Wind Speed Sensor Made with a Computer Fan

If you want to measure the wind speed outdoors, the proper tool is called an anemometer. These can, of course, be purchased, but as shown in the video below by YouTuber ‘MindDump’ you can make one with very basic tools and a PC fan.

Here, the fan is spun by a series of ping pong balls cut in half and attached with wooden dowels from a craft store, forming a crude version of what you’d expect to see spinning around on a weather station. When the fan is spun it produces an AC electrical signal that can be measured using an Arduino’s analog input pin. Since this signal isn’t constant, it’s sampled over five minutes, with the maximum reading during this time output over serial.

Of course, an analog output doesn’t automatically correlate to wind speed, so he had his wife drive along at 25 miles per hour while he measured the analog output. With this data point and a zero reading at zero miles per hour, he was then able to extract a simple linear correlation to relate analog inputs to real-world data. Although there are many ways one could go with this type of setup, it’s neat to see what one can do with a little imagination and readily-available components!