If you’re a sailor or kite flyer it’s a must to know wind speed; and even if you’re neither of these, it’s fun to watch the display. The measurement range here will depend on how you set it up but typically you’ll be able to read speeds from just a few km/h upwards. Cost? Well, depending on how you source the components, you’re looking at not much at all!

And best of all, this is a project that will totally stun your friends or spouse – they will wonder how the hell you made a working instrument

Fig.1: the anemometer uses the internals of a discarded mouse to generate a frequency output proportional to wind speed. This signal is fed into an amplifier (salvaged from a cassette player) which feeds a charge pump circuit made from a handfull of passive components. The resulting voltage is displayed on the speedo.