Why is my QR code not detectable / scannable by mobile devices?

QR Code Design Basics

A QR code is comprised for modules and the eye. The module area contains all the data, the Eyes are used as a guide and for orientation purposes. The VioQR software allows uses to customize the QR code design by modifying certain key elements of the QR code, however extensive modifications can cause the QR code to now work and be detectable. Hence please use the guidelines provided in this article to design or customize QR codes that do not impact the fundamental elements that carry information for the QR code to work.

PLEASE ALWAYS TEST THE QR CODE MUTIPLE TIMES BEFORE PUBLISHING IT FOR USE.

There are many reasons that could prevent your QR code from being detectable, here are a some of them:

Logo position or logo size

1. If you add your logo to the QR code, it should not cover more than 30% of the data area.
2. The logo should not cover any of QR code eyes, covering eyes will result in detection failure.

Note

If you are using custom shapes, let’s say a t-shirt shape, the logo can cover more than 30% of the whole image, not the actual QR code area, but in the area outside of the actual QR code.

Below are some examples of scannable and unscannable QR codes.

CUSTOM EYE WITH CUSTOM MODULE

Eyes and patterns

You can choose either to use custom eyes or custom patterns, not both of them. Patterns with small module size are difficult to detect by mobile devices. You can still use custom modules with custom eyes if units are connected to each other. 

Here’s is an example of custom eyes and modules that has a high chance of not getting detected

CUSTOM EYE

Here’s is an example of default eyes and custom modules this design has a high chance of getting detected. 

CUSTOM MODULE

Here’s is an example of custom eyes and  default modules this design has a high chance of getting detected. 

BASIC QR CODE WITH LOGO

BASIC QR CODE WITH LOGO AT THE MIDDLE, IT DOES NOT COVER MORE THAN 30% OF ITS DATA AREA.

QR CODE SHAPE WITH LOGO

LOGO WITH CUSTOM SHAPE THAT COVERS THE TOP RIGHT EYE OR ANY EYE.

QR CODE SHAPE WITH BIG LOGO

LOGO WITH CUSTOM SHAPE THAT’S OVERSIZED COVERING THE MODULE DATA AND THE EYES.

QR CODE SHAPE WITH CORRECT LOGO SIZE

QR CODE WITH CUSTOM SHAPE AND THE LOGO IS POSITIONED AT THE CENTER OF DATA AREA, AND IT DOES NOT COVER MORE THAN 30% OF IT.

QR CODE SHAPE WITH LOGO OUTSIDE QR CODE DATA AREA

QR CODE WITH CUSTOM SHAPE AND A LARGE LOGO THAT DOES NOT COVER THE DATA AREA.