Wednesday, September 18, 2013

Heating control weather compensation

This time of year the temperature can vary widely in the mornings. Some mornings it can be 13/14 degrees, in which case there is no need for heating, and other days it can be well below 10, which can be pretty chilly!

I decided to have a quick go at a bit of simple weather compensation for my heating control system. Rather than adding it into my server software I decided to write a simple perl script that acts as a client.

First thing is to scrape the temperature from Using lynx and getting the text in perl is easy.

Then for getting the programs into the server, I considered various complicated options, but then I thought of having a couple of pre-cooked programs based on temperature ranges. So in my script I determine which of 3 ranges it is in, currently less than 3 degrees, 3-9, 9-13 or 13+ and send a set of commands to the server based on the outcome.

use strict;
use warnings;

use Net::Telnet;
use Data::Dumper;

my $host = "localhost";
my $port = 2349;


my $command = "lynx  --dump";

print "Retrieve weather data...";
my $current_weather = `$command`;
print "\n";

#use the feels like temperature
#   Feels Like 12 °C
#   Feels Like 12.5 °C
my $temp = -99;
if(($temp) = $current_weather =~ /Feels Like\s+(.*?)\s+/){
 print "Temperature is $temp\n";
 if($temp > 13){
  print "temp too high, doing nothing\n";
 } elsif ($temp > 9) {
  #warmest programs
 } elsif ($temp > 3) {
 } else {
  #coldest temp program

sub send_programs{
 my ($file) = @_;
 print "About to use data from file $file \n";
 my $t    = new Net::Telnet( Timeout => 5, Dump_Log => "dump.log.filename.txt" );
 $t->open( Host => $host, Port => $port );
 $t->put("ClientName Perl Weather Compensation ($temp)\n");
 open(IN, $file) || die "cant read file $file : $!";
 while(my $line = <IN>)
  chomp $line;
  #replace multiple spaces with singles
  $line=~s/\s+/ /g;
  print "send: $line\n";

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