I used an LCD shield to display the current temperature and speed of the fan, but you can use the circuit without the LCD display. You also need to select the transistor by the type of fan that you ...

Thermistor is a semiconductor device made of materials whose resistance varies as a function of temperature. A thermistor can be used to compensate for temperature variation in other components of an ...

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.