I realized that the uploaded model for the XY motor mount was not what I thought; it was missing the Hall Effect sensor mounts that are clearly shown in the photos. Not sure why and I could not find a source file that had them, so I suspect I made mods in openSCAD and then did not save them. Silly!

I've also included the 28BYJ_48 geared stepper motor and mount source files (openSCAD) that are referenced by the XY motor mount.

The case for the Arduino Mega controller was too small, so I made changes to make it taller. That provides more space inside for wiring. It also seemed a good idea to add a reset button and a second button that I can use for mode selection or something -- I've not yet decided as I need to review the existing code.

The next, and final step is to design a mount for the third 28BYJ_48 that moves the fine focus of the scope. Two more gears are needed, so back to my custom openSCAD gear generator, which will likely result in an update to that source. The code to control fine focus should not be too hard; I will use left and right mouse buttons for closer (down) and father (up).

This all will have to be done in the next 11 days as I need the unit to show to Grade 7-9 students at a summer engineering camp with a focus on Arduino programming. Quite looking forward to it!