Lock my screen with a smartcard

I bought a new Keyboard. A "Dell Smart Card Reader Keyboard" as the Name says it has a smartcard reader integrated in it. Now I wanted that if I pull the smartcard my screen locks and if I push it back in it unlocks. Here is the demon code to do so :

#!/usr/bin/perl

use ExtUtils::testlib;
use Chipcard::PCSC;
use Chipcard::PCSC::Card;

use Data::Dumper;

use warnings;
use strict;

my @mycard = [
            59,
            105,
            0,
            0,
            36,
            148,
            1,
            2,
            1,
            0,
            1,
            1,
            169
           ];

sub compare_arrays {
my ($first, $second) = @_;
no warnings;                  # silence spurious -w undef complaints
return 0 unless @$first == @$second;
for (my $i = 0; $i < @$first; $i++) {
  return 0 if $first->[$i] ne $second->[$i];
}
return 1;
}

sub checkCard(){
#-------------------------------------------------------------------------------
my $hContext = new Chipcard::PCSC();
return 1 unless (defined $hContext);

#-------------------------------------------------------------------------------
my @ReadersList = $hContext->ListReaders ();
return 1 unless (defined($ReadersList[0]));

#-------------------------------------------------------------------------------

my $hCard = new Chipcard::PCSC::Card ($hContext, $ReadersList[0]);
return 1 unless (defined($hCard));

#-------------------------------------------------------------------------------
my @StatusResult = $hCard->Status ();
return 1 unless (defined ($StatusResult[0]));

if (not compare_arrays(\@mycard ,\@{$StatusResult[3]})) {
  return 0;
}

#-------------------------------------------------------------------------------

$hCard->Disconnect($Chipcard::PCSC::SCARD_LEAVE_CARD);
undef $hCard;
#-------------------------------------------------------------------------------

$hContext = undef;

}

my $forked  =0;
daemonize();
while (1) {


# Device was found and command should be executed
if (checkCard()==0 && $forked == 1) {
  system("/bin/sh -c \"killall xscreensaver\"");
  system("/bin/sh -c \"xscreensaver -no-splash &\"");
  $forked =0;
}

# Device is gone and command should be executed
elsif ( (checkCard()==1) && ($forked != 1) ) {

  my $pid =fork();
  if ($pid == 0) {
    system("/bin/sh -c \"xscreensaver-command -activate\"");
    exit(0);
  }else{
    $forked = 1;
  }

}

sleep ( 2 );

}


# Become a daemon
sub daemonize
{
  chdir("/");
  close(STDIN);
  close(STDOUT);
}