Check out vavuud website to look at real deal which you can purchase to support the application. They have tested their one in a wind tunnel so it's quite accurate.
Step 1: Shopping
2 sets of measuring spoons, I used 2 x 5ml spoons.
Neodymium magnets (the shinny strong ones) I got mine out of a fishing game
Small bearings, I got mine for a couple of dollars from a model shop, but you can get them from some toys as well.
A few old pens.
3.5mm headphone jack ( cheap headphone will work)
Other tools you need are scissors, soldering iron, small hack saw.
Step 2: Cutting And Welding
Find a round plastic rod around the house. I used a thick spray bottle tube. Cut this about 60mm long
Using your soldering iron, weld the plastic parts together as shown. This was the first time I have tried it and it worked ok,
Step 3: Bearings
Using the soldering iron I made two indents in the top of the section which the rod would locate into.
Step 4: Head Phone Jack
Step 6: Magnets
Step 7: Application
Step 8: Calibration
Good luck, and if you can, please support the original Vavuud wind meter, they have put a lot of time and resources into developing the app.