External venetian blind automation

Hello all,

I am currently building my house (a passive house). I am planning to make home automation with an arduino. This house has external venetian blinds that are used to increase or decrease the amount of sun entering the house. They can be completely openned, completely closed and the mid position is obtained after complete closing through the right impulsion. We can then play with the correct angle position to shade a minimum the sun.

Those shutters are made from Schenker and as a basis will be installed with an switch up (for the blind going up) and a switch down (for the blind going down) on the wall (directly connected to the motor of the venetian blind). This is a simple switch similar to any roller shutters.

I would like to set-up a way to connect the arduino and control the blind automatically (for example, when there is too wind, we open it, when too much sun on the summer, I move a bit the blind to decrease the glare, etc... the best would be that the blind follow the path of the sun...). For that I have planned to bring an anemometer, a sun power measuring device.

The electrical motor has two limit-switch sensors (one on the upper position and one on the bottom position).

  1. Do you have any schematic to connect the arduino and monitor that venitian blind (with relay , etc ?) and in particular, how to monitor the intermediate position and put the blind to the right angle ?

  2. Is there a way to keep the manual switch on the wall and let it prioritized among the arduino ? how to manage that ?

  3. Finally, how to operate two blinds in parallel the same way. Upstairs of my house I have two windows that will have two parallel venitian blinds. (I was told we should not connect two electrical motor in parallel).

Thanks a lot for your help.

As soon as I move forward, I will give you more update on that project.


A long time back I attached a servo to a standard venetian blind such that it could operate the slats. Somebody recently posted a similar question so I checked my venetian blinds and noted the slat wand took ~6 turns for full range of operation. Hobby king has a 6 turn sail winch servo that probably could fully operate the wand.

Thanks a lot for your reply but I already have the electrical motor integrated into the venetian blind.

The venetian blind is motorized and sold as such. The motor is connected to two wall switch (one button up and one button down).

My goal is thus to not modify this part that will be existing.

THose external venetian blinds are not like traditionnal ones we found inside houses. They are made of aluminums. Slats are something like 6 cm wide. Griesser or Schenker are manufacturing that kind of for passive houses.


I am speaking to question 1 here:

To automate the motor you will need a motor shield and possibly a power supply.

To specify what kind, could you send a link or picture of your blind system? Is the motor DC? What are its voltage and current specifications? Is there a power supply (big square magnet) to the motor included in the system?

A possible solution: Small systematic motor bursts would angle the blinds in increments determined by your light sensor. Your light sensor would determine intermediate position because it is unlikely a position monitoring stepper motor is included with the blind system. In any case, to speak any further one needs to see the venetian blind specifications


Thanks for your reply.

Find attached the schematic of the motor already integrated in the Venetian blind. Seems to be a motor from the manufacturer Somfy, J4 type.
The motor is AC 220 V current ranges from 0.4 to 1.1 A depending on the blind and motor used (width of window).

The light sensor is a good idea but how would you adjust that depending on sun lights in different period of the year ? I am not sure to understand.


For that motor, you will probably need a relay shield, with 220 V contacts (light duty).

Why are there two down switches in the schematic (AB1 & AB2)? Is one of them halfway?

I agree with you on the relay shield but the think is that it seems we can not connect both in parallel as we could have on one side a manual command and at the same time a command sent by the arduino through the relays.
I am not quite sure why there are 2 buttons down. I would guess this is maybe one is to decrease the venetian blind and close them completely and the other is to decrease the venetian blind up to the parallel slats.
I do not have yet the blinds in my hands. I am currently requesting more informations to my house builder.


Any other idea ? If someone could share a schematic for this Venetian blind to arduino connection, I would be most gratefull!

Thanks again.


Stil questionning myself on how to keep my wall switch (up and down) while monitoring the venetian blinds automatically (they have motor integrated).
How to keep priority on the manual switch... how to avoid up in manual and down sent by the arduino not to destroy the motor.

If any schematic exists, let me know. I would be very enthusiastic to test some of those and share that in the forum!


Hi Nikito

I'm looking at buying similar blinds from schenker (storen.ch) while renovating my house, were you successful in your undertaking? If so what solutions did you go with?

I want to be able to control my blinds mostly to avoid the place heating up too much, so it would be part of a network with a few sensors as well.