
Hackers use an ordinary light bulb to spy on conversations 80 feet away - harambae
https://www.forbes.com/sites/daveywinder/2020/06/14/how-to-use-an-ordinary-light-bulb-to-spy-on-conversation-80-feet-away-security-research-lamphone-hack/
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seesawtron
Previously discussed here:

[https://news.ycombinator.com/item?id=23510617](https://news.ycombinator.com/item?id=23510617)
[https://news.ycombinator.com/item?id=23498185](https://news.ycombinator.com/item?id=23498185)

Reminds me of a 2014 work by MIT on extracting audio signals from vibrations
of objects in a video [0] which I found was truly fascinating. I guess someone
was paying attention to bring this to production mode out of the lab.

[0] [http://news.mit.edu/2014/algorithm-recovers-speech-from-
vibr...](http://news.mit.edu/2014/algorithm-recovers-speech-from-
vibrations-0804)

~~~
mehrdadn
Also interesting (though different):
[https://en.wikipedia.org/wiki/The_Thing_(listening_device)](https://en.wikipedia.org/wiki/The_Thing_\(listening_device\))

~~~
seesawtron
What a beauty!

"The Thing" was designed by Soviet Russian inventor Léon Theremin, best-known
for his invention of the theremin.

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thelazydogsback
That's why those good-ol'-fashioned windowless, inner, Faraday-caged rooms
with concrete foundations separate from the rest of the building with their
own isolated power-supplies are still probably the go-to place for the
paranoid. I remember those in a gov contracting facility in the Boston area --
I'm sure there are more.

~~~
contravariant
You forgot the dampened suspension and vacuum/air gap.

~~~
throw1234651234
Let's not get carried away - that's for earthquake / nuclear shockwave
protection, not information security.

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pixxel
> hooking up an electro-optical sensor to a telescope and pointing it at a
> light bulb, but that's the meat and potatoes of the sub $1,000 (£800)
> hardware hack at least. Fluctuations in air pressure on the surface of the
> hanging bulb are created by the sound of conversation, or music, and make a
> hanging bulb vibrate.

Isn't this the same technique used to listen in on a conversation using a
glass window?

~~~
braythwayt
One thing that's not obvious to me from TFA is why an incandescent bulb is
called out specifically. It seems to me that a hanging LED bulb would be just
as vulnerable, as might a glass chandelier of sorts.

I also wonder whether Christmas trees with hanging ornaments are vulnerable.
These are often placed in a prominent window, so it might be quite easy to
start listening in on conversations in people's living rooms or business
lobbies.

~~~
phkahler
>> One thing that's not obvious to me from TFA is why an incandescent bulb is
called out specifically.

Because they produce light continuously. An led, CFL, or other will actually
flicker at 120Hz.

An incandescent bulb still has 120Hz power going in, but because it depends on
heating to produce light and the filament has some thermal capacity, this is
largely smoothed out.

~~~
hoytech
I have noticed LED bulbs keep glowing for a short period of time after turning
them off:

[https://www.quora.com/Why-do-LED-bulbs-keep-glowing-even-
aft...](https://www.quora.com/Why-do-LED-bulbs-keep-glowing-even-after-
switching-it-off-and-then-they-slowly-dim-out)

I imagine there is still some flicker, but it seems to be smoothed out pretty
well on LEDs also.

~~~
phkahler
I've seen that too. I think they're using a phosphor of some kind to convert
UV wavelengths to visible light. That would have some persistence for those
wavelengths.

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vpribish
already submitted here, from the real source not the lousy forbes article :
[https://news.ycombinator.com/item?id=23498185](https://news.ycombinator.com/item?id=23498185)

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fortran77
Source:
[https://ad447342-c927-414a-bbae-d287bde39ced.filesusr.com/ug...](https://ad447342-c927-414a-bbae-d287bde39ced.filesusr.com/ugd/a53494_443addc922e048d89a664c2423bf43fd.pdf)

Modern LED fixtures and lamps may be more resistant to this. Who has a hanging
incandescent bulb anymore? That being said, a person looking for bugs may not
notice a otherwise normal looking hanging incandescent fixture.

~~~
nine_k
A lot of bars, cafes, etc use decorative bulbs with thin, easily vibrating
wires inside (even though LED-based). I can imagine such a bulb at a home,
too.

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mikece
While the title is about lightbulbs this looks like the same principle as
using a laser to measure the vibrations on the surface of a window in order to
listen to the audio inside a room (something that's been science fact since at
least the early 90s). I don't see why the laser or optical sensor couldn't be
measuring vibrations of something _inside_ the room: a clear line of sight and
a mylar balloon might be the perfect tool for such passive surveillance trick.

~~~
braythwayt
"Ok, we want to know Raganwald's age. Point a laser at the mylar Happy
Birthday balloons and let's listen in on the singing. Take notes! Are you one,
are you two, are you three..."

Um, chief?

"Shhh! I'm listening! Are you fifty-one, are you fifty-two..."

Chief!

"Be quiet, damn you. Ok, he just turned 58. Did you get that?"

Yes, chief. I got that. When I pointed the laser at the balloons, I could
clearly see a "five" balloon, and an "eight" balloon, and while Raganwald has
some very old-fashioned ideas about programming, I don't think he's eighty-
five.

"Good work. Now make me another coffee."

~~~
artsyca
This is the comment I'd like to end my HN career on. Goodnight for now and
very pleasant dreams.

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credit_guy
This is very unlikely to be practical in any way. Just ask yourself how many
times you've seen a lightbulb in the last five years. Sure, you've seen plenty
of light fixtures, lots of neon tubes, some LED bulbs, etc, but an old
fashioned light bulb, not enclosed in any type of lamp shade?

That aside, how are you going to discretely point a telescope at the light
bulb from a distance of 25 meters? You might as well point a parabolic
microphone at them and get a better signal.

~~~
bakedbeanz
I've seen a fair number of naked lightbulbs in the last few years in hipster
restaurants, coffee shops, etc. If done right, it can actually be a pleasing
aesthetic.

I think your general point is right though, it's not terribly practical.

~~~
dehrmann
Half of those are actually LEDs.

[https://en.wikipedia.org/wiki/LED_filament](https://en.wikipedia.org/wiki/LED_filament)

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csunbird
A different site, but the topic was posted before (and made to front page):
[https://news.ycombinator.com/item?id=23498185](https://news.ycombinator.com/item?id=23498185)

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prodpo
We need a device like a mask or helmet which can encrypt our voice before put
it to the internet. Just like a VR glasses.

