My home automation

#!/usr/bin/perl

system( "logger 'HAL - dmx_prod_rebooted' ");

$inc_up = 5 ;
$inc_down = 5 ;
$min_intensity = 70 ;
while (true)
{
   use Device::SerialPort ;
   my $port = Device::SerialPort->new("/dev/ttyAMA0") ;

   $port->baudrate(9600) ;    $port->parity("none") ;
   $port->handshake("none") ; $port->databits(8) ;
   $port->stopbits(1) ;       $port->read_char_time(0) ;
   $port->read_const_time(1) ;

   #Set Status's
   @files = <dmx_set_*.txt> ;

   foreach $file (@files) {

      $channel = $file ; $channel =~ s/.txt// ;
      $channel =~ s/dmx_set_// ;
      chomp($channel) ;

      open (FILE, $file) ;
      $intensity = <FILE> ;
      close (FILE) ;
      chomp ($intensity) ;
      if ( $intensity > 255 ) { $intensity = 0 } ;
      if ( $intensity < $min_intensity ) { $intensity = 0 } ;

      if ( ${variable_."$channel"} != $intensity )
      {
         if (${variable_."$channel"} < $intensity )
         {
            $set_intensity = ${variable_."$channel"} + $inc_up ;
            if ( $set_intensity < $min_intensity )
            {
               $set_intensity = $min_intensity ;
            }
         }

         if (${variable_."$channel"} > $intensity )
         {
            $set_intensity = ${variable_."$channel"} - $inc_down ;
         }

         $port->write( pack "C", $channel ) ;
         $port->write( pack "C", $set_intensity ) ;
         system( "logger 'HAL - dmx_lighting_set $channel - $set_intensity' ");
         ${variable_."$channel"} = $set_intensity ;
         select(undef, undef, undef, 0.05) ; #Sleep a bit

      }
   }
   $port->close() ;
   select(undef, undef, undef, 0.1) ; #Sleeep 100 mS
}