Android Thermostat is a fully functional open source thermostat built on Android. It has many features not found in traditional thermostats including the ability to run multiple schedules, track usage and access to an API.
This is the server portion of the application that runs on the thermostat itself. It is responsible for monitoring the inside and outside conditions, running the schedule and sending the commands to turn the fan, heater and air conditioner on. It has no real interface of it's own, but rather exposes an API that the Android Thermostat client application connects to in order to provide an interface. You need to run both this application and the Android Thermostat client on the thermostat itself and you can then run the Android Thermostat client on other devices to act as a remote control.