Difference between revisions of "Code/tp-theft-lcars"
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Revision as of 23:28, 13 November 2010
#!/usr/bin/perl # tp-theft-lcars v0.1 (http://thinkwiki.org/wiki/Script_for_theft_alarm_using_HDAPS) # This script uses the HDAPS accelerometer found on recent ThinkPad models # to emit an audio alarm when the laptop is tilted. In sufficiently # populated environments, it can be used as a laptop theft deterrent. # # This file is placed in the public domain and may be freely distributed. # # Here comes a modified version which requires an internet connection and gnash. # It shows a LCARS red alert flash animation from Star Trek Voyager instead of a beep. use strict; use warnings; ############################## # Audio volume (0..100) my $volume = 70; my $play_cmd = "gtk-gnash --fullscreen http://www.lcars.org.uk/lcars_files/LCARS_prey_emergency_scan_analysis.swf"; ############################## # Other tweakables my $thresh = 0.20; # tilt threshold (increase value to decrease sensitivity) my $interval = 0.1; # sampling interval in seconds my $depth = 10; # number of recent samples to analyze my $pos_file='/sys/devices/platform/hdaps/position'; my $verbose = 1; ############################## # Code sub get_pos { open(POS,"<",$pos_file) or die "Can't open HDAPS file $pos_file: $!\n"; $_=<POS>; m/^\((-?\d+),(-?\d+)\)$/ or die "Can't parse $pos_file content\n"; return ($1,$2); } sub stddev { my $sum=0; my $sumsq=0; my $n=$#_+1; for my $v (@_) { $sum += $v; $sumsq += $v*$v; } return sqrt($n*$sumsq - $sum*$sum)/($n*($n-1)); } my (@XHIST, @YHIST); my ($x,$y) = get_pos; for (1..$depth) { push(@XHIST,$x); push(@YHIST,$y); } my $alarm_file; # flags ongoing alarm (and stores saved mixer settings) while (1) { my ($x,$y) = get_pos; shift(@XHIST); push(@XHIST,$x); shift(@YHIST); push(@YHIST,$y); my $xdev = stddev(@XHIST); my $ydev = stddev(@YHIST); # Print variance and history print "X: v=$xdev (".join(',',@XHIST).") Y: v=$ydev (".join(",",@YHIST).")\n" if $verbose>1; my $tilted = $xdev>$thresh || $ydev>$thresh; if ($tilted && !(defined($alarm_file) && -f $alarm_file)) { print "ALARM\n" if $verbose>0; $alarm_file = `mktemp /tmp/hdaps-tilt.XXXXXXXX` or die "mktemp: $?"; chomp($alarm_file); system('/bin/bash', '-c', <<"EOF")==0 or die "Failed: $?"; ($play_cmd) & EOF } select(undef, undef, undef, $interval); # sleep }