I can't even make a clocky-repeaty thing work.

Two methods.
Method 1 on the left is simple, uses a small amount of space, but breaks easily and is hard to start depending on your speed setting.
Method 2 on the right uses a piston, it's toggleable, easy to start, but it takes up a bit of space, not too much. It makes a bit of noise, too.
There's a third method I don't want to even bother with since it's been made so obsolete it's not even funny.
I usually use method 2.