Derek ( dereksoftstuff on the forum ) has put together a nice windmill data logger and performance testing software package. Its based on the LM3S6965 micro evaluation kit ( shown on the right ), a well priced micro controller with lots of built in features.

Derek has put together a Youtube page with several videos showing how to set up and use the "Wind Doctor" software, and you can download the software for free. Links at bottom of page. In Dereks words....

After giving a considerable amount of thought into starting a meaningful DIY project, I finally decided upon a wind turbine renewable energy system. But I couldn't find any DIY systems that gave sufficient information on kWh produced for the year, and probable pay-back times.

So how could I pick a really good performer for my project?

The answer was to first develop a simple performance tool, that anyone could use to log their turbines data. Then, when enough people had published their performance results, I (and everyone else) could see what worked and what didn't. So, the Wind Doctor was created.

The performance measurement tool consists of 2 parts

1. A microcontroller connected to the wind turbines and anemometers, that logs speed and power data over time.
2. A GUI program to run on a PC/laptop, that displays the data collected by the microcontroller.

It's simple to use, and presents the logged data in several different views.

a. Real-time view of rpm, volts, current and power over 60 seconds - updated at 1 second intervals.
b) history view of data over minutes/hours/days/weeks timebases.
c) power curve

No need to worry about Gigabytes of data, there's just charts showing you what you want. It allows multiple turbines/anemometers to be configured in the same system, so that comparisons can be made, and backup/snapshots of charts can be stored on the PC filesystem. Well, the performance tool's done, but the wind turbine is taking a bit longer ...

Links.