
Ultrasonic Networking via Web Audio - mmahemoff
http://smus.com/ultrasonic-networking/
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jared314
The same technique was used in the first TV remotes[0]. It drove people with
good hearing nuts, had interference issues with natural phenomena, and had
fundamental bandwidth limitations.

Otherwise, it is a cleaver hack around the lacking device-to-device wireless
support.

[0]
[http://en.wikipedia.org/wiki/Remote_control#Television_remot...](http://en.wikipedia.org/wiki/Remote_control#Television_remote_controls)

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kumar303
FYI, Web Audio is about to land in Firefox 25
[https://bugzilla.mozilla.org/show_bug.cgi?id=779297](https://bugzilla.mozilla.org/show_bug.cgi?id=779297)

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dave1010uk
This looks similar to what [http://chirp.io/](http://chirp.io/) is doing, only
more open. It's great to see interesting advancements like this, especially
using web technologies.

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stephengillie
Cool! I'm wondering how this could be used (or interfere) with a Parallax
Ultrasonic Ping sensor for Arduino and other microprocessors. Maybe attaching
the Ping sensor to a RasPi's GPIO (general purpose in/out) pins will allow for
ultrasonic RasBMC remote?

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mbell
Doubtful, any purpose built ultrasonic sensor will likely be running at much
higher frequencies than you can play with via a standard audio chain. The Ping
for example runs at 40khz but the most you'll get out of a standard issue
audio chain is ~20-24khz, depending on the corner frequency of the analog
filters on the input / output and driver / mic response.

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paul9290
Very cool! A lot can be done with the web audio API.

We used it to sync audio across devices to create one huge stereo; all play
same audio in unison.

Here's a demo vid of 50 people & their devices blasting a public domain song
[http://vimeo.com/71647538](http://vimeo.com/71647538) in sync.

We're a bit weary of blasting the "good," music across devices in any demo due
to the public perfomance copyright act.

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chaser7016
That's 50 peoples' smartphones or smartphones, tablets and laptops all playing
at once?

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paul9290
It was a mix of conference attendees' iPhones & iPads. I didn't instruct
anyone to use Chrome on their laptops.

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danpeddle
The same concept is currently being used by the Hex3 JAJA stylus to
communicate pressure information - it is really quite elegant.
[http://www.hex3.co/products/jaja](http://www.hex3.co/products/jaja)

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gojomo
Payment startup Clinkle is apparently using ultrasound in their app:

[https://news.ycombinator.com/item?id=5964173](https://news.ycombinator.com/item?id=5964173)

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Pwntastic
Is the title here misspelled? Ultasonic vs UltRasonic?

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mmahemoff
Sorry, updated that.

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angersock
Very cool!

In undergrad I made a super-ghetto optical frequency-multiplexed parallel
port; it hadn't occurred to me to do the same with web audio.

Hmm....

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moocowduckquack
It makes nasty clicky noises.

edit - at least, the emoticon demo on a macbook air does.

