Hey All,

I'm trying to read wind speeds from a NRG 40 anemometer that generates and A/C signal. It generates a sine wave between 0 and 125 Hz. The peak to peak voltage can range from 80mV to 12V.

Please correct me if I am wrong as most of the following information I've accumulated from other forums:

The frequency generated by the sensor is too low for the arduino to pick up itself. I'm not sure how to change that.

The sinewave must be converted into a frequency using a converter. Some of the hardware I've seen mentioned are LM231 and LM2907.

 

The arduino can easily handle measuring the frequency. All you would need to do is convert the signal into a 5V square(ish) waveform. So amplify the small signals and limit to 5V. A simple op-amp will do the job - LM358 for instance.