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 ...

This is an easy tutorial showing how you can control the brightness of an LED or adjust the speed of a DC fan using Arduino Board, a small BC547 transistor and a potentiometer.

Eclipse CDT & Arduino Plug-In An alternative to the Arduino IDE is Eclipse, a development environment used by professional and hobby developers. It’s open-source software and extensible via plugins.