Leonardo da Vinci's wind-measuring machine is an anemometer. Around 1483, he designed a hinged wooden plate that moved when struck by wind; a graduated scale indicated the wind's strength, while the plate's orientation helped show its direction.
The instrument was intended to support Leonardo's studies of flight and atmospheric motion. He understood that wind could be compared systematically rather than merely described, making the device an early attempt at quantitative meteorology. The hinged plate is often called a plate anemometer.
Modern anemometers commonly use rotating cups, propellers, or ultrasonic sensors to measure wind speed. Leonardo's design did not provide the precision or continuous recording of later instruments, but its basic purpose was the same. It should not be confused with a barometer, which measures air pressure, or a wind vane, which indicates direction alone.