics as generally understood means this is 99% likely to be nonsense, another reasonable application of Ockham's Razor would be that the VCs passed because it's snake-oil.
I've always found it odd that people talking about sexism use 'woman' like it's an adjective. Common use has made it one, but it used to be just a noun. Anyway, my point is that we don't say "man founders" or "man drivers" or "men professionals".
Grammatically, it's an apposition [1] and "woman" is still a noun. This particular construct is uncommon in English, but not all that rare, either. E.g.: Science museum, prime time television, district court judge.
Thank you for the info, I hadn't come across that term before. There's still a difference in how we talk about men and women, which I find odd to engage in when trying to combat sexism, but I was unaware it was grammatically correct (and 'men [pastime]' just sounds wrong).
It is because woman are considered to be the adjunct, not the norm, not the average, not the expected or assumed. Its even obvious in the word itself - a prefix on the word "man", which can and is often used in place of "person" or "human", and will describe a person who is more than likely assumed to be of the masculine persuasion.
A+ on not putting "Woman" in the headline for the article, though!
Yes, it is. It's wif-man, so a "person who is a wife" as opposed to an unmarried girl. That's why women is pronounced [wimen], because that's the original etymology.
Corrected, I didn't notice his name in the article. Still, he invests in a disproportionately high number of women-founded/co-founded companies, 4/16 as opposed to an average of 1/14 (by 2010 figures). See edits.
What if we came up with a way to directly connect the device to the ubeam device? Like some kind of connecting wire through which the energy could travel? THEN we'd have some serious efficiency!
The ability to create a directional soundwave powerful enough to move specific objects from across the room would be a highly useful invention of its own, quite aside from remote power charging.
Batteries are both lossy and environmentally problematic objects to manufacture and dispose of. Also, a good fraction of all the energy used by society is spent hauling around energy storage. Wireless power would help fix both these issues even if it was fairly lossy compared to a copper wire.
I doubt wireless power will catch up to the efficiency of battery power any time soon. Batteries have been around a long time and have the ability to time-offset local renewable energy resources such as solar power.
Most of us here are discussing the science of this thing. But let's just say that the science somehow miraculously works. Would any of you actually want to buy that big square thing and put it in your rooms? I can't imagine I would.
I don't hate wires so much that I want to be bathed in high-power ultrasound.
And you know what, I have an invention that means your laptop will continue to work in almost any position - you won't have to keep a clear view between charger and laptop. You can turn around, lie down, have a colleague stand over your shoulder. There are some limits, sure, but it gives you a fair bit of freedom to move, and it allows a ton of power to be more effectively transmitted along its full length (with negligible loss), and you can use it anywhere you can find consumer power. It's called a 'wire'.
Electronics have gotten miniaturized, but that doesn't mean that a mechanical device that generates sound vibrations can be miniaturized. For example, an iPhone contains the computing power that used to take up a large room, but we don't have loudspeakers that are 0.01 inches in diameter and deliver the same sound output as conventional ones.
Antennas aren't mechanical devices; they don't need to transfer mechanical energy to air molecules. Also, their size is constrained by the power they need to emit as well as the wavelength of the signal, so we aren't going to see a cell phone antenna that's on the same scale as a transistor in an integrated circuit (tens of nanometers). An antenna that can only put out a microwatt of power won't be able to hit a cell tower that's a couple of miles away.
> Afterward, she said, “I would go back to that person and he would say, ‘Oh, yeah, that should work.’ ” Each expert seemed to dwell in his own private silo, so that whenever she crossed from one discipline to another, she would run into the same wall of constricted thinking.
I do a lot of cross-protocol work, and I've seen that a lot from "domain experts".
Me: Why can't we just do X?
Them: It would violate the standards, and industry practice!
Me: how could anyone tell?
Them: Uh... they couldn't. Good idea. Let's do it.
There's a danger in letting your brain ossify. Cray used to hire young people for precisely this reason:
> Once asked why he often hires new graduates to help him with early R&D work, he replied, "Because they don't know that what I'm asking them to do is impossible, so they try."
"Each expert seemed to dwell in his own private silo, so that whenever she crossed from one discipline to another, she would run into the same wall of constricted thinking."
Keeping abreast of emerging tech is hard for specialists whom are focused deep within their silos. It's always good for teams to include broad-minded generalists that continually survey the landscape, connect the dots, and keep the team's reservoir stocked with fresh developments from the outside world. At some point a specialist may recall something from the reservoir that turns out to be the missing piece that enables your team to break through the silos and jump the curve.
Honestly, I couldn't read the second page of that article because I felt too badly about forming an impression of the (surely brilliant) Ms. Perry from it.
The stoner quote was immortal, but I'll raise you:
Nothing in her training prepared her for this kind of research. She was an astrobiologist, after all.
It’s one thing to pull an idea out of your head and shape it into a prototype. But it’s a whole other thing to figure out how that device will get out of your test kitchen and into the marketplace.
Hum... in this particular case, the problem is to make a prototype. If you have a working prototype for safe wireless energy transmission, no doubts that you'll find customers willing to buy it.
Even if you had a working prototype, there's no way people will buy it until you can solve reliability, yield, cost, etc. A prototype that took 100 tries to make and cost $1000 and works only for a minute under the right conditions will never find a buyer. It's not enough to transmit wireless power - you need to transmit wireless power cheaply, reliably, safely, durably, etc.
Especially when what you're competing with is a conventional power supply that costs less than $10 to make, is small enough to carry in your luggage and can be used wherever there's an electrical outlet. (The device in the article is going to require an unobstructed path between the charger and the device to be charged, so it won't work very well in a place like a coffee shop where there are lots of bodies and furniture in the way.)
Here's what I've been wondering. A transformer provides very efficient wireless power transmission but on a few centimeters. Has anyone considered scaling up a transformer? Would that increase the range?
What if we made a house sized one and buried it under the house? Could that provide wireless electricity to the whole house?
You're talking about inductive charging, which is basically how electric toothbrushes charge. It's recently been built into new devices (my Nexus 4 supports it) but obviously requires they be placed on a charging mat/station. Perhaps in the future it could be built into desks, so that everything placed on them charges. I would imagine (but I'm no EE/physicist) that these get terribly inefficient when you scale them up.
Why not a desktop dock with multiple inductive coils (the kind used for smartphones)? Proven to work, cheap to make, (much) higher efficiency. Using acoustics seems weird, even lasers would be better :-)...
I was feeling really bad about myself, but then I realized: without such skepticism the surprise and delight of proving others wrong (not to mention being proved wrong) would be lessened, and so my skepticism does serve a useful purpose, and I could go on living with myself again. This is one skeptic who's hoping that he's wrong and that the inventor is right!