Greetings
I'm currently laying up the digital part of the circuit in Eagle with an Arduino Nano as the plugin CPU. I'll then move onto the analog part, starting with the existing circuit but I expect to move to an all op-amp solution pretty quickly.
I may integrate the wind speed measuring stuff into my BeRTOS Arduino branch GitHub - g8ecj/bertos: BeRTOS real-time operating system stuff as I then get an LCD display "for free" 
Got a few wrinkles in my wind turbine project to test out in the meantime so I may be a couple of weeks before I get to etch some copper!!