This articles describes how you can use I2C (TWI) communication, Arduino and temperature sensors to measure 3 different temperatures. It can be very ...

Now you can build your own room temperature monitor using an Arduino board. The circuit is a combination of an Arduino UNO board, LM35 temperature sensor, ...

You'll need an Arduino along with a bunch of various sensors to get the project rolling, and once it's all set up you'll have a simple, but cheap system to monitor your home.