Small but working QR codes

[RageTester]

How to make small qr code images that can still be read after you upload them online?

I managed to scan 42x42 pixel QR code on local machine, but... So far web compression has destroyed every single one, even some of the huge QR codes I make. Nothing works after uploading...

working QR

fail

[Alex Atkin UK]

I think you may find the biggest problem is having to hold your phone (I presume this is what you are scanning with) too close to the screen for it to focus.

If I zoom the second image then try to scan it, works fine on my S10.

[manikyath]

its mostly a matter of the image being displayed sharp enough, and whatever you're using to pick it up (presumably being a camera) being able to focus on it.

 

maybe putting a 2-3 pixel white border around the code would make things a tad better?

 

the biggest one is working fine for me, the other two arent big enough for my phone to focus on them, but i've scanned that size on actual handheld scanners before, off screens.

[RageTester]

Thank you very much, it works!

[Kilrah]

Smallest one works on my iPhone but not with my Android phone. Both can focus, but obviously the performance will depend on the app used to scan.

 

The dots on it are so small that they're basically indistinguishible from the LCD's grid...

 

 

The fact some appear grey suggests something might be happening with the LCD refresh as well.

[RageTester]

11 hours ago, Kilrah said:

Smallest one works on my iPhone but not with my Android phone. Both can focus, but obviously the performance will depend on the app used to scan.

 

The dots on it are so small that they're basically indistinguishible from the LCD's grid...

 

The fact some appear grey suggests something might be happening with the LCD refresh as well.

Yeah well I wanted smallest that works without using zooming and white border around QR code helped with that... tested on my old laptop screen and cheap Hisense A5 smartphone camera, so I will stick with around 50-60 pixels width. Going even smaller isn't much of a gain, but can cause problems...