bluetooth signal strength (RSSI)

[Vishal]

hi
i'm developing an application for bluetooth local positioning system
based on the signal strength(RSSI values) in windows.
however i'm not able to find any stack or plugin for getting the RSSI
value in windows. does any of u know how to get the signal strength of
various
bluetooth agents from a windows platform?
regards
vishal

[ErisDS]

Most of the stacks, except for the Microsoft one have an
implementation that allows you to access the RSSI value

I tried to do a local positioning project last year using BlueSoleil
and programming in C++, unfortunately the RSSI value as reported by
Bluetooth is not robust.
I found I was getting values like 0 or 100 and nothing between, there
is not enough resolution or variation in the reported signals to
accurately locate a device.

WIFI on the other hand reports it's RSSI much more robustly and I used
that instead.

I'd be interested to hear if you get Bluetooth working with
positioning and what hardware you are using if you do!

Eris

[Vishal]

hey ya i'm workin on a localisation project too. wat algo or formula
did you use for calculating distance and the position?

[ErisDS]

Like I said, there was no way to do this using Bluetooth RSSI, as my
devices only ever reported extreme values and there was no resolution
with which to calculate localisation except for "in range" and "not in
range" !!

I ended up using the WiFi RSSI value and using a footprint matching
algorithm, whereby data was recorded as a footprint model of what the
signals looked like when a device was in a particular area (I used a
grid of one metre squares) and then live data was matched to the
model.

It worked perfectly for my needs and appeared to be very accurate (I
think I recorded something like 85% accuracy).

My project was done in C# using OpenNETCF.

[Vishal]

ohh... ya the values are highly unreliable.. but my part in the
project is to jus get the RSSI values using java on a windows
platform.. is it possibl? u hav any links or examples for it??