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Headphones can be hijacked to surreptitiously record audio

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Re: Headphones can be hijacked to surreptitiously record audio

#111

Post by [deleted] »

ChuckMcM wrote: post #93
IshKebab wrote: post #57

The bit you want to know: > Their malware uses a little-known feature of RealTek audio codec chips to silently “retask” the computer’s output channel as an input channel

Not a "little known" feature, it is the feature that lets you plug your head phones into any of the 6 jacks that it looks like it fits in on the back of your computer and the little pop up says "Are those headphones you just plugged in?" you say yes and that jack is retasked as as headphone jack even though it was the subwoofer output according to the legend on the computer plate. Its a "feature" that they have sold…

[deleted]

Re: Headphones can be hijacked to surreptitiously record audio

#112

Post by mountaineer22 »

bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

Did you know you can use a DC motor as a speaker, too?

I have not tried using a motor as a mic.

Re: Headphones can be hijacked to surreptitiously record audio

#114

Post by posterboy »

CogMonster wrote: post #68
posterboy wrote: post #63

makes me wonder if the same thing goes for screens, because the reverse photoelectric effect in LEDs can be reversed.

You would still need a lens to form an image on the screen.

notice flatscreen viewing angles, they don't have isoform radiosity, almost like through a lense.

Re: Headphones can be hijacked to surreptitiously record audio

#115

Post by telekid »

bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

How do you dial a zero?

Edit: Just realized why a zero is in the '10' position on a rotary phone. Huh.

Re: Headphones can be hijacked to surreptitiously record audio

#116

Post by amelius »

bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

How would this trick translate to the modern world of proprietary protocols? Would MacGyver have a fighting chance?

Re: Headphones can be hijacked to surreptitiously record audio

#117

Post by ptaipale »

telekid wrote: post #115
bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

How do you dial a zero? Edit: Just realized why a zero is in the '10' position on a rotary phone. Huh.

Yes, except in the Swedish phones, where the numbering starts from 0. So dialing 0 would make 1 pulse, dialing 1 would make 2 pulses, and dialing 9 would make 10 pulses.

Re: Headphones can be hijacked to surreptitiously record audio

#119

Post by mikey_p »

mountaineer22 wrote: post #112
bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

Did you know you can use a DC motor as a speaker, too? I have not tried using a motor as a mic.

Good ole' Servodrive. I've read some threads with Tom Danley on a few message boards and he is one incredibly fascinating individual.

Wouldn't the efficiencies between input/output transducers be inverse? A servo drive transducer would use very little energy to produce a lot of acoustic output, so wouldn't it require a large amount of acoustic input to generate any signal at all?

Re: Headphones can be hijacked to surreptitiously record audio

#120

Post by JimmyAustin »

mathiasben wrote: post #109
bcheung wrote: post #83

Here's a neat party trick for you. I had a MacGyver moment in the past where I made a phone call with only are pair of old earbuds and a phone cord (no switches, no dial pad). A speaker is basically the same thing as a microphone in reverse. Normally it takes an electrical signal to move a physical element that creates the sound waves. But you can also move the element and it will generate an electrical signal. To di…

I've used this before in a pinch too, speaker as a microphone in reverse. that got me wondering... would it be possible to use the same principle with another type of listening device. Focusing a laser beam on a window allows you to hear a conversation in the room. so could the same principle be applied and allow a laser beam to transmit audio?

I'm not 100% sure of the math involved, but I think any laser that impacts a window enough to vibrate it would probably just melt it instead.
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