Variants : Single action vs dual action
This project is declined in 2 variants that only differ by a few small 3D-printed pieces and screws.
In this variant, there is only one slider attached to the belt, meaning you can only move the curtains from one side to the other, like this:
This is the design I went for as it was the only viable option in my case given the geometry of my windows. I have entirely tested this configuration and have it in use in my home.
This variant uses two sliders and can therefore move curtains positioned on either side of the window, to to center, like this:
Note that this is still using only one motor ! This setup will likely fit most configurations. I have partially tested this variant but have not performed full validation of the system in its entirety. However, the hardware differences with the single action variant are very limited (literally 3 more small 3D-printed parts and 4 screws and nuts) and the code is identical so I assume there should not be too many problems but use it at your own risk !
I designed this project under the constraint that it had to be ceiling-mounted. That means I spent some time designing the ceiling brackets but not so much time on the wall brackets as I'm not using them. I have however tested them but not mounted on the walls. So again, you can use these brackets but you might better off designing your own or using someone else's.