| ▲ | ilamont 5 hours ago | |||||||||||||||||||||||||||||||
In the 80s one of my high school teachers said her husband was an engineer who worked on surveillance technology and described how windows could be used as recording devices. People's voices inside caused the window to have minute vibrations, which could be measured by a laser pointing at the window's exterior and reflected back and then turned into audio output. Essentially, turning a window into a microphone diaphragm. It blew my mind. I just looked it up, the technique was apparently invented by a Soviet engineer 40 years prior - Leon Theremin, who is also known for the musical wand heard on Led Zeppelin II and various 1960s horror movie soundtracks. https://people.ece.uw.edu/nikitin_pavel/papers/RFID-vox_2013... | ||||||||||||||||||||||||||||||||
| ▲ | zzzoom 4 hours ago | parent | next [-] | |||||||||||||||||||||||||||||||
Similar technique around the same time presented at SIGGRAPH: | ||||||||||||||||||||||||||||||||
| ▲ | claytonjy 5 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||
Vaguely similar, since electrical wires emit EM fields that are disturbed by human bodies, you can use a special camera to see who's in a building based on those disturbances. I'm not sure how high-fidelity or easy to spoil it is, but this was real technology at least 15 years ago. | ||||||||||||||||||||||||||||||||
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| ▲ | shimman 4 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||
I recall a HN thread (or maybe it was a github project) about using a similar tactic to figure out keypresses in offices. Very interesting stuff. | ||||||||||||||||||||||||||||||||
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| ▲ | darksim905 3 hours ago | parent | prev [-] | |||||||||||||||||||||||||||||||
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