[hypercube33]

I half expected this to have a button/mode to show custom QR codes...

[phirks]

I tried, that's why it's 21x21. Still haven't managed to get it to read.

[hturan]

I might be wrong, but you might need need (at least) a 23x23 LED matrix to have a white border around the outside to give it the contrast needed (the "quiet zone", since QR data is black).

[phirks]

This is why my first prototype had a white border around it. The LEDs were red back then, so I don't know exactly what I was thinking, but I was aware of the problem.

https://github.com/Nicholas-L-Johnson/flip-card/blob/main/me...

[nine_k]

Could as well display the name and/or email, if rotated just so.

[mcdonje]

That's a good idea!