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Connecting the wind sensor for Arduino

For discussion of DIY weather equipment - sensors, accessories, improvements to existing kit etc
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Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Connecting the wind sensor for Arduino

Post by Areecki »

Hello
Welcome
I have a question. Is it possible to directly connect to the wires that connect the anemometer and wind vane with termohydro station from 1090 wh? I wanted to connect the cable there that will short-circuit the reed relay the signal to the Arduino, and in turn, count it short and give the current wind every 1 sec. Do not damage the operations of arduino current station? Do I need to buy a separate anemometer and wind vane?
I would like to connect to the site cubes R11 which comes to the sending station outside.

Maybe someone has an electronic circuit diagram of door station WH 1090?
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
AllyCat
Posts: 1124
Joined: Sat 26 Feb 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Connecting the wind sensor for Arduino

Post by AllyCat »

Hi,

Yes, the Fine Offset sensors can be connected to an Arduino, I believe that's what the WeatherDuino does (or can) use.

Details on the sensors can be found in the "Photos of...." sticky thread in the Fine Offset section. The anemometer reed switch is connected to the two middle pins of the RJ11 connector, so just needs a Pullup or Pulldown resistor on a suitable Arduino input pin.

The wind direction is indicated by one of 8 (or 16) resistance values connected across the two outer pins. Typically, that can be detected by connecting in series with (say) a 10k ohms resistor across the supply-ground connections and reading with an ADC input pin. A lookup table is normally used to determine the 8 (or 16) directions from the (non-consecutive) sequence of values.

Cheers, Alan.
Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Re: Connecting the wind sensor for Arduino

Post by Areecki »

Yes I know that the wind speed is 2 middle pins.
I do not know which place to connect a wire running from the Arduino to the anemometer so as not to damage or arduino electronics or electronics station.
I want to use the same anemometer to display the wind on the Arduino which is connected to the station all the time. Is the power of the Arduino 5V will not damage the outer stations? I just want to train and work on one Arduino wiatromierzu. Do not want to install a separate anemometer for Arduino.
Maybe you should use a transistor or a diode rectifier so that the current from the Arduino has not gone to the weather station installation. Exactly which pins on the Arduino can be zipped Leonadro more secure 2 pins from the anemometer?
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
AllyCat
Posts: 1124
Joined: Sat 26 Feb 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Connecting the wind sensor for Arduino

Post by AllyCat »

Hi,
Areecki wrote:Exactly which pins on the Arduino can be zipped Leonadro more secure 2 pins from the anemometer?
That's probably a question for an Arduino forum. Not only don't I know (much) about Arduinos, but I thought there is more than one type.

But if it's using a 5 volt rail (the station uses 3v or less) then yes you may need an "interface" circuit of some type. It should be reasonably "safe" to first try just a resistor of at least 10k ohms from the positive side of the anremometer reed switch to an input of the Arduino (the earths must of course also be connected). However, if the Arduino input has a "pull up" input stage then you might need a diode "pointing to" the anemometer instead.

Also, you certainly can NOT use the Wind Vane to drive both devices, because of the way the Fine Offset Analogue-Digital conveter works.

Cheers, Alan.
Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Re: Connecting the wind sensor for Arduino

Post by Areecki »

I have this wind sensor :
http://www.maplin.co.uk/p/maplin-replac ... 25fr-n76nf
And I have a few questions.
Is this the same wind sensor which is the Fine Offset stations WH WH 1080 or 1090? Basically, I'm talking about its construction and counting the wind speeds in relation to the pulses per second.
Wind sensor of this manufacturer: https://www.sparkfun.com/products/8942 I give here http://mile-end.co.uk/blog/bits/Weather ... sembly.pdf that at 1,492 MPH winds (2.400 KM / H) reed contains 1 time in 1 second.

Has anyone had contact with wind sensor from Maplin? Is the size of the construction and conversion is the same? I would like to connect the sensor under the Arduino and do not know how to write the code to read the wind was at 1 second.
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
AllyCat
Posts: 1124
Joined: Sat 26 Feb 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Connecting the wind sensor for Arduino

Post by AllyCat »

Hi,

Yes, that sensor is the same as in all the Fine Offset stations and generates two pulses per revolution (as has been much discussed on this forum). The FO transmitter module counts the number of pulses in each two second "window", so the station converts each pulse to 0.75 mph. I guess the 1.492 (in one second) is a result of conversion from metric units. I don't know which is more correct, but FO only claim an accuracy of +/-10% above 5 m/s (+/-1 m/s if below 5 m/s).

Sorry, as I said above, I can't help with Arduino programming. Personally, I use a PICAXE micro because it has the possibility of using a wireless interface (i.e. battery-powered).

Cheers, Alan.
Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Re: Connecting the wind sensor for Arduino

Post by Areecki »

so
I read your posts on the forum regarding whether it is a short one over a full rotation or two. And the same with his anemometer came to the conclusion that a full rotation of the blades is 2 pulses generated. Https://kesslerarduino.wordpress.com/20 ... r-station/ here I found a very useful project just do not understand (I'm Polish) what exactly is this sentence:

"The datasheet shows the rain gauge That and the anemometer are magnetic reed switches, every 0.011" of rain Causes a momentary contact and a 2.4km / h wind will cause a momentary contact every second for the anemometer. "

Is the program reads every second pulse, and counts all pulses and then divided into 2.
It seems to me that a more accurate measurement method is to count all the pulses and the distribution of 2.4 km / h (1,492 MPH) on the half that is 1.20 km / h (0746 MPH) for 1 pulse per second.

The problem is that my project wants microcontroller programmed to count the time interval between pulses and the interval to compute the wind pull rates.
Counting the number of bursts within one second seems to me to be less accurate.

I have to make sure that 1 pulse within 1 second (1000 ms) generates wind 0.746 MPH = 1.20 km / h or 1.492 MPH.
Here : https://learn.sparkfun.com/tutorials/we ... nderground , here : https://kesslerarduino.wordpress.com/20 ... r-station/ and here : http://www.sparkfun.com/datasheets/Sens ... embly..pdf is 1.492 MPH for 1 pulse in 1 second ?
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
uncle_bob
Posts: 505
Joined: Wed 17 Aug 2011 2:58 pm
Weather Station: WeatherDuino Pro2
Operating System: 2008
Location: Canberra

Re: Connecting the wind sensor for Arduino

Post by uncle_bob »

Hi Areecki,

Like mentioned above, Werk_AG has done all this already with the WeatherDuino Pro2 system.
His Fine Offset wind and rain sensors to connect directly to the Arduino Nano. It may be a good idea to check out his schematic here: http://www.meteocercal.info/forum/Threa ... Schematics and maybe download his TX unit code to see how he made it "tick". That should give you real good helping hand without having to re-invent the wheel.
(I think/hope he will be OK, with this)

Cheers Bob
Interested in building your own Weather Station? Maybe check out the WeatherDuino Pro Project Here
Conder, Canberra Weather
Image
Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Re: Connecting the wind sensor for Arduino

Post by Areecki »

Bob,
Arduino can expect short reed in 2 ways. The first way is to count pulses in a given period of time eg. One second (1000 ms). This method is not good because when one short per second wind generates 2.4 km / h is 2 short-circuit wind will generate 4.8 k / h and 10 short-circuits the wind 24.0 km / h. But how to get the wind, eg. 3,6 km / h and 29.8 km / h?

Arduino has to count the time between short circuits and convert it into the wind.
Must read the break in milliseconds between short-circuit the reed. And so, for the wind 2.4 km / h, this break is 1000 ms, the wind 24 km / h, this break is 100 milliseconds. But how to calculate the value of which corresponds to break wind, eg. 369 milliseconds or 856 milliseconds?

Do you have the code to the plate with the link?
I know the wiring diagram itself, it needs as it is programmed.
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
uncle_bob
Posts: 505
Joined: Wed 17 Aug 2011 2:58 pm
Weather Station: WeatherDuino Pro2
Operating System: 2008
Location: Canberra

Re: Connecting the wind sensor for Arduino

Post by uncle_bob »

Areecki wrote:Bob,
Do you have the code to the plate with the link?
I know the wiring diagram itself, it needs as it is programmed.
The code is also available on the site. Here's the link http://www.meteocercal.info/forum/Threa ... st-Release

I don't know how Werk_AG measures the wind for sure, but I know it does measure to low levels. It's even lower than what the Davis Protocol allows (1mph resolution).
Interested in building your own Weather Station? Maybe check out the WeatherDuino Pro Project Here
Conder, Canberra Weather
Image
AllyCat
Posts: 1124
Joined: Sat 26 Feb 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Connecting the wind sensor for Arduino

Post by AllyCat »

Hi,
Areecki wrote:Arduino has to count the time between short circuits and convert it into the wind.
Certainly, at very low rotational speeds, measuring the time for one revolution (or pulse) is an alternative method, but AFAIK rarely done for meteorological wind speeds. Note that the "pulse" is NOT short, so you must measure the period of the waveform, i.e. between two rising (or falling) edges of the pulses (not the space inbetween). Then it's just necessary to calculate the reciprocal (by division) of the period to determine the frequency (e.g. revs/second) of the pulses.

But measuring the period probably creates more problems than it solves. Is the friction of the bearing sufficiently low to give accurate results at low windspeeds? What happens (in the program) when the rotor dosen't turn at all (at low windspeed)? Normally, even a "gust" is averaged over (typically) two seconds, so a simple count within a two second "time window" is the obvious method (and doesn't involve mathematical complications of division and/or floating point calculations on a simple microcontroller).

Cheers, Alan.
Areecki
Posts: 60
Joined: Thu 26 Nov 2009 4:01 pm
Weather Station: Viking 02047 (WH 1090)
Operating System: Windows XP SP3
Location: Poland
Contact:

Re: Connecting the wind sensor for Arduino

Post by Areecki »

This is from Poland but look like very nice
http://mikrokontrolery.blogspot.com/201 ... z-diy.html
This is good too : http://mile-end.co.uk/blog/?p=56
Viking 02047 ( klon WH 1090)
http://areecki.ihq.pl/pogoda/index.htm
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