Combined wind sensors

Anemometers (old Greek ἄνεμος anemos 'wind' and μέτρον métron 'measure') or wind gauges are various measuring instruments for the local measurement of the speed of a flow field, especially the wind speed.

The oldest known anemometer is the wind plate, which is also called a plate, oscillating plate, pressure plate, or deflection plate anemometer. This instrument was probably invented in 1450 by the Italian architect Leon Battista Alberti and subsequently described by Leonardo da Vinci around 1500 in a sketch of his own design.

In 1846, the astronomer Thomas Romney Robinson then measured the wind speed using a new anemometer he had developed with hemispherical shells. At first, this construction had only two such shells, but later a further pair of shells was arranged in a crosswise fashion in order to achieve a more uniform rotational force. This type of anemometer is still in use today for meteorological measurements. It is probably the best known type of anemometer.

A wind direction indicator, also called a wind vane, weather vane or, to a limited extent, an anemoscope, is a display instrument for determining the wind direction. It is based on the fact that a movable measuring element aligns itself with the dynamic pressure of the wind.

A wind direction indicator can be regarded as a static system with only one mechanically stable state of equilibrium. The flag surface, which is arranged asymmetrically to the axis of rotation and on which the wind exerts a torque if it is not aligned parallel to the wind direction, serves as the input element. The wind direction sensor itself again serves as the output element, since its orientation in wind corresponds to its direction (cf. also directional stability).