I am hoping to interface an NRG #40C anemometer to an Arduino. The anemometer outputs a frequency which is linear with the wind speed which equates to 1.711 mph/Hz. However the output voltage ranges from 80mV p-t-p to approximately 12V p-t-p at 60Hz, which approximates to a wind speed of 100mph. The manufacturer states that the voltage is non-linear with wind speed, so as the wind speed increases so do both the frequency and amplitude, but only the frequency is a linear increase.
I have no design experience but I am quite competent at the construction of projects. I am hoping that someone has, or able to design, a suitable circuit that will convert the variable amplitude sine wave into a square wave suitable to be fed to a digital input pin on an Arduino and then convert the frequency to the wind speed. The software side of this is quite easy
An alternative would be a frequency to voltage converter, but I am still concerned regarding what I see as a massive range of input voltages.