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Quietnet: Chat client that works over near-ultrasonic sound

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Re: Quietnet: Chat client that works over near-ultrasonic sound

#11

Post by STRML »

brownbat wrote: post #2

I'm glad people are realizing that radio waves aren't the only ways to send signals around a room. I really want someone to make a wireless, powerless keyboard where every key's click is tuned to a slightly different sound. Keylogging by acoustic emanations is a well researched technique, I just think it could be a feature if we made the keyboard right. https://www.schneier.com/blog/archives/2005/09/snooping_on_t...

Would be great, until you had more than one in a room - what a mess that would be.

Re: Quietnet: Chat client that works over near-ultrasonic sound

#12

Post by songzme »

Can this be accomplished on mobile devices? This could be a clever trick to implement interesting multiplayer games on train rides, airplanes, where wifi is not available.

From a quick research, it seems that iPhones are not able to play ultrasonic sound: "iPhone 4s is rated for 20Hz - 20,000Hz, which means it cannot generate ultrasonic frequencies." - http://stackoverflow.com/questions/10034346/ios-how-to-produ...

Re: Quietnet: Chat client that works over near-ultrasonic sound

#14

Post by mseebach »

songzme wrote: post #12

Can this be accomplished on mobile devices? This could be a clever trick to implement interesting multiplayer games on train rides, airplanes, where wifi is not available. From a quick research, it seems that iPhones are not able to play ultrasonic sound: "iPhone 4s is rated for 20Hz - 20,000Hz, which means it cannot generate ultrasonic frequencies." - http://stackoverflow.com/questions/10034346/ios-how-to-produ...

I would suspect those environments to be much too noisy for that to work.

Re: Quietnet: Chat client that works over near-ultrasonic sound

#16

Post by sp332 »

songzme wrote: post #12

Can this be accomplished on mobile devices? This could be a clever trick to implement interesting multiplayer games on train rides, airplanes, where wifi is not available. From a quick research, it seems that iPhones are not able to play ultrasonic sound: "iPhone 4s is rated for 20Hz - 20,000Hz, which means it cannot generate ultrasonic frequencies." - http://stackoverflow.com/questions/10034346/ios-how-to-produ...

Those "ratings" mean the sound will be distortion-free +/- 3dB over that range. You can still make some noise higher or lower than that, it will just be more distorted. I know iPhones support audio formats with at least 96 kHz sample rate, so you should be able to play half that or 48 kHz sounds without too much trouble. It might have some kind of band-pass filter built in, but the ratings won't tell you.

Re: Quietnet: Chat client that works over near-ultrasonic sound

#17

Post by jbanon »

songzme wrote: post #12

Can this be accomplished on mobile devices? This could be a clever trick to implement interesting multiplayer games on train rides, airplanes, where wifi is not available. From a quick research, it seems that iPhones are not able to play ultrasonic sound: "iPhone 4s is rated for 20Hz - 20,000Hz, which means it cannot generate ultrasonic frequencies." - http://stackoverflow.com/questions/10034346/ios-how-to-produ...

This operates within that range at 19K, which is well above what most adult humans can hear: https://github.com/Katee/quietnet/blob/master/options.py#L2

That's not to say it would work on an iPhone.

Re: Quietnet: Chat client that works over near-ultrasonic sound

#18

Post by songzme »

songzme wrote: post #15

Just installed and tried all the necessary packages, but for some reason it simply doesn't work. Here's a screenshot: http://cl.ly/image/180b0k3X332g I'm using a retina macbook pro 15 inches

Tried again, this time I get an 'o'. http://cl.ly/image/0e1A2c2i1Y16

Re: Quietnet: Chat client that works over near-ultrasonic sound

#19

Post by amitparikh »

mseebach wrote: post #14
songzme wrote: post #12

Can this be accomplished on mobile devices? This could be a clever trick to implement interesting multiplayer games on train rides, airplanes, where wifi is not available. From a quick research, it seems that iPhones are not able to play ultrasonic sound: "iPhone 4s is rated for 20Hz - 20,000Hz, which means it cannot generate ultrasonic frequencies." - http://stackoverflow.com/questions/10034346/ios-how-to-produ...

I would suspect those environments to be much too noisy for that to work.

Unless it's noisy at or near the desired communication frequency, it is trivial to isolate the signal and completely mute out the noise.

In this example, at ~19 kHz, a properly configured high-pass filter could easily remove any human-talking sounds.

Re: Quietnet: Chat client that works over near-ultrasonic sound

#20

Post by mcb3k »

songzme wrote: post #18
songzme wrote: post #15

Just installed and tried all the necessary packages, but for some reason it simply doesn't work. Here's a screenshot: http://cl.ly/image/180b0k3X332g I'm using a retina macbook pro 15 inches

Tried again, this time I get an 'o'. http://cl.ly/image/0e1A2c2i1Y16

Are you sending and receiving on the same computer? I feel like that might cause issues. Are you able to use two separate computers to test?
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