Forrest O. Fab Academy

Week 16. System Integration

Hand scale test print

I wanted to hold a version of the design made with the web app.

Web simulation test print.

Prusa Mini, 24 hour print, generic white PLA.

One idea is that this will become the "nucleus" of the soft version of the pixel ball. Electronics and battery.

Another idea is to scale this so that LEDs can be embedded on the inside.

Design with positive and negative space

The mesh that my design app outputs has overlapping shapes where the ropes rest against each other. Prusa slicer doesn't have a problem with this. It makes the perimeter and infill as if the shape is unioned. But trying to do any other Boolean modelling on the shape in Blender or JS made a lot of broken and sad meshes.

I found a workaround: export positive and negative space as 2 separate STL files, then combine them with Prusa Slicer.

  1. Rope simulation and mesh generation works as before.

Screenshot of sphere of LED sockets.

  1. LED positions and rotations calculated and previewed.

Screenshot of generated positive and negative.

  1. Slice the rope mesh and preview the LED positions with it. Export positive and negative STLs.

(Possible enhancement is to do this all with SDF modeling.)

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  1. Load the positive STL in Prusa Slicer.

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  1. Right click the positive and choose Add negative volume > Load… to subtract the negative STL from the positive.

The rectangle in the both positive and negative STLs is for registration. They import with the correct orientation relative to each other, as they are saved. When they are lined up correctly, the registration tabs negate each other.

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Click "Enter 3D Print Mode" on the rope simulation web app to try the new LED socket parameters and multiple STL generation.

Test print

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Smaller test print, with the sockets scaled for some bigger LEDs that I wanted test.

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The white filament absorbs more if the light than I hoped. I need to experiment with clear filament.

Plan A

I'm talking myself out of embedding the LEDs on the inside of the ball, and thinking that I'll go back to the soft design. I can still use the generated 3d print as the internal case for the electronics.

  • [] Hinge and clasp design for internal case.
  • [] Battery holder
  • [] Sewing soft outer case
  • [] v1 of Arduino software

Plan B

Light labyrinth Plan B illustration.

A gimbal like this for the middle of the softball-sized labyrinth ball. Instead of compass, a single focused LED shining up ▲ with battery down ▼ for weight. It will always shine up, so you could manually make the light follow the path. Throw out the microcontroller and LED strips. Done.