Some anemometers use a small motor attached to the shaft. As the vanes turn they generate a voltage that can be measured with A2D. You'd need a free-running motor that's well protected from the weather. Possibly over- engineering compared to the optical method and might not give such good results at very low wind speed -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads