the Sonos is a uPnP based system there is no IR or way to traditionally control it. Everything needs to be done via HTTP calls. He’s using an Ethernet Shield to translate the RS232 events to uPnP messages.
This IoT project explores how to connect Arduino to Ubidots and Android. One important aspect in Arduino Internet of things programmin is how to connect arduino to internet and store date to IoT cloud platforms using arduino ethernet shield. This aspect is important because it is possible to store data in the cloud and then analyze it. Once the data, like sensor values, is on the cloud is possible to access it using smart phones and control remotely the Arduino board.
More complicated clients, one which monitor updates from the steward looking for changing conditions, and reacting to them on behalf of the user by asking the steward to perform actions, are entirely possible. Technically speaking these are intelligent agents working in a multi-agent system with shared goals of making life more convenient for the user. We like to think that we're implementing magic.
Reads a light and temperature sensor and exposes their values (JSON) over a simple HTTP server running on an arduino (with ethernet sheild). Also exposes the value of a relay which can be updated over HTTP.