Linux/Ubuntu/BluetoothLoginAndLocking – TJworld
http://tjworld.net/wiki/Linux/Ubuntu/BluetoothLoginAndLocking
That led me to searching for some bluetooth tools and I discovered two absolute winners. The first is a #Gnome applet called BlueProximity that automatically locks and unlocks the system based on how far away a #Bluetooth device is. The second is a bluetooth Pluggable Authentication Module (PAM) for authentication based on the presence of a Bluetooth device.
The result of using both is that I can now log-in and automatically have the screen lock/unlock (and run other commands) based on the presence of my mobile phone. Seeing as it is usually in my pocket this means if I walk away from the PC I don’t need to remember to manually lock the screen.