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 ...

Here is an Arduino experiment with a famed linear active thermistor chip MCP9700A from Microchip Technology Inc. The chip comprises an analog temperature sensor that converts temperature to analog ...

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.