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Templator for Coldcard Paper Wallets

Just looking for some cool paper wallet templates? Go to outputs subdir and take any of the PDF files for use on Coldcard. You can view them with normal PDF programs, but they have been specially prepared for editing by the Coldcard.

How It Works

  • an artist creates the PDF with background artwork, blank spots for QR's
  • locations for pubkey, privkey QR's and any text blocks are defined mm by mm, in build.py
  • run build.py to add placeholders objects for the 2 QR codes, related variable text
  • a template file--which looks and acts like a PDF---is constructed, in ./outputs
  • use the resulting (pdf) file on Coldcard via a MicroSD card
  • the Coldcard can find what it needs inside the PDF template and will modify it with final values

Design Tips

  • you must include whitespace around the QR code: more the better, and should be fully 'quiet'
  • QR will have background white with black pixels ... so do not place over gradient

TODO

This project isn't done yet!

  • make it easier to add new templates; pull meta data out of build.py into other files
  • build a gallery of useful examples
  • make many seasonal templates, starting with Nov/Dec holidays

References

QR Sample images

  • Made a zero-border verion 4 image here: https://www.nayuki.io/page/qr-code-generator-library

  • With 8 pixels per module, like we will be doing.

  • Edited with Preview.app

  • Command to go from PNG with alpha and some text into simple PNM file:

    `pngtopam -mix -background=#FFF qrsample-pk.png | pamditherbw -threshold | pamtopnm > qrsample-pk.pnm