The Dallas 1-Wire devices (DS1820, etc) will repay study if you want 12 sensors in the room.
They will need to be daisychained, not connected via a star topology... but just three wires from host, to sensor0, to sensor1....
For rapid development, you may want to start this project with a PC rather than an Arduino, as host... but once various things ironed out, the Arduino could be "trained" to do the work.
Very non-trivial... but 12 sensors in inherently non-trivial, and a little work to get started with 1-Wire will repay you with years of being able to do many fun, or at least useful, things.
The following is mine, a mish-mash of imperfect early efforts and more recent, more informed articles....http://www.arunet.co.uk/tkboyd/e1didx.htm
In the Arduino world, we often just put a single sensor on an Arduino pin, and thus get around the issues of "addressing" ONE of several chips on a MicroLan. You can, in theory, "talk" to many (100?) 1-wire chips... temperature sensors and more... using just one Arduino pin... but to do that, you have to master "advanced" 1-Wire concepts, beyond those used by Arduino/1-Wire users.