Anemometer

An anemometer is a device used to measure the speed and direction of the wind. There are several different types of anemometers, but the most commonly used is the cup anemometer, which consists of three or more small cups mounted on cross arms rotating around a vertical axis. The wind speed causes the cups to rotate, and their rotation speed is proportional to the wind speed. Anemometers are widely used in meteorology, navigation, environmental monitoring, and also in industry, where they are used to monitor atmospheric conditions, for example on construction sites, airports, or wind farms.

My interpretation of the model found on the web (link in the description).