The Vaavud Sleipnir is a device that measures the wind speed and direction for outdoors and sports enthusiasts. The asymmetrical blades ensure that the rotor accelerates slightly when the largest blade is hit by the wind. A built-in high-frequency sensor measures the speed of the rotor and determines the wind direction by comparing the point of maximum velocity to the compass direction. The data is automatically shared with others via the Vaavud smartphone app.