zlacker

Despite this being a 2016 paper, it's worth noting that this is true in general and has been common(ish) knowledge among electrical engineers for decades. Highschoolers and undergrads in electrical engineering classes often discover this independently.

What's notable about this paper is only that they demonstrate it as a practical attack, rather than just a neat fun fact of audio engineering.

As a fun fact, an LED can also be used as a photometer. (You can verify this with just a multimeter, an LED, and a light source.) But I doubt there's any practical attack using a monitor as a photosensor.

>>lynndo+(OP)
Yes! LEDs as photometers is something that you don't really see around much anymore, but it is really cool. Even an LED matrix can be used as a self-illuminating proximity sensor with the right setup.

https://www.youtube.com/watch?v=GaAtpAuNN_o

>>lynndo+(OP)
and has been common(ish) knowledge among electrical engineers for decades.

Not only is it common knowledge it's how drive-thru kiosks work!

Source: I used to test microphone/speakers for a kiosk OEM.

>>Anecho+Vl
Is it really a single unit that acts as both the speaker and mic? Can it do both simultaneously? Is that why it sounds so trash?