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.