You can also listen for audio simply by measuring any vibrating surface with a laser. Which goes all the way back to the late 40s, used by the USSR. |
replyFun fact, it was invented by Leon Theremin. The inventor of the Theremin.
1940s? The LASER device was invented in 1960. The Soviet spies used an infrared light beam.
replyThe point was light being used for audio, not specifically laser as a light source.
replyYou seem to keep responding to multiple people defend your point, but he used 1320 MHz in the thing which is not light.
replythe words you use matter.
You are completely wrong.
replyHere's what Theremin invented: https://en.wikipedia.org/wiki/The_Thing_(listening_device)
Yes, he invented the technique of monitoring audio through light. How was I wrong there?
replyThe Thing uses a radio signal at 330 MHz (or perhaps a second or third harmonic). These radio waves have a wavelength of about a meter, which is about 6 orders of magnitude longer than an optical wavelength. It's a fundamentally different mechanism than laser Doppler vibrometry.
reply>The theremin is an electronic musical instrument controlled without physical contact by the performer.
replyhttps://en.wikipedia.org/wiki/The_Thing_(listening_device) is a fun read for people who haven't seen it before
replydeleted
replyFunnily enough, first time I've seen it mentioned was in Ghost in the Shell manga from 1990s, where Major's side business illegally offers military grade optronic touch/etc senses in artificial skin for cyborgs, using measurements of bending fiber optic loops
reply> Back in the day it was CRTs emitting measurable waves through the neighborhood, with some papers even going as far as restoring the displayed image through a wall.
replyIt's been some time since I've thought about Van Eck phreaking: https://en.wikipedia.org/wiki/Van_Eck_phreaking
I don’t get your point. Yes, there’s a lot of eavesdropping techniques available to actors with nation state capabilities (or with a lot of time, money, and expertise). This is another one of them. It’s good to be aware of things like this because it helps you better understand threat modeling for applications that require serious hardening.
replyThere may also be unusual applications of this, like the traffic counting mentioned by another commenter.
(For anyone who needs hardening against things like this, you need a SCIF.)
Just toss a doppler laser interferometer on a window, mirror, etc. At least with fiber-optics you need physical access. Single mode (I think that's most of FTTH) is pretty insensitive to vibration and hard to localize so you'd really have to install something.
replyIn this context, is line of sight with the ability to emit and receive laser radiation at the target not ‘physical access’?
replyNot for an exterior window.
replyAh, but of course. How could I forget about my trusty pocket doppler laser interferometer!
replyThis is a "high school project funded with pocket money" level of DIY, with €25 of parts.
replyYours is not built in to your watch? You should go and have words with Q.
replyMicrowave beam-forming says what?
replyI didn’t hear it say that. I guess I’m not the target. :P
replyIncluded in the next version of Flipper. /s
replySo when AI takes over the world, it will have a convenient tap into every living space of every hoomin. Lovely.
replyFiber optic interrogators are (for now) expensive and bulky, so I don't think commercial modems are capable of that (yet).
replytrackers are also now becoming near microscopic
replythey track BUTTERFLIES from Canada to Mexico by attaching tiny trackers with eyelash glue
* https://celltracktech.com/products/ctt-blumorpho
smaller than a tic-tac candy (about two match-heads)
* https://cellular-tracking-technologies.github.io/ctt_documen...