Start by stripping all switches down to their bare PCBs. The idea is to use the push button switches inside the Home Easy HE308 switch and connect them to the push button switches from the Bye Bye Standby wall switches and then stuff it all in the wall.

Carefully solder wires to each BBSB switch and then solder them to the HE308. As the PCB of the HE308 connects some of the pins, it wouldn’t work when I tested it. No problem though, it just meant that I had to get my faithful Dremel out and dremel away all PCB lines surrounding the switches.

Make sure you test it once it’s all been connected up, not just when you’re finished putting it back into your wall ;) At this point in time, make sure you have set the address codes to the correct modules.

As the whole package is larger than my backbox, I removed the bottom from a plastic backbox and used a hammer and old screwdriver to chisel away at the wall behind it. Once I had everything inside and made sure that it was still working, I discovered that the edges from the backbox were larger than the switch itself. Doh!

I took everything out again and carefully reduced the edging until it all fitted neatly underneath the switch.

I started off with a 4 port powered USB hub, which I had lying in a drawer and plugged my iPhone charger leads into it, expecting them to instantly charge my two iPhones. But to my surpise, nothing happened… so another quick Google later, I came accross a blog entry of Carl Hutzler, which details why they won’t charge. All you have to do is sacrifice the hub and forego it’s PC functionality by cutting the D+/- lines and short them. A quick test shows they now finally charge themselves. Apparently it is better to stick 2x 100K Ohm resistors on the D+/- lines, which I will do at some point, but for now, this will do.

All I now had to do was find a suitable SWMBO friendly container, and as our furniture is all beech, the tea storage container I found for £1.99 at QD stores was perfect. I just needed to gut the compartiments out and put something on top of the plastic lid. At my local crafts store I found a small foam pad for 50p which was nice and soft. Unfortunately I got my measurements all wrong, so I messed up the black pad, but SWMBO came to the rescue by rummaging through my kids crafts drawers by digging up a piece of brown padding.

The final thing to do is then drill some holes at the locations convenient for your devices, and put it all together. Job done!

#!/usr/bin/perl
# /usr/local/bin/cc-classic.pl
 
use Device::SerialPort qw( :PARAM :STAT 0.07 );
 
$port = "/dev/currentcost";
 
$ob = Device::SerialPort->new($port)
      or die "Can not open port $port\n";
$ob->baudrate(9600);
$ob->write_settings;
$ob->close;
 
open(SERIAL, "+>$port");
while ($line = <SERIAL>)
{
  if ($line =~ m!<ch1><watts>0*(\d+)</watts></ch1>.*<tmpr>\s*(-*[\d.]+)</tmpr>!)
  {
     $watts = $1;
     $temperature = $2;
     print "watts:$watts temp:$temperature";
     last;
  }
}
close(SERIAL);

This would give me the two values I am interested in; watts and temperature (since it sits in the garage node 0 ;)) in Cacti’s format:

$ /usr/local/bin/cc-classic.pl
watts:761 temp:11.3

But today, I received my new unit, a Current Cost CC128. It’s main benefit is that it supports individual appliance monitors, which makes the output even more useful. So, armed with a draft copy of the CC128 XML output document, I prepared my script to read as follows:

#!/usr/bin/perl
# /usr/local/bin/cc-cc128.pl
 
use Device::SerialPort qw( :PARAM :STAT 0.07 );
 
$port = "/dev/currentcost";
 
$ob = Device::SerialPort->new($port)
      or die "Can not open port $port\n";
$ob->baudrate(57600);
$ob->write_settings;
$ob->close;
 
open(SERIAL, "+>$port");
while ($line = <SERIAL>)
{
  if ($line =~ m!<tmpr>\s*(-*[\d.]+)</tmpr>.*<ch1><watts>0*(\d+)</watts></ch1>!)
  {
     $watts = $2;
     $temperature = $1;
     print "watts:$watts temp:$temperature";
     last;
  }
}
close(SERIAL);

And guess what… that works just fine ;)

For those who read diff:

$ diff /usr/local/bin/cc-classic.pl /usr/local/bin/cc-cc128.pl 
2c2
< # /usr/local/bin/cc-classic.pl
---
> # /usr/local/bin/cc-cc128.pl
10c10
< $ob->baudrate(9600);
---
> $ob->baudrate(57600);
17c17
<   if ($line =~ m!<ch1><watts>0*(\d+)</watts></ch1>.*<tmpr>\s*(-*[\d.]+)</tmpr>!)
---
>   if ($line =~ m!<tmpr>\s*(-*[\d.]+)</tmpr>.*<ch1><watts>0*(\d+)</watts></ch1>!)
19,20c19,20
<      $watts = $1;
<      $temperature = $2;
---
>      $watts = $2;
>      $temperature = $1;

Please note, the above only works with 1 sensor (the main transmitter), so it is likely to change in the future. For now it suits my need.

One day I’ll write something about how it’s all been done, but for now you’ll have to suffice with some pretty graphs.

Here’s the daily graph for the temperatures in our bedrooms for the past 24 hours:

And recently I added a Current Cost meter to my network, which gives me the shocking facts about my electricity usage for the past 24 hours:

The above graphs are updated hourly, and I’ve got other graphs too, extending the period of graphing. You can find them here for the time being.

Update 25.1.2009

And now you’re able to follow the stats on twitter: http://twitter.com/awoogadotnl