Equipped with Ethernet interface, Arduino controls a boiler to maintain the set temperature and publish environmental data via Internet on Pachube, and the web interface allows setting the temperature remotely via Internet. The project is designed to control an heating system in order to keep the temperature in a room above a certain value, which can be set from Internet or a Personal Computer by LAN, because ours is not a simple thermostat but a complex unit managed by Arduino, which can connect to a local network with ethernet interface. The thermostat allows many functions, including the publication temperature measured at regular intervals (set by firmware), as well as the state of the boiler (on or off). The datas are published on the website http://www.pachube.com, which provides a database which stores user data, also makes available a series of gadgets to be able to view this data directly into web pages. See on www.open-electronics.org