
Spies can eavesdrop by watching a light bulb's vibrations - lelf
https://www.wired.com/story/lamphone-light-bulb-vibration-spying/
======
Jestar342
A friend of mine had a side-gig at an electronics factory that used to
fit/repair government printers, telegram, and fax machines in the 80s. When he
first started he noted that the schematics said to double up the number of
capacitors. When he raised this as a potential error in the schematic with his
boss, he was told that it was quite deliberate and was there to stop giving
away what was being printed by anyone measuring the power fluctuations. Feels
kinda obvious now but when I first heard it I had a mini-mind-blown moment.

~~~
polishdude20
That seems like a good way to make a piece of equipment just not work. The
stuff inside the printers also probably relies on proper capacitor values.

~~~
jstanley
Seems unlikely. It's probably ~all digital, so I expect the capacitors are
literally only there for filtering the power supply.

~~~
gugagore
If you learn about
[https://en.m.wikipedia.org/wiki/Decoupling_capacitor](https://en.m.wikipedia.org/wiki/Decoupling_capacitor)
you'll see that there is more to the consideration than "just use the highest
capacitance capacitor".

------
codezero
In college for a project I wanted to encode messages over small brightness
variations in light bulbs. It's a pain to deal with AC, so I ended up doing it
with a laser pointer. It turned out to be stupidly easy with a laser pointer
and photodiode attached almost directly to a pair of PC speakers. All these
devices have a +5v DC signal. I could attach my iPod headphones to the laser
pointer directly, then the photodiode to the speakers, and boom, music at
about 100 yards, with almost no quality decrease, though I didn't do anything
quantitative :)

I've always wondered what places communication started getting hidden since we
went online and no longer rely on things like numbers stations or drop boxes
(though I assume dead drops still exist)

~~~
amatecha
K what? That's amazing! Apparently I need to learn more about lasers.... haha
:) I guess it's pretty "fragile" since the slightest misalignment of the
source laser & destination sensor would mean a total loss of signal, right?

~~~
martyvis
Free space optical system *intentionally" spread the laser beam using a lens.
The light beam still consists of parallel rays, and when they hit the
receiving lens they focussed again on the receiving diode (or whatever
sensor). The idea is to accept that the beam will be disperse in the air, or
due to variation at the transmitter, but still to catch enough of the
transmission. [https://en.wikipedia.org/wiki/Free-
space_optical_communicati...](https://en.wikipedia.org/wiki/Free-
space_optical_communication)

~~~
codezero
Awesome. Thanks for the wiki link, will check that out.

------
ravenstine
One way you can do this without another light source is to bounce a laser beam
off a window or other things that are reflective.

In fact, the same principle can be achieved with radio. The Russians once
planted a device in a wooden seal they gave to a US ambassador as a gift
which, when a focused radio beam was aimed at it, would reflect and oscillate
that beam due to vibrations in the air.

[https://en.wikipedia.org/wiki/The_Thing_%28listening_device%...](https://en.wikipedia.org/wiki/The_Thing_%28listening_device%29)

~~~
balls187
Most of my office windows at Boeing had little ultrasonic buzzers on them to
prevent such an attack.

On my offices was actually in a large farad cage to reduce/eliminate EMF leaks
from workstations.

~~~
acidburnNSA
Wow. That's super interesting. So it was considered a credible threat.

Huh you can actually buy such things on Amazon.

[https://www.amazon.com/Shomer-Tec-SHLSD-Laser-
Surveillance-D...](https://www.amazon.com/Shomer-Tec-SHLSD-Laser-Surveillance-
Defeater/dp/B00ABV7J0C)

Edit: yikes, those reviews...

~~~
ravenstine
It's basically a 555 timer, some resisters, and a piezo buzzer. Hardly worth
50 bucks! You can build one yourself for a mere fraction of that.

~~~
freehunter
For a big business like Boeing, buying one at $50 would be far more palatable
than building one from parts.

~~~
ravenstine
Dang, you're right! _This is a business I need to get into._

~~~
zszugyi
I'm sure getting vetted to be a vendor for DoD/Government projects is super
easy.

~~~
culturestate
Vendor qualification isn’t _easy_ but it’s also not especially difficult as
long as you’re an American citizen with no criminal history. Figuring out the
paperwork is half the battle.

Being _selected_ as a vendor, on the other hand...

~~~
55555
Do you have any links where I could read about either topic?

~~~
culturestate
As an SME, everything starts with the GSA - there’s a good overview at
[https://www.usa.gov/become-government-contractor](https://www.usa.gov/become-
government-contractor)

Past that, the hoops you'll need to jump through depend a lot on which
department is handling procurement. If you look at defense-related contracts,
you'll also have to go through personal clearance (which can be difficult by
itself at higher levels).

------
helios_invictus
This technology and technique has been known for a number of decades.
Intelligence agency use a variety of counters to avoid this issue. SCIFs don't
have windows for a reason. The standoff distance for intel buildings are far,
and well monitored for similar reasons. Some facilties use double insulated
glass with a randomized noise maker in the frame. Some corporate board rooms
use similar technology and safe guards.

------
kanobo
Tomorrow's news: Privacy Lightbulbs that vibrate pre-recorded messages to
throw these pesky spies off their trail is invented.

~~~
SilasX
Since you mention it, I got to thinking about whether we can have a microphone
equivalent to the physical covers for webcams -- that is, a physical means
that ensures the device can't detect anything usable, even if an attacker was
able to turn it on without you knowing.

Something like, a vibrating module that you don't really notice but which
clouds out any sounds the microphone would pick up (or, to go your route,
injects fake audio). You turn it on when you want to be sure the microphone
isn't listening, just like you can cover the webcam.

~~~
plutonic
You mean something like this [0]? You could use this to trick your
computer/phone into using the audio jack for its microphone, but since the
mic-lock passes no usable signal, you'll be better protected. It doesn't
otherwise incapacitate the internal microphone, though.

[0] [https://www.amazon.com/Mic-Lock-Microphone-Blocker-Pack-
Surv...](https://www.amazon.com/Mic-Lock-Microphone-Blocker-Pack-
Surveillance/dp/B07C6LMSJ3/)

~~~
SilasX
It would need to block the microphone itself that picks up ambient noise -- I
don't think there's anything on e.g. a MacBook Air that you could plug that
into and block sound.

------
Puts
Apparently this is 1947-tech:
[https://en.wikipedia.org/wiki/Laser_microphone](https://en.wikipedia.org/wiki/Laser_microphone)

I even remember there where schematics for a laser-microphone circulating on
the early 2000s internet that could translate the vibrations of windows into
sound.

~~~
OkayPhysicist
I built one of those in college. Hardware's super simple, but actually getting
it alligned is a total PITA.

------
GhostVII
Important caveat:

 _The voice and music recordings they used in their demonstrations were also
louder than the average human conversation, with speakers turned to their
maximum volume_

I can clearly see vibrations in glass near loud speakers with my naked eye,
but when someone is speaking I generally can't see any vibrations. Still
really cool that they were able to reproduce sounds this way, but it's not
like you can spend 1k and be able to actually listen to conversations using
this method.

~~~
lostmyoldone
If their chart is correct, the 30cm mirror show a 20db improvement in SNR at
200Hz compared to 20cm, same curve but 20db lower gain.

That is an absolute crazy scaling, I'm not entirely sure how that's possible,
though I have a suspicion. If it's an actual scaling law that can be
exploited, I would expect you can extend this to entirely practical audio
volumes on a shoestring budget.

------
wallacrw
I've always wondered -- if I used this on the board room window to listen into
public company earnings meetings, is that inside information? Technically, the
information is "public" in that anyone could do what I'm doing...

~~~
pmoriarty
Along similar lines, I've wondered about how often restaurant and bar owners
have bugged their own premises.

There's probably a lot of valuable information discussed in such
establishments.. especially, say, around Wall St.

Regarding the legal aspects, I'm not sure how much of a legal expectation of
privacy one has in a "public" place such as a restaurant or bar, and we've
pretty much already accepted ubiquitous video surveillance in such places
(even if such videos are often without sound).

Someone could potentially infer speech just by lipreading soundless videos,
but if someone did decide to use audio surveillance on their own property in a
bar, restaurant, or other place of business, is there any law against that?

Quite apart from the legal and ethical objections that might arise against
doing this, I'm sure some business owners are not above giving in to the
temptation to spy on their patrons, especially if there's a big profit motive
(like getting access to inside information by spying on Wall St execs
gossiping over drinks or dinner).

That's not to mention dirt that might be revealed in conversations considered
to be "private", which could be used to blackmail people or for other
nefarious purposes.

The technology to perform such spying has been around for a long time, and in
a bar or restaurant the owner (or rogue employee, or customer even) wouldn't
have to resort to exotic techniques such as this light bulb trick. A simple
microphone would suffice.

~~~
briandear
> Along similar lines, I've wondered about how often restaurant and bar owners
> have bugged their own premises.

In a few select Houston strip clubs.. all the time, or at least ten years ago
some did, the ones owned by certain organizations. I haven’t been around that
scene for a decade, so I can’t speak to now. I know of a few other places that
seemed to magically never have trouble with city officials or permitting.
Another such place, an after hours club, was frequented by the mayor’s “party-
oriented” daughter, never had trouble with police raids, or fire marshals. The
venue survived unscathed until the next mayor took over and such leverage
became unavailable. The Texas Alcoholic Beverage Commission was the only real
challenge, but often the local cops would be knowledgeable about pending raids
and would graciously provide some advance notice. It certainly helped that
many of those cops were paid as off duty private security by the venue. DEA
was another frequent adversary, but those folks aren’t as undercover as they
thought they were. I might suggest that the DEA was (or maybe still is,) one
of the more sketchy law enforcement agencies in the government.

Just under the surface of “normal,” there is some really fascinating stuff
that goes on.

------
imglorp
The article involves a remote device watching the light bulb but it would also
make sense to think about devices in the room as well.

Your device might have its microphone disabled, in hardware even, but I wonder
if the ambient light sensor has enough gain to see audio frequency variations
in room lighting. We already know hard drives and speakers and whatever else
can act like mics for exfiltration...

------
Romanulus
All cool tech aside, I'll be sure to update the single light-bulb hanging from
a thread in my interrogation room now.

------
mdturnerphys
Previous discussion of source:
[https://news.ycombinator.com/item?id=23498185](https://news.ycombinator.com/item?id=23498185)

------
2OEH8eoCRo0
Didn't anyone watch or read Clear and Present Danger? Laser microphone. This
has been done for the past 40 years or so.

------
kainer
Those stories keep fascinating me, ever since I talked about side-channel
attacks during my study times.

Re-creating CRT images through walls, listening in on keystrokes through the
electric wires of a building or learning about traffic patterns while
observing network interface flashing LEDs.

Just a fascinating world when you leave aside what they are aimed towards.

------
irontinkerer
I was expecting to be dissapointed (I thought this was going to be a test in
the same room, with perfectly calibrated equipment) but I was wrong. Very
impressive that you can do this at that distance and with affordable ($400)
equipment. I wonder how long intelligence agencies have been using this
capability.

~~~
hinkley
I knew someone who started building one of the laser based units in the fall
of 1990, in high school. So that's 17 or 18?

By the end of the decade or beginning of the next, we had telecom hardware
companies filtering the signal to the activity LED so that you couldn't read
packet info out of the flickering.

Odds are good that someone combined those ideas a lot earlier than we might
like to think.

------
partiallypro
I'm not sure on the cost, but I know it's common to use lasers at an angle on
windows to spy on conversations via a laser microphone. That requires less of
a line of sight. Is this a cheaper method?

------
anigbrowl
I'm getting tired of these stories, it's always the same set of researchers
doing different variations on the same thing, and feels increasingly like pg's
submarine.

------
arkanciscan
I suspect this only works on incandescent bulbs. My house is full of Philips
Hue bulbs, so suck it spies!!!

------
monadic2
Pretty sure state intelligence has been doing this for decades, and we all
know the laser-off-the-window pane trick by now.

I’m much less worried about spies than I am about the powers directly around
me, namely my own state and the large corporations that run society.

I have no clue who greenlit this article but it seems starved for context not
spoon-fed by the research team itself.

------
mycall
Stealth light bulbs. Create all angles that won't reflect light back to
source.

------
Milank
One more reason to use LED!

------
pier25
This is only for incandescent lightbulbs, right?

------
josefrichter
“Published spying technique” – ironic

------
badrabbit
Well color me surprised /s

------
opal9
this sounds like something samy kamkar would make

------
feralimal
Sorry - but that sounds like BS. Think about it - a hanging light bulb
vibrates when you speak... Really? I don't see any movement, and I'm right
there.

But yet, that can be picked up 25m away by a telescope? With equipment that
costs less than $1000? No way.

Sounds like some phony story to me, that's meant to make us think spies have
superpowers, or even that we're all being spied on. (Which we are, but not
like this.)

~~~
meritganset
I can't tell if this is serious or not. You realize that not all vibrations
are visible by eye, right? In fact, the vast majority aren't.

~~~
feralimal
Do you really think a telescope can pick up the reflected vibrations from a
lightbulb, using a telescope 25m away?

~~~
bbbobbb
Here similar experiment, 6 years ago:
[https://www.youtube.com/watch?v=FKXOucXB4a8](https://www.youtube.com/watch?v=FKXOucXB4a8)

If you think that actual government agency cannot do even more easily with
better equipment in 2020 you're kidding yourself.

~~~
feralimal
I watched the video. I'm sorry, but its inane. This is the worst sort of
science magic. In fact its just trickery.

Do you seriously think that you have been provided evidence in that video? All
that happened is that I ended up looking at a leaf and packets of things that
weren't moving at all. That's not evidence!

It says that they are picking up vibrations from a leaf or bag of crisps. But
they don't show you those vibrations. They just give you a bunch of graphics
and fuzzy sounds and tell you that they have done something.

You do see that this is could be very simple video trickery right? As with the
initial article - there's a claim, but nothing to really be able to use to
verify that claim. Just a graphic, and references to Shazam. Perhaps this is
guerrilla marketing for Shazam? Its a more viable thesis anyway, given the
evidence!

~~~
phpnode
They provide the matlab code and source inputs for their experiments, you
could attempt to verify their results if you don't believe the video.

~~~
feralimal
Should we _believe_ videos and articles?

I think we should demand more. We are being presented science right? We should
be able to recognise that this article and the videos, etc are just presenting
a claim. They are not providing any evidence. This is just a story.

~~~
phpnode
I'm not sure what you're asking, the tools are there for you to replicate
their experiment.

~~~
feralimal
I'm saying, if someone writes an article and it is published, should we
believe it?

You're saying that I should use tools to replicate the experiment. Great -
this is what we should do before we accept something as true. Otherwise, we
are in the realms of 'belief'.

So, do you believe this story? And did you do due diligence, and confirm with
the tools that it is true? Or did you skip that bit and believe it despite the
fact that NO evidence is presented at all? Be honest when you answer please!

Stepping back a bit, I'm not saying anything so drastic. I certainly don't see
why I'm being downvoted. I'm really talking about __applying the scientific
method personally __. I 'm saying don't accept articles, videos by default,
without even critically reading what is being presented. I really think its
pretty obvious stuff, tbh!

