This project uses a wind speed sensor connected to an Arduino board to measure wind speed. This can then be used to determine how much power your fan needs to run at different speeds.

DFRobots are open-source hardware robots that can be programmed using Arduino IDE software. They have multiple sensors (including temperature, humidity, light, etc.) and are capable of performing basic functions like opening/closing doors, moving motors, turning lights off/on, raising/lowering flags, etc.