Processing 1.0 - Processing Discourse - Bluetooth Signal Strength

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Index › Programming Questions & Help › Programs › Bluetooth Signal Strength

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Bluetooth Signal Strength (Read 1512 times)

claude

Bluetooth Signal Strength
Aug 19^th, 2009, 6:44am

Hi,

I am currently working on my bachelor thesis project.
It will be kind of an exhibition with dynamic images.

Therefore I want to (roughly) locate the people in the room based on the bluetooth signal strength of their mobile phones.

(Any hints on how) is this possible?
I experimented with the bluetoothDesktop library, but it seems like it is only possible to check whether there is a bluetooth enabled device or not...

I could use several mac minis w/ bluetooth or some arduino boards.

Thanks for your input,
Claude

claude YaBB Newbies Offline Posts: 4	Re: Bluetooth Signal Strength Reply #1 - Aug 19^th, 2009, 6:45am Hm sorry for the double-post. I got an error in favorites.pl or similar, if I checked the "Add to Favorites" checkbox...?!

Cedric YaBB Moderator Offline Posts: 1838	Re: Bluetooth Signal Strength Reply #2 - Aug 19^th, 2009, 7:10am Maybe you can delet the other posts. your project, is it about the location of the people or about bluetooth? Cause i believe there are better ways to "roughly" locate them as with bluetooth strength if this is not what your thesis will be about.
	twitter.com/CedricKiefer

PhiLho YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: Bluetooth Signal Strength Reply #3 - Aug 19^th, 2009, 7:40am You can go to your extra posts and delete them from there. Not sure if you can reliably triangulate people positions from such information in a small space. Have you researched if it has been done before? Of course, it also suppose people have a phone, with Bluetooth, activated (they can activate it if asked, of course).

blindfish

Re: Bluetooth Signal Strength
Reply #4 - Aug 19^th, 2009, 10:06am

I think there's a certain amount of latency involved in using Bluetooth, particularly at the initial stages where the mobile device is synchronising. It may also require user interaction to make it happen... and then there's still the question as to whether it's actually feasible. I'd be concerned about signals bouncing off (or having to pass through) walls, bodies etc... I suspect it would be very hard to track people, even roughly. I looked into a similar concept using wireless: in theory possible, and I'm sure it's been done, but in practice it was very difficult to implement because of the erratic nature of the signals involved.

Unless Bluetooth is an integral part of your research I suspect there are much better options out there to do this...

Where is the what if the what is in why?

claude

Re: Bluetooth Signal Strength
Reply #5 - Aug 20^th, 2009, 10:26am

My project is about the location, the techniques I use are up to me.
I first thougth about RFID, but time is running and using some small PCs with bluetooth built-in seems to be much easier. Especially as I am not that into soldering, Arduino etc...

I know, that this only works if the users have bluetooth enabled on their phones, but as I said technique doesn't matter - it's rather a proof of concept. And I need to get it done Wink

The Location is small, just about 10 to 12m along a wall. So with 3 PCs I can cover the area well.
(If I limit the space behind the users, so that the depth of the room plays no role)
And there are no walls or other signal-distracting objects.

Bluetooth Tracking has been done (in a much larger scale):
3w techradar dot com /news/phone-and-communications/mobile-phones/festival-fans-tracked-by-bluetooth-
scanners-613562 (Remove spaces and insert dots, I am not allowed to post URLs, yet...)

With bluetoothDesktop I already managed to detect phones - without user interaction. It just needs to be turned on, of course.
But bluetoothDesktop provides no information about the signal strength...

Of course I am open to every solution using bluetooth or not,
but for me it seems the easiest, and more important fastest, way to use existing technology...
I googled before posting, but could'nt find other bluetooth libaries, do you know any?

blindfish

Re: Bluetooth Signal Strength
Reply #6 - Aug 20^th, 2009, 11:16am

I'm still sceptical - the link you posted looks like a very different setup: it's over a large area so they probably just tracked when people passed within range of the individual bluetooth sensors and collated the data from all the sensors to get people's movement over time. That's very different to using signal strength to determine position.

In a small space like the one you're using I'd much rather use something like video - e.g. a camera from above if the room is high enough - or floor sensors. Probably much more straightforward to implement and probably much more reliable... and both are proven methods of doing this kind of thing.

It's a shame it's not an outdoor project - you'd probably also get the accuracy you need using GPS.

Edited:

Actually here's a link (PDF) to a paper describing a project that uses video tracking. See section 4.4.

Where is the what if the what is in why?

Cedric YaBB Moderator Offline Posts: 1838	Re: Bluetooth Signal Strength Reply #7 - Aug 20^th, 2009, 11:36am i would recommend video tracking as well...
	twitter.com/CedricKiefer

claude

Re: Bluetooth Signal Strength
Reply #8 - Aug 22^nd, 2009, 10:21am

I share your concern, regarding the bluetooth case - it's a much larger szenery, so maybe they just tracked if the person is in the radius of a tracking device or not...

Hm, I thought about video tracking before.
Sure thing it's easier to implement, since it has be done before.

But the room height is only about 2,5m, therefore I would need several cameras for video tracking.
Is it possbile to merge these video streams to one big tracking stream?
Thought about using several PS3 Eye Cams, because they offer 75° FOV and high FPS rates at a reasonable price.

Do you think it is possible to identify a unique person moving without markers on their heads?
Just based on "size" and maybe color of their clothes...?

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