It’s probably more than can be taught in a single class but how about guiding a class through one of the hundreds of Arduino POV projects and combining it with reducing the final board to using only the ATMEGA chip instead of the Arduino? Maybe this isn’t as possible as I hope?
For replacing the Arduino with the chip I’m referencing this Instructable.
This would be an example POV project, though the 3d printed parts could be replaced with something less refined - or combined with a separate 3d class!