This project uses a 28BYJ-48 5V stepper motor to change the angle of a set of vertical blinds (it is not powerful enough to raise a roller blind). The motor is mounted vertically below the end of the blinds and drives the pull cord, so no modification of the blinds is required. The drive wheel fits a pull cord with 3mm diameter beads, 4mm apart.

First push the drive wheel onto the motor and then seat the motor in the motor case. Then do a test fitting so that you can mark the holes in the wall where the motor will be placed. Make sure that the pull cord does not have any slack against the drive wheel. The vertical slots in the mounting case allow for adjustment of the tension in the cord. Once the holes are drilled you can fix the mounting case to the wall and finally fit the cord guide. I used two M4 * 26 screws which grip nicely.

I use Home Assistant to control my blinds with ESPHome. Details are here [https://github.com/RoadkillUK/Motor-on-a-Roller-Blind-for-ESPHOME](https://github.com/RoadkillUK/Motor-on-a-Roller-Blind-for-ESPHOME) for the setup I use.