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Wind sensor alternatives to FineOffset. Any ideas?
#91
Hi,

It's virtually impossible to calculate theoretically, nearly always done by comparison against a "known" anemometer and/or a known windspeed (e.g. in a wind tunnel). AFAIK, about the only easily "calculate-able" anemometer is the "Ultrasonic Time-of-Flight" type.

Search on the web for "Anemometer Factor" and you may find something like this analysis. Wink

Cheers, Alan.
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#92
Ok,
But if you take the line :
10 37.4
It gives 37.4/10/3.6 = 1.038 m/s

This mean that the anemometer form factor is not linear !
If I draw the curve, the factor is close to 1 from 10km / h and goes up to 2 for very low speed.

(30-11-2015, 04:33)Werk_AG Wrote: I haven't calculated it! It is in the table provided by Steve link.

(27-11-2015, 21:49)Werk_AG Wrote: ...
For your anemometer, you may also need to know the wind speed correspondent to 1 click / revolution, and make the necessary changes in the software.


Code:
Revolutions vs. Wind Speed
Revs/sec Frequency    Airspeed km/h
    
1.0                       6.5


6.5 Km/h = 1.80 m/s (WeatherDuino Pro2 internally always use Internacional System Units)
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#93
Hi,

Note that the Fine Offset Anemometer generates TWO clicks (pulses) per revolution! So you need to be very careful whether pulses or revolutions are being specified, Also, the FO transmitter counts over a period of two seconds, so the minimum resolution is 0.75 mph, or one revolution/second corresponds to 3 mph (approximately 1.3 m/s or just under 5 km/hr). Many users seem to believe that their FO anemometer under-reads, but measurements suggest that actually they over-read !

Cheers, Alan.
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#94
If thing the WM918 Anenometer is 1 click per revolution.
MeteoCercal - Air Quality Data
Click here to watch at my ThingSpeak channel



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#95
Hi Werk

I have the 2 Inspeed sensors now and made up some fittings to mount them. i have used your style of mounting the pvc pipe. I am ready to hook it up but the wind vane outputs 0-3.3V and I saw somewhere a calibration routine you suggested for someone but I can not seem to find it now. I have both wired up to plug straight into my V3.1 TX boards but wanted to know about the cal program.

What else should I know about it.?

I see I need to select the inspeed 8 pulse for the speed but it was that 3.3V that I need to do something with?


By the way i got CumulusMX working and also rebooting straight into CumulusMX as well. I really like Cumulus and your weatherduino working together its a reallyneat system
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#96
(03-06-2018, 07:44)markkkk42 Wrote: Hi Werk

I have the 2 Inspeed sensors now and made up some fittings to mount them. i have used your style of mounting the pvc pipe. I am ready to hook it up but the wind vane outputs 0-3.3V and I saw somewhere a calibration routine you suggested for someone but I can not seem to find it now. I have both wired up to plug straight into my V3.1 TX boards but wanted to know about the cal program.

What else should I know about it.?

I see I need to select the inspeed 8 pulse for the speed but it was that 3.3V that I need to do something with?


By the way i got CumulusMX working and also rebooting straight into CumulusMX as well. I really like Cumulus and your weatherduino working together its a reallyneat system

Hi Mark,

Regarding the wind vane, if this is the first time you are connecting an analog wind vane to the TX board, the calibration procedure is automatic, you just have to manually do some complete rotations of the wind vane.
If you had previously used a different analog wind vane, then the previous calibration settings must be erased. The simple sketch bellow will do it for you:

Code:
#include <EEPROM.h>                // Library to write and read from eeprom      

byte Min_vane_reading_Eeprom_adr   = 20;
byte Max_vane_reading_Eeprom_adr   = 22;

void FirstRun_SetEeprom()
{
 EEPROM.put(Min_vane_reading_Eeprom_adr, 1023);
 EEPROM.put(Max_vane_reading_Eeprom_adr, (int)0);    
}

void setup() {

FirstRun_SetEeprom();
}

void loop() {

}

Copy and past to your arduino IDE, compile and upload it to your TX unit. Then reprogram the TX unit with the latest TX software.
Also, don't forget that for analog wind vanes, the JP1 jumper should be left open.
MeteoCercal - Air Quality Data
Click here to watch at my ThingSpeak channel



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#97
I had a Davis one which is analogue of course but it is a 5V one. This one is 3.3V  so I will replace that routine and do a recalibrate. Thanks for that Werk. The windspeed for the 8 pulse seems to work fine

I think I will replace my davis wind sensors with these ones as well up at my farm I quite like the look and feel of them
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#98
Thanks Werk

Did as you said and the inspeed windvane is working fine Smile
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#99
I have been using the Inspeed wind vane and 8 pulse wind speed sensor now for 2 weeks and I have to say it is so much better than the Davis and FO ones. I got mine from a guy in the USA they were US$75 each basically and well worth the money although I did have to make up my own adapters to fit them to a T bar as they are imperial sized not metric. I dont get the weird wind gust issues with it like the Davis one and the accuracy is extremely good for the direction as well. I have these setup at home but I will get another set for up at my farm and replace the Davis ones. 

At home I got CumulusMX working and working headless and the weatherduino goes into that . CumulusMX is also such a great program and it updates very fast. I have been using CumulusMX doing the WU uploading as well . I think I am going to make both sites exactly the same as I am really happy with both systems
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