Ultrasonic Networking via Web Audio | Hacker News Reader

Ultrasonic Networking via Web Audio

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51 pointsmmahemoff16 comments

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...

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

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

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?

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.

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 in sync.

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

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

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

That is interesting...assuming you can address individual devices and get some concept of relative position you can likely create some pretty interesting psychoacoustical effects with that many point sources. Probably highly dependent on being able to control relative latency though.

Actually what you speak isn't hard to do at all.

We have a long list of ideas (one you speak of and many more) we'll be shooting video of in the coming days and weeks.

We're thinking there are a ton of use cases and innovative/interesting things that can be done using http://SpeakerBlast.com :-)

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

Payment startup Clinkle is apparently using ultrasound in their app:

https://news.ycombinator.com/item?id=5964173

Is the title here misspelled? Ultasonic vs UltRasonic?

Sorry, updated that.

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....

It makes nasty clicky noises.

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

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