Return-Path: Date: Wed, 4 Oct 2006 21:29:55 -0300 From: Cris To: bb.bluez@magitech.org, BlueZ users Message-Id: <20061004212955.cc67bc36.ml133@netpole.com.br> In-Reply-To: <4910207664.20061004141916@magitech.org> References: <4910207664.20061004141916@magitech.org> Mime-Version: 1.0 Cc: Bluez-users@lists.sourceforge.net Subject: Re: [Bluez-users] Automatic Object Pushing when Devices Enter Range Reply-To: BlueZ users List-Id: BlueZ users List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Sender: bluez-users-bounces@lists.sourceforge.net Errors-To: bluez-users-bounces@lists.sourceforge.net On Wed, 4 Oct 2006 14:19:16 -0700 bb.bluez@magitech.org wrote: > Hello all! > > I'd really like is a way to register or specify a script to be called > whenever a device comes within range. I'd expect the script to be passed the > address of the device, allowing me to interrogate it regarding it's > capabilities, and so forth. > > The alternative is, of course, to call "hcitool scan" every few seconds, > compare with a log of the known or seen ID's, and process from there, but as > we were all taught in grammar school CS, polling is bad mm'kay. The way bluetooth allows to discover nearby devices will not allow to avoid some sort of polling: One device needs to be in inquiry scan mode, the other needs to do an inquiry; one needs to be trying to receive an inquiry signal, the other must send it. It depends a bit on the volume of traffic you expect here. If you don't expect ever more than a few devices per hour and can accept not to send the file to more than one device at the same time, you can use the 'inq' command to hcitool. At least the last time I checked, the 'scan' command to hcitool is misnamed. It's reall only an inquiry with a subsequent request for the remote name (more work to do for bluetooth and thus more time lost for data traffic); hcitool 'scan' has nothing to do with a `scan' in bluetooth terminology, which is the listening of the device for inquiry or page attempts. Anyway, unless you want to log those `userfriendly' names, it's useless in an unattended situation. In this case of very low and limited traffic, you could write this using as a script, but you are likely to run into problems in the area of authentication (pin codes) for the way bluez handles things. As volume of traffic grows, the bluez becomes inappropriate: Bluetooth's basic concepts are event-oriented and designed for small and/or embedded devices. Both are defeated by bluez: The library locks in a select loop while waiting for the answering event (rather than let the application do this, which could handle other things in the meanwhile), and the use of dbus is certainly not for small devices (just look at the huge amount of libraries pulled in for installing dbus). You can get around the lock by forking each command, but then, you need to do some IPC which is much more complicated than really needed. In the end, a solution for some a bit more serious traffic will require you to write this in a language like C. Either you use the lower level functions in the bluetooth library, avoiding that loop, or you write it all by yourself from scratch (my choice). But in this situation, you still might want to consider using two (or more) bluetooth radios, using one only in periodic inquiry mode, as you can not detect a nearby device while transmitting the file. HTH -- Cris ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Bluez-users mailing list Bluez-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-users