Automated smart blinds retrofit device with WiFi , MQTT and light measurement capability.
You can find project details on GitHub
There is set of files for each side of window.
You have to measure the ball chain dimensions and try which pulley will work better for you. In my case, balls have 3mm in diameter and centers are 3,5mm apart. I am using ball pulley 2, which has better grip.
Plasty Mladec PETG
Moving parts cleaning
I chamfered all edges of printed parts with sharp knife, and then grinded moving parts with sand paper.
Designed in Autodesk Inventor