[Bug] Problems using camera to scan QR from Coldcard Q screen

[nervetrip]

No matter what I do, I can't get Krux running on Yahboom to scan any QR codes displayed on a Coldcard Q.

Here's a throwaway seed phrase on the Q with screen brightness turned to the minimum (25%) and a desk lamp illuminating the area:

Krux refuses to focus properly when scanning the Q screen. I've tried so many times with different distances, angles, screen brightness, ambient light levels, etc. These pictures illustrate what I'm seeing on the Yahboom screen. Note that my fingers are fully in focus, but Krux can't seem to focus on the QR code. I took the pics when it was as good as I could get it, it certainly was often even worse.

However, Krux scans QR codes from my computer screen without any issues. The QR code is fully in focus on the Krux screen:

Lastly, I can take a picture of the QR code on the Coldcard screen, display it on my computer, and then Krux successfully scans it.

Although you'll note that it scans all the seed words in capital letters, and indicates that the 12th word is invalid. I assume this is an unrelated issue (not due to camera focus problems described in this issue). I'm thinking that loading this style of QR code content is probably a feature enhancement for Krux.

I'm not sure if this issue qualifies as a bug, feature enhancement, or user error. But I'm hoping firmware/camera tweaks might improve QR code scanning from Coldcard screens. And if it's user error, I'm open to suggestions on how to improve QR scans.

[jdlcdl]

I'm thinking that loading this style of QR code content is probably a feature enhancement for Krux.

I agree, it looks like the qrcode represents first 4 chars of each word in uppercase (while krux can scan complete words in lowercase). Im not aware that it knows to downshift case and to extrapolate the full word... yet.

Does the yahboom have a camera lens wheel where you can fiddle with focus? If it does, that might be the trick for reading the q screen. ???

Nice write-up!

[odudex]

Thank you for the detailed report!
I have a Q here and want to confirm the issue.
By rotating the camera lenses (this can be tricky at first), you can adjust the focus and be able to scan closer, smaller QRs from phones and smaller devices. Anti-glare, activated by pressing the bottom button while scanning with Yahboom, could also help in these cases.
However, Krux can't read this standard (chopped uppercase words). I didn't know it until I saw this issue. Krux can read plain text words, SeedQR (word number), and CompactSeedQR (mnemonic bytes).
As Krux already has code to autocomplete chopped words, we could implement this quickly. But it would help a lot if Q could increase the QR frame to the recommended 2 QR blocks (currently 1) or, even better, use the full screen to show the QR.

[jdlcdl]

it would help a lot if Q could increase the QR frame to the recommended 2 QR blocks (currently 1)

Ahhh, Now I see it. The full-white quiet-zone margin around the qrcode contents.