Ploopy Nano trackball with button

The Ploopy Nano is a great little trackball that's just a trackball. No mouse buttons!

There are, however, contacts on the PCB to put the trackball into bootloader mode (by shorting them with a paperclip), and these can be used to add a switch. With modded firmware, you can then assign any mouse/keyboard command available in QMK to the button. I've configured it as a left mouse click. When I wiggle the trackball it changes to scrolling mode, and I can return to mouse mode by pressing the button.

This remix enlarges the shell to allow for a switch and button to be added on the left corner. Unfortunately, it's only possible for it to go on the left due to the design of the Nano's PCB.

Materials

• A Ploopy Nano
• A 6x6x6mm micro push switch
• Two 6-7cm lengths of wire to connect the switch to the PCB
• An extra screw that's similar to the one that came with your Ploopy Nano
  • I sourced mine from my box of random screws. It doesn't have to be exactly the same.
  • The second screw isn't absolutely necessary. It just seems wrong to not have it.

About that micro switch

So, here's the thing. I extracted my 6x6x6mm switch from the PCB for a Bambu Lab Wireless Mouse kit, because it was sitting around unused and I wanted to practice desoldering components. Other square, push-type micro switches might work, but there may need to be some adjustments. If you need some help with that, let me know.

I used the middle-button switch that's under the scroll wheel, because it has a smaller body and taller pushbutton than the left/right switches.

Note that rectangular mice switches won't work without significant modifications. They're too tall and wide.

Print instructions

I used 0.1mm layers for a smooth finish. At the very least, I recommend it for the top shell and button. The base can be 0.2mm.

The top shell needs support under the lens cavity only. Check your preview carefully to ensure that your slicer doesn't add it anywhere else (e.g. the screw holes).

Test-fit the button before you assemble everything. I made the tolerance fairly tight so that it can be sanded down to fit, rather than having the button be too small. No one likes a loose and wobbly button.

Assembly instructions

1. Solder the switch to the bootloader contacts on the PCB.
2. Place the reflective tape that came with your Nano in the shell.
3. Place the PCB and switch in the base.
4. Mount the button onto the switch.
   • If it's a tight fit, use a hobby knife to scrap away a bit of plastic. It should be just a bit loose on the switch, so that it can adjust to the hole in the top shell.
5. Put the lens in the top shell, sliding one edge under the retaining lip.
6. Put the shells together and test that the button clicks.
   • If the button won't move, then you may need to sand down the shell or button, or loosen the button's fit on the switch.
7. Secure the shells with the screws.
8. Put in your bearings and ball.
9. Done!

QMK/VIA firmware

You can now enter bootloader mode by holding the button when you plug in the Nano.

I use plodah's ploopy_viamenus firmware, which enables me to program the Nano using VIA in a web browser. Huge thanks for adding the Nano button at my request!

Another prebuilt option is the Wiggleball firmware by pandrr, which is configured for the button to change between mouse and scroll modes. I learned that this switch mod is possible from pandrr's Github.

If you need help with firmware, the folks in the Ploopy Discord, Ploopy subreddit, and Trackballs subreddit are fantastic.

Enjoy!

This remix mirrors the right side of the original Nano shell to make it symmetrical, then adds a push button to the left corner to make it asymmetrical again.

I also added a small lip on the lens cavity that helps keep the lens in place when assembling the device.