Building an Anemometer.

 

Well I finished the anemometer rotor and spindle assembly. Here's a quick description of how it came into being..............

While winding coils for the wind turbine alternator, I accidentally dropped a bearing into the inside of one of the spools of wire. It slipped in ond end but was a real tight fit in the other. "Hmmmm" I thought. Perfect for a simple anemometer. Every spool was the same. Tight one end, loose at the other. So I joined two of the empty spools together, so that I'd have a tight fit at both ends. A length of 8mm all thread fitted nicely in the bearings, letting the spools rotate on the shaft. Now all I needed was a rotor arm to hold the wind cups. I CNC'ed some from some old PCB I had lying around and then surfaced the traces off. This was then bolted to the spindle (empty spools). Next up was some cups to catch the wind.......The best I could find off hand was some deodorant can lids, so on they went. A small magnet was glued into a hole drilled into the bottom of the spool spindle. This acts on a small reed switch attached to the spindle mount.

So with all the bits wired and ready to go, the family jumped in the car for some testing and calibration. We did several runs at various speeds and came up with a formula to convert the RPM reading into MPH. It worked a treat. Job done.

Oh yeh, right................... We returned home and put the anemometer up in the garden. It turns out that it needs about 7 MPH wind just to get started. So I decided to extend the rotor arms and try to find some better shaped cups.

 

Here are some pics of the modifications.....

 

 

The extentions are some strips of PCB bolted to the original rotor.

The new cups are actually my duaghters balls cut in half... ;-)

This version spins in a very slight wind. Should be just the job. All I have to do now, is run some more calibration tests.

When I have more time I'll put up a video of the anemometer working and the LCD display showing the results.

A quick update.... I blew the anemometer circuit up by accident, so for now it's on hold untill I get more time. Ooops.