shantz-locker.sh

#!/bin/bash
# Shantz Webcam Autolocker
# A simple, useless script to monitor motion in front of your PC, autolock it when you are away and autounlock it when you come back.
# Kinda useless cuz there is no security and any kind of motion triggers the unlock.
# But still if you like it, then give me a shout at http://tech.shantanugoel.com or http://blog.shantanugoel.com
# The home page for this script is at http://tech.shantanugoel.com/shantz-webcam-autolocker

#Usage: ./shantz-locker [-l <LockThreshold>] [-u UnlockThreshold] [-s LockScanInterval] [-t UnlockScanInterval]
#LockThreshold - Determines the threshold (based on no. of samples sans motion) to lock your PC. Default is 5
#UnlockThreshold - Determines the threshold (based on no. of samples with motion) to unlock your PC. Default is 2
#LockScanInterval - How soon to check if there is motion when your PC is in unlocked state. Default interval is 5 seconds
#UnlockScanInterval - How soon to check if there is motion when your PC is in locked state. Default interval is 2 seconds


motion_sample_cnt=0
motion_sample_max=2
gap_sample_cnt=0
gap_sample_max=5
sleep_time_lock=5
sleep_time_unlock=2

while getopts "l:u:s:t:" flag
do
    case $flag in
    l)  echo "Updating Lock Threshold to $OPTARG"
        gap_sample_max=$OPTARG
        ;;
    u)  echo "Updating Unlock Threshold to $OPTARG"
        motion_sample_max=$OPTARG
        ;;
    s)  echo "Updating Lock Scan Interval to $OPTARG"
        sleep_time_lock=$OPTARG
        ;;
    t)  echo "Updating Unlock Scan Interval to $OPTARG"
        sleep_time_unlock=$OPTARG
        ;;
    ?) printf "Usage: %s [-l <LockThreshold>] [-u UnlockThreshold] [-s LockScanInterval] [-t UnlockScanInterval]\n" >&2
        exit 2
        ;;
    esac
done
#echo "$motion_sample_max $gap_sample_max $sleep_time_lock $sleep_time_unlock"

wm=`printenv | grep GNOME_DESKTOP_SESSION_ID`
if [ -n "$wm" ]
then
lock_cmd="gnome-screensaver-command -l"
unlock_cmd="gnome-screensaver-command -d"
else
lock_cmd="xscreensaver-command -l"
unlock_cmd="xscreensaver-command -d"
fi

state=0
curr_time=0
last_time=0
#0 is unlocked 1 is locked

while [ 1 ]
do
    curr_time=`date +%s -r autolock_motion.jpg`
    if [ $curr_time -eq $last_time ]
    then
    gap_sample_cnt=`expr $gap_sample_cnt + 1`
    #echo "increment gap $gap_sample_cnt"
    else
    motion_sample_cnt=`expr $motion_sample_cnt + 1`
    #echo "increment motion $motion_sample_cnt"
    fi

    if [ $gap_sample_cnt -ge $gap_sample_max ]
    then
    gap_sample_cnt=0
    motion_sample_cnt=0
    if [ $state == 0 ]
    then
    state=1
    `echo $lock_cmd`
    #else
    #echo "reset motion ctr"
    fi
    fi

    if [ $motion_sample_cnt -ge $motion_sample_max ]
    then
    motion_sample_cnt=0
    gap_sample_cnt=0
    if [ $state == 1 ]
    then
    state=0
    `echo $unlock_cmd`
    #else
    #echo "reset gap ctr"
    fi
    fi

    if [ $state == 0 ]
    then
    sleep $sleep_time_lock
    #echo $sleep_time_lock
    else
    sleep $sleep_time_unlock
    #echo $sleep_time_unlock
    fi

    last_time=$curr_time
done