Indoor Positioning System Tracks Your Phone Using Sound Waves | Hacker News Reader

Indoor Positioning System Tracks Your Phone Using Sound Waves

motherboard.vice.com

40 pointschmaynard14 comments

Interesting idea - beacons provide 3d tracking. There used to be a product that tracked a 3d pen using three long microphone tubes in a Cartesian arrangement. The pen sparked, the microphones received the 'tick', and the relative timing determined the pen position. My brother used it back in the 90's to measure finger position on cadavers in a 'hand research' lab (research used to create more useful artificial limbs).

This article gave me a notion: how about a 'sonar' app for your phone? Transmits tics and times their return, maybe plays a tone to give you an idea of distance to obstacle. For the blind?

Interesting idea! A quick google search shows there is at least one Android app, but they have the trouble of supporting multiple Android devices (some of which don't have the necessary hardware).

My assumption would be that potential users need an app that would work 99% of the time, but this might be a very interesting side project none the less.

Yeah this app has been around forever, iirc I used it on the original G1! (Or N1? It was a long time ago.) One issue they have is that for optimal accuracy, you need raw access to the multiple microphones but the manufacturer uses the mics to perform audio scrubbing before the data gets to the app.

Can you point to app, please?

https://play.google.com/store/apps/details?id=com.dicon.sona...

Last updated in 2012...

isnt that how whiteboard trackers work (in 2d)? teardown of one https://www.youtube.com/watch?v=qfEOjfzYoVI

There are several companies trying to do indoor gps with blue tooth low energy beacons.

http://indoo.rs/ and yc company http://estimote.com/ also see Apple's iBeacon.

i have never been able to get these devices to work well enough for gps type apps. so glad to see someone is trying a new approach.

We are also, https://flair.co, but more room occupancy than navigation. Navigation and trilateration with any accuracy is incredibly difficult.

I'd be curious to hear what the challenges are. Is it simply that signal strength is too noisy to be used reliably? (I.e., interference, multipath, attenuation when the subject walks behind furniture, etc.)

I was attending a theatre show a few days ago, and thought that the sound system could deliver a better experience if the positions of mics on stage could be tracked as cast moves around, and the mixing adjusted accordingly. Naturally, BLE was the first thing that came to mind.

There are a lot of things. The device's antenna pattern and orientation are a big part. Metal in/around any of the devices. Signal/Noise. etc. You can try to improve with a lot of calibration but it will also be subject to noise from every audience members bluetooth radio too.

Afaik these guys have a very well working solution based on WiFi signals http://www.walkbase.com

They started with the "indoor location app for people" idea, but later found a business when the phones are just being tracked for store etc. layout optimization.

Wasn't this in the Batman movie?

This has existed for at least a decade http://cricket.csail.mit.edu/

And here http://www.mccormick.northwestern.edu/news/articles/archive/...

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