UBeam's Meredith Perry shows her wireless charging technology really works
usatoday.com
usatoday.com
> In all this time, have reporters still not learned to press on the key questions? "How much power is being received?", "How much is being sent?", "What's the efficiency?", "How much does it cost?", "Have you proved it safe?", and "If this is what you have now, what were all those 'prototypes' you were talking about 2 years ago?". But those are actual questions that matter, and basically we know the same today as we did yesterday (which indicates it was an awesome PR piece, lots of coverage with no actual info).
http://liesandstartuppr.blogspot.com/2017/05/whats-in-pictur...
http://liesandstartuppr.blogspot.com/2017/06/someone-was-pay...
http://liesandstartuppr.blogspot.com/2017/06/what-does-it-ta...
I think they're right that you're being sarcastic, due to the word "offhand".
However, if we read your comment seriously (you are seriously stating it) then I actually agree with it: this means the "wrong" part of your comment is the /s (which you didn't include) and otherwise your comment is very solid.
I'd like to defend it.
Here are just some of the off-hand ideas that were demonstrated in this video:
- Beam forming
- Vision for device tracking. (VISION!!! DO YOU HAVE ANY IDEA HOW OFF-HAND OF AN IDEA THIS IS?)
- Inclusion built into every manufactured phone and uBeam beamers located all over the place, so that even a trickle ends up recharging the phone "throughout the course of a day" -- assuming you aren't actually using it.
- Have it be something you don't even notice. (So that for this reason it doesn't matter if it barely works). ie if you have your phone in your pocket for an hour while you sit and talk to your friend, it goes from 51% to 83% charge. That is a good and viable definition of "don't even notice it."
These are extremely off-hand ideas. It is extremely possible that adding a dozen other extremely off-hand ideas are all that it would take to make this a viable, pervasive technology, built into everything.
For example, it was demonstrated on a huge receiver that is much larger than the phone it was attached to. A couple of off-hand ideas about how to make the receiver smaller might be all it takes to make this more interesting.
There are further possible off-hand ideas. add in about a dozen and, if they have appropriate patents, they have a monopoly on a charging solution.
When you have a choice of two cafes across the street, and if you spend an hour in one of them your battery will be 10% more charged than before you entered, would you choose that one over the other one?
You would if you were at 1% battery level and waiting for an important client.
Bam. You've just made a case that this brings free users to cafes as a direct competitive advantage, much like having wifi might.
And what was this -- oh, right: an off-hand marketing idea I just had.
Don't dismiss off-hand ideas.
If you like, it's all Steve Jobs ever contributed. Send them - send them all. You might end up making uBeam work.
Note: I have no association with the company or any horse in this game.
That's the most offhand description of what Steve Jobs contributed that I've heard. Let's not minimize the contributions of people when we have no idea what went into making them successful.
That one can deliver 112dB sound pressure at 30cm range. 1000 of those would deliver 142dB at 40KHz. (10x = 10dB). If they're all wired to one amp, you get a straight beam. The demo indicates they're only getting a straight beam; steering the beam requires electronics behind each transducer. Quite possible, but runs up the cost. If they wire up the transducers in rings and drive them with slightly different phases, they can tighten up the beam focus. Since the receiver is smaller than the transmitter, focusing would help. Frequency is probably around 40KHz; if you go higher, losses in air go way up.
I haven't worked out the drive power for this thing, but it's probably a few watts per transducer, or a few kilowatts for the whole array.
So they have a 142dBA 40Khz beam about 200mm square. They ought to be able to do some short-range charging with it.
Notes:
* That's a high-powered ultrasonic beam. Is it hazardous? Most of the literature on ultrasonic safety involves energy coupled directly to skin, as with ultrasonic scanning, where there's a gel to improve transmission. Generating high energy in air is rarely done. It's certainly going to heat up anything in the beam. The safety issue is a big deal. All that energy has to go somewhere.
* How far can they project this? At 40KHz, meters, maybe tens of meters.[2] Attenuation gets much worse with frequency, so this thing probably works in the low ultrasonic range. Early PR from UBeam talked about megahertz ultrasound, but the range would be a few millimeters up there.
* Efficiency is terrible. Kilowatts in, watts out.
* That array of transducers isn't cheap. Those things are usually a few dollars each. But in quantity, that could come down.
So the demo they did, at under 1m range, is possible, but doesn't mean it's a useful technology.
[1] https://www.americanpiezo.com/images/stories/content_images/... [2] http://www.kayelaby.npl.co.uk/general_physics/2_4/2_4_1.html
What something costs when you make it at scale you tend to find out when you make it at scale, and if they are going to revolutionize the transducer market that alone would be worth a fortune, never mind transmitting itty bits of power to cellphones.
IE if you believe her, it implies the ones they need to make are not that cheap.
(Note: I'm fairly familiar with ultrasonics, and certainly the price varies depending on what you are trying to do. The ones in my ultrasonic cleaner are not the same as the ones i use do to sensing tasks)
And if the transducers they need to make are not cheap then the whole project is dead in the water anyway. Wireless charging with a custom backing or sleeve over a phone that costs a fair amount of money coupled with a large array of expensive transducers every so many meters in whatever space you're trying to use the system in would likely not take off, assuming they can get the efficiencies working in the first place.
Probably milliwatts out, you have the conversion efficiency twice, once when you convert from electricity to ultrasound and then the reverse, where the reverse conversion gets the interference of the wave-fronts of all the sound waves emitted by all the transducers at the source all mixed up. It's not going to arrive as a nicely coherent wavefront.
That really is not going to help, and any losses to heating the air also need to be factored in.
Chances are the uBeam will end up pivoting to an ultrasonic heating system for coffeeshops.
Also, where do you see the 32x32 array?
Is it this pic?
https://www.gannett-cdn.com/-mm-/6e692618ead22efd1bb5f481476...
To me that shows a 10x10 array of much larger transducers.
The other device (the white ceiling tile) shows 7 hexagonal arrays each with 144 transducers, that works out to almost 32x32 for all 7 but they may be steering the beams to different phones from different arrays (they claim up to 5 phones) so it may be that only one such blade is active for a phone. And the total size of that array is much larger than 200 mm square.
It's hard to tell; not enough resolution. Maybe that's just a grille over something else.
It would be straightforward to do this with microwaves. Transmitting from a microwave source to a rectenna works fine.[3] Efficiency has passed 50%. The solar powersat people have been fooling around with this for decades. But even a few watts of microwave power indoors is a safety concern.
What scares me about this thing is the claim that kilowatt levels of ultrasound are safe. Power levels like that are used to weld plastic.
[1] https://www.youtube.com/watch?v=Qxd7VYujMgQ [2] http://dm.ncl.ac.uk/benfreeth/2010/07/23/parametric-speaker/ [3] https://phys.org/news/2015-03-japan-space-scientists-wireles...
I thought that was the cover in front of that 7 petal arrangement.
> I'd assumed that was a tightly packed array of off-the-shelf aluminum ultrasonic transducers.
Ok, could be. But to me it looks like a cover over this:
http://liesandstartuppr.blogspot.nl/2017/05/whats-in-picture...
No contest about the microwaves, that would work just fine (it would also cook everything in its path).
> Power levels like that are used to weld plastic.
Yep. Ultrasound friction welding of PVC.
There is an article linked below that claims 53% efficiency for ultrasound energy transmission at 1 meter.
I dunno. There's too much obfuscation here. Are there any high-resolution pictures of the transducer array with the cover off?
[1] http://www.robotshop.com/en/ultrasonic-range-finders.html
At 0:54
Thanks, John - I will never understand how you find the time to know everything.
You can buy a new phone but if you slip it into a sleeve that size then that still affords plenty of room for a rigged demo. (Sorry, professional deformation at work here.)
What would be far better proof that it works is a simple caloric setup showing how much power is transferred per unit time at which distances and angles from the transducer tile.
Also, where do the optical lasers come in? To find a target to steer beams to using phased arrays of transducers?
If so that would imply only line-of-sight.
edit: so yes, the article confirms line of sight only and very low levels of power delivery
1) interference
2) efficiency
Lots of transmitters will interfere with each other, you'll get all kinds of interference patterns at the receiver which will negatively impact efficiency.
And to that point, the second efficiency issue is that you will spend a ton of money to get a trickle of power to those phones, an inductive coupled system in the base of the table would deliver a large multiple because of the tighter coupling (decreased distance, fewer losses because of the medium chosen, electromagnetic coupling is well understood and efficient, acoustic coupling is fraught with all kinds of inefficiencies and hard to make work in a practical setup with useful levels of power).
I find these stories fascinating not by what they say about the technology but more what they say about the state of education in engineering these days and the ability to believe the impossible is possible. I wonder sometimes if someone told these people "if you can imagine it, you can BUILD it!" and they took that statement literally.
There has been a tremendous amount of work in energy harvesting from ambient sources which is really pretty amazing. There was a fun paper on harvesting sound for energy in 2013 [1]. The key of course is how much energy and at what efficiency.
The CEO's point was that if you can charge anywhere you don't need a full charge, you just top off. It would be interesting to see if it can charge while being used (so net positive charge). In the video at least you can see their device for showing the beam footprint.
I'm also wondering "why talk now?" clearly burned by previous skepticism, why not just wait until you have a fully realized product or are they doing a fund raising round and need some outside validation after their disastrous first go?
[1] http://www.enggjournals.com/ijet/docs/IJET13-05-06-118.pdf
If that delivers meaningful power within the typical usage envelope the tech is real. And of course you get to inspect the guts of the box to avoid 'gotchas' of the battery variety.
Now the thing that really gets me is some work I saw on developing a vibration powered sensor for highway bridges. So the best power source they found was a small wind turbine. But when they tried them out on a bridge out in the middle of nowhere, the problem was they were just too much of an entertaining object for people to shoot. So they made this rather large pipe with a magnet on springs inside and were able to harvest energy from the low frequency vibrations of the bridge moving around.
[0]https://www.microgensystems.com/ [1]http://www.ni.com/white-paper/12128/en/
The important lesson here is that USA Today and similar papers can be fooled by a rigged demo and a sincere voice. Read the front page with similar skepticism!
http://www.eevblog.com/forum/projects/the-ubeam-faq/
(There's more discussion about the recent developments in the last few posts.)
And without you using it. As soon as you start using it you'll be back to normal, and likely there would not be enough power to put a meaningful charge into anything the size of a laptop with this system.
Unless phones are going to use a small fraction of the power they use today I don't see this working in practical setups.
> And in that case it doesn't need to be as efficient as a wire since it can start charging as soon as you get home until you leave.
10 seconds plugged in to a wire would give you more juice than an hour or two hooked up to those transducer arrays.
Hands are much denser than air. Not only does UBeam need to track where the receiver is, they need to hit the target without going through your hand or body to avoid another large efficiency loss -- I believe the typical figure for air/soft tissue boundaries is 99%.
Wirelessly transmitting energy is fine. It's reliably transmitting a meaningful amount to tiny, moveable objects near people that's the problem. You end up with unfeasible combinations of tracking, safety and efficiency issues. Serious work on remote power transmission doesn't start with consumer devices.
Technology changes over hundreds of years. Turing spent his life building basic computational devices and I have a supercomputer in my pocket. I can assure you I am not smarter than he.
The same laws of physics that bankrupted Tesla's wireless energy transmission schemes are still in effect today.
Tesla tried to transmit energy using coils and antennae, both of which were fairly well understood at the time.
uBeam is trying to do something similar, but over much smaller distances (a few meters rather than all over the globe from a single transmitter) and using soundwaves.
So at face value uBeam's goal is much more achievable than Tesla's.
The most important component in transmitting energy using soundwaves is called a transducer, it takes electrical energy and transforms it into a soundwave with some measure of efficiency (higher = better, the remainder is heat which you need to conduct away from the transmitter). It can also do the reverse, convert soundwaves back into electrical energy.
Transducers exist in a number of varieties, the ones most suitable for energy transmission work using the piezoelectric principle (a magnet based system or electrostatic system would not have a high enough efficiency at those frequencies).
So, to transmit energy using soundwaves you need at a minimum two transducers, a generator to power the transmitter (which is a fairly simple device that outputs a repetitive wave form, or a much more complicated device if you want to 'steer' the soundwave by changing the phase between the signals with which multiple transducers are powered).
But for now let's just assume one transducer to send and one to receive with.
You then need to point the receiver at the sender and vice-versa or it will not work, also, any objects in between the sender and the receiver will attenuate the signal to the point where it probably also won't work.
The transmitter and receiver each have their own conversion efficiency, and the expanding wave-front from the transmitter will hit an area much larger than the receiving transducer by the time it arrives there leading to further loss. Then there is loss due to friction in the air.
All these losses are multiplied with each other and that is what makes this whole affair so fragile. The problem is that if it works at all it will need an input power that is large enough to cause serious concern about the risks associated with pumping that much energy at a frequency where it can do real harm into a space occupied by humans and pets.
Likely we're talking about at a minimum 100's of watts and possibly 1000's of watts in order to output a very low amount of power at the receiver. No 'modern components' or 'additional research' is going to change the basics.
Assuming that article linked elsewhere in this thread is true then 53% of the energy transmitted will be lost at 1 meter. Assuming for the moment then that half is lost for every meter that would mean that you're going to have a 3dB loss for every meter of path-length. That means that if you want to transmit over 3 meters (ceiling to a table) you'll have to input 8 times as much power on the input side as you will get on the output side. And that's not counting any other conversion losses, that's just the best case that I've seen so far from one transducer to the other without knowing the specifics of that setup because I can't read the paper.
But consider that the very best case and what I can see in the linked demo is not within orders of magnitude from that level of efficiency.
So uBeam is - as far as I'm concerned - still very very far away from being either a reality or even a feasible concept, the fact that it would be nice to have does not make it any more real, for the moment it seems as though practical obstacles will prevent it from ever becoming real.
So I remain skeptical and would very much wish that uBeam would give at least one demo that did not leave you with more questions than you started out with, they have had all the chances in the world by now to substantiate their (outrageous) claims, and they've already considerably walked back their initial claims and have by now more or less admitted that their previous demos were staged (as was suspected at the time).
If it were real, they would've given the demo to someone with technical sophistication. They wouldn'tve bothered taking a trip to a phone store, since all the observers already had their own phones. And, also, the laws of physics would be slightly different.
But this scam isn't aimed at us. It's aimed at investors, who will never read this Hacker News thread, or any other thread where smart people are around to debunk it. Because if they did read that sort of thing, they wouldn't be an investor.
The sensors + batteries in the box is an absurd claim.
No more absurd than that uBeam will deliver meaningful power using ultrasound. So if they are going to show a demo that does what they claimed originally then the contents of the box would definitely be subject to scrutiny.
I've had a really nice rigged demo tried on me during a tech DD once and that tech was a lot more believable than what is on display here so some skepticism is warranted.
Also note that the 'charging' indicator lighting up is mostly a function of applied voltage and not so much of the current flowing, even a tiny bit of current would do the trick.
I should measure with one of the phones here and a variable power supply what it takes to get that indicator to come on but I know it can't be much because a small solar cell will do it too.
http://www.instructables.com/id/How-20-Make-a-Solar-Cell-Pho...
(Conveniently does not mention how much current flows but that's right in the spirit of tfa.)
https://www.osha.gov/dts/osta/otm/new_noise/appendixc.pdf
tldr: Maximum 115 dB
Here is a calculator to convert decibels to watts:
http://www.sengpielaudio.com/calculator-soundlevel.htm
tldr: ~0.3 watts per square meter
Surface area of a google pixel: 14.3cm x 6.95cm = 0.01 square meters
Therefore approximately 0.003 watts over the surface area of a phone at safe volumes. At 5v that's 0.6 mA. Barely enough to light up LEDs. It looks like they're working with larger holders, say 20cm x 20cm that's 0.04 sq meters or 2.4 mA at 5v. It takes about 10 mA to trip the "charging" indicator on an android phone:
http://liesandstartuppr.blogspot.com/2017/06/what-does-it-ta...
This is based on the raw power of the sound waves. There will be inefficiency converting from sound to electricity, so they are probably dealing with greater than 115 dB sound at the phone. They are probably just barely tripping the charge sensor for 100 hour charge times. If they are charging significantly then they are working with very excessive excessive sound levels (>125 dB).
Given imperfect transducers for 100% conversion of sound to electricity and the above dimensions they would have to be working with > 122 dB sound at the phone for 10 mA charge current.
So, it's either a scam or it's not safe. Jamming that much air pressure in a small space will cause problems and will probably be inefficient.
Sound is not a laser. You can beam form it, it just won't be as tight as a laser, or even a flashlight. You can't expect clean narrow patterns within a 45 degree cone from the source. There will be high and low intensity interference patterns. You can even see it in the demo.
And this is why I don't want uBeam doing the testing- they're certainly not going to go, "Welp, this technology has some negative health effects. Better return those venture bucks and shut down the company!"
Any test they do is the scientific equivalent of "Man declares himself not guilty of fraud."
The line voltage is not the limiting factor. To get gigabit speeds your need to transmit at RF frequencies, and that hundreds of miles-long power cable is one giant antenna that will interfere with other users of the spectrum.
The power levels used in home powerline network gear are tiny, and the sources of interference much smaller. And even they have power and interference restrictions from the FCC to protect other users of the spectrum.
The tech seems to be the same whereas it tracks the position of the device then beams the power. Note however that Cota only sends one WATT of power per device.
How much does UBeam sends?
All the pics also seem to show the charging sleeves with their backs pointed at the unit. If they can't work from other directions, that's a huge red flag.
I'll concede that I probably use my phone less than a lot of people, but this looks like a "solution in search of a problem" to me. I'm still using a Nexus 5 that's several years old, and my battery rarely drops below 80% over the course of the day. (I only charge my phone when I sleep, and never "top it off" during the day.)
When I do need to charge it, I plug it in, and can get a full charge in about an hour, if I remember correctly.
Even if we were to assume that this product is viable technologically (which is a big "if"), my hunch is that it won't be viable commercially for much longer as advances in battery and phone technology make it irrelevant.
I wonder how they'll combat the inverse square law and make their technology actually feasible.
Usually the inverse square law is very much in effect when it comes to audio, this is because the medium (waves in air) behaves as water does with waves do in a pond rather than say the light coming out of a laser or any other focused source of electromagnetic radiation.
Distance from the transmitter will very much be a factor.
I think uBeam is another Theranos, but granted at a much smaller scale. Still can't believe it has raised so much money and so much press without basic questions really being answered.
The research was aimed at basically heating carcinomas above the 44 oC needed to kill the cells.
So you can focus an ultrasound beam, but it seems like a heck of a way to charge a phone.
That's the whole point of the exercise here: if the efficiency isn't there the whole thing is dead because you can't be pumping kilowatts into space in order to get a few watts (or milliwatts) back out. The difference between the two will get converted into heat!
So the only way this will work is if the efficiency is really high, much higher than seems to be feasible right now.
Abstract: An alternative approach to the wireless transfer of energy is proposed, employing acoustic waves in air. Unlike conventional methods, acoustic energy transfer is able to achieve energy transfer at high efficiencies over distances that are large in comparison to the dimensions of the transmitter and the receiver. This paper gives an overview of the principle and explains the different loss mechanisms that come into play. A theoretically limit on the achievable efficiency is calculated. It exceeds that of a comparable inductively coupled system by an order of magnitude. First preliminary measurements indicate that AET is feasible, although the measured efficiency is lower than the predicted theoretical limit.
Is there anything in that paper that could explain the difference?
I don't know any more because that was how I found that and skimmed the paper about three years ago, for a prior discussion of uBeam here on HN.
The maximum output they measured was 37 uW, so 1000 of these would output ~37 mW, with an input power 1000's of times higher.
If anything this paper is a nice example of how theory and practice differ. It also highlights another big loss factor for ultrasound power transmission, the angle of incidence, the power falls of as the co-sine of the angle between the transmitter and the receiver (maximum at 0 degrees, minimum at 90 degrees).
Or some valuable wallets.
No technology is too inefficient when dopamine is on the line. Kilowatts of ultrasonic beams aimed at your head to give your phone a trickle charge.
Wow, phones are something like 60% battery at the moment. Imagine cutting that in half?! Phones could become much more powerful.