Wind Sensor, Rev. P - Technical details needed

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Manon
Posts: 1
Joined: Mon Jul 06, 2015 8:17 am

Wind Sensor, Rev. P - Technical details needed

Post by Manon » Mon Jul 06, 2015 8:30 am

Hello,

I just started working with the Wind Sensor, Rev. P.
Currently am missing some technical details or some sort of data sheet for this sensor, and I could not find anything in the forum.

I have connected the sensor and it seems to work fine. I see changes of the output voltage when I blow against it. But in order to use it in a reasonable way, I miss additional information.

Here are my questions:

a) What is the formula for converting the output voltage to the wind speed in m/s?
I've seen that there is a formula in the Arduino sketch for the sensor:

Code: Select all

float windMPH =  pow((((float)windADunits - 264.0) / 85.6814), 3.36814);
But I am not sure if this is the correct formula and if it is usable as it refers to specific ADC values. For example, the zero level in the formula seems to be 264, but the zero voltage of my sensor is around 1.5 V which results in an ADC value of ~360.
So, it would be very helpful to have a table or formula which connects wind speed and output voltage. Then, it would be usable with any ADC.

b) Is there any calibration of the zero level for wind sensor rev. P? Apparently it has no trimpot like the rev. C sensor. My sensor has a quite stable zero level of 1.4-1.5 V (when covered with a glass). Is this correct? The value seems quite high to me if the maximum voltage is at 3.3 V

c) In the sensor description it says that there is a hardware compensation for ambient temperature. Does this mean that the wind speed output of the sensor is already compensated for ambient temperature? And does it mean the the temperature output is just an optional information?
Or do I need to do a compensation in my software using the wind speed and the temperature value?

d) What is the formula for converting the temperature output (in Volts) to the actual temperature in Celsius or Fahrenheit? (same issue as for the wind speed output)

e) How should the sensor be mounted for best sensitivity? Should the side with the components face the wind direction?

Sorry for the long post, but I tried to sum up all my questions.

Thanks in advance for your help.

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