I know there are already a bunch of QR code generators out there on MakerWorld, but none of them solved my very specific problem, so I built my own.

The story behind it

I'm a big fan of printing rugged travel cases for my card games like Flip 7, Skyjo, UNO and the rest. They make it so much easier to throw a deck in your bag and take it on holiday or to the park instead of lugging the whole bulky box around.

But there's always the same issue: I leave the box at home, and with it the rulebook. And of course, the one moment someone asks "wait, what was the rule for...?", nobody remembers.

So I came up with this: print a single small card that lives with the deck. On it: a QR code linking directly to the rules PDF. Pull out your phone, scan, done. The big box stays home, the rules come with you.

Yes, very niche, I know. But maybe a few of you out there have the exact same problem and this solves it for you too.

Features

- Fully parametric, works with any common card size (Poker, Bridge, Skat, Euro/UNO/Skyjo, Yu-Gi-Oh, Tarot, square Dobble, Mini, or fully custom)
- Paste any URL: your rules PDF, BoardGameGeek page, YouTube tutorial, whatever fits
- Optional label text for the game name
- Classic playing card suit decorations in the corners (♠ ♥ ♦ ♣ or all four)
- Each element is a separate object, so you can assign different filament colours in Bambu Studio for clean two-tone prints
- 100% self-contained `.scad` file, no library imports, no dependencies
- MakerWorld Customizer compatible, change everything from your browser

Print tips

- Slice with a filament change at card thickness for a white card body with dark QR and suits
- 0.4 mm nozzle works fine, just keep the QR margin generous so modules stay readable

**Troubleshooting**

If your print comes out messy or hard to scan, two tips that solved it for me:

1. Set the QR height to 1 mm. Lower values can cause issues with module separation on FDM printers, 1 mm gives you reliable, clean modules every time.
2. If your URL is long, run it through tinyurl.com or bit.ly first. A shorter URL means fewer modules in the QR code, which means each module gets bigger and prints much more cleanly. This makes a huge difference if your link points to something like a Google Drive PDF with a long path.

Update

Added a universal rules card to the project that works for any game. Print one and keep it handy for the friends who ask about the rules every five minutes mid-game. Teach them the proper way with a classic Rickroll.

If you create your own cards for specific games, feel free to upload them and add them as print profiles to this model. Would be great to see a little collection grow over time.

Credits

- QR code algorithm based on [scadqr](https://github.com/xypwn/scadqr) by xypwn (MIT License). Huge thanks for making the math available.
- Special thanks to [QR Code Generator (qrcode for mail, wifi, etc)](https://makerworld.com/de/models/476280) for inspiring this project. Their model handles the general-purpose case beautifully, mine is the playing-card-specific cousin.