BLUEZ: How to determine if known device is reachable
 

Hi,

I'm trying to use bluetooth to determine what devices are around me (context awareness). For this purpose I use bluez api in a way that I turn bt on, start device scanning and than I catch signals DeviceFound. The problem is that this signal is emitted only if devices are not paired. If for example I have my computer which has been paired with my phone I won't get signal that this device has been found.

The question is: how can I determine if known devices are in range (in a nice way :) ) - any ideas?

My first idea was to try to connect to every possible known device and catch errors but this is not the thing...


Thank you for your answers,
Best regards,
Skomialek

Re: BLUEZ: How to determine if known device is reachable
 

An acceptable way would be to ping it but that would still be polling. Unless all known devices are instructed to reconnect automatically, I guess you can't rely on a passive notification.

Re: BLUEZ: How to determine if known device is reachable
 

Is there any way to simply 'ping' the device using bluez api (I mean without manual connect/disconnect procedure)

Re: BLUEZ: How to determine if known device is reachable
 

I suppose you could look at BlueProximity ...

Re: BLUEZ: How to determine if known device is reachable
 

Thanks, but I'm not looking for a desktop app. What I'm trying to do is to make maemo based device aware what BT devices are in its range :)

Re: BLUEZ: How to determine if known device is reachable
 

You can simply do a bluetooth scan ... which will give you a list of device at promity with their mac address ... store this and compare.

Re: BLUEZ: How to determine if known device is reachable
 

Only ones which are set to discoverable. Even if you're paired, but the other device is not discoverable, you won't see it this way.

Since non-discoverable devices will only respond to direct requests, the only way to see them is with direct requests such as L2CAP echo requests (aka bluetooth ping.) Sure, this is polling, but repeated scans are also a form of polling.

Re: BLUEZ: How to determine if known device is reachable
 

I was thinking that you could look the source code ...

Re: BLUEZ: How to determine if known device is reachable
 

yes ... this is what i've been do' . it turns out that it lists paired devices but doesn't list connected ones (but those I can check in device properties) . The problem was probably in my other phone's bt power saving properties. If I leave the phone and don't use it it doesn't get detected ... when I was angry that it doesn't get detected I simply removed pairing on both devices and this way bt got awaken :)...

sorry for bothering you... problem solved (actually it's never existed..)

Best regards,
Skomialek

Re: BLUEZ: How to determine if known device is reachable
 

http://blueproximity.svn.sourceforge...py?view=markup

It seems to establish an rfcomm connection to the known device, in order to get the signal strength (RSSI) and make an estimation of the distance to the device.