NRG 40 Anemometer to an Arduino Mega

Thread Starter

Denis Clement

Joined May 18, 2017
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.


Joined Jun 4, 2014
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.