I have set of sensors

  1. NRG #40C Anemometer:
    Output signal:
    • Signal type: Low level AC sine wave, frequency linearly proportional to windspeed.
    • Output signal range: 0 Hz to 125 Hz
    • Output voltage at 60Hz: 12 V (peak-to-peak) typical.
  2. NRG #200P Wind Vane (page 3): Output signal:
    • Signal type: Analog DC voltage from conductive plastic potentiometer, 10K ohms.
    • Transfer function: Output signal is a ratiometric voltage
    • Output signal range: 0 V to excitation voltage.

What I need to use this with ESP8266 or ESP32 - preferably on GPIOs not on analog input?


1 Answer 1


If you want to use ESP8266 / ESP32 you will have to use the analog inputs, you can not use GPIO(as they only measure High or Low values).

NRG 40C: You wont be able to measure 12v peak to peak with the ESP, as it exceeds the absolute maximum ratings of the chip (you can check Absolute maximum ratings on the ESP datasheet).

NRG 200P: If you can supply the anemometer with 3.3v, then you can measure the output signal with the ESP.

  • \$\begingroup\$ As I understand you are saying that e.g. ESP32 is only 3.6V tolerant, but indicator of wind speed is frequency not voltage. Can I use voltage divider to reduce voltage to acceptable level? \$\endgroup\$
    – user19291
    Aug 7, 2020 at 8:27
  • \$\begingroup\$ Yes, in the 40C anemometer the frequency changes in function of the wind speed. But the signal is still 12v peak to peak, that is far beyond what the 3.6v absolute maximum ratings. You could use a voltage divider to scale at around 3v. You need also find out the signal is between 0 to 12v, or from -6v to 6v ( for example) as you may have to add some offset to have positive voltages at the ADC. \$\endgroup\$
    – Mark3859
    Aug 7, 2020 at 12:16

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