These considerations and others suggest a microcontroller solution. A system running Linux seems like overkill indeed

If I were starting this now and the only outcome was to open and close curtains then I would be using a microcontroller.

I first heard about the Raspberry Pi many years ago and have been meaning to experiment with one periodically ever since so this is a good 'excuse'. Plus, it forces me to improve my Linux skills which in and of itself is a good outcome.

Besides, when this project was started, microcontrollers were not on my radar...