Hi
I am currently building a tachometer for wind turbine shaft. My question is what kind of sensor type should I use? Hall effect or IR (reflective object sensor)? Which one is more weather proof ? which one is easier to implement?

 

Hall effect sensors are generally more robust... IR sensors require line-of-sight and run into problems when things get dusty/muddy/rainy/snowy.

As far as ease to implement, they are about the same, unless you are referring to an IR sensor like those Sharp IR distance finders, then Hall effect sensors would be much easier...

 

Can you not monitor the AC frequency of the output voltage?