On Monday, January 27, 2003, at 11:55 AM, Craig Pugsley wrote: I too am new to the listserv and the Jaguar dev tools. Hussain, would you like to try and do something together? My background is Java programming, so I'm really interested in Cocoa-Java. However, as far as I can see, there aren't any Bluetooth APIs written is Java. I would really like to write something along the lines of the Address Book.app (using the system-side address book API) functionality, but try to address some of the niggling issues I have with it: - If you have linked your mobile phone with Address Book.app (using the bluetooth button on the interface), everything is fine. The problems start if you move you phone out of range - at which point you have to re-connect your phone. --> I would have the app check for devices every couple of seconds if something was connected, should be connected, but for some reason isn't (i.e. the mobile has moved out of range). Unfortunately you won't be able to get anywhere near the time granularity that you want here. Bluetooth doesn't really provide a mechanism for proximity detection. To simulate that, you essentially have to page the device (either with a connect or name request command) over and over. The problem there is that while paging a device, no other Bluetooth connections can be created and existing connections will be slowed down to some extent. The paging process typically has a timeout of 15 seconds (long enough to more or less guarantee that if the device is in range that it will see the page). Additionally, because of lower layer timeouts in the hardware, in some cases its possible for the timeout to be even longer. So you end up with a period of at least 15 seconds (worst case - i.e. when the desired device is not present) where performance is degraded and no other connections can be created. There's also the lesser consideration of the power usage during paging. If you're on a laptop running on battery, its possible that could affect overall batter life (I do not have any hard data to support this however). In general its probably a bad idea to continuously look for a device when you don't expect it to be there. In practice, you'd only be able to look for the device every minute or so which wouldn't really give you the immediate behavior you want. In theory, the periodic inquiry functionality may be better suited to proximity detection, but typically cell phones don't support being discoverable all of the time. And even if they did, it would have a definite negative impact on batter life. Now given all of that, you're still welcome to try it out. I just wanted to warn you ahead of time so you know some of the pitfalls going in. - Eric _______________________________________________ bluetooth-dev mailing list | bluetooth-dev@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/bluetooth-dev Do not post admin requests to the list. They will be ignored.