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Wearable Microphone Jamming

sandlab.cs.uchicago.edu

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Re: Wearable Microphone Jamming

#121

Post by wolrah »

speedybird wrote: post #110
dylan604 wrote: post #99

Earlier quoted context omitted.

It's almost like you missed the point. The cops are playing music because someone else is recording them. That is the counter surveillance.

Copyrighted music won't prevent video of cops breaking the law from being used in court, so don't let that tactic dissuade you from recording the police.

Right, but it does help them keep videos from being spread as easily if they get taken down. It sure does seem like the only reason cops ever get punished is public pressure, which relies on people seeing the video.

Re: Wearable Microphone Jamming

#122

Post by thatguy0900 »

Fnoord wrote: post #120
joshstrange wrote: post #118

Earlier quoted context omitted.

> 'Their own gain', the police work for the public interest. If that isn't the case, something is wrong with your police force. I agree. Something is very wrong with our police force. Also, it might not be allowed anywhere in the world but it absolutely happens in most of not all places (police getting away with tampering with evidence).

If we cannot keep people who are supposed to protect us accountable (even via a trusted third party like internal affairs [1]) we as society have a problem. And we do have a problem: a problem of trust, at the very least. I'd like to think they do get caught, and I'd also like to think most cops in society can be trusted . There's dirty (and I use that word liberally) cops everywhere in the world, yes, also in The Ne…

the fundamental problem is that the majority of good cops dont rat out the minority of bad cops, either out of a sense of brotherhood or because theyll will face retaliation if they do. The "rotten apples" saying, of course, is that a few rotten apples spoiles the whole bunch. Good cops don't just suddenly snap one day and commit corrupt acts out of nowhere, the people they work with know what they are like and what they do.

Re: Wearable Microphone Jamming

#123

Post by system2 »

AlbertCory wrote: post #78

How about camera jamming with UV (for example, on your car's license plate)? I imagine this has been discussed on HN before (if so, just send me the link),

Or buy the super dark glass like plate cover just like the ghetto Los Angeles people use.

Re: Wearable Microphone Jamming

#124

Post by system2 »

dtgriscom wrote: post #69
foreigner wrote: post #57

It's illegal for movie theaters to jam cell phones. If this actually works and becomes popular, I don't imagine it would take too long before this became illegal too.

It is illegal to jam a cell phone's EM signals, and it isn't because of the jamming's effects on the specific phones, but because of the jammer's unauthorized transmissions in regulated radio frequencies. The FCC takes their job fairly seriously, especially when someone makes a product that is designed to break their regulations. But, the FCC has no jurisdiction over sound.

>the FCC has no jurisdiction over sound.

Until they need to.

Re: Wearable Microphone Jamming

#125

Post by ris »

Raidion wrote: post #96
ris wrote: post #79

Earlier quoted context omitted.

But you could surely just randomly vary the beamforming to get the same effect, right?

Beam still has to be in the direction of the mic, which wouldn't help if your body is blocking most of the direct waves. You get some scattering, sure, but I think ultrasonic is pretty absorbable, right?

But the same is also true for rotating the bracelet isn't it?

Re: Wearable Microphone Jamming

#127

Post by psd1 »

ziml77 wrote: post #49
4k4ndr wrote: post #43

Earlier quoted context omitted.

I am curious about ANC as well. I used to wear headphones with ANC 8h+ a day and started to hear noise in my ear.

I don't see why that would happen. ANC plays an inverted signal to counter noises. It's not just perception that it makes sound quieter. When the original sound wave and counter sound wave collide they physically cancel out.

Right, that's the ideal case. What might happen is that you get incomplete cancellation that varies with frequency; so you might get higher sound pressure at certain frequencies.

Re: Wearable Microphone Jamming

#128

Post by Johnythree »

soylentnewsorg wrote: post #106
Johnythree wrote: post #35

Earlier quoted context omitted.

It just relies on cheap microphones being fairly non-linear. A quality microphone, with a decent low-pass-filter would be immune to this kind of hack. Think about it, why aren't our ears affected?

> why aren't our ears affected they're affected listening to the raw microphone capture. that's because the noise generated is much louder than the speech. so listening to raw microphone capture with this thing on, you can't make out words at all - just a few syllables here and there. the key is that the full voice signal is still captured by the microphone. you then filter out the additional noise (your conference s…

> they're affected listening to the raw microphone capture.

Well, of course.

But I was talking about listening directly, not via a microphone.

The whole point of the device that the white noise is not evident to listeners in the vicinity. If it was, people would not be able to speak to each other.

Which means that it's caused by intermodulation in the crappy microphone. Therefore a better quality mike (and a LPF) would remove it.

Re: Wearable Microphone Jamming

#129

Post by pepoluan »

ris wrote: post #125
Raidion wrote: post #96

Earlier quoted context omitted.

Beam still has to be in the direction of the mic, which wouldn't help if your body is blocking most of the direct waves. You get some scattering, sure, but I think ultrasonic is pretty absorbable, right?

But the same is also true for rotating the bracelet isn't it?

The bracelet does not have directional speakers, so the ultrasonic waves will kind of spread everywhere, bouncing off hard surfaces, and ultimately reaches the eavesdropping device.
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