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Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

Unknown Lamer posted about 2 months ago | from the energy-everywhere dept.

Power 138

vinces99 (2792707) writes "Imagine a world in which your wristwatch or other wearable device communicates directly with your online profiles, storing information about your daily activities where you can best access it – all without requiring batteries. Or, battery-free sensors embedded around your home that could track minute-by-minute temperature changes and send that information to your thermostat to help conserve energy. This not-so-distant 'Internet of Things' reality would extend connectivity to perhaps billions of devices. Sensors could be embedded in everyday objects to help monitor and track everything from the structural safety of bridges to the health of your heart. But having a way to cheaply power and connect these devices to the Internet has kept this from taking off. Now, University of Washington engineers have designed a new communication system that uses radio frequency signals as a power source and reuses existing Wi-Fi infrastructure to provide Internet connectivity to these devices. Called Wi-Fi backscatter, this technology is the first that can connect battery-free devices to Wi-Fi infrastructure. The researchers will publish their results at the Association for Computing Machinery's Special Interest Group on Data Communication's annual conference this month in Chicago. The team also plans to start a company based on the technology. The Pre-print research paper.

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Sponsors (4, Funny)

penguinoid (724646) | about 2 months ago | (#47604683)

And now a word from our sponsors, the NSA. Oops, I mean look a distraction.

Re:Sponsors (4, Interesting)

viperidaenz (2515578) | about 2 months ago | (#47604745)

That's actually how the NSA snoop on monitor cables.

They attach a device that looks like an EMI suppression choke that taps in to the red wire on a VGA cable. They use a microwave transmitter/receiver and the amount of RF it reflects back is based on the signal on the wire.
Doesn't need batteries and doesn't transmit any thing so you can't detect it.

The only difference here is the use of WiFi as the RF source.
I don't see how they can patent something that's been done since at least 2008 by the NSA. It's the same idea except ".... over WiFi". Like all those "... on a computer" patents...

It's described here
http://en.wikipedia.org/wiki/N... [wikipedia.org]
Item 35, RAGEMASTER

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47604771)

"doesn't transmit any thing so you can't detect it."

If it is reflecting RF, it is in effect, transmitting. However the key part is that the transmission time is controlled and powered externally, and simple direction finding equipment will be overwhelmed by the external transmitter. But if you think there are no way to locate such items, I've a bridge to sell you.

Re:Sponsors (1)

bonehead (6382) | about 2 months ago | (#47604829)

If it is reflecting RF, it is in effect, transmitting.

Well, no. I see what you're trying to say, but... No.

Pretty much by definition transmitting and reflecting are different and separate things.

I suppose it's possible to reflect a signal that you also transmitted, but it would be pointless, since the reflected signal will always be weaker than the transmitted signal.

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47604869)

That still only works with analog.

I'm not terribly fond of the idea of spying in the first place, but it's this bizarre moral grey area where knowing too little is dangerous and knowing too much is dangerous for everyone.

Let's take three typical scenarios
1) Terrorism
2) Pedophilia
3) Voyeurism

In the first case, the kind of data requires capturing the proof to get a warrant to arrest/seize/intercept the action, but you can't show your hand.
In the second case, simply knowing the data is on the computer is proof enough to just bust in the door.
In the third case, along with corporate espionage, it still requires the spy to be within a distance capable of recording the data.

In the case of this backscatter solution, it's been done before. Hold up a CFL bulb near a radio transmitter, it will light it up a little. If you bring a tube to a cell tower or radio tower it will actually light up a lot more. But in doing so it's not "free" energy. You could technically steal electricity by having the right gear and living near power lines. The power company would indeed notice.

So to pull it off WiFi, would undoubtly degrade the WiFi signal. By how much, we'll probably never know as I don't see this technology being too practical.

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605533)

So to pull it off WiFi, would undoubtly degrade the WiFi signal. By how much, we'll probably never know as I don't see this technology being too practical.

It degrades the signal in the radio shadow of the interceptor. there's nothing passive you can do to degrade the signal outside of the radio shadow. This isn't hard to understand if you don't believe in magical pixies; Imagine a stage light, you can stand in front of it, and someone standing behind you will have a shadow on them, but there's nothing you can do to prevent the light radiating out in other directions short of standing right in front of the light to block the entire aperture. You can't just reach out into the air and grab flux without physically placing something there to collect it (for this, ionic plasmas count as a physical thing, but energy harvesters are not generating ionic plasmas).

So yea, if you stuck a 100% efficient energy harvester (or just a big enough bag of water) in front of a cell tower, you could block service, but if you're 50m away and standing on the ground, there's virtually nothing you can do to block the service without generating active interference.

-puddingpimp

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605541)

Three words:

miniature
black
hole

Re:Sponsors (2)

bonehead (6382) | about 2 months ago | (#47604807)

Like all those "... on a computer" patents...

And then those were all copycatted by "on the Internet" patents.

Which, in turn, are now being copycatted by "in the cloud" patents.

Everyone on the planet can see the absurdity of it except for a very select few morons. Unfortunately, it's those select few morons that we hire to work in the Patent Office.....

There was a time in my life when I believed certain things but was afraid to mention them, lest I be branded paranoid. Two decades having gone by now, it turns out I was actually unrealistically optimistic.

Re:Sponsors (1)

Opportunist (166417) | about 2 months ago | (#47604967)

They sure as hell know. But they also know the value of job security.

Re:Sponsors (1)

bonehead (6382) | about 2 months ago | (#47604999)

Given our success in the "War on ...",

Given our success in the "War on Drugs", we should declare war on prosperity.

Given our success in the "War on Terror", we should declare war on freedom.

Seems like the only thing we accomplish when we declare "War on" something is to ensure that it will propagate and grow. /me declares "War on Giant Piles of Cash in my Bank Account".

(Oh, wait, I already won that war decisively. It was a scorched earth sort of thing. Recovery won't be possible within 10 lifetimes....)

Re:Sponsors (1)

Zanadou (1043400) | about 2 months ago | (#47605103)

You forgot one:

"Given our success in the "War on Child Pornography", we should declare war on rational thinking."

Re:Sponsors (2)

MitchDev (2526834) | about 2 months ago | (#47605943)

You forgot one:

"Given our success in the "War on Child Pornography", we should declare war on rational thinking."

Religion would sue you for patent infringement...

Re:Sponsors (1)

ultranova (717540) | about 2 months ago | (#47606791)

Given our success in the "War on Drugs", we should declare war on prosperity.

Unfortuntely, that was one war the Powers That Be actually wanted to win, rather than keep going in perpetuity, so they did. After all, prosperous people are hard to control, since they can afford to think beyond mere survival.

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47604919)

Thank goodness nobody uses VGA cables any more.

Re: Sponsors (1)

Teranolist (3658793) | about 2 months ago | (#47605471)

I am in fact still using VGA to connect my beamer and I'm pretty sure somewhere out there is at least one person that would love to tap into my 24/7 3D goatse stream!

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605135)

I don't see how they can patent something that's been done since at least 2008 by the NSA.

NSA is never going to claim prior art (and if asked to testify will probably lie to the court and say no such device exists) and the patent holder is never going to sue NSA for patent infringement.
I can totally see how they can patent it. Not legally so, but everyone isn't equal to the law.

Re:Sponsors (5, Interesting)

SuricouRaven (1897204) | about 2 months ago | (#47605331)

Further than that. The Great Seal bug - widely considered one of the most audaciously planted listening devices of all - operated on the same idea. It used vibration - ie, sound - to mechanically modulate a reflected radio signal. No electronic components required at all.

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605563)

That is just one way NSA taps a video signal. There's also satellites with interferometry that can image the waves from a DVI, VGA, or pixel on an LCD or air molecule from space. Besides interformetry there is also van eck phreaking. None of these techniques require a dongle attached to the system or wifi/internet connection and work form space or radar platforms through the ionosphere.

Another method is to bypass the electronics and do neural mapping of visual memory instead.

http://www.OregonStateHospital.net/d/story.html#nsabrainlink

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605691)

That is just one way NSA taps a video signal. There's also satellites with interferometry that can image the waves from a DVI, VGA, or pixel on an LCD or air molecule from space.

From orbit?? CSI dreamland bullshit. Mentioning the existence of Van Eck phreaking -- which is practically implemented from a MUCH smaller distance (inverse square) by carefully tuned antennae -- does not salvage this first paragraph into the realm of possibility.

Using interferometry it is possible to detect the presence of one or more computing devices by the aggregate of their emissions, but resolving individual signals on a wire (in time domain) you fall prey to the same scattering effect that renders visual optics unreliable, the author is stating that the NSA can 'see' bacteria from space while the best compound microscopes can barely glimpse them.

I'll grant you if a passive device is affixed to the video cable which precisely focuses and circularly polarizes some EM towards the satellite there is a slight chance in hell of resolving the signal from orbit... but doing screen captures from your $5 Wal-mart cable, gimmie a break.

Re:Sponsors (0)

Anonymous Coward | about 2 months ago | (#47605945)

This may be the best argument ever against Monster Cables.

Re:Sponsors (1)

Goody (23843) | about 2 months ago | (#47605869)

That's actually how the NSA snoop on monitor cables.

They attach a device that looks like an EMI suppression choke that taps in to the red wire on a VGA cable.

What if all the wires in your VGA cable are gray?

Re:Sponsors (1)

RevWaldo (1186281) | about 2 months ago | (#47606201)

COTTONMOUTH: (see image at right) A family of modified USB and Ethernet connectors that can be used to install Trojan horse software and work as wireless bridges, providing covert remote access to the target machine.[18] COTTONMOUTH-I is a USB plug that uses TRINITY as digital core and HOWLERMONKEY as RF transceiver. Cost in 2008 was slightly above $1M for 50 units.

So AudioQuest has been working with the NSA this whole time?

.

Re:Sponsors (4, Insightful)

TubeSteak (669689) | about 2 months ago | (#47604765)

If they're talking about launching this commercially, it means the Alphabet Agencies have been doing it for years now.

Re:Sponsors (3, Insightful)

Dutch Gun (899105) | about 2 months ago | (#47604803)

Internet of things, huh? I think I'll wait a generation or two until they hammer out the worst of the security issues. One of the latest missteps was caused by a smart bulb that embedded the encryption key in the firmware [smh.com.au] . Oops. Yeah, no one would think to look there, right? There's likely going to be an entire generation of devices that will have the same sort of flaws that early wireless routers had - essentially, the result of average programmers (i.e. non-cryptographic experts) trying to invent cryptographic solutions.

Re:Sponsors (1)

MitchDev (2526834) | about 2 months ago | (#47605923)

Everytine I see story like this, about the "Internet of THings" constantly spying on us, I throw up at how sad humanity has gotten that they think this is a good idea...

What a world we live in (1)

Anonymous Coward | about 2 months ago | (#47604685)

I can't believe they're actually advocating for RF pollution as a way to power things.

Re: What a world we live in (0)

DigiShaman (671371) | about 2 months ago | (#47604707)

That, and it would reduce the WiFi range of the device it's pulling energy from. Back scatter my ass, it's parasitic loss of an RF signal regardless.

Re: What a world we live in (1)

Anonymous Coward | about 2 months ago | (#47604725)

Because the signal that ounce off your wristwatch is really what give you that 11th bar of signal strength.

Re: What a world we live in (3, Interesting)

skids (119237) | about 2 months ago | (#47604819)

Really the wristwatch is a silly example; there are better ways to harvest energy on a wristwatch than RF leaching. Stationary objects that can't rely on kinetic energy harvesting could utilize this technology, though.

Anyway, they did test for the interference potential of this, and it was indeed very little at the rates/distances acheived.

I think they should see how much they could *increase* the effect of the reflection on WiFi signals. Then they could look to market passive devices that, instead of being purposed for the "internet of things", are purposed to work in cooperation with MIMO/spatial multiplexing to dynamically adapt the RF environment to increase the overall bandwidth of WiFi devices, allowing an access point to turn them on and off until it gets just the right reflections. Then license that to WiFi vendors to sell them lithographed by the thousands into wallpaper or just thrown helter skepter on top of drop ceiling tiles.

Re: What a world we live in (2)

AmiMoJo (196126) | about 2 months ago | (#47605843)

Wifi is already too good in many situations. We should be mandating that new houses are basically Faraday cages to cut down on RF interference from wifi, Bluetooth, energy monitors, smart meters, video senders, wireless headphones and all the other random devices people own these days.

Re: What a world we live in (1)

drinkypoo (153816) | about 2 months ago | (#47605941)

We should be mandating that new houses are basically Faraday cages to cut down on RF interference from wifi, Bluetooth, energy monitors, smart meters, video senders, wireless headphones and all the other random devices people own these days.

We're also going to have to mandate some way to get their cellphone signals out of the house for that. At the point when it's all IP (all the way down) then that will be a reasonable idea.

Re: What a world we live in (1)

mrchaotica (681592) | about 2 months ago | (#47606779)

Can't you just stick an antenna on the roof (or in the attic, if you didn't include the attic cavity in the faraday cage)?

It seems like a stucco (metal lath) house with a standing-seam metal roof and metallic-tinted windows, with those things electrically connected together, would work... is there anything else that would need to be done? (In particular, is it important to stop signals from leaking out the bottom? And what about grounding?)

Re: What a world we live in (1)

drinkypoo (153816) | about 2 months ago | (#47606885)

Can't you just stick an antenna on the roof (or in the attic, if you didn't include the attic cavity in the faraday cage)?

At minimum you need two antennae, one on the inside to pick up your signal and one on the outside to send it on (and vice versa). And you're going to need the external to be omnidirectional, so that it doesn't have to be fiddled with when new cell sites come up, and the interior to have a sort of cone-shaped coverage pattern to cover the house beneath it. Then you'll need to poke a new hole in your roof to pass the antenna lead, which should be as short as possible. Not using an amplifier (etc) will attenuate the signal somewhat, but using a nice antenna on the roof should mitigate that.

More likely you'll need an amplifier or micro-cell in your house. Which means significantly more money, and an upgrade every time cellular technology is upgraded.

As you know, if it were all just IP, then you'd just have one IP-based connection to worry about. You'd have one or more ethernets in the house like normal, and your connection to the world would involve a gateway with a modem in. It wouldn't matter which technologies were involved on either side. The world is headed this direction anyway, and only people trying to sell you something you don't really want will tell you otherwise.

Re: What a world we live in (1)

DigiShaman (671371) | about 2 months ago | (#47606011)

We should be mandating that new houses are basically Faraday cages

We should be mandating that new houses are priced out of the market for first time home buyers. Seriously, people 35 and younger purchasing a home is at an all time low since 2004. And it's not the material that's the most expensive, it's the labor. So while I share the frustration of regulating and curtailing RF pollution, mandating a solution such as this isn't going work; at least not this this current economy.

Re: What a world we live in (0)

Anonymous Coward | about 2 months ago | (#47605899)

I have a solar watch. It lasts days face down.

ZigBee + that watch = problem nonexistent.

Re: What a world we live in (0)

Anonymous Coward | about 2 months ago | (#47604735)

Or possibly increase it if the receiver is choking on destructive multipath distortion.

Re: What a world we live in (1)

KingOfBLASH (620432) | about 2 months ago | (#47605425)

Sounds great where do I get one? I've got about 3000 wifi access points coming into my apartment I'd like to degrade...

Seriously though, I can see how if you live in the country this maybe requires you to pump additional power into your wifi device. But in any city, wifi range is MUCH bigger than apartment size, and it's a non-issue.

Re: What a world we live in (1)

Kythe (4779) | about 2 months ago | (#47605951)

I don't think so. This isn't like siphoning energy from the E-field around a power line (which actually does result in loss of power): electromagnetic signals are radiated away and go to heating the environment if they're not received.

Somebody (re)discoverd the crystal radio (2, Insightful)

Anonymous Coward | about 2 months ago | (#47604713)

Powered by radio waves.

Correct me if I'm wrong (0)

relisher (2955441) | about 2 months ago | (#47604719)

Correct me if I'm wrong, but didn't Tesla say wireless charging like this was impossible?

Correct me if I'm wrong (0)

Anonymous Coward | about 2 months ago | (#47604753)

I have no idea what they said, but it's trivial to get power from radio waves. It's easy to build your own circuit to do so.

https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1RQEB_enUS598US598&ion=1&espv=2&ie=UTF-8#q=crystal%20radio%20circuit%20diagram

It's a matter of how much power you can harvest. An earphone uses a few microwatts of power whereas a car motor uses kilowatts. 9 orders if magnitude difference. 1,000,000,000x

Re:Correct me if I'm wrong (1)

Anonymous Coward | about 2 months ago | (#47605003)

No, the main problem with a system like this for distributing power (besides inefficiency) is actually charging for it.

Wireless power transmission makes it extremely hard to monitor usage and thus extract payment.

Re:Correct me if I'm wrong (2)

nukenerd (172703) | about 2 months ago | (#47605417)

Wireless power transmission makes it extremely hard to monitor usage and thus extract payment.

TV companies have found a solution.

Re:Correct me if I'm wrong (4, Interesting)

SuricouRaven (1897204) | about 2 months ago | (#47605343)

Tesla had a long-range high-power transmission system up and running. It just wasn't commercially viable - the transmission losses were so huge, you'd have to pump in orders of magnitude more energy than you get out at the other end. There are some impressive photos of him standing by light bulbs in a field, powered by a transmitter many miles away - but not shown is the sizeable power station he had hooked up to run the thing.

Re:Correct me if I'm wrong (0)

Anonymous Coward | about 2 months ago | (#47606321)

While there are some hefty arguments against it, there have also been a few findings supporting his target ideal of (simplified) using the ionosphere as a massive distribution grid. As with nearly all of his inventions, many scientists said it was impossible and spouted numerous counter-models, but the efficient wireless distribution idea is among those Tesla was not able to prove before his defunding and eventual death.

Re: Correct me if I'm wrong (0)

Anonymous Coward | about 2 months ago | (#47605895)

What about solar panels?

Re:Correct me if I'm wrong (1)

drinkypoo (153816) | about 2 months ago | (#47605929)

Correct me if I'm wrong, but didn't Tesla say wireless charging like this was impossible?

You are wrong. In fact, Tesla said the opposite.

Re:Correct me if I'm wrong (1)

bobbied (2522392) | about 2 months ago | (#47606437)

Correct me if I'm wrong, but didn't Tesla say wireless charging like this was impossible?

You are wrong. In fact, Tesla said the opposite.

I read the original post to be sarcastic, basically saying Tesla already said this was possible....

WTF is the "Internet of Things"? (0, Insightful)

Anonymous Coward | about 2 months ago | (#47604737)

I mean I hate "Internet of Things". Stupid term created by stupid people for stupid people.

It's just a phrase (0)

Anonymous Coward | about 2 months ago | (#47604873)

I mean I hate "Internet of Things". Stupid term created by stupid people for stupid people.

Sure, the term is a bit stupid, but the technology and the intent aren't.

So, what it boils down to is this: are you going to get hung up on a rather silly term, or are you going to realize that it's just a term and that the term makes not slightest bit of difference to the physical reality of the devices?

Since you don't like "stupid", I suggest that you don't act stupid --- don't get hung up on a phrase.

Re:It's just a phrase (4, Insightful)

Opportunist (166417) | about 2 months ago | (#47604977)

no, the intent is not stupid.

It's malicious.

Don't get me wrong, I'd love to have my gadgets talk to each other. But in this day and age, I doubt that I get to choose the topic.

Re:WTF is the "Internet of Things"? (0)

Anonymous Coward | about 2 months ago | (#47604891)

I mean I hate "Internet of Things". Stupid term created by stupid people for stupid people.

In your stupid opinion.

IoT is about connecting devices (appliances, "things") that are not traditional computing devices (computers, phones, tablets, game console, etc) to the Internet. The "thing" could be a health device you wear, your home's water meter, a vehicle sensor embedded in the road, etc. It could be virtually anything so using the word "thing" is not such a bad idea. I'm open to hearing a better phrase for the concept but IoT isn't bad.

Re:WTF is the "Internet of Things"? (2)

Mr D from 63 (3395377) | about 2 months ago | (#47605749)

The "internet of things" is a pure marketing play. It broad brushes a huge spectrum of possible devices even though any single item typically only applies to a small slice of that market. It is too broad and useless when describing anything in particular, but will be used so that every related product can be considered a big freakin deal. Investors... please line up at the door.....

What was old... (3, Interesting)

Anonymous Coward | about 2 months ago | (#47604739)

...is new again:

http://en.wikipedia.org/wiki/The_Great_Seal_bug

Nice to see the idea being put to a less nefarious use. :)

Re:What was old... (2)

freeze128 (544774) | about 2 months ago | (#47604971)

If your smartwatch has to be the size of the great seal, then I think they need to re-think this technology.

Re:What was old... (1)

Opportunist (166417) | about 2 months ago | (#47604979)

I think you are being overly optimistic if you think that this technology would not be used to spy on people.

iFind (1, Insightful)

enoz (1181117) | about 2 months ago | (#47604763)

This sounds just what iFind [slashdot.org] was promising before they were suspended from kickstarter [slashdot.org]

Re:iFind (4, Interesting)

ljw1004 (764174) | about 2 months ago | (#47605029)

It's very different from iFind...

This paper flat out says that it's impossible to harvest enough energy from RF sources to power any kind of radio transmitter. Instead, it takes advantage of the existing idea that although you can't transmit your own signals, you can at least selectively block or intefere with someone else's RF signals. And the paper's clever invention is to apply this known technique to wifi in particular, so as to work with off-the-shelf wifi routers.

By contrast, iFind claimed it could harvest enough energy from RF to power a bluetooth transmitter.

Re:iFind (4, Insightful)

MattskEE (925706) | about 2 months ago | (#47605221)

It only works because it has a very low bitrate of 1kbps:

The UW’s Wi-Fi backscatter tag has communicated with a Wi-Fi device at rates of 1 kilobit per second with about 2 meters between the devices.

Although the authors claim that "The Wi-Fi Backscatter tags do not require any batteries and can harvest energy from ambient RF signals" they make no attempt to back up this claim with measured or estimated energy efficiency of this transmitter. The standard metric for high efficiency transceivers is joules per bit, because low bitrate communication always consumes less energy than high speed, but the only useful way to compare it to another high efficiency transmitter is to see if it can transmit a certain amount of data for less energy.

While I don't expect every paper to address every aspect of a technology, they should not then turn around and make baseless claims like "We believe that this new capability is critical for the commercial adoption of RF-powered Internet of Things." in a length 12 page paper [washington.edu] that fails to address the one metric which would allow them to make such a claim.

Re:iFind (0)

Anonymous Coward | about 2 months ago | (#47605553)

You can in fact harvest enough energy to power a radio transmitter. You can't harvest enough energy to run a Bluetooth radio because it requires periodic beacons. If on the other hand you want to transmit a short 64-bit message at 1200 BAUD FSK once every hour, it's probably feasible.

Re:iFind (1)

bobbied (2522392) | about 2 months ago | (#47606475)

You can in fact harvest enough energy to power a radio transmitter. You can't harvest enough energy to run a Bluetooth radio because it requires periodic beacons. If on the other hand you want to transmit a short 64-bit message at 1200 BAUD FSK once every hour, it's probably feasible.

If you have a purposely built RF emitter to charge up the device by supplying enough energy, you can do what ever you want. Some RF-ID tags work this way. Problem for ANY device that uses WiFi for this is that these devices run under Part 15 of the FCC's rules, which limits your transmit power to about 1/2 watt delivered into an ideal antenna (it's actually limited in field strength, not TX power.) This is simply NOT enough power to charge anything beyond a very short distance because the induced voltages are extremely low (micro volts) at these field strengths.

There are other RF sources out there that may have higher field strengths that you can use to glean power, but I dare say that WiFi signals are just not going to be enough, unless you up the power level quite a bit or keep the transmitter really close by.

Throwies (0)

Anonymous Coward | about 2 months ago | (#47604781)

Remember throwies? Magnet+battery+LED. Throw it up on exposed steel beams, water towers, stainless trim, etc. Mostly a harmless prank except that somebody eventually has to remove them to avoid permanent marks on surfaces due to weathering. I can't help but picturing "lighting up" their networks with a bunch of throwies. Cheap Solar Cel + ID Chip = a neighborhood with a much different appliance profile than they think. Refrigerators in the garden, all needing milk. Blenders up a tree. Microwaves in the bushes. Not as amusing for passers-by as LEDs on buildings; but maybe it might teach somebody a lesson.

Deja Foo (0)

Anonymous Coward | about 2 months ago | (#47604859)

Didn't we just have this argument, like, a month ago?

Re:Deja Foo (1)

bobbied (2522392) | about 2 months ago | (#47606551)

Didn't we just have this argument, like, a month ago?

Yes we did, but apparently the laws of physics got changed and this time it works..... (not!)

This whole, "Yea, we can just get free RF energy by collecting it and do xxx with it." idea suffers from being exposed to reality and the laws of physics. Now, I'm not saying that transferring energy using RF isn't possible, surely it is, only that at the RF field strengths available in your standard residence do not represent enough of an energy source to make any device that uses available back-scatter practical unless you make it REALLY big or you purposely provide high field strengths (i.e. transmit High intensity RF energy) for it to use. Unless your off the shelf WiFi transmitter is *really* close (like under a foot), the energy you can glean from it's signal is vanishingly small (basically fractions of a micro watt), which is not enough to run much more than the circuits needed to collect it.

Re:Deja Foo (0)

Anonymous Coward | about 2 months ago | (#47606695)

Being somewhat familiar with the topic, I believe the idea they have works in theory, but won't work in actuality. If you read the paper, you see that rather than trying to transmit anything, they're trying to interfere with signals. This can be done with amazingly low amounts of power, especially when you're considering you're interfering with signals in the area of -60dBm. These aren't strong signals you have to interfere with (also, for what it's worth, their plate looks to be nearly a square foot, though they claim with no basis that it can be shrunk).

The problem I see is, it relies on power modulation for communication, a high RSSI counting as a 1 and a low RSSI counting as a 0. This is a good idea in theory, but I've been working on indoor localization based off of wifi signal strengths (basically look at what routers are around and RSSIs for each are, compare to what they should be vs what you're actually seeing, and figure out where you are). What you learn with that in practice is that wifi signal strength is probably the most unstable thing on earth. A human body for example is -30dB of impairment. .001% of the signal makes it through a human body. So trying to figure out what it should be when you don't know how many people are around and how they're moving makes a huge problem. Hell, florescent lights make a huge amount of noise that messes with you, and we won't talk about cars driving by or my current bane, air conditioning. All these things cause me problems, so I guarantee that they will cause problems for these guys as well. And the problems are so severe that they limit me to maybe around 10m accuracy, which isn't very good. And occasionally, you get way further off than that.

Very short range (1)

Animats (122034) | about 2 months ago | (#47604875)

They're talking about very short ranges, like under 2 meters. This may not be too useful.

What we need in wireless power is for the inductive charging pad industry to get their act together. There are at least three competing standards (QI, PMA, and WiPower/Rezence), so they're not widely used. Last February, the PMA and WiPower groups agreed to develop multi-mode charging pads that will power both PMA and Rezence devices. Then there are some Samsung devices that will charge from either a Qi or a Rezence pad, but not a PMA pad.

YOU FAIL IT (-1)

Anonymous Coward | about 2 months ago | (#47604935)

by fundamental BSDI is also dead, is not prone to an operating system of the warring would like to and arms and dick [amazing4reskin.com] may do, may not provide sodas,

don't need any of this.. (0)

Anonymous Coward | about 2 months ago | (#47604983)

but thank you anyway.

Why use wireless power? (2)

AYeomans (322504) | about 2 months ago | (#47605047)

... when there's much more energy in light or heat?
Solar cells power calculators and garden lights pretty well. Domestic lights put out 5-100 watts of power distributed around a room.
Wifi power levels are much lower - 0.15 watts or so.

Re:Why use wireless power? (1)

Mr D from 63 (3395377) | about 2 months ago | (#47605781)

That's my thought. Although this device takes no internal power to cause the back scatter effect, how useful can it be if whatever data is to be collected is likely provided by something that needs a power source to begin with. If its just a static device, then its not much more that a longer range RFID. If it is active, it needs power.

Wonderful (4, Interesting)

sjames (1099) | about 2 months ago | (#47605059)

Oh great. You take a walk during lunch because you're concerned about your health. You stop to re-tie your shoe. Too bad your watch tattled that you just paused in front of a 'bookstore' that sells gay porn.

Suddenly you get spammed with offers for gay porn. It's also too bad your employer was exempted from EOE because it's against the corporation's sincerely held religion, so you get fired in the process.

Sadly for you, as you take that long walk back to your parking space you pause a gain (you'll never learn!) next to a fast food joint. By the time you get home you have an e-mail informing you of the increase in your health insurance premium.

The internet of things could be interesting if those things would report to a server that I own and control. Too bad most corporations make internet enabled things report to them so they can sell your personal information to the highest bidder with no questions asked.

Re:Wonderful (1)

AmiMoJo (196126) | about 2 months ago | (#47605789)

Why would anyone buy such a device? They would quickly become like those black boxes insurance companies offer to install in your car to "lower premiums for good drivers". They are too stupid to realize that you need to put your foot down a bit when your car only has a 1.0 litre engine, so report that you are accelerating excessively hard. Once people realize they they get rid of them, and the same will happen to any device or app that tries to screw the user.

Also, what kind of crappy spam filter lets ads for gay porn through? I don't think you have a very realistic scenario there.

Re:Wonderful (1)

tibit (1762298) | about 2 months ago | (#47606043)

The black boxes measure physical acceleration. Sure, they can log the throttle angle, but those two things aren't in a linear relationship, and you can't infer much from the throttle angle other than determining what the driver was trying to do at the time of the crash (WOT, idle, in-between). At the very least the acceleration is a function of RPM and mass air flow. How the latter relates to throttle angle is very engine dependent.

stealing power ? (1)

thygate (1590197) | about 2 months ago | (#47605119)

Won't this just put a greater load on the Wifi transmitters, or dampen the signal ?

Re:stealing power ? (1)

fleebait (1432569) | about 2 months ago | (#47605621)

Won't this just put a greater load on the Wifi transmitters, or dampen the signal ?

It will take about as much power as a mirror does sucking the power out of a light bulb.

Re:stealing power ? (2)

Kythe (4779) | about 2 months ago | (#47605963)

Exactly. It's like saying a telescope sucks power out of whatever it looks at. Electromagnetic radiation doesn't work that way.

Didn't the slashdot community get a kickstarter pr (-1)

Anonymous Coward | about 2 months ago | (#47605131)

Seems like every time someone says "not possible" here, someone eventually proves them wrong.

Lab experiment (0)

Anonymous Coward | about 2 months ago | (#47605205)

All great comments from the tinfoil hat folk ;), but just look at the practicality of all this. It still is a long way of.

What they do, is in effect the same mechanism they use to detect planets if far away solar systems. Because the light from that sun dimms only slightly (because the planet deflects/absorbs the light), they can detect a planet (or at least, they hope so). So they did this in a lab for the RF and so called "internet of things" devices, and were able to have a whopping range of up to 65 cm, communicating by fluctuating the signal strength of the wifi signal to morse code data, just like they use the light pattern coming from the star te determine the size and orbital period of the planet). WOW! Obviously, there are a lot of things wrong with this. Cranking the range up will be massively difficult for one. What about when multiple devices do this: I thinks it will be extremely difficult to keep them apart. Also, just being able to communicate, does not make it a useful thing. Mostly you'll need power to sense or act. This has to come from somewhere, too.

I'd say this is still years from being a commercially viable product, if at all.

Re:Lab experiment (0)

Anonymous Coward | about 2 months ago | (#47605797)

Here's a simpler one:
What they do, is in effect 433MHz far-field RFID on 2.4GHz.

Re:Lab experiment (1)

tibit (1762298) | about 2 months ago | (#47606063)

For multiple devices, the GSM-like CDMA would be viable. Each transmitter can use its own Gold code.

Re:Lab experiment (1)

tibit (1762298) | about 2 months ago | (#47606099)

s/GSM/GPS/, duh.

I'd rather recommend sunlight backscatter (0)

Anonymous Coward | about 2 months ago | (#47605251)

It (hopefully) tends to be more energetic.

Re:I'd rather recommend sunlight backscatter (1)

bobbied (2522392) | about 2 months ago | (#47606577)

It (hopefully) tends to be more energetic.

At least during the day, with no clouds or other shade producing things between you and the sun.

The summary is one of my worst nightmares (0)

Anonymous Coward | about 2 months ago | (#47605275)

BTW Europe does pretty well regarding saving heating by using insulation and a couple of stratetically placed sensors (outdoor, indoor temp, heating circuit outgoing, heating circuit back) coupled with a real programmable heating control unit (insulation levels, night programm, backoff, etc). Thermal efficiency of around 92% is not uncommon.
This simple example show that we don't need crazy complex stuff.

Indeed (1)

jandersen (462034) | about 2 months ago | (#47605367)

Can you ...

...Imagine a world in which your wristwatch or other wearable device communicates directly with your online profiles, storing information about your daily activities where you can best access it â" all without requiring batteries.

All to well, I'm afraid. What I can't imagine is what the hell I or anybody else would want that? I'm not much of a Luddite, but being constantly online is just not part of my lifestyle, and seeing the quality of the online natterdom, I feel no attraction at all, on the contrary. It's just like having a million TV channels, all of them showing Big Brother and Coronation Street and nothing else, 24/7.

Foil suits. (0)

Anonymous Coward | about 2 months ago | (#47605371)

We need to build tin foil suits. The hat is just not going to do it for us anymore. Pass me the roll.

Once again (0)

Anonymous Coward | about 2 months ago | (#47605489)

... a way to cheaply power and connect ...

Once again the 'E' word and the 'F' word is missing - encryption and firewall. Putting something on the internet is not practical if it can't support encryption and a firewall.

Seems vapourware to me (0)

Anonymous Coward | about 2 months ago | (#47605495)

Technically, the device would need to harvest power from 2.4GHz RF and then use that power to power its own transceiver and CPU. Sorry, but I don't see this happen. Harvested RF may be in the order of microwatts. How on earth is this going to power anything besides maybe, a very low dutycyle / long period beacon of some sort? It's just not plausible.

Re:Seems vapourware to me (1)

bobbied (2522392) | about 2 months ago | (#47606615)

Technically, the device would need to harvest power from 2.4GHz RF and then use that power to power its own transceiver and CPU. Sorry, but I don't see this happen. Harvested RF may be in the order of microwatts. How on earth is this going to power anything besides maybe, a very low dutycyle / long period beacon of some sort? It's just not plausible.

Clearly, you understand the physics involved here.... Be warned, there are those who don't and will argue with you. When they fail, they will then resort to "We really don't know what's possible in the future!" which is generally correct, but chances are this won't be possible without a wholesale overturning of our understanding of physics which will likely require a whole new kind of math to describe...Even with "Common Core" I don't think this will happen...

I will .... (2)

cascadingstylesheet (140919) | about 2 months ago | (#47605517)

I will continue to call the phrase "Internet of Things" stupid, for as long as you continue to hype it.

The battle of pointless endurance is mine!

Of course (1)

msobkow (48369) | about 2 months ago | (#47605549)

But having a way to cheaply power and connect these devices to the Internet has kept this from taking off.

Of course it has nothing to do with cost, uselessness, or invasion of privacy. People are just waiting for this technology in Bumfuck Nowhere like they've been waiting for "home automation" all these years.

*LMAO*

Re:Of course (1)

Areyoukiddingme (1289470) | about 2 months ago | (#47606047)

People are just waiting for this technology in Bumfuck Nowhere like they've been waiting for "home automation" all these years.

I've been waiting for "home automation" for years, and by that I mean digital control of my electrical outlets. I even have some X10 equipment that I've been using every day for more than a decade. I only have it because I got it during their $10 for a four-pack promotion, around the turn of the millenium. I've never bought any at the regular price.

Having just now looked at their web site for the first time in 6 or 8 years, I see they finally got a web designer who wasn't an SEO spam specialists crossed with the design sensibilities of a used car salesman. That's a step up. They now have a module integrated into an outlet, which is a another step up, but it's still overpriced and undoubtedly is even flakier than the big boxy modules I have (and which they still sell, identical to the modules I have). Still, the protocol lacks any security whatsoever, so in this day and age, it probably isn't wise to use it at all.

Imagine a world ... (1)

PPH (736903) | about 2 months ago | (#47605701)

... where you can't take the batteries out of things to keep the from spying on you.

Was this supposed to be a comforting thought? (1)

pslytely psycho (1699190) | about 2 months ago | (#47605713)

"Imagine a world in which your wristwatch or other wearable device communicates directly with your online profiles, storing information about your daily activities where you can best access it â€" all without requiring batteries."

Because I certainly don't feel comforted by it.....

Hey Everybody! (1)

Ol Olsoc (1175323) | about 2 months ago | (#47605911)

Inforwars called. They said all of ya are at the wrong website.

New? Hardly! (1)

Muad'Dave (255648) | about 2 months ago | (#47605925)

Take a look at how RFID chips have worked since day one [washington.edu] - they use the incident RF to power the chip that then back-modulates the transmitted signal. In other words, the RFID tag actively modulates the load impedance it places on the antenna causing changes in the radar cross-section of the tag. The tag transceiver sees these variations in cross section as data from the tag.

Re:New? Hardly! (1)

bobbied (2522392) | about 2 months ago | (#47606663)

RF-ID tags take pretty high field strengths to charge up before they can interact with the near field. This means you have to get the reader within about 2 wavelengths of the transmitter and provide pretty high field strengths for the tag to work. There are tags that work a greater distances, but they too require high field strengths to "charge" or carry batteries. Either way RF-ID tags require field strengths that require tens of watts and directional antennas to produce, even over short distances.

Commercially available WiFi devices are extremely low power which means they are very low field strengths. There simply won't be enough power out there to do anything close to what the proponents claim is "possible". There is just not much you can accomplish with a few micro-watts.

Re:New? Hardly! (1)

Muad'Dave (255648) | about 2 months ago | (#47606881)

I never said it was efficient, just not novel. I understand the RFID technology pretty well - we did have tags that would read from 10m or so with about 4W EIRP (1W power + 6dBi antenna). The other thing that you run into is that no one wants a tag with an antenna anywhere near the length required to be efficient. A 1/2 wavelength dipole at 915MHz is still 16cm overall.

If this were developed years ago and if you were to rely on transmitters outside the home, they'd use the pager transmitters at 450/460 MHz to power things. These were beastly strong and transmitted 24x7. Today cell signals would be a good choice. I haven't done the 1/r^2 math, but I bet the proximity of the WiFi will beat the power density of just about any external-to-the-home transmitter.

Chip me now (0)

Anonymous Coward | about 2 months ago | (#47606065)

Will it power the rfid tag embedded in my skull? I demand to be tracked constantly by always on devices embedded in my skull or ingested so that I can share all the gross details on facebook and with our very own intelligence services. You can never know enough about your social and bodily habits!

NSA (0)

Anonymous Coward | about 2 months ago | (#47606871)

Must be a wet dream for NSA

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