Using a motion sensor, a CO2 sensor, a temperature and a light sensor, we are monitoring our studio space @ Science Centre TU Delft. A small installation makes use of light signals to communicate the sensor values through the room and transform them into colored light code; this way we always know the state our space is in.
This is how it works:
The sensors communicate their values to an arduino. The arduino transforms the data into light signals, which are then sent to a LED par. Whenever values change, this LED par starts blinking to send a message to another LED par. A light sensor senses the blinking light and translates (using another arduino) the received signal into colored light. The color, as final output, represents the sensor values: the state the space is in!
Check out https://pachube.com/feeds/22289 for our Pachube feed.