My father has got a solar water heater system with a SPIII Solar Water Heater Controller. The controller itself is some crappy closed source with a bad interface (non-standard compliant HTML interface) - however it works.
In order to collect all environmental data from the house we decided to buy a Raspberry PI and a few Arduino devices.
So far we are able to collect data from the SPIII Solar Water Heater Controller using curl and from the Current Cost
device (via cosm.com as proxy) using the following bash code:
{% gist 3872852 %}