[OLPC Networking] [Server-devel] RSSI value questions

[John Watlington]

On Apr 2, 2008, at 4:00 PM, Martin Langhoff wrote:

> On Wed, Apr 2, 2008 at 3:38 PM,  <david at lang.hm> wrote:
>>  the problem with trying to use sound is that it requres a clear  
>> path from
>> the servers to the laptops, something I would not expect to see  
>> very much.
>> it's also very sensitive to the direction the laptops are pointing.
>
> Absolutely, and the XS doesn't have mics, even less directional  
> mics ;-)

It's in that hole on the left hand side of the screen...

> The 802.11 signal will also have dirty paths in some directions.
> Strategic antenna location and signal timing is the only way I can see
> this working. It would be fantastic to have a simple thing to demo
> physics and maths based on such triangulation.

At 2.4 GHz, the interference between multiple paths makes
signal level measurement pretty useless for determining position.
If you do this to a number of spatially distributed access points,
you can improve the estimate...   This is how the Bluetooth Location
service works...

wad