A refreshed version of a design I created years ago and released on a different 3D print sharing site.

It's pretty simple to print. There's no overhangs or supports, it prints flat on the bed. If you can print a calibration cube, you should be able to print this.

Print a base, 2 big gears, and one small gear.

[Edit: 19 May 2023] I didn't leave enough clearance for the gears to fit on the pegs, so I refreshed all the files.