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

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 7 days ago \| parent [-]
		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...