gistfile1.pl

#!/usr/bin/perl -w

# Reads data from a Current Cost device via serial port.

use strict;
use Device::SerialPort qw( :PARAM :STAT 0.07 );

my $PORT = "/dev/ttyUSB0";

my $ob = Device::SerialPort->new($PORT);
$ob->baudrate(57600);
$ob->write_settings;

open(SERIAL, "+>$PORT");
while (my $line = <SERIAL>) {
    if ($line =~  m!<tmpr>\s*(-*[\d.]+)</tmpr>.*<ch1><watts>0*(\d+)</watts></ch1>!) {
        my $watts = $2;
        my $temp = $1;
        exec "rrdtool update /etc/cron.cc/rrd/powertemp.rrd N:$watts:$temp";
    }
}