Grepular

I recently decided that I was going to monitor and graph the temperature in my living room. I wanted to do this purely for curiosity, so didn’t want to spend much money on a solution. The HTPC in my living room runs Ubuntu, so I looked for a USB thermometer which is supported under Linux and came across the TEMPer Winter USB Thermometer on Amazon. For only £15.49 (including delivery). I decided it was worth a try.

It took a few weeks to deliver because it came from Hong Kong, but once it arrived it didn’t take long to set up. There were no instructions or drivers. I simply plugged it into my HTPCs USB port and ran the following Perl script (as root):

#!/usr/bin/perl
use strict;
use warnings;
use Device::USB::PCSensor::HidTEMPer;

my $pcsensor = Device::USB::PCSensor::HidTEMPer->new();

my @devices = $pcsensor->list_devices();
foreach my $device ( @devices ){
   print $device->internal()->celsius()."C\n" if defined $device->internal();
}

I saved the script as “temperature.pl” and now all I have to do is SSH into my HTPC and do this:

root@gum:~# temperature.pl
17.5C
root@gum:~#

Of course, I had to install the Device::USB::PCSensor::HidTEMPer Perl module first using the cpan command. I also wanted to graph the temperature in my flat over time, so I wrote another Perl script which uses RRD to collect the data and generate hourly, daily, weekly, monthly and yearly graphs. You can take a look at the script here.

Below is an example weekly graph generated by my script. The spikes that you see correspond to when I turned my heater on. I also have a Z-Wave setup which allows me to remotely turn my heater on/off, but I will talk about that another day.