Help with analog windmeter and analog input on aWemos D1 (not mini)

ESPHome
1

Hi,
I’ve setup a windmeter type adafruit anemometer. It has an analog output . The range is 0.4V = 0m/s
and 2V = 32m/s
Here’s the code I use in ESPHome

sensor:
  - platform: adc
    pin: A0
    name: "Windsnelheid"
    unit_of_measurement: "km/h"
    accuracy_decimals: 2
    update_interval: 1s
    filters:
      - multiply: 3.3
      - calibrate_linear:
          # Map 0.0 (from sensor) to 0.0 (true value)
          - 0.41572 -> 0.0
          - 2.0 -> 116

I multiply it by 3.3. I 've seen somewhere that the Wemos has a build in voltage divider. I think this is correct because of the measured voltage of 0.41572V when the meter is not spinning.

0.41572 is the voltage that is measured by the A0 pin in ESPhome (not multimeter)
The extra calibration is conversion to km/h

The problem is that I never measure windspeeds higher then let’s say, 20km/h

Is this sensor setup correct ?

Thx!

2

Config looks ok.

20km/h should give you 0.7v by the ADC. 40km/h should be 1v. What are you seeing?

3

Hello, thx for looking at it.
The values I get do not match the windspeeds measured at a nearby airport. 2km away
At the airport 26km/h at this moment, I measure +/- 4 km/h

I’ve never seen it measure more than 20km/h
The logs of ESPhome sensor show:

21:15:07][D][adc:056]: ‘Windsnelheid’: Got voltage=0.14V
[21:15:07][D][sensor:092]: ‘Windsnelheid’: Sending state 2.35980 km/h with 2 decimals of accuracy
[21:15:08][D][adc:056]: ‘Windsnelheid’: Got voltage=0.14V
[21:15:08][D][sensor:092]: ‘Windsnelheid’: Sending state 2.83172 km/h with 2 decimals of accuracy
[21:15:09][D][adc:056]: ‘Windsnelheid’: Got voltage=0.14V
[21:15:09][D][sensor:092]: ‘Windsnelheid’: Sending state 2.35980 km/h with 2 decimals of accuracy

I guess: 0.14 * 3.3 = 0.462 looks ok …

4

Airport anemometers are typically mounted at 10m. Speeds at that height can be dramatically different than ground level.