merch-gyro

Startup merch you can print yourself. This is a print-in-place gyroscope fidget: three rings and a core, each spinning on its own pins. You put your logo on it in the browser and download a two-colour file. It prints in one go, with no supports and nothing to assemble.

Make yours: merch.hammantlabs.com

I built it in my first week as CEO of Orbital, because we needed merch. The Orbital one is in examples/orbital/: 3MF or STLs.

Using it

1. Drop your logo into the centre. SVG is best; PNG and JPG are traced.
2. Put text round the ring, or drop in your wordmark. Each letter is laid on the arc without being bent.
3. Add a bottom line (your URL), then pick colours and a fit.
4. Download the 3MF. In Bambu Studio or OrcaSlicer, the body is filament 1 and the logo is filament 2.

Everything runs in your browser. Your logo is never uploaded anywhere.

Printing

Size	56 mm across, 8.6 mm tall
Time	about 30 minutes and 14 g of PLA on a Bambu P1S (9 per plate: about 3 hours)
Settings	0.2 mm layers, no supports, no brim
Colour	the logo is the top 3 layers, so a whole plate needs one colour change
One-colour printer	print the one-colour STL and add a filament change at 8.2 mm
After printing	twist each ring gently to free it

If the rings fuse on your printer, choose Loose (0.6 mm gap). If they rattle, choose Snug (0.4 mm).

How it works

• Rings: each ring is a band cut from a spherical shell, so it can turn through its neighbour without touching.
• Pins: 45-degree cones, so they print without supports. Each one sits in a cone-shaped socket with 0.35 mm of clearance all round.
• Axes: they alternate X, Y, X, which makes it a true gimbal.
• Artwork: it's raised 0.6 mm and kept inside a radius where it can never hit the next ring, whatever the logo.

The geometry is built with manifold (WASM), text with opentype.js, and the preview with three.js. There's no build step: index.html plus ES modules in src/.

• src/gyro.js: the geometry, the arc layout and the print-in-place checks (it runs in Node too)
• src/art.js: reads your SVG or PNG logo
• src/text.js: lays out text for the ring
• src/export.js: writes the 3MF and STLs
• src/preview.js: the spinning 3D preview

Tests

npm install
npm test               # geometry: every fit, every ring, 24 angles
npm run serve          # then, in another terminal:
node tests/e2e.mjs     # drives the real page in Chrome

npm test checks the guarantees as numbers for each fit:

• Four separate parts.
• No overlap at any angle, including all three rings tumbling at once.
• A 0.2 mm nudge in any direction is still free, so the gaps are real.
• A 1.5 mm push always hits something, so nothing can fall out.

Licence

The code is MIT. The Orbital name, cross and wordmark are Orbital's trademarks and are included as an example only; see TRADEMARKS.md. The fonts are SIL OFL.