Wireless Power Demonstrated 124
Necroloth and other readers sent in the story of Witricity's latest demo at the TED Global conference in Oxford, UK. The company is developing a system that can deliver power to devices without the need for wires. The idea is not new — electrical pioneers Thomas Edison and Nicola Tesla assumed that power would be delivered wirelessly. The BBC quotes the inventor behind Witricity's tech as saying that Tesla and Edison "...couldn't imagine dragging this vast infrastructure of metallic wires across every continent." eWeek Europe notes some hurdles the technology must overcome: "The 2007 experiment it is based on had an efficiency of only around 45 percent, but [Witricity's CEO] promised power delivered wirelessly would start out 15 percent more expensive than wires, and improve on that." Intel has also demonstrated wireless charging.
So what are the chances of... (Score:2)
A wireless Taser?
Re:So what are the chances of... (Score:2)
Re:So what are the chances of... (Score:3, Interesting)
Okay ... so what about a taser that works by firing the "head" of the taser but without the trailing wires.
Heck, if that sort of approach worked (a huge "if" personally), the next obvious steps would be to miniaturize the "heads", perhaps make them burn out after a single use (cheap materials, built in resistor that burns out as the current crosses it) ... ... then pack a few of them into a magazine and we've created a rather nice "Assault Weapon" when you're trying to keep casualties to a minimum and are only dealing with "soft" targets (Law Enforcement/Security/Hostage applications sound the most likely).
I predict these are "five to ten years away". ;)
YMMV but I still think it sounds like a neat concept, even if the technology can't/won't support the idea. The single biggest hurdle to the idea is the current need for a stun gun to have those wireless leads leading back to the "body" of the gun. If you can find a away to remove those (even if it means you are now firing a small projectile that isn't expected to penetrate much if anything), it can open the advancement up quite a bit.
Re:So what are the chances of... (Score:1, Interesting)
check out the Tetanizing Beam Weapon [archive.org]
Re:So what are the chances of... (Score:2)
Re:So what are the chances of... (Score:2)
Okay ... so what about a taser that works by firing the "head" of the taser but without the trailing wires.
Not what you meant, but you can fire the whole thing [wired.com]. From a shotgun.
Re:So what are the chances of... (Score:2)
If I were a conspiracy theorist, I'd say the government would start feeding our babies pills to subtly alter their bone structure or do unnecessary surgery to add in antenna to resonate with secret government wireless tasers.
But that's just wonky because of the logistics of the plan.
Call it a immunization shot and require it for doing pretty much anything, and none the wiser.
Re:So what are the chances of... (Score:2)
Try UV lasers to ionise a path through the air and send your taser pulse down that.
Standard interface? (Score:4, Insightful)
This is old stuff (Score:3, Funny)
Thinkgeek has sold wireless extension cords for a long time [thinkgeek.com]. I wonder if Witricity has solved the issue about domestic cats getting in between the source and destination...
Re:Standard interface? (Score:1)
This is only a good idea if the standard included a communication bus and spec for voltage, polarity, and amperage negotiation. Without these things, we would have a lot of burnt out equipment. Unfortunately, this would also increase the complexity and cost of the small devices and chargers, but hopefully the volume of the components used would lessen the expense.
Re:Standard interface? (Score:4, Insightful)
I think that's massive overkill. Just provide a 12V rail, a 5V rail, and a ground using a polarized plug. Heck, you can probably dispense with the 12V rail. A 5V rail by itself should cover the vast majority of portable electronics these days. Amperage negotiation? Build the supply so that if it is under too much load, it sheds power connections, then periodically switches which jacks are shed. That's much cheaper to design, and it doesn't unnecessarily add to the complexity of the devices that use it.
Re:Standard interface? (Score:1)
That would be great, if 1.5v-3v devices could automagically operate safely with 5v. Essentially, your concept requires the device to convert DC voltage, which isn't cheap, and generally very wasteful. However, on the charger end, they could have an switchable transformer and produce the desired voltage.
Re:Standard interface? (Score:3, Insightful)
DC to DC regulators are very cheap, for low power needs - which is what you are talking about for most small devices that use wall warts.
Here's a bunch of devices, with datasheets & prices.
ahref=http://www.semiconductorstore.com/pages/asp/category.asp?id=56rel=url2html-27418 [slashdot.org]http://www.semiconductorstore.com/pages/asp/category.asp?id=56>
They start at about $1 and go all the way up to 3.86 for a device that can do dual power rails of exactly that spec - 5v to 3.3v.
Of course, if you don't care quite as much about efficiency, or you are only stepping down your voltage a little, you can always use an LM78xx (where xx is the output voltage needed) they cost a buck or two also, and with very few additional components needed.
Re:Standard interface? (Score:2)
any electronics running as low as 1.5V is going to need to be supplied from a local regulator (either linear or switcher depending on whether the manufacturer cares more about cost or efficiancy) anyway because that is the only way to keep the voltage stable enough.
Notice that this is how PCs are done nowadays, 12V supply from the PSU to local switchers that provide the high current low voltage power needed by the CPU(s) and GPU(s)
Re:Standard interface? (Score:2)
This is only a good idea if the standard included a communication bus and spec for voltage, polarity, and amperage negotiation.
That's electricity. All that matters here is frequency and amplitude. It'll be up to the receiving device itself to manage voltage and polarity. Amperage is a matter of the transmitter having a sufficient amplitude at its particular frequency, nothing more (power = amps x volts).
USB (Score:2)
Power sharing (Score:2)
Yeah, especially if you're living in an apartment, you get to borrow your neighbour's power (and vice versa).
Do you get arrested if you keep forgetting to turn on your "power sender", but leave your "power receiver" on?
Wireless is great (Score:2)
First came free internet now comes free power.
Thomas Edison ??? (Score:4, Insightful)
Electrical pioneer my ass, he just got lucky once and was able to afford to hire good talent ( like Nikola ). But i totally agree that Tesla proved it was possible ( and WAS a pioneer ). But he also proved that it takes more then tech to make such a project work, it also needs funding. As brilliant as he was, a businessman he wasn't, and we were set decades behind on projects such as this.
Re:Thomas Edison ??? (Score:2)
Edison has gotten far more coverage in the history books (at least US ones), He was probably best at business, although he is known as an inventor. On the other hand, Tesla was, without a doubt, the greatest engineer that has ever lived. He is proof that a formal advanced education is not necessary for scientific greatness. It is too bad that most people don't realize the impact he truly had.
Re:Thomas Edison ??? (Score:2)
ya, i should give Edison credit for his business savvy.
Just was irritated to see his name in the same sentence as Tesla in this context and went off on a mini-rant.
Re:Thomas Edison ??? (Score:3, Interesting)
Some points you should know:
Most of the consumer devices you use today are direct descendants of Edison's inventions.
Edison was no Crook either - even if only paying my sweet grandmother ~17 cents a day around the 1920's.
He was indeed eccentric toward the later years of his life however, and experienced what many would consider a form dementia today.
His list of inventions towers over just about all other modern inventors - I suggest all of you look them up - there are many, many stories to tell. From movies to music, refrigeration to your TV, he's been involved in some way.
Re:Thomas Edison ??? (Score:2)
Most of the consumer devices you use today are direct descendants of Edison's inventions.
They were 'his inventions' only because his employees created them. So i guess technically you are correct, but that is stretching intellectual honesty. Sort of like saying Bell Labs invented the silicon transistor, when it was actually employees of the labs that did..
. ...and by the way - it was Marconi that invented most of what was later attributed to Tesla... and returned to Marconi only recently by world courts.
I call BS. And even if its true they gave them back, Marconi used Telsa's work to achieve it, AFTER Tesla did, so Tesla earned the credit and should retain it.
Re:Thomas Edison ??? (Score:1)
Re:Thomas Edison ??? (Score:2, Insightful)
Actually, it's the other way around. Check [wikipedia.org] your [tfcbooks.com] facts [wikipedia.org].
Re:Thomas Edison ??? (Score:1)
Re:Thomas Edison ??? (Score:2)
There is actually some interesting insight into this debate at the University of Kentucky Library in Murray, KY (of all places).
I'm not going to go in to details, as I've been labeled a crank a few times to many lately, but if you have access check out the Stubblefield papers in reference to Tesla, ignore the respective wiki article, and form your own opinions.
plug: gotthefire.net
Re:Thomas Edison ??? (Score:1)
My only real point was sharing the stories of my grandmother - sharp as a tack - and memory like a steel trap. Edison was real, and his inventions so wide spread you can not live in the modern world without them. And yes, many of them were engineering inventions - one of my favorites being his joint project with Henry Ford in creating Charcoal (the same stuff you use to cook burgers on) as Henry was looking for yet another fuel source for his autos aside gasoline, or his chief choice of ethanol.
Re:Thomas Edison ??? (Score:2)
Edison invented one major thing:
The mass production of inventions.
Everything else was either stolen or subcontracted.
Did you know Edison didn't believe in Ohm's law?
Re:Thomas Edison ??? (Score:1)
Edison not a crook? Oh now there's a good one. I suggest you do some reading about the man and his actions instead of relying on the words of someone who was under his employ. "Le Voyage dans la lune" might be helpful in your search for accurate information on the man.
Re:Thomas Edison ??? (Score:4, Funny)
Re:Thomas Edison ??? (Score:3, Informative)
Electrical pioneer my ass, he just got lucky once and was able to afford to hire good talent
Luck favors the prepared.
1869 Stock ticker
1874 Quadruplex telegraph [wikipedia.org] [Polar modulation]
Rights sold to Western Union for $10,000. [about $170,000 in 2005 dollars Historical Value of U.S. Dollar [mykindred.com]]
Menlo Park was in the business of invention. That in itself was a new idea.
1877 Phonograph
The most interesting thing about the phonograph is that no one saw it coming.
1880 Incandescent lamp.
Edison needed a lamp which could be wired in parallel. His team had to design every component - down to the wiring, fixtures, fuses and switches that would be safe for use in the home.
Re:Thomas Edison ??? (Score:2)
A little more on Edison. (Score:2)
The Stock ticker is merely a different telegraph. The Quadruplex telegraph was based on J. B. Stearns duplex telegraph. The incandescent lamp was invented by Swan. The phonograph was probably the only thing major invention in that list that he made a major contribution to.
The improved stock ticker.
Edison's improved stock ticker included his key contributions to printing telegraphy. His most significant improvement was a mechanism that enabled all of the tickers on a line to be synchronized so that they printed the same information. Because the printers frequently fell behind the transmitter by one or more letters, exchange companies had to send employees to the offices where printers were running out of "unison" to reset them.
One of the most effective and longest used devices was Edison's screw-thread unison. With Edison's device the transmitting operator could bring all the printers on a line into unison by sending electrical impulses to turn the shaft of each machine until a peg sitting in a screw-thread on the typewheel hit a stop. Edison also designed an improved typewheel-shifting mechanism and a paper feed so that his ticker required much less battery power. Edison also devised a transmitter for his stock ticker that used a keyboard like that of a typewriter. Edison's ticker was used on the stock exchange for several years before being replaced, but it continued to be used until about 1960 for many other purposes, including the transmission of sports scores. Stock Ticker [rutgers.edu]
The improved stock ticker netted Edison $40,000.
Quadaplex telegraphy.
While working on duplex telegraphs, Edison realized that he could send four messages simultaneously by combining the duplex with a diplex for sending two messages in the same direction. The common approach to diplex was the use of weak and strong batteries to produce signals of different strengths, with relays at the receiving end designed to respond to one or the other signal. However, it proved difficult in practice to prevent the sensitive weak-signal relay from responding to the stronger signal current. In essence, Edison used a cascade of electromagnets to bridge over the time during which the reversed current regenerated the magnetic field in the main relay magnet. This solution represented an important approach that Edison often took when confronted by particularly intractable problems - rather than completely eliminate a defect he found a way to use its own effects to obviate the problem. The quadruplex continued to be used into the twentieth century. Quadruplex Telegraph [rutgers.edu]
The incandescent lamp
In addressing the question "Who invented the incandescent lamp?" historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Wilson Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance lamp that made power distribution from a centralized source economically viable.
Thomas Hughes, has attributed Edison's success to the fact that he invented an entire, integrated system of electric lighting. "The lamp was a small component in his system of electric lighting, and no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, and the parallel-distribution system. Other inventors with generators and incandescent lamps, and with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting." History of the light bulb [wikipedia.org]
The common thread in these stories is Edison's ability to see the problem as a whole - and deliver a commercially viable solution to the problem as a whole.
Re:Thomas Edison ??? (Score:2)
Edison was very much a crook. How it is exactly that Tesla ended up being labeled some sort of lunatic while Edison is considered some sort of modern Renaissance Man is quite beyond me.
Re:Thomas Edison ??? (Score:2)
It's called politics. Edison new how to work the crowd, Tesla was a lunatic mad scientist. Edison new how to play the game of marketing, tesla annoyed his own followers. Edison was the Bill Gates of his day. an acceptable scientist, but a really good marketer. Tesla is like RMS. a mad scientist.
Re:Thomas Edison ??? (Score:2)
I say "Grumpy Visionary"
cool site [printfection.com]
IMO, Edison was a Business genius like Gates but Tesla was a true Creative Genius, not just an inventor.
Re:Thomas Edison ??? (Score:2, Insightful)
Re:Thomas Edison ??? (Score:2)
The same way psychopaths on the dole get named "captains of industry" while people who actually work their asses off every day barely make enough to live on.
Re:Thomas Edison ??? (Score:2)
Re:Thomas Edison ??? (Score:1)
Re:Thomas Edison ??? (Score:1)
The resonator you mentioned was far too effective - it ended up destroying his building - so maybe resonating wasn't the way to go either.
I don't remember the original sources for these, but here [blogspot.com] is a film about him and his work - sounds like parts of his life were pretty good.
Re:Thomas Edison ??? (Score:2)
You should read up on Tesla's work in Colorado Springs. His 8hz source would reach many miles.
Ideally, he wanted to set up quite a few transmitters world wide. I believe the number was in the dozens. That would sufficiently provide power around the planet.
There are a few fatal flaws with this. Once you make power available everywhere, it's impossible to meter. It didn't require much tech on the receiving side. A couple metal rods, if I remember correctly. Say you managed to get the population of a country to use some sort of metering device, rather than just using their own unmetered receivers. That doesn't mean a neighboring country would manage their own laws. Why should you give away your perfectly good power, and let third world countries have electricity? It's all economics, no one cares about the pesky "for the good of all mankind". Power generation is a capitalist business. They make power, so they can make money. Even if a tax was levied on every person in a country, you can't guarantee that the neighboring areas will tax appropriately. There would be no way to stop their service for failing to pay.
The second is tactical. If you want a tactical advantage over someone, you remove infrastructure services. On a small scale, like SWAT raiding a building, they may drop power to the building before they raid it. The target is now in the dark and disoriented. On a larger scale (like a country), one of the first stages of an invasion is to knock out their infrastructure. Power generation plants are frequently the first to go. In modern terms, that can be an air strike or covert operation. Some things will work on batteries and/or generators for a while, but that time is limited. If you can't eliminate their power source, because it's everywhere, you no longer have the tactical advantage.
The technology could have been perfected. It would never be implemented simply because there's no good profit in it.
Re:Thomas Edison ??? (Score:2)
It would never be implemented simply because there's no good profit in it.
I die a little everytime I hear something like this.
Re:Thomas Edison ??? (Score:2)
Are you sad about hearing it, or sad knowing that it's the truth?
If we as a people could live and work for the benefit of humanity rather than money, the world would be a much different place.
A few people actually embrace that idea. Unfortunately, it will be a long time before it becomes the rule rather than the exception.
Re:Thomas Edison ??? (Score:1)
I'm pretty sure he fried elephants also.... just my 2cents....
Tesla and Edison predicted it... (Score:3, Interesting)
Re:Tesla and Edison predicted it... (Score:2)
Are you talking about "Blowups Happen" or "Magic Inc."?
Re:Tesla and Edison predicted it... (Score:2)
No, Waldo. "Blowups Happen" was a (premature, somewhat unwarranted) cautionary tale about nuclear power. Magic Inc could be a cautionary tale about... lessee... nationalized health care. Yeah, that works for me. But Waldo (usually bundled with Magic Inc) was (at it's core) about human physical deterioration brought on by widespread broadcast power.
Re:Tesla and Edison predicted it... (Score:2)
Well, we haven't listened to Gibson about the "black shakes" caused by too much RF - heck we put RF gear near our heads daily.
Why would we stop now when we can charge it while wearing it? (cancer? naaaaaaah)
Re:Tesla and Edison predicted it... (Score:2)
That's right, it's been decades since I've read them. Time to dig in the book pile again.
Thanks.
Re:Tesla and Edison predicted it... (Score:2)
Heinlein also wrote about a character that was effectively immortal. Banged his daughters, his sisters, his clones, went back in time and banged his mom and his dad, gave his best friend a sex change so he could bang it, got the AI running a planet and the AI running his ship bodies cloned from him (so he could bang them) and really pretty much humped everything that moved, while being a bigger bad ass than the illicit love child of Dirty Harry, Chuck Norris, and Vin Disel.
A good wordsmith, but not exactly Cassandra.
Re:Tesla and Edison predicted it... (Score:2)
Efficiency? (Score:2)
Mmmm; I'm under the impression that the problem with contact-free power is a significant loss in efficiency. So, if I have to use 25% more power (for example) to charge all my devices just so I don't need to connect a wire, that sounds like a great way to make stuff cost more due to increased electricity demand.
If I were building power plants, of course, this would sound like fantastic news.
the problem with contact-free power (Score:2)
I, on the other hand, always thought the problem with contact-free power was cancer.
Re:the problem with contact-free power (Score:1)
Mmmm; I'm under the impression that the problem with contact-free power is a significant loss in efficiency.
I, on the other hand, always thought the problem with contact-free power was cancer.
Considering the large amount of EMI emitting transformers and oscillating devices found in the common nerd's dwellings, I doubt adding a little more would hurt all that much, relatively speaking that is.
Edison? (Score:3)
Re:Edison? (Score:3, Informative)
You can build a reasonably efficient resonant power transfer doohickey in your backyard out of some copper tubing, some low loss tuning capacitors, a RF power generator, and some diodes and filter caps on the far end to turn the received RF into DC.
I've built one to couple 4MHz pulses across to a rotating experiment for ultrasound measurement: http://n3ox.net/files/us_ring.jpg [n3ox.net]
You couple 'em that tightly, and they're like 99% efficient at transferring power.
But even with Tesla aside, this isn't new... it's just not as vastly useful as people re-discovering it seem to think it is. It doesn't work over gigantic distances, only moderate ones, and there's no engineering you can do to get around that. It's near-field coupling between resonant circuits. That said, I think it might end up pretty useful for non-contact charging of your electric car like TFA suggests. That's a *good* application for it, and it has more efficiency than "ordinary" inductive coupling.
Re:Edison? (Score:2, Interesting)
But even with Tesla aside, this isn't new... it's just not as vastly useful as people re-discovering it seem to think it is. It doesn't work over gigantic distances, only moderate ones, and there's no engineering you can do to get around that.
The misunderstanding a lot of people have is that they think Tesla was chasing *truly* wireless power - when in fact this was probably never his goal. Tesla was always chasing after something he called "longitudinal waves" in an attempt to perform worldwide "wireless" power transmission - he even called one of his companies World Wireless [pbs.org].
Tesla certainly wasn't foolish enough to believe this distance was possible with purely wireless transmission, but instead investigated single-wire transmission systems using the ground as the single wire. His initial success at single-wire transmission was at Colorado Springs in 1900 with three lightbulbs in a closed circuit loop with no power source and a transmission source a hundred feet away. In this experiment, as in his later vacuum tube powering experiment performed at considerably greater distances (eventually miles away), the objects in question were always had a metallic contact with the ground.
Take a look at figures 3, 6, and 7 on this page: http://amasci.com/tesla/tmistk.html [amasci.com]. This seems the most likely explanation for the experiments at Colorado Springs and Wardenclyffe. Wardenclyffe in particular is where we find Tesla sinking iron rods 300 feet into the ground, burning out local power station dynamos with his energy demands, and constructing a massive omnidirectional transmission tower.
The reasonable conclusion from all this is that Tesla was always pursuing single-wire transmission schemes in which literally the entire Earth itself was the single wire, and the transmission medium for the wireless component was the entire ionosphere. "World Wireless" seems to have been meant quite literally, which was in keeping with all we know about Tesla's personality. Unfortunately, as we all know, Tesla needed something like an order of magnitude more funding than JP Morgan was willing to provide - particularly after Marconi.
Beyond that, though, Morgan would have probably pulled the project even if Tesla had gotten it working: if single-wire worldwide transmission was in fact his intention, it would've been impossible to meter consumption on a per-user basis.
Retarded. (Score:5, Insightful)
Blasting large amounts of EMI solely to avoid the need to put a battery in something is stupid. Right now EM radiation is controlled to the lowest levels it can practically be in order to achieve some transfer of information between two or more points. Any power transfer system is going to muck up what's already in the air. It's called Shannon's Law -- and no matter how you sex up the technology, the fact is you're raising the noise floor doing this.
Bad engineer. No cookie for you.
Re:Retarded. (Score:1, Insightful)
It's called Shannon's Law -- and no matter how you sex up the technology, the fact is you're raising the noise floor doing this.
Bad engineer. No cookie for you.
Except that energy transfer is not information transfer, and doesn't really require any bandwidth. Of course, every emission has *some* bandwidth due to noise, etc, but you should be able to do wireless power with very narrow band oscillators and I suspect you have confine emissions to the the ISM (industrial, scientific, and medical) bands. Maybe it needs a little bit of slow digital transmission if you need to sync devices and chargers beyond just whether or not there is another resonant device around (you don't want charging stations trying to feed power to each other).
But the fact of the matter is that resonant power transfer requires sharply resonant circuits, so you can't emit much power over a wide bandwidth even if something goes wrong.
Re:Retarded. (Score:2)
http://powercastco.com/wireless-power-calculator.xls [powercastco.com]
Re:Retarded. (Score:2)
We'll have practical flying cars before we have practical wireless electricity. Hell, we'll probably have over-unity energy before we have practical wireless electricity!
Re:Retarded. (Score:2)
How is that any different than Ethernet over Power?
(I'm not an engineer, someone please explain)
Re:Retarded. (Score:2)
Ethernet over powerlines noises up the powerlines, but won't add much EM interference to your wireless, e.g.. I believe the GP is saying that wireless energy transmission is going to make any wireless communication have to compete with the noise, going from a hiss to a yell, like the 2.4Ghz noise of millions of microwave ovens suddenly turning on while you're reading this on your iphone's wifi.
In practicality, that means your phone batteries will die much faster as it has to pump out 1 bar worth of power in a 5 bar zone (that is, it will have to raise the power output to be heard by the tower over the noise, even if the tower is nearby). That means your wifi will be interrupted much easier, or have much lower bandwidth, and won't be usable for long distances. And all these communication devices that have to "yell" to be heard, will be adding just that much more noise for other devices.
the energy-transfer here is non-radiative (Score:2)
Re:the energy-transfer here is non-radiative (Score:2)
It's non-radiative only as long as there's no object in the vicinity which happens (by chance of it's structure) to resonate with it and form an antenna.
If Witricity used something like coded spread-spectrum for it's magnetic waveform, that would be very unlikely, and make stealing power more difficult too. But from the little description in the articles, it looks like it depends on a simple narrow band resonance. An unlucky mechanical structure could resonate with that and radiate.
Re:the energy-transfer here is non-radiative (Score:2)
Re:the energy-transfer here is non-radiative (Score:2)
I believe I understand the meaning of non-radiative and near-field, but I won't claim expertise.
As a simple thought experiment, a Witricity receiving coil connected by ordinary cable to a radiating antenna resonant at the same frequency, with all three components impedance matched, would clearly be a mechanical object which passively coupled with the transmitter and produced a (radiating) far field.
The transmitted field's shape is modified by antenna elements in the vicinity of the transmitter. With complex impedance, that is enough to make the whole assembly produce a far field component unless the transmitter has active compensation, i.e. it senses and adapts with a complementary field shape, which is not easy.
The question is whether the far field component so produced is so tiny as to be effectively zero, or not.
How unlikely is it?
I'm guessing it's very unlikely unless there's the equivalent of impedance matching components in just the right places in one's random household object. It's hard to judge the likelihood of that.
Perhaps "does not unintentionally couple with standardised wireless power sources" will become a design requirement for new electronic devices as they become more common :-)
Re:Retarded. (Score:1)
Just because you're much closer to 102.5's radio tower doesn't mean you can't listen to 93.3.
They're not adding the Gaussian white noise that Shannon's Law refers to, they're going to pump at some specific frequency, so you presumably get to filter it out for your communication channel.
Re:Retarded. (Score:2)
Just because you're much closer to 102.5's radio tower doesn't mean you can't listen to 93.3.
Get close enough to 102.5's tower and it does. And the farther it is from 93.3's, the farther you have to be from 102.5's tower to hear 93.3.
Look up "receiver quieting".
Yes they're different frequencies. But the sharp tuned circuits are AFTER the first few stages. Saturate the front end and you can forget listening to the quiet stuff.
So things like this need to be in bands far enough removed from the signals of interest that the minimal tuned circuits at the front end of the receiver can reject them adequately to keep the front end's electronics working correctly.
Re:Retarded. (Score:1)
Re:Retarded. (Score:2)
Actually, one the main problems they will have is dealing with ETSI EN 300 330-1, which governs the field strength of inductive based transmitters.
The USA also has a similar FCC standard but in screwed up volts/m units.
We develop 134kHz RFID equipment, which pushes right on the boundary of this standard, and it aint a lot of power.
eg a 1200mm x 600mm antenna can just power a 1" RFID tag at 1.5m
Remember near field systems loose strength from the transmitter at 1/r3.
So to obey the standards and get useful power you either need to be very close, or use ferrites to help close the magnetic field.
Wireless power has been around for a few years now (Score:3, Informative)
http://www.powercastco.com/ [powercastco.com]
They even won a best of CES 2007 award from CNET:
http://reviews.cnet.com/8301-12760_7-9673092-5.html [cnet.com]
They released working wirelessly powered Christmas tree lights in December 2007 as a consumer product!
http://news.cnet.com/8301-17938_105-9793204-1.html [cnet.com]
So this type of wireless power tech has been available in consumer products since 2007 and it appears that there has not been a lot of interest. I am really mystified as why nobody cares. Is it because they mistake this technology for some other kind of well known technology? I can't figure out the psychology here.
not all wireless power is the same (Score:5, Informative)
Full disclosure: I know Prof. Soljacic at MIT, who founded WiTricity, although I personally have no financial interest in the company; all of the above information is public and published, however.
Non directional? (Score:2)
I can see a few potential problems with that
Re:Wireless power has been around for a few years (Score:2)
So this type of wireless power tech has been available in consumer products since 2007 and it appears that there has not been a lot of interest. I am really mystified as why nobody cares. Is it because they mistake this technology for some other kind of well known technology? I can't figure out the psychology here.
I'm going to place a guess that it involves price, and possibly obscurity.
Admittedly, I am just going by the $400 pricetag on that tree from 2007, but most people that would be preparing and setting up a christmas tree today, have been doing so for awhile already and in most all cases don't see a drawback to the wires. They have wired things up before, so the process is pretty well understood and worked around.
Now, as a geek I would love to have these, but for me it would be specifically for the reason that they are wireless lights.
To non-geeks, the primary function of christmas lights is to pretty up the tree (well, or 'tradition' maybe), and both wired and wireless lights would do that job. I can see lack of wires helping it be more attractive for sure, but these days most christmas tree wires are green colored to blend in and hide, and due to the fact everyone they know would have the same setup, it's not like you are the odd guy out with some weird freak setup.
Compare a $10 string of lights (Or $1-2 from discount/dollar stores) to $400 for wireless, when both perform the primary function identically, many will go for the cheapest option. Especially considering some people have no problems paying under $20/year for new strands of wires, just to avoid having to untangle them or replace bulbs. It isn't exactly a long term investment item ;}
Clearly the wireless light tree is an investment, but that still goes back to the fact not many people are in the mindset to invest in one.
Then there is the problem of obscurity.
Even I had no idea this product was on the market until you pointed it out. And I think it is awesome and would like something like this!
Most non-geeks have no such desire, thus wouldn't go looking for it, and are less likely to run across it being mentioned (such as I just did on a tech site, from another fellow geek)
I hate to say "If I didn't know about it being a geek, how would any non-geek know?" but it really feels like that.
I dunno, just thinking out loud. Those are my guesses anyway. :D
PS, thanks for the links!
And if you're wearing a tinfoil hat (Score:2)
Yay!!!
As a physicist... (Score:5, Informative)
You'll be getting a memo from the Tesla Death Ray department shortly; Not observing it won't save you.
Re:As a physicist... (Score:1)
I'd like to be the first to complain that resonant power transfer has nothing to do with quantum entanglement.
Entanglement, no. Tunneling, yes... if you like to market your device by insisting on quantum descriptions of things that involve transition rates of 10^28 photons per second. A ~10MHz photon doesn't pack a very big punch, energy-wise.
It's a classical effect but can be framed in quantum terms for "welcome to the future" cred.
Tesla did not just assume that you could do this (Score:2)
Re:Tesla did not just assume that you could do thi (Score:1)
Re:Tesla did not just assume that you could do thi (Score:1)
Causing Cancer (Score:2)
Re:Causing Cancer (Score:2)
Only in California.
Re:Causing Cancer (Score:1)
Re:Causing Cancer (Score:2)
Re:Causing Cancer (Score:2)
I remember some idiots claiming to be allergic to wireless signals once.
http://www.foxnews.com/story/0,2933,358001,00.html [foxnews.com]
We already have wireless power almost everywhere (Score:2)
... at least in good weather during the day.
Comment removed (Score:2)
Re:Splashpower (Score:1)
"Wireless" charging was done before that. GM charged its EV1 with a "wireless" inductive paddle system. Google Magne Charge. I'm sure the technology was around before that.
Meh. (Score:2, Interesting)
To quote John Dvorak: "My toothbrush has been doing this for years."
(ducks)
Cost hides the ineffiency hides the cost .... (Score:2)
Inefficient use of an energy resource is NOT what is needed. Even if it cost as little as wire, it delivers energy less efficiently and puts more demands on resources to deliver the energy. And, no, it will never be efficient because of the square law [wikipedia.org].
Our problem isn't the energy consumed, it's that through inefficiency we waste resources.
Where does the lost power go? (Score:2)
If it's only 45% efficient, and powering a 20W light bulb (guessed), and apparently doesn't radiate or heat people...
Where is it dumping the remaining 55% (11W)? Does the transmitter just get hot safely?
Wireless Power is a great idea (Score:1)
Wireless Power gives everyone a warm fuzzy feeling... oh, wait...
*sigh* (Score:1)
Edison??? Really?? Puhleeze........!
From TF(BBC)A (Score:2)
"Wireless power system shown off" [article title]
Well, that's one state necessary for a fully functional system, but I'd be far more impressed if it was shown on.
Who's going to lug around the transmitter and receiving unit (if not internal to the device) when they can stuff a thin wire in their pocket?
Can't violate the laws of Physics (Score:2)
Scotty is right. This idea is ludicrous. Sending power as magnetic fields is a major fail. The near-field which they're touting as a panacea, it inevitably falls off as the cube of the distance. So you need a sending coil about as big across as the distance. You want to hang a 10-foot coil on the ceiling to power your laptop in a 10 ft radius?
And there won't be a single standards body that will approve pumping many watts of 30m waves into living spaces.
backwards (Score:2)
That should be:
"electrical pioneers Nicola Tesla and Thomas Edison"