DetectPhone

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                            detect_phone                         /||    |\
                         vvlachoudis@gmail.ch                     ||    |
                                2012                              `.___.'

About

detect_phone is a tiny little bash script that detects the presence of a person by pinging his bluetooth phone. If the person is in close range (<10m) then it kills the screen saver if any.

The problem

In my work I have set my linux desktop to start the screen saver locked with password after 1 min of inactivity. Many times per day I have to leave my office, which immediately locks the computer. When I return I have to type in my password... which becomes somehow annoying :)

The idea

I was thinking if there was a way to avoid all this password typing, just by detecting my presence in the office. Moreover, not to launch at all the screen saver if I am present and not working in front of the computer.

Solution

The solution was simple, a bash shell script, with an infinite loop, checking periodically if the screen saver is running (every 5s). If yes then ping my telephone's bluetooth (which has a short range ~5-10m), and if it replies then kill the screen saver.

I am using KDE with the kscreenlocker as screen saver. The program starts automatically in KDE by placing the program in the ~/.kde/Autostart. However it can easily be modified to work for any desktop environment (gnome, xfce, lxde...)

Future

More correct would be to incorporate this functionality inside the screen savers and not as a separate shell script...

Customize

For the moment there is not any initialization apart editing directly the script file. You have to modify the 3 lines

1. BTHW="xx:xx:xx:xx:xx" with the appropriate bluetooth hardware address you want to detect. To Find out your hardware address either you have to look on your phone's system settings, or by making it visible and scan it with the command $ hciconfig scan

2. LOCKPRG="xscreensaver" This script is limited to xscreensaver (it use some xscreensaver magic) You can check out original source: https://github.com/vlachoudis/DetectPhone But original source wont correctly work with xscreensaver

3. MIN_SIGNAL_STRENGTH=-11 Replace with bluetooth strength level (less is worse) on which we try to do "autounlocking" To check those levels set DEBUG=true & run script & watch for level index

4. SLEEP=5 Set the sleep time (seconds) for checking.

5. TIMEOUT_AFTER_LOCK=30 Delay in seconds after lock event

6. DEBUG=false Set true to get some additional info for adjusting setting to your case

Install

Autostart the program when login in the desktop enviornment

• KDE: Copy the programin the ~/.kde/Autostart/ directory
• GNOME:
• XFCE:
• LXDE:

Just start this script in background (setsid ./detect_phone.sh)