> Now the question is: Where does one get (buy or make) the wind vane? This is what I do for a living. Check out http:\\www.nrgsystems.com Our anemometers are the best value around. (Not quite the cheapest) Or look for "weather stations" on the web, several cheap sensors are available. Most of them work. At least moderately well. At least for a while. :) In the industry, the term wind "Vane" is a wind direction vane, commonly known as a "weather vane", it swings around into the wind to measure wind direction. (Ours have a special potentiometer so the PIC can read back wind direction using A/D). What you want for a rotating anemometer is either a cup-wheel (vertical axis, usually 3 cups), or a propeller of some kind. The aerodynamics of propellers are very complex so they tend to be non-linear. (there is a lift component as well as a drag component generating the spinning torque). The aerodynamics of cup wheels are drag only, so they tend to be fairly linear, once the wind is giving enough torque to swamp the bearing drag. If you roll your own, you'll have to calibrate, which is non-trivial. For cheap and PIC-compatible, (besides my own products), check out the Dallas "1-wire" weather station. It has a cup anemometer which goes onto that bus. It was a demo / promotion last year, their web site might still have the info. > > How about wind mills? Any sources for making or buying the business end of a > wind power system? > I need a low cost to make, $0 to operate water pump for my passive solar > heat storage system design. For homebrew stuff, look at Home Power magazine. They might have a web site, can't remember. My opinion is that homebrewing this kind of stuff is rarely "worth it" (that is if you count your time), but it might be fun anyhow. Any project that requires a PIC AND an arc welder is always interesting. :) Regards, ------------ Barry King, Engineering Manager NRG Systems "Measuring the Wind's Energy" www.nrgsystems.com Phone: 802-482-2255 FAX: 802-482-2272