I worked as a prototype design engineer at a company where we had to know the answer to a very important question:  How fast is the wind blowing from 10-1000 feet overhead?  Working with an electrical engineer, I prototyped a sensor system based essentially on the tilt angle of a sphere-on-pendulum assembly.  Angle of tilt measured by an onboard accelerometer would correspond to a certain wind speed, transmitted wirelessly or datalogged on board.  The relationship between tilt and speed was not straightforward, so I did what anyone in my position would do and took a prototype to a wind tunnel at NASA for calibration.