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Matchstick-Sized Sensor Can Record Your Private Chats Outdoors
wabrandsma sends this story from New Scientist:
"A sensor previously used for military operations can now be tuned to secretly locate and record any single conversation on a busy street. [A] Dutch acoustics firm, Microflown Technologies, has developed a matchstick-sized sensor that can pinpoint and record a target's conversations from a distance. Known as an acoustic vector sensor, Microflown's sensor measures the movement of air, disturbed by sound waves, to almost instantly locate where a sound originated. It can then identify the noise and, if required, transmit it live to waiting ears. Security technologist Bruce Schneier says this new capability is unwelcome – particularly given the recent claims about the NSA's success at tapping into our private lives. 'It's not just this one technology that's the problem,' Schneier says. 'It's the mic plus the drones, plus the signal processing, plus voice recognition.'"
Gene Hackman was doing this in the 1970's http://www.imdb.com/title/tt0071360/?ref_=sr_1
Only the State obtains its revenue by coercion. - Murray Rothbard
I can imagine the same people collecting all of our online data now adding offline conversations to it. Imagine adding this to an insect sized flying drone and releasing many of them into your city. The could go anywhere and record anything.
While the sensor measures the vector direction of sound, it measures the *SUM* of all sounds impinging on that point. With a single point sensor, you can't separate the direction of a particular one.
Now, a reasonably small array of these sensors (maybe as small as 30cm across) might be able to accurately localize the source, in the same way that your brain can tell what direction a sound is coming from with just two ears.
Of course, it will also be confused by multipath and reflections, although if adequately characterized, those could be used for localization as well, since the reflected paths have different spectral properties.
There are LOTS of sensors that are tiny and easily deployed these days, using all sorts of sensing modalities. And processor horsepower and tiny comm to get the signals to the processor are easier to get too.
Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land. I actually would have more concerns about private industry: they're not subject to most privacy laws (at least in the U.S.): The wiretap laws, for instance, refer only to comms over a system. If you want to set up a big acoustic array at the beach and record everyone's conversations, process it, and sell the product to whoever, that's perfectly legal. Or set that array up out on the pubic street in front of your house, or the thermal imaging camera, or the mmWave wall penetrating radar or whatever.
So, it's those laws and common decency is where the efforts should concentrate.
http://www.youtube.com/watch?v=Ldir1vtNMnQ
I usually agree with Bruce. But unless that quote was taken way out of context, he is wrong here. Technology isn't the problem. It never is. It is the people salivating at the thought of using it against us. Even those who think they are doing us a service to keep us safe: when they invade our privacy, they are the problem. The tech? It's actually cool. There are probably - how would someone jaded to the world of sound and copyright put it - many non-infringing uses of the tech. It can probably even be used in a way that isn't spying. For example recording a conference speaker (with permission) in a noisy room or the like.
...everybody has it. The last thing we need is awesome tech only spies and generals possess (weapons of mass destruction/contamination being a notable exception). So yes, this is unwelcome technology, but since it's already there, we might as well let everybody have it.
Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land.
What governments would those be which are restrained by the law, let alone common decency?
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
And budget. Monitoring people used to require paying someone to listen to the tapes. The advent of computers has greatly brought down the cost of mass-monitoring by allowing the computers to sift through the vast collection and just flag the potentially interesting things for human examination.
I think the coarse hair would block the sound waves on a pubic street, thus rendering the technology useless.
Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land.
They are?
If you want to set up a big acoustic array at the beach
Were I to surveil the beach, I'd be more interested in visual than auditory information. YMMV.
All joking aside, I'm skeptical of the technical claims of superiority, other than small size. That's tempered by my lack of knowledge of acoustics. I think of it in terms of analogies to optics or radar (as a physicist I once knew said, a wave is a wave is a wave). You need an array to locate the direction something is coming from. Roughly speaking the larger the array relative to the wavelength, the more precisely you can determine direction, and the more you can spatially filter that source from other sources. You can do that with small optical sensors (e.g. a camera or your eye) only because of the short wavelength of light. Radar antennas with the same directionality and resolution need to be much larger. At 1kHz (a frequency you definitely need to understand conversation) the wavelength of a sound wave is 343mm. For radio waves that's the wavelength you'd get at 875MHz. You need a fairly big antenna to get decent resolution. That can be accomplished by widely spaced sensors (antenna elements, whatever) and some serious signal processing. I don't see how one of these sensors can have any serious directionality by itself, or having three in the same place pointing at x, y and z directions can do much.
One difference I can think of between electromagnetic radiation and sound waves is that the former are transverse waves and the latter are longitudinal waves. Does that make much of a difference for these purposes?
Thank goodness I'll be dead.
That wouldn't be a problem on Brazilian streets.
It should be easy to jam. Just make a recording of your voice and that of whoever you're talking with and play both at the same time near enough this gadget can't distinguish the difference.
How about sensors the width of a matchbox?
The sum of all sounds start to really become singular when able to reprocess the source narrowing it down to a 3D origin, if you take exception of farts that is, but using simple frequency bandpass filters, they are easily filtered out by traditional means.
Technology has not always been here. This is totally new.
Note to old school eavesdroppers: don't get rid of all your parabolic dish microphones just yet.
I deny that I have not avoided attaining the opposite of that which I do not want.
multipath and reflections
are already used in DSP to model rooms and sometimes even to reconstruct 3D shape from sound alone
Who logs in to gdm? Not I, said the duck.
... If you want to set up a big acoustic array at the beach and record everyone's conversations, process it, and sell the product to whoever, that's perfectly legal...
Unless you are openly and obviously (to the subjects being recorded) voice recording, most states don't allow the type of action you posit there. At least ONE party from each conversation has to consent to any recording and in 12 states EVERYONE must consent. There are limited "Presumed Consent" exceptions but a public beach would not be one of them. There is a quick review here:
http://www.wingfieldaudio.com/surreptitious-recording.html
Not sure about "through the walls" video/audio recording but I'd bet peeping tom laws would be made to suffice...
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
Jokes get modded down? Is a reincarnated Puritan moderating tonight?
It's not always about spying and surveillance. It's not always about privacy and big brother. This technology would be endlessly useful in a search and rescue situation! Imagine pinpointing an unconscious person's breathing and directing rescue personnel to that location, or locating the cries of a small trapped / lost child. Or a victim stuck in a structure fire! Do you have any idea how LOUD structure fires are!?! Not to mention that unlike the Hollywood portrayal, fires are pitch black! Finding people and the potential of leaving people behind are some of the hardest things that firefighters do. I can think of countless uses for such a device as this for fire and rescue.
Tough room, kid. Go work the borscht belt for a few years.
I deny that I have not avoided attaining the opposite of that which I do not want.
That's true for a single snapshot of sound in any given instant. But if you collecting acoustic data over a period of time, transient sounds (noise) average out, and the loud peak (gunshot) or cyclical nature (engine) of certain sounds of interest should ease their extraction, with sufficient processing.
That was my impression too (one of my grad school courses was on acoustics and sonar design). That's what they do in submarines - make a great big phased array microphone. But if you follow the link in TFA to the company's site, they have a PDF which gives a bit more info on how their sensors work:
So whereas a phased array sensor works by comparing the arrival times of a wavefront at different locations to determine the direction the wavefront is traveling, it sounds like their gizmo is measuring in 3 dimensions the actual movement of air molecules caused by the sound wave, and deriving the wavefront travel direction from that.
Didn't all those Google apologists told us all, over and over, in the past couple years that, if you send unencrypted signals out to public places for everyone to pick up, you can expect no privacy? Those signals are fair game for anyone with the technology to pick it up.
So how can you expect to have a "private" chat out in a public busy street? You are sending out unencrypted sound waves for everyone which has the technology to receive it, right? RIGHT?
Where the hell are all those people now?
What governments would those be which are restrained by the law, let alone common decency?
A representative government is a product of the law so of course it is restrained by the law. Just because individual actors within the government aren't 100% restrained by the law does not invalidate the principle that a representative government operates within the law.
The alternative to your nihilism is pure might-makes-right. Don't let the perfect be the enemy of the good.
When information is power, privacy is freedom.
One difference I can think of between electromagnetic radiation and sound waves is that the former are transverse waves and the latter are longitudinal waves. Does that make much of a difference for these purposes?
It's been explained already by Solandri but I'll give it a try. The sensor measures the displacement of the air, not the pressure. The GP post argues that it measures the vector sum of the displacement caused by all sounds, and this is correct. I imagine a small light ball that's magnetically suspended and being pushed around by the air, and the movement of the ball is recorded (this is probably not how it's done, I imagine it would have a highly non-linear frequency response). If there are two sounds from different directions with different frequencies, you could easily tell them apart -- e.g. the ball is moving up and down fast, and left and right slowly. If the sources have the same frequency, or it's just some broadband noise, you can't tell them apart. You could probably do it easily with two vector sensors and relative timing, but the whole point was that you can do it with one sensor in plausible conditions.
As for electromagnetism / sound, you are right that the transverse/longitudinal distinction makes a difference. The air displacement is analogous to the electric field. An RF antenna sort of measures the projection of the electric field onto some given axis, and an omnidirectional antenna measures approximately the absolute value of the electric field. (A mic may measure pressure, not displacement, but these are alternative variables for discribing the same wave). An analogous RF detector to the sound vector sensor would be three small linear antennae pointing in linearly independent directions, measuring the x,y and z components of the electric field as functions of time. The transverse / longitudinal distinction comes in here: the EM waves have an additional degree of freedom, namely polarisation. The E field can point in any direction perpendicular to the direction of propagation. Given the polarisation vector you can thus only constrain the vector to the source to a plane.
Because they CANT get past the fact that battery technology DOES NOT EXIST to power this crap.
Look ma, no batteries required, and this was decades ago.
https://en.wikipedia.org/wiki/Thing_(listening_device)
Looks like you lose this round, son.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
The moderator probably doesn't know what Brazilian waxing is and couldn't put the joke together properly.
Here is a NSFW link explaining it a bit. I'm serious, there are naked women on the page to explain the differences in styles so even though it is wikipedia, you are warned.
http://en.wikipedia.org/wiki/Bikini_waxing
Every person who cares about these issues should declare in a public video of him/herself a political prisoner in advance.
--
Another fine opinion from The Fucking Psychopath®.
I don't think this sensor works in the traditional sense that you are familiar with. It is inferring information about a wave from the wave itself as it passes through the air. It actually looks at the medium the wave travels through itself and how the waves interact with it's surroundings not what the waves represent or the information it carries. Think of it more like your surround sound system when you connect a mic in the middle of the sitting area and the speaker timing is adjusted so the sound is centered around that location. Except in this case, it can derive information about the location of the speakers.
Now how this thing supposedly works is not by hearing the sound itself, but measuring the wave itself as it passes through the air. It has two elements on a sensor and three sets of the sensors in one sensor. Both elements of each sensor is heated and when the wave passes, one cools more then the other and the voltage resistance either increases or drops. This allows precise measurements of the wave and it's form which is then be processed with the other two sensors back to what originally created it. There is also a sound pressure transducer on the sensor that picks up the wave itself. So the one complete sensor actually analyses the sound wave from 4 points of information relatively close and can recreate the entire wave form in a 3 d representation which should infer the point of origin without needing separate sensors to triangulate from.
Think about how a wave flows through the water as you toss a rock into it. Not only does it have height hirer then the surrounding water, but it also radiates out in an arc or circle from where the rock landed. If you look close to the impact, you can see the entire wave and have a pretty accurate idea of the impact sight. If you look further away, you only see parts of the arc of the wave. You can still find the impact site by drawing 90 degree angles from the arc of the wave and where they cross like the spokes on a bicycle wheel, should be the center of origin. That's what this thing does but with a much smaller portion of the wave. It can recreate the entire wave and determine information from it. Or that seems to be the claim.
In this case, if you can determine enough information about a single section of a wave with enough precision to recreate the entire wave in 3d, you can work the arc of the wave and pinpoint where it originated from. If you filter all the waves to a single one specific type or specific like types, you can process those into the sounds that created the waves originally. You can likely do so to a degree better then normal hearing will allow too- as long as the wave from the sound can reach the sensor.
Now what I think might be frightening about this is that if I understand it correctly, all the information about all the waves can be stored and processed later with knowing where the sensor specifically was and all the conversations could possibly be decoded in the future with the locations of the conversations being pinpointed. What this might mean is, with enough time, the information can be synced with surveillance video that is impossible to pick up all conversations but you can single out on a specific person in the video by referencing their location and listen to the conversation of that location in the room. In other words, someone could use these and not only pick up all the conversations, but store video alongside them so later they can be put with a face or actions of people. Suppose you are at a protest and you tell everyone the cops are on their way, block the streets or stop blocking the streets. All the witnesses don't remember who said what, but not only can they hear it from the sensor, because of the abilities to pinpoint the locations they could locate person and see them from rather crappy videos of the event.
On earth. Up here in space I'm looking down on you. My lasers trace Everything you do. You think you've private lives Think nothing of the kind. There is no true escape I'm watching all the time. I'm made of metal My circuits gleam. I am perpetual I keep the country clean. I'm elected electric spy I'm protected electric eye. Always in focus You can't feel my stare. I zoom into you You don't know I'm there. I take a pride in probing all your secret moves My tearless retina takes pictures that can prove. I'm made of metal My circuits gleam. I am perpetual I keep the country clean. I'm elected electric spy I'm protected electric eye. Electric eye, in the sky Feel my stare, always there There's nothing you can do about it. Develop and expose I feed upon your every thought And so my power grows. I'm made of metal My circuits gleam. I am perpetual I keep the country clean. I'm elected electric spy I'm protected electric eye. I'm elected electric spy I'm elected. Protected. Detective. Electric eye
uses the temperature difference in the cross section of two extremely sensitive heated wires to determine acoustic particle velocity
They're using hotwires -- commonly used in wind tunnels to measure fluid velocity.
I just got back from a pleasure trip. I took my mother-in-law to the airport.
I think it would be New England Patriots coach who really really wanted this.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
it sounds like their gizmo is measuring in 3 dimensions the actual movement of air molecules caused by the sound wave, and deriving the wavefront travel direction from that
Intuitively I can see how that works (although intuition isn't always good physics of course). But if you could get decent resolution this way, why don't they use something like this on subs instead of large phased arrays? Acoustic waves in both air and water are longitudinal waves, so you should be able to sense direction the same way. It seems like the inventive part of this thing is the MEMS technique, the heated wires, etc. I find it hard to believe that with lots of room and power available (e.g. on a sub) you couldn't have created something that does this sort of sensing years ago.
An interesting phrase. As if you can "outlaw technology" or "outlaw manufacturing" especially when the objects are tiny and the theory and manufacturing technique are openly available. Yes I would like to roll back time to when the world seemed saner and more real. On the other hand, that time may be fictional.
Some key points I think are:
1. Asymmetry of huge computing resources (huge disk space for storing a large number of sound fields over time, huge bandwidth for storing them, access to power requirements, huge processing capacity for processing prior to storage, and postprocessing of existing data, and all of this in coordination with similar storage of surveillance video or visible light fields, and possibly other spectra e.g. microwave for skeletal structure).
This asymmetry means that those in power / with access to huge computing resources makes this technology fundamentally put the individual or groups not in power at a disadvantage. Public disobedience would be more dangerous. Also, you cannot as easily take a walk to have a private conversation if you are worried about bugging.
2. On the other hand, construction of extremely small drone + camera + transducer + air pressure vector sensors might make it feasible to drastically increase transparency of "closed door" proceedings and "privacy" of public figures / those in power by the individual or groups not in power. The fly on the wall (or the fly that flew in from the window / air duct) so to speak. Conceivably this could be a power balancing tool.
3. This type of microspying capability might be useful in penetration of fanatic regimes, groups, individuals which covers quite a lot all the way from "axis of evil" scientists and politicians to terrorist groups, nihilist cults and rogue scientists. Though current technology and some elbow grease probably would be sufficient. This conceivably could improve global security, in the sense of reducing the risks of nonlinear weapons.
So while it certainly is "unwelcome technology" from the perspective of an individual, for example it frankly nauseates me, (2) suggests a small number of such devices could be controlled by those not in power to potentially level the impossible 0.0001% vs. 99.9999% world we live in now and as such have potential value in protecting human rights, and (3) seems like a good idea if you happen to live in the footprint of a potential nodong missile with dirty bomb tip, i.e. Alaska, u.s. west coast, or anywhere nearer to rogue states, i.e. Japan, Israel, and all the other neighbors who could be bullied into cooperation.
Personally I am not looking forward to all these nauseating technologies that will be arriving in coming years, but on the other hand that's what comes from living in the future and not a static middle ages. Hopefully some courageous souls will also arise to help figure out what to do about them.
(c) Judas Priest FTFY
Very true udachny. It will be interesting to see the command and control networks needed long term.
Autonomous to a sat.
Autonomous to a local van.
Direct control from a local van, site or building with a short lived power supply.
The other question is the ability to hide the control signals from been taken over or triangulated back to their masters.
Before this tech makes it to court rooms expect a lot of countermeasures in place.
Domestic spying is now "Benign Information Gathering"
"Acoustic zoom" beam-forming microphones have been available since 2010. Their main commercial product is an "acoustic camera" with 128 microphones on an 0.4 meter disk. They have other surveillance products, but they are "not approved for unlicensed users". This is already in use at FCI Otisville, a US prison. "This technology allows an operator to listen to various locations within the range of the system without any movement of the equipment. ... (T)his ability means the operator does not have to move about in order to "point" the equipment at his target and thereby draw attention to him potentially compromising the investigation."
With these systems, if you have enough recording bandwidth, you can record all the microphones and do the beam-forming later. So it's possible to pick the target at playback time. Squarehead is partnering with Galleon Embedded Computing, which makes 8 terabyte recorders full of flash devices capable of recording at gigabit Ethernet rates, so that's presumably what they're doing.
There are several other vendors now. This isn't really that hard to do.
So this technology is already out there, listening to crowds and pulling out single conversations.
'It's the mic plus the drones, plus the signal processing, plus voice recognition.'"
No it isn't.
It's not about the technology, but how... or more importantly whom, exploits it.
I have a feeling that these could easily be fooled by placing several speakers which emit variable barely audible sounds whit are emitted at random times of random frequency and of random length and changing volume.
Mod parent up. This is not a microphone, it's a differential hot wire anemometer.
This kind of technology sounds like it would be pretty awesome for filtering out background noise, allowing the user to take part in normal conversation without having to strain to catch the words from among the surrounding cacophony of sound. I kind of want one...
I remember seeing a presentation by these guys when they were probably still a recent startup company at Twente University, must have been around 15 years ago. Their sensor is build with MEMS technology and consists of 2 or 3 tiny wires (maybe 1x200 micron) that are suspended over a valley etched out of a silicon wafer. When these wires are heated up, a sideways airflow will cause tiny difference in temperature between the wires that can be read out by measuring the resistance. At the time, their target application was low-cost microphones for use in mobile telephones. IIRC, the sensitivity of this sensor had a sensitivity that rolls off as 1/f inherent to the involved physics and they were struggling with the noise at high frequencies in the reconstructed sound. Looking at their website, the sensor still looks exactly the same. Assuming no major breakthrough (I could imagine they lowered the noise by a factor 10 meanwhile, but not that they solved the 1/f problem), I guess the major change now is that they can do more fancy signal conditioning with a DSP in real time. Too bad they went for the military market, but I guess that is a way to slap a few 10-Euro sensors together and sell them as a 10kEuro package. Does anyone know what could be done with these direction sensitive flow-sensors that cannot be done with a phased-array of conventional microphones?
karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
While the sensor measures the vector direction of sound, it measures the *SUM* of all sounds impinging on that point. With a single point sensor, you can't separate the direction of a particular one.
Sure you can... it's standard signal analysis stuff. There are actually a lot of really cool applications to vector sensors.
But if you could get decent resolution this way, why don't they use something like this on subs instead of large phased arrays?
Shh... they do. Well, they use arrays of vector sensors. But, shh....
In ideal principle I think you are correct. However, recent evidence would indicate that somewhat more than a few individual actors are considerably less than 100% restrained.
There are alternatives to both the status quo and nihilism. Do not let rhetorical absolutism be the enemy of practical observation and action.
Scruting the inscrutable for over 50 years.
Well yeah, if you want to pinpoint the source of a massive transient or the source of an annoying continuous whistling sound or a never-ending repeated playback of some secret message, this sensor could work. But it would not be very useful for recording private conversations.
But look at it from this side: a normal microphone measures pressure as a function of time, i.e. p(t). If their is only one source of sound, you can reconstruct the sound wave at the source. If there are two sources, it becomes impossible to distinguish. This transducer will generate three signals: vx(t), vy(t), and vz(t). If you have three sources of sound, then you could, with proper tuning and calibration, disentangle the signal and reconstruct the output of each of the sources individually. As soon as there are more than three sources, say in a pub with 20 conversations going on at the same time, you cannot do this anymore simply because there are more bits of data being transmitted than being transduced; you would need to solve a system of three equations with twenty unknowns.
Avantslash: low-bandwidth mobile slashdot.
TFA mentions 3 sensors "placed orthogonally" so... yeah.
"The last thing we need is awesome tech only spies and generals possess (weapons of mass destruction/contamination being a notable exception). "
Just curious - why do you exclude these (weapons of mass destruction) from your definition of technology=good if everybody has it? It suggests you are declaring that the declaration that technology should be accessible to all is qualified by value judgements - who gets to make the judgement call? you, me, random person in Afghanistan/Bolivia/Estonia? the UN?
If nuclear weapons are not ok, how about large aerial launched bombs/missiles? How about hand grenades? or hand guns? wonder what the qualifying point is and how you came to it.
allowing the computers to sift through the vast collection and just flag the potentially interesting things for human examination.
Or allowing them to go back and review every bit of communication you ever been involved in once they decide you're "a person of interest".
Who is John Galt?
I looked at the company's web site. The technology description indicates that the sensor is a coplanar parallel pair of tiny hot wire anemometer elements located very close together. This structure measures the component of air velocity that is across the wire pair, in the wire pair's plane. Three of these sensors, mounted so they're mutually orthogonal (one each in the XY, XZ, and YZ planes) give the full vector field for air velocity. There is another co-located sensor that gives the pressure (intensity). So one small sensor assembly (about the size of a big kitchen match head) gives high accuracy directional information and time series pressure data. This data set contains everything needed to locate and record a sound source.
If governments can use such technology to spy on citizens, than why not citizens use it to spy on governments, and individual politicians? Who would you think has the most to hide?
Thank you for all the time you spent explaining this.