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Wireless devices go battery-free with new communication technique
- leeoniya 13y agoi imagine the signal would have to be reflected in a highly directional manner or at very close distances. it's cool nevertheless, but i think storing some solar power in a capacitor/coil would produce more powerful rf communication bursts at least for outdoors applications.
- rentzsch 13y agoAm I the only concerned that once a few billion of these energy parasites are deployed everyone will have to have to use more energy to broadcast the same signal the same distance?
- acqq 13y agoObserving the situation when I'm in the densely populated area where I have problem in communicating with my own WiFi base because of the noise from other people's stations, I can imagine exactly two potential problems: 1) In densely packed areas, the devices first installed stop working as soon as there are more devices, due to noise. 2) In far-away places, not enough energy for devices to work.
- adestefan 13y agoIt's not noise from other WiFi devices that cause problems in denay packed environment. The problem is the available bandwidth is consumed by other devices. Bluetooth uses the same frequencies as WiFi, but overcomes the problem by using frequency hopping and a method of adapting to the environment.
- eksith 13y agoThat's not how radio travels though. Instead of thinking of it as a beam that may be diverted by these, think of it as a bright light (omnidirectional) at a distance. If there are "things" in the way, some of that light will bounce off and cast a shadow behind those things. Or they may reflect some of the light against the neighbors and you'll get some illumination behind obstacles. Some of these obstacles can be transparent to the light, translucent, semi-opaque or completely opaque (I.E. Paper, Wood, Concrete, Concrete with rebar, Steel facade). But since the signal travels in all directions, there won't be enough attenuation caused by these that are any more significant than actual obstacles to reception. A bigger problem may be interference from neighboring devices that function the same.
- lucaspiller 13y agoActually if you are close enough to the transmitter you can cause issues. I remember at school we went on a tour of the local transmitting station. It was used last century for worldwide transmission of BBC World Service. At the peak of operation in the 80s, it had ten 500 kW transmitters. Anyway, so apparently one of the local farmers decided he wanted to cut his electricity costs. I'm not sure exactly what he did, but it was something like this (on a bigger scale), which did actually cause detectable issues. I think he ended up in prison after they caught him :s
- csmatt 13y agoDoes the increase in radio receivers require an increase in the energy to broadcast to the same area?
- josh2600 13y agoIt's more Shannon-Hartley: http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem (I think).
- acjohnson55 13y agoNope. If it were inductive or capacitive transmission, this would be the case, but for far-field radiation, it's generally not.
- dlhavema 13y agoduplicate: http://news.ycombinator.com/item?id=6004470 http://news.ycombinator.com/item?id=6004470
- csmatt 13y agoThere are those times when the device you're powering isn't supposed to be visible and would benefit greatly by the reduction in size from shucking the battery.
- eksith 13y agoI did an experiment a while ago on whether I could use a crystal radio to light up an LED. Short answer, yes. Long answer, only in very short pulses and that still required a fairly strong AM signal. I guess, this absorbs frequencies of a much wider range.
- beambot 13y agoBackscatter is (indeed) phenomenally interesting. We used it to build "cyborg" dragonflies [1] and to build battery-free tags capable of transmitting video and audio [2]. We've demonstrated fully-passive tags (at 915MHz UHF) capable of 100Mbps communications. Using ambient signals as the carrier is a pretty cool extension. [1] http://www.wired.com/wiredscience/2013/06/dragonfly-backpack-neuron/ http://www.wired.com/wiredscience/2013/06/dragonfly-backpack... [2] http://www.travisdeyle.com/publications/pdf/2013_rfid_rich_media_tags.pdf http://www.travisdeyle.com/publications/pdf/2013_rfid_rich_m...
- Stwerp 13y agoIt seems like this would work over extremely short distances since the carrier signals at tags A and B are basically the same. If ambient backscatter is going to be implemented over a larger area, the multipath or modulation of the carrier seems like it will be problematic. Also: From measurements we have seen, the ambient RF power levels vary _drastically_ with location from TV transmitters.
- beambot 13y agoI believe you re:ambient signals (or rather, no reason to disbelieve you). For those who are unfamiliar with backscatter modulation / passive UHF RFID... most systems are forward-link limited: the limitation on range is dictated by the ability to harvest enough energy to powerup the tag. At a fundamental level, backscatter modulation is little more than a reflector that modulates its radar cross section. You could imagine building massive spinning reflectors to serve the same purpose at very low datarates. As for conventional tags, I've seen read ranges on the order of 30-100 meters using directional antennas. You can build systems that are limited by receiver sensitivity, eg. by using different RX-TX antennas or by using a battery (not for transmission, but for very low power load-modulating the antenna). This is a classic radar problem -- but you can get pretty substantial ranges.
- rdl 13y agoIs there a secret Lollipuff robotics application in the works? :)
- aroman 13y agoAs a human this fascinates and excites me because of the possibilities for innovation. As a hacker this fascinates and excites me because of the potential for abuse and, well, hacking. This is really cool stuff. I can't wait to see what is built with this technology and how it will get broken.
- twinge 13y agoIndeed. This reminds me of "Larson Localizers" [1] from Vernor Vinge's "A Deepness in the Sky": "Among the unsuspecting, they are an espionage miracle. Abused, they lead to ubiquitous law enforcement, and a quick end to civilization." 1: http://en.wikipedia.org/wiki/A_Deepness_in_the_Sky#Localizers http://en.wikipedia.org/wiki/A_Deepness_in_the_Sky#Localizer...
- revelation 13y agoThis would be awesome for home automation devices (sensors, actuators and stuff). It's a pain to have a battery for each little button and sensor.
- gcb0 13y agowouldn't deploying this in big numbers work against the solution itself? you would have so much noise in the existing signals that the main signal, as well as the bounced signals, would be useless? Also, can we just say this is a cat's whisker receiver[1] that instead of powering a speaker/headphone powers another transmitter? [1] http://en.wikipedia.org/wiki/Crystal_radio http://en.wikipedia.org/wiki/Crystal_radio
- beambot 13y agoThis is the same principle as long-range UHF RFID tags. There is a communications protocol (Gen2) that deals with collision detection and multiple access to allow for hundreds (thousands?) of tags in the same space. Part of the protocol involves a tunable value for "the probability that an individual tag should respond."
- jacquesm 13y agohttp://www.spybusters.com/Great_Seal_Bug.html http://www.spybusters.com/Great_Seal_Bug.html
- s_q_b 13y agoI remember, as a small child, building a powerless radio that vibrated the speaker using the strength of the radio transmission itself. Is ambient backscatter is the same thing, except across much wider frequencies ranges?
- Stwerp 13y agoBackscatter refers to reflecting RF power. Ambient backscatter is modulating the reflections of the ambient RF signals as opposed to beaming a signal in from a source as RFID does. The device you built uses the incoming signal to power the device as well as drive the speaker. The devices in this article are using the incoming RF signal to both power the device as well as reflect for wireless communication.
- jzelinskie 13y agoYou're talking about Crystal Radios[0], right? [0] https://en.wikipedia.org/wiki/Crystal_radio https://en.wikipedia.org/wiki/Crystal_radio
- s_q_b 13y ago:) Yes, I am. It was part of an electronics kit my father bought for me. I remember carefully placing the pieces between spring-end contacts to construct the basic circuits. Building electronics from scratch is very satisfying. I think I may get into DIY drones soon to scratch that itch.
- gavinlynch 13y agoObligatory Tesla Post.
- marshray 13y agoYeah, I hear The Hyperloop pods have been designed to fit the Model S.
- gavinlynch 13y agoNikola Tesla... Wireless transfer of energ...--nevermind.
- marshray 13y ago;-)
- frozenport 13y agoWill this destroy signal integrity for everybody in the vicinity?
- jpmattia 13y agoIt's roughly as small of a perturbation to the radiation field as, say, a tinfoil hat.
- ChuckMcM 13y agoThis is very cool. There was an interesting project at a former employer which used ambient light to power conference room schedule displays, attached to the outside of conference rooms. Something like that with e-ink would be even nicer (you can save up energy for changing things rather than keeping an LCD on) There was also some interesting robotics work out of Mark Tilden's lab called BEAM which was primarily solar powered things but it would be really cool to do those things with backscatter powered energy harvesting devices.
- hedgehog 13y agoRadish? https://developers.google.com/gdata/articles/radish https://developers.google.com/gdata/articles/radish
- deleted 13y ago[deleted]
- Stwerp 13y agoFor anyone else interested, the full paper is available here: http://conferences.sigcomm.org/sigcomm/2013/papers/sigcomm/p39.pdf http://conferences.sigcomm.org/sigcomm/2013/papers/sigcomm/p...
- leishulang 13y agoalso harnessing the power from sound: http://www.instructables.com/id/Harnessing-sound-power/ http://www.instructables.com/id/Harnessing-sound-power/ When lose an item in house, shout loudly and it will appear on radar ;)
- JoeAltmaier 13y agoWhat kind of havoc does backscatter/reflection wreak on normal tv/radio signals? Do I want this noise in my house?
- barbs 13y agoIf I understand this correctly, the backscatter is always there. It's residual radiation from the Big Bang. It's also why analogue tv sets show static when not tuned to a station. TV and Radio stations output a signal that's much stronger than the backscatter, so that's what gets received by the TV or radio set. I could be wrong about any of this though...
- oakwhiz 13y agoI think you may be referring to cosmic background radiation. That's a different thing from backscatter off of an ambient radiation source.
- ignostic 13y agoThis was my question, too! According to the paper: >"Finally, we test the interference of ambient backscattering and find that, even in less favorable conditions, it does not create any noticeable glitches on an off-the-shelf TV, as long as the device is more than 7.2 inches away from the TV antenna." It's discussed in more detail in 6.4. So far they've looked mostly at TV interference. I'd be surprised if it interfered with anything else at all, but that's all I could find for now.
- oakwhiz 13y agoThis communication method creates a type of interference called inter-symbol interference, or ISI, for any intended receivers of the carrier transmission. ISI is basically what happens when echoes cause a signal to interfere with itself. Since this communication method modulates the amount of echo in the carrier transmission, I can only assume that any typical anti-ISI techniques used by most receiver designs (e.g. rake receiver) would be confused by the rapidly-changing ISI caused by these devices, increasing the total noise present in the received signal.
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- arjn 13y agoThis is a very interesting development. Kudos to the UW folks for this great piece of research. Few questions :- - Would there be a problem if the devices were inside an enclosed/shielded area (I assume there would be) ? - Isn't the data rate dependent on the kind of ambient wavelengths available ?
- Lagged2Death 13y agoThere was a time when battery-less electronics might have excited me, but these days dis-connectable batteries/power supplies and real, hardware off switches seem like important, useful features for just about anything.
- zhemao 13y agoJust put a Faraday cage around it by wrapping it in tin foil. </sarcasm>
- noonespecial 13y agoI know, its a joke, but just the other day, I was thinking about faraday cages and how maybe it wouldn't be terrible to have one around the house and if I could pull it off with tin foil... I was seriously considering tin foil to stop snooping from government rays. What. A. World.
- adestefan 13y agoI live in a house with aluminum siding and foil wrapped sheathing.
- j45 13y agoThis needs to be in any 2013 year in review article. The implications for this with existing and new technologies is unique and doesn't happen often enough, presuming my understanding is correct :)
- knieveltech 13y agoWould anyone be willing to explain the proposed benefits of an "Internet of Things"?
- samatman 13y agoLogistics is a multi trillion dollar industry. I doubt there's a larger sector of the economy than moving things around.
- marshray 13y agoYeah, let's kill it off!
- 1rae 13y agoI think it has more to do with Ubiquitous computing. Turning everything into a potential computer or sensor and then connecting them all together into a giant invisible network. Shaping the physical world to be more intelligent or interactive seems a lot more interesting that just tracking things that move around for logistics purposes.
- nkorth 13y agoI was just reading the Wikipedia article about crystal radios yesterday. Does this have anything to do with them?
- zw123456 13y agoThis non-sense has been posted a number of times and concluded that it is RFID redux.
- dhughes 13y agoThis reminds me of a spark-gap transmitter but without the spark.
- neya 13y agoIsn't this something like what Tesla proposed earlier? Can someone elaborate how this is different from Tesla's proposition? Thanks!
- benjaminva 13y agoFrom my first read it seems that I will not be able to pay with my "backscsatter creditcard" in a Faraday cage or anywhere, where background radiation is strongly shielded. But from a general stand point, I really like the idea.
- ck2 13y agoHmm, imagine a massive array of those like solar panels that work at night.