[JT118]

Hi,
I plan to use my old WM918 wind sensor, the schematic is similar to the davis 6410(20k pot.).

Could someone give me the wiring to the RJ12 TX unit please ?

Thanks

See here;

MeteoCercal Fórum / WeatherDuino Pro2 / WeatherDuino Pro2 - Hardware v / Fitting Davis Anemometer and Wind Vane 7911 & 6410 to WeatherDuino Pro2

http://www.meteocercal.info/forum/thread-387.html

It should work.

[laulau]

Hi,
I dismantle the wind sensor to remove C2,C3, and R4 for the vane.
   
Should i keep C1 and R2 for the anemometer ?
(those are less acessible)
Laurent

[JT118]

Hi,
I dismantle the wind sensor to remove C2,C3, and R4 for the vane.

Should i keep C1 and R2 for the anemometer ?
(those are less acessible)
Laurent

Have a look here:

http://www.lexingtonwx.com/anemometer/

and see if you can get it as near a possible to this. So long as the TX board receives an on / off signal from the instrument, it should work.

[laulau]

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.

I've searched on Google without success!
Is it possible to calculate it ?

[werk_ag]

Hi,
I dismantle the wind sensor to remove C2,C3, and R4 for the vane.

Should i keep C1 and R2 for the anemometer ?
(those are less acessible)
Laurent

I see no problem in keeping C1 and R2.

I've searched on Google without success!
Is it possible to calculate it ?

Certainly it is, but I don't know how to do it.

[JT118]

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.

I've searched on Google without success!
Is it possible to calculate it ?

If you want to know the number of clicks, you can hear the reed switch (if you hold it close to your ear) go on and off if you turn the cups, you will hear either one or two very faint ticks per revolution. If you want the other maths, this is more complex but looking at the WM pictures the dimensions look similar to the Davis instrument so the Davis settings 30 will probably work, if it is one click per revolution, I am not sure which of the other anemometers on the list are two clicks and similar dimensions but the FO setting 10 on windspeed TX config tab would be starting point.

[laulau]

Steve (from Sandaysoft) wrote

Is this of any help? http://www.qsl.net/zl1vfo/wx200/wind_sensor.htm

[werk_ag]

Yes, it is! All you need to know is there.

For your anemometer you can chose type 11, and then change #define FORM_FACTOR 1.26 (line 79)
to
#define FORM_FACTOR 1.80

[laulau]

Thanks,
But how did you calculate this number ?

[werk_ag]

I haven't calculated it! It is in the table provided by Steve link.

...
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)