I understand the code itself is a different make up of black/white grids to get your phone to recognize a linked site. But at some point won’t we completely run out of possible image combinations making them obsolete or is it something that regenerates a new site to QR connection? (On mushrooms so I might not have asked this very well lmao)
Basically will we run out of QR codes and if not how is there an endless supply?
In: Technology
QR can store arbitrary information. Small black squares represent 1, white squares 0. This way you can directly construct binary numbers from it. These binary numbers can be a text (see ASCII table that converts 2 digit hex number – which is 2×8 binary digits – to a single character like ‘a’ or ‘X’). That’s how you can encode an URL or any other text into QR code.
However, you and me, we can create our own system, e.g.:
0000 …hello
0001 …something bad happen
0010 …I will come to you
0011 …do nothing
0100 …how are you?
0101 …good
0110 …bad
0111 …afraid
…etc.,
and then we can encode a message (one or more of these) into one QR code. So – we can create an app for us that will take that text, convert it to those numbers & those numbers it will put into QR code. On other phone, the same app could scan the QR, get those number from it and then convert those back to the original text.
QR codes can be big and store a lot of information. See
[https://en.wikipedia.org/wiki/QR_code#Design](https://en.wikipedia.org/wiki/QR_code#Design)
Interesting thing is also that QR codes are immune to damage or imprecise reading by the camera. Simple idea behind error correction codes is that you put there some additional information that helps in guessing what was the original, i.e. let’s encode just two words: “yes” and “no” like this:
00000 …yes
11111 …no
…then the message:
00100 00001 00111 11110 01001 10111
was probably “yes yes no no yes no”. If you receive e.g. “00111” it is more likely that it was “11111” than “00000”.
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