The Climaduino Controller is Raspberry Pi-based and interacts with the Arduino-based Climaduino Thermostat to provide a web interface optimized for mobile use. The Web Controller allows parameters on the Thermostat to be tweaked and generates historical graphs of temperature and humidity readings. It also can be used as a programmable thermostat.

The controller communicates with the thermostat over a serial connection provided over USB. There is a USB cable connecting both the Arduino and the Raspberry Pi. The controller leverages the Django web framework and JQuery Mobile to provide a site optimized for mobile.

See the instructable with all the information here: http://www.instructables.com/id/Introducing-Climaduino-The-Arduino-Based-Thermosta/