hi
so basically I need a tachometer sensor that can read the RPM of the small scale wind turbine generator. The tachometer must output RPM as digital signal, which in turn enter the microcontroller for data analysis. Does this kind of tachometer exist? or do i have to build one? as described on this site
http://www.pyroelectro.com/tutorials/digital_tachometer_rpm/index.html

Edit*
I also read about people building tachometer using bicycle-speedometer. Is possible to feed output of speedmeter into the microcontroller?

http://www.instructables.com/id/Tachometer-made-from-a-bicycle-speedometer-cycloc/

 

I would use a slotted opto coupler, or hall effect sensor, and feed the pulses into your micro,and count the pulses per revolution.

 

What type of generator does your turbine use? If it has an AC output and rectifier you can get a tach pulse from one of the AC windings (before the rectifier).