Spherical trackball

This is a functional one-button USB trackball shaped like a sphere. It does not sit on a desk, you have to hold it in your hand.

It was made using:

• a 57.2mm billiard ball
• PMW3360 optical sensor
• the PCB from here: https://github.com/jfedor2/rp2040-pmw3360
• Omron D2FC mouse button switch (or any other switch with the same footprint)
• this PCB for mounting the switch: https://github.com/jfedor2/mouse-switch-mount-pcb
• 2.5mm zirconium oxide (or silicon nitride) bearing balls
• M2x4 screws for mounting the button and the switch PCB
• M3x4 screws for mounting the main PCB
• 3x10mm wood screws for assembling the case

The top part needs supports, the others don't.