Controlling 4 window actuators based on windforce, winddirection and rain

I’m new to Arduino.

A friend of mine thinks Arduino could solve my question but he doesn’t know how.

I have a


I’m new to Arduino.

A friend of mine thinks Arduino could solve my question but he doesn’t know how.

I have a roof with 4 windows facing the 4 winddirections and the sloped windows are close to each other.

On these windows there are 4 actuators 2 A 24 DV which drive each a window opening and closing the window by a chain : type : WMU 862-1 0750 0104

See attachments

About Motorlink

On the actuator there is a 3th green wire that should read how much the window is opened (so counting the opening by time should not be necessary). I’m told this 3th green wire is of the same type als IO-homecontrol of Velux.
See the brochure of Motorlink on the 3th wire.
So there are 4 windows : 1 in the North, 1 in the East, 1 in the South and 1 in the West.

Until now I control the action of the 4 windows with manual switches using the white and brown wire and inversing the polarity to open and close.

I want to control as much as possible the following actions based on windforce, winddirection and rain : to create chimney effect for cooling and ventilating, avoid wind pulling on the open windows, avoid water inside, ventilate in warm weather, close in cool weather, etc.

Windsensors are possible with Modbus, 0-10V, or 4-20 mA

If the wind is N the S window should open, SW wind opens N and E windows : to create chimney effect. (If possible even gradual : N opens S fully, SW opens N and E half, SSW opens 75 % N and 25 % E etc.)

Windows should also close gradually with heavier wind / open gradualy with less wind.

So both parameters winddirection and windspeed interact : mulitplying the factor for the winddirection N 75 % (in the last example) by the factor for the windforce for example 60 % = opening 45 %.

Above 5 bft and/or when rain : all windows closed.

Below 2 bft all windows open.

To avoid to much action of the actuator a kind of average over the last 15 - 30 minutes should be used or maybe using steps for opening and closing.

Except for sudden increase in wind speed or change in winddirection at higher windspeeds : immediate action, or faster reaction based on higher wind speed or maximum speed.

Maybe I need other sensors as well : inside / outside temperature, humidity.

All ideas are welcome.

I would like to adapt the interaction of the parameters based on experience of the controller adapting to the best logic.

It should be possible to overrule the controller by switches.

I know I’m asking a lot, and would be satisfied with some control.

Until now I seached for domotic controller and weatherstations but all have problems with the winddirection parameter.

I think the outside sensors should be protected against lightning avoiding the Arduine to explode.

I am no electronic specialist but I can connect and weld some components if I know what to do.

Many years ago I programmed in machine language on a 8080 PC and I am sure I could draw a flow chart of the algorithm if I could understand the program language.

Can this be done with Arduino ?

What Arduino and other components would I need ?

Can I do this with my limited electronic and IT-knowledge ?

Or is this too complicated and do I best continue with my 4 manual switches (each time I use them I get frustrated because I know this could be automated) ?


WMU 86x-88x-n install 1210-UK+D+DK.pdf (215 KB)

WMU 86x+88x_data_ver04-UK.pdf (727 KB)

Can I do this with my limited electronic and IT-knowledge ?

Maybe, maybe not. Your project has several different parts, such as hardware/code to drive the motors, open/closed position of the windows, determining wind direction and velocity, etc.. Determination of wind direction and velocity might be the more complicated part, so you should start there and see if you can figure that out.

Thanks for the reply.

First of all, of course something went wrong sending my first post as I pushed the send button too fast.

And then the final post got very long.

I’m somewhat surprised you think the windmeter and winddirection meter might be the most complicated part.

I really thought that was the real easy part as, in view of all the other complications, I was planning to buy a commercial windmeter and winddirection meter + rain sensor.

So I’m definitely not building the windmeter and winddirection meter myself, the project being complicated enough.

I found that most of the windmeters and winddirrection meters have an output of Modbus, 0-10V, or 4-20 mA, and sometimes 2 or even 3 of these outputs.

I thought the difficult parts would be :

  • finding a good algorithm for using wind average and direction to avoid too much actuator action, but avoiding damage to the windows by sudden storm (although the windows and chain engine are really solid);

  • maybe leaving the idea of continual gradual change and prefering some steps with average thesholds;

  • reading and using the data out of the actuators regarding the degree of opening of the windows by use of the 3th green wire of MotorLink;

  • combining all the incoming and outgoing parameters; making the algorithm and programming it.

As said before I made an enumeration of all the things that could be useful in a perfect world, but I’m willing to go for less than perfect.

Sometimes I see such actuators on windows of a skylight in shopping malls in different directions and always notice not all the windows are open in the same time. So some logic / algorithm should be applied.

Thanks to everybody for all ideas.


As said before I made an enumeration of all the things that could be useful in a perfect world, but I'm willing to go for less than perfect.

If you already have some parts of the project sorted out to your satisfaction, that is good. I suggest you need to move the work on your project from a complex "pie in the sky" concept to working on some specific part that you haven't figured out. What have you completed so far?

Sorry for the delay but I was thinking about the project.

I made a flowchart in attachment but it is handwritten.

I hope you can read it. If not I try to search an application for drawing the flow chart.

I knew the project was complicated, and could get more complicated by thinking about it and it did.

I hope it gets easier.

Some thinks I’m doubting : basiclly I need a good compromise between enough actuator action and too much action based on some “intelligence” thinking.

Do you think I can realise this project with my limited knowledge and what hardware Arduino parts do I need ?


flowchart control 4 actuators based on windforce winddirection and rain.pdf (107 KB)

Do you think I can realise this project with my limited knowledge and what hardware Arduino parts do I need ?

If all you have done so far is "think about it", then the project probably won't happen.

No, no, this project will go on, just because I think about it first.

Right now I plan for 2 options both using the Davis Vantage Pro 2 weather station :

First option.

    With Vantage Pro® and Vantage Pro2™

WeatherLink for Alarm Output with Connector Block
Now you can automatically turn heaters, fans and other devices on or off
using your weather station. For each of four outputs, you can enter up to eight
different weather parameters. Enter threshold values for each, select from
nine different test conditions, and link the entries together as you choose.
For example, you could activate a fan to cool your house—but only if the
difference between the inside and outside temperatures is more than 5°F,
it’s more than 72°F inside and it’s between 5:00 p.m. and 6:00 a.m. Our
connector block provides the interface between your weather station and an
electrical device. For high-power devices, you may also need to
add electrical relays (not supplied by Davis). Connection to a
PC is not required except for initial setup.
6544 WeatherLink for Alarm Output

See manual in attachment.

Current Wind Speed X X X X X X
10 Minute Average Wind Speed X X X X X X
Wind Direction (when two
thresholds are used, they are
used to define a sector of the
compass to check). The smallest
difference between the two is
used as the sector to check, i.e.,
you can never set a sector larger
than 180 degrees

Wind Direction: When using the between and not-between check types, the Alarm Output data logger is intelligent enough to handle the North rollover. For example, if you set “IF Wind Direction is between 350° and 10°”, the alarm will be active when the wind direction is between 350° and 10° including 355°, 0°, and 5° and any directions in between. Reversing the entries will cause the alarm to be active for most wind directions excluding those around north.

Then I think I would need a simple relais + impuls switch DPDT – Double Pole Double Throw to reverse polarity (window open or closed) when using pulse alarm activation or 2 timers + a DPDT relais when using continious alarm activation.

Second option is to use an interface KTA-282 Modbus TCP Weather Station Gateway
 Connects a Davis VantagePro2 or Vantage Vue
to a Modbus network
and then to work with KNX Home Automation


07395-219_Adendm_06544.pdf (398 KB)

AN_29-weatherlink-alarm-vantage.pdf (174 KB)


I made some inquiry into the control of green houses but this doesn’t provide a solution since the windows in green house are only controlled in 2 opposite directions (N / S, etc.) and not in 4 directions. Using a system for green houses in my case with 4 windows in each wind direction would mean using 2 double green house controllers an furthermore a single weatherstation cannot be shared by the 2 controllers. So too many issues. Basically the controller for green house acts on inside and outside temperature. The desired inside temperature is set according to the crop, for example 26 °. If the inside temperature is 40°, so too hot, and the outside temperature is 20°, first gradually the windows opposite of the wind opens bit by bit, if necessary until the window opens above horizontal position (creating a suction by a kind of opposite spoiler effect). Note the green house windows have top hinges not bottom hinges for this reason. If the fully opened window opposite of the wind doesn’t give the desired temperature then bit by bit the window facing the wind is opened in a smaller degree than then opposite window. For controlling I’ve also been thinking about PLC of Siemens LOGO that can be connected to home automation KNX .

The most common standard is KNX or LON. There is also Modbus, a kind of industrial standard (I think compatible with KNX and LON). My actuators and the Davis weather station + interface are Modbus compatible. So for now I could make the controller stand alone and later on I could connect the Siemens PLC LOGO the a general home automation KNX or LON. I doubt now : Arduino or Siemens PLC. Could I connect Arduino later on to KNX or LON ?

Another idea is not to use my own weather station but to use the data that are available on line on an internet page of a weather station about 100 meter further. I could log these data into the Arduino or Siemens PLC avoiding the cost of installation of the weather station, risk of lightning, etc.