Based on voltage and resistance, here is are the simulated waveforms for the schematic shown.

Fixed vibrations

I've shortened the distance between where the blades connect to the main shaft. I've also put bolts in to permanently hold the pipes and blades at the correct angles. That seems to have solved the vibrations as high wind speeds. The RPM is also higher at high wind speeds, thus capturing more energy.

As soon as we get our new asphalt roof put on our home, I'll attempt to put the VAWT up on top of the roof where it can get higher average wind velocity. I'm also planning to put some solar panels up there.

better connection

I've made a better connection between the windmill and the generator.
It works much better.

We had some >20 mph winds today and I had to stop the windmill due to vibrations.
I need to figure out some strategy for reducing the vibrations at high wind speed.
That is the fun of this project - there is always something new to improve upon or invent.

Conneced up the generator

I've connected a steel cable between the generator and the windmill.
You can see a movie of this at http://www.youtube.com/watch?v=Pjai2SFBu-c&feature=channel

I've modified the central post of the VAWT to make it less susceptible to vibrations. The center steel pole now has a 1 inch diameter rather than 3/4 inch diameter.
Watch the video at http://www.youtube.com/watch?v=7jj7lEQg6As

More Efficient VAWT

This new design is awesome!

Lower cost, more efficient, and easy to build

Modified windmill hub

I've modified the hub of my VAWT to improve the rotation Here is a video