The cover story in the December, 2014 issue of Scientific American was about “World Changing Ideas, 10 Transformative Technologies”. I usually take articles like this, which predict the next big techno revolution, with a grain of salt (or less than a grain, since I’m trying to keep a low-sodium diet). Science magazines are good at tracking the latest interesting ideas coming out of the research labs and theoretical papers, but they aren’t all that sharp regarding market economics. And they often do not appreciate the engineering challenges and the skills that are needed to bridge the gap between an interesting new technology and the means to design, produce and successfully market a new gizmo (or gizmo system). <\/p>\n
So, you see all sorts of interesting possibilities in magazines like Popular Science and SciAm (although really, SciAm should go back to its former focus on “pure science” and leave the inaccurate predictions about the impact of emerging discoveries in the real world to mags like Popular Science). But very seldom do you look actually look back 3 or 4 years later and say “hey, they were right about those thingies, which they said would soon be in use”. <\/p>\n
One of the big-ten technologies that SciAm thinks will be a game changer is “wireless charging with sound waves”. The subtitle to the article sums it up: “An efficient way to beam electricity through the air”. In a nutshell, a young woman named Meredith Perry<\/a> got interested in the idea of using ultrasound waves to beam sound energy at a battery recharger on a laptop computer or a cell phone (could be other things too, such as electric toothbrushes or flashlights, if the idea works), such that the charging device could work without plugging into a standard 120 volt electrical outlet. <\/p>\n The overall idea is to shoot the energy needed to recharge a battery thru the air, as opposed to through an electrical power cord. That could theoretically free you from needing to find a plug in a Starbucks or an airport waiting room when your IPhone or tablet computer needs a recharge. It might be convenient at home too; think about all the little power AC\/DC converter boxes that you now have in your house for things like speakers, answering machines, small tools, etc. Imagine if you could have something installed in your floor or ceiling and let it keep all of your little devices going, via the silent sound of energy flowing thru the air. No more worrying about finding another power outlet to plug an AC\/DC converter box, into, and then hoping that the cord is long enough to where ever you want to put the speaker or flashlight charger or clock-radio.<\/p>\n There are already systems that use magnetic resonance and electrical inductance to pass energy through the air, but because of basic physics, their power drops off very quickly as you get further from the transmitting source. As such, you would need to shoot out a big blast of energy from a wall or ceiling to make sure that a charging device 15 feet away gets enough power to keep something running or to recharge a battery within a few hours. And those blasts of energy could be harmful to humans or animals that are near to such transmitting sources — sort of like what happens inside a microwave oven or near an airport radar dish. The ultrasound idea is appealing because the physics of sound are different, in that the energy transmitted by sound doesn’t drop off as quickly. And hey, ultrasound is not heard by humans and most animals, so it “sounds” likes a slam dunk!<\/p>\n Well, it certainly does sound like a slam dunk to Ms. Perry. She founded a company called uBeam<\/a> to develop and eventually manufacture and sell this technology. She hopes to ship the first batch of products in two years. The idea also sounded pretty good to some venture capitalist funders — Ms. Perry was able to raise $10 million<\/a> in equity funding from them in 2014. So, she has a real technology start-up company going with real money and real employees. Hey, maybe Scientific American has actually picked a winner this time!<\/p>\n Still . . . there was something about the description of how her sound recharging devices will work that raised a red-flag in my techno-oriented mind. Not that my techno-oriented mind is particularly techno-oriented. I have an engineering degree and have remained interested in science and technology throughout my life, but I am not by profession a scientist or engineer. Nor am I professionally involved in the business end of developing or selling technology. <\/p>\n Nonetheless . . . we are talking here about constantly beaming radiation through the air in places where people spend a lot of time, e.g. in restaurants, offices, or living rooms. Just because it’s sound does not make it any less potentially harmful than a microwave or X-ray. The fact that you can’t hear it does not make it any less dangerous. I’m not one of those people who thinks that you will get cancer if you live too close to a power line, but I still wonder if we don’t already have enough energy in the air with all the radio transmitters, radar applications, movement detectors, wifi, etc. that we now live with. <\/p>\n I didn’t like the part about how uBeam “focuses ultrasound to create a hotspot of energy” (which is then converted by a piezoelectric crystal into electricity for recharging or running a small device). Perhaps the sound energy coming off of the transmitters along the walls and ceilings will be below any damage threshold for people (and pets!), but what about at or near those “hotspots”? What if you or your cat are sitting or maybe sleeping next to such a hotspot, how much of an energy wallop does your own body get over a few hours? Once the “investigative journalists” start latching onto to this, would people still want uBeam’s in their homes or offices or local hang-outs?<\/p>\n But hey . . . I haven’t done any calculations here, maybe I’m just being a worry-wart. I mean, you would think that those people who coughed up the $10 million would have checked into this, if they expect to ever make any dough on uBeam. Then again, people have put money in sillier things in the past. So what are the geeks saying about uBeam?<\/p>\n I did a search, and as you might guess, people are saying a lot of different things about whether uBeam is feasible and economically desirable at engineering levels that both accomplish the job effectively and yet keep people (and once again, pets) completely safe. Some people say that the energy levels involved are so low as not to be worrisome. But others aren’t so sure about that. I’ve seen a handful of articles giving some real numbers. They start with the power wattage needed by a typical recharging device. A new Apple IPhone charger needs 5 watts. You probably know about watts — the lightbulbs in your house are rated by watts (remember the good old-fashioned 100 watt bulb?). Can uBeam safely deliver 5 watts to an IPhone by soundwaves without any short or long-term effects on people or small animals? <\/p>\n The problem actually isn’t nearly as inscrutable and abstract as, say, figuring out how superstrings might combine both gravity and quantum physics in one set of equations. Basically, the question is, how loud does the ultrasound need to be in the room to get 5 watts to a particular point (or many points, really, as a uBeam setup will typically be recharging say 10 devices in a home or maybe 30 or 40 devices at once in a Starbucks). Yes, I know that human ears can’t hear the frequency range that ultrasound is in, but as with a dog whistle, there are still sound waves in the air nonetheless. <\/p>\n And sound, whether audible or not, is measured in decibels. Recall that for sounds that you hear, anything over 90 DB starts to get unpleasant. Lawnmowers get up around 85-90, and jackhammers and sirens are about 125 DB. Anything past 100 DB gets you into the zone where it takes less and less time to start causing or contributing to permanent hearing loss<\/a>. <\/p>\n Supposedly, ultrasound isn’t quite as bad as audible sound, but Wikipedia says that long-term exposure to ultrasound over 120 DB begins to cause hearing loss<\/a>.<\/p>\n The Canadian government set standards<\/a> for human exposure to ultrasound at 110 DB. The question is, can less than 110 DB of ultrasound get an IPhone recharged as quickly as a plug-in recharger? The physicist “Danny” says that at 100 DB<\/a>, you won’t get anything near 5 watts across, and at the same time your dog won’t be entirely safe either. <\/p>\n Other people have criticized Danny for not considering “phased array” technologies, which might make the sound wave concentration more efficient. But Nikita, a photonics PhD student<\/a>, says that phased array is a pretty complicated technology (it was developed by the military to track jets and missiles), and will be difficult to make work in a living room or a restaurant. An electronics engineer named Dave says<\/a> that for starters, the uBeam set-up is going to have to get a location signal from the device that wants to be charged. OK, in the age of Blue Tooth, that’s not so hard. But even then, the phased array system would have to deal with the fact that the sound beams need to be aimed in a room with lots of stuff in the way, such as lamps, bookcases, and people (and that stuff might be moving around too). So it will still be pretty hard to get a good concentration of energy at any particular point, unless there is nothing else in the room except for the IPhone or tablet computer or rechargeable flashlight or whatnot. <\/p>\n And even if you could aim and concentrate enough 100 DB beams to get a localized “hotspot” zone nearing 5 watts, there will still be a zone around the charging device where the decibels will be getting up there, past the 110 DB safety zone. What if you (or your dog or cat) happen to take a nap with your head near your IPhone or clock radio? Are your ears going to be OK? And actually, it’s not just ears — enough sound energy can cause damage to any living cell<\/a>, like a burn.<\/p>\n Personally, I don’t think that people are going to want to be around uBeam, once they realize how it works. Ultrasound has many safe and beneficial applications, as any pregnant woman knows. But a 5 minute scan or tooth cleaning is different from a 24\/7 energy device inside your home or office. The idea of ultrasound recharging is already being developed for implanted medical devices<\/a> such as heart pacemakers. That is a limited, occasional use where a targeted ultrasound energy transfer might make sense. There could well be other industrial applications for ultrasound energy transfer. But as to Ms. Perry’s dream of “free[ing] us up in terms of how we interact with the physical world” and “untether[ing] us from the wall”, IMHO the laws of physics and human psychology just aren’t going to buy it. <\/p>\n So, I predict that uBeam is going to be another one of those interesting practical ideas that you sometimes come across in an old issue of a magazine, and it makes you wonder “why didn’t this actually happen?” That’s my prediction. But then again, my predictions might not be any better than the SciAm editorial staffs’ predictions regarding what will or won’t become a “world changing idea”. If Ms. Perry does come up with a good, risk-free way to get enough sound energy thru the air in a crowded human setting so as to keep your laptop and alarm clock going, well . . . if so, then she and her backers will be the ones getting rich, and they can laugh at me and all the other engineering-naysayers, all the way to the bank!<\/p>\n","protected":false},"excerpt":{"rendered":" The cover story in the December, 2014 issue of Scientific American was about “World Changing Ideas, 10 Transformative Technologies”. I usually take articles like this, which predict the next big techno revolution, with a grain of salt (or less than a grain, since I’m trying to keep a low-sodium diet). 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