Bluetooth as proximity sensing problems

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Will Pearson

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May 16, 2011, 4:29:22 PM5/16/11
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As far as I can tell there is no way to force an android phone to
remain discoverable in bluetooth. So even though I think you should be
able to do discovery and maintain a serial connection, I don't think
you'll be able to do player sensing. Unless we pair everyone/thing at
the start of the game. Which is not really feasible being of the order
of n^2 connections ( n*(n+1) /2 to be precise).

We could still location based stuff with other bluetooth devices and
discovering them from the phone. Not quite sure what else we could do
indoors. Set every phone as an access point (probably only 2+?) and
get signal strength? Hmm scrub that doesn't look like you set peoples
phones up as AP automatically (understandably), unless we ndk? Which
means mesh networks are out as well.

Will

Bob Clough

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May 16, 2011, 4:36:50 PM5/16/11
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we could go the other way, force the *gun* to stay in discoverable mode?

Sam Cook

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May 16, 2011, 5:00:55 PM5/16/11
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would it be possible to use wifi strength for positioning given a suitably large number of wifi nodes?

</newb question>

S

Will Pearson

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May 16, 2011, 5:52:26 PM5/16/11
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On 16 May 2011 22:00, Sam Cook <sam.lind...@gmail.com> wrote:
> would it be possible to use wifi strength for positioning given a suitably
> large number of wifi nodes?
> </newb question>

If wifi strength was omni directional and dropped off reliably you
could do it with 3 (draw three circles the weaker the signal the
bigger, see where they intersect) I think. As it is not (due to walls
etc) you might be able to get a decent proximity warning by just
comparing signal strengths. E.g. if freds signal strengths are
3,5,6,9 and bobs are 3,6,7,9 they might be close, even if you don't
know where they are. It'd be worth experimenting with.

Will

Will Pearson

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May 16, 2011, 5:57:05 PM5/16/11
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On 16 May 2011 21:36, Bob Clough <par...@ivixor.net> wrote:
> we could go the other way, force the *gun* to stay in discoverable mode?
>

Hadn't thought of that. Hmm.

It should work, although it might up the power draw a lot.

Or have a very short range? I've noticed that arduino bluetooth
devices can come in different power draws/ranges. I'm not sure of the
ranges of the ones we have.

Will

Sam Cook

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May 16, 2011, 6:08:27 PM5/16/11
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I suppose it depends on how accurate we want it to be. 

Making it mildly unreliable might be quiet fun in and of itself...


S

tom

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May 17, 2011, 7:17:37 AM5/17/11
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its more than that though, we need the signal strengths really. I'll
have a play with android and see what I can pull out of it, I'm sure
I've done this before but might be wrong

If not then the proximity stuff will have to be IR beacons, which the
gun can then relay to the phone for processing

Bob Clough

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May 17, 2011, 7:24:59 AM5/17/11
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Just a question, but how necessary *is* proximity sensing?  Is it something we could cut for now, then have an add-on module for at a later date? 

tom

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May 17, 2011, 7:26:06 AM5/17/11
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not really, and its nothing that couldnt be bodged together with IR beacons

Just a nice thing to have that we can probably hack in later

Sam Cook

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May 17, 2011, 7:46:29 AM5/17/11
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We do have most of a year to poke this and develop it if we want it ready for makerfaire

S
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