autolock

#!/bin/bash

SESS_PROC=`pgrep gnome-session -n -U $UID`
SESS_PROC_ENV="/proc/$SESS_PROC/environ"
export `xargs -0 -a $SESS_PROC_ENV`

# Your phone bluetooth mac address
PHONE_MAC="64:A2:F9:84:AA:54"
# Less means it actives at a smaller distance
SIGNAL_THRESHOLD=15
# Less means it will lock faster (beware it gives you less time to act if there is a problem with this script)
REFRESH_INTERVAL=10

INITIAL_CONNECTION=`hcitool rssi $PHONE_MAC 2>&1`

while [ "$INITIAL_CONNECTION" = "Not connected." ]
do
    notify-send -u normal "phone never connected, autolock will stay disabled until connected"

    sleep 30
    INITIAL_CONNECTION=`hcitool rssi $PHONE_MAC 2>&1`
done

notify-send -u normal "phone connected, autolock will start monitoring signal strength"

while true
do
    SIGNAL_WEAKNESS=`hcitool rssi $PHONE_MAC | tr -dc '0-9'`

    if [ $SIGNAL_WEAKNESS -lt $SIGNAL_THRESHOLD ]; then
        echo "phone is near"
        sleep $REFRESH_INTERVAL
    else
        echo "phone is far"
        gnome-screensaver-command --lock
        # gives 60 seconds to troubleshoot if lock is unwanted
        sleep 60
    fi

    echo
done