what are QR codes and how does my phone camera associate them with a link or URL

236 views

what are QR codes and how does my phone camera associate them with a link or URL

In: 103

24 Answers

Anonymous 0 Comments

The tldr is that QR codes are basically just fonts.

When a qr code opens a website it’s because the text was literally just www.blahblah.com in the qr font.

Bar codes work in exactly the same way, just a font.

Anonymous 0 Comments

The tldr is that QR codes are basically just fonts.

When a qr code opens a website it’s because the text was literally just www.blahblah.com in the qr font.

Bar codes work in exactly the same way, just a font.

Anonymous 0 Comments

The tldr is that QR codes are basically just fonts.

When a qr code opens a website it’s because the text was literally just www.blahblah.com in the qr font.

Bar codes work in exactly the same way, just a font.

Anonymous 0 Comments

[removed]

Anonymous 0 Comments

[removed]

Anonymous 0 Comments

[removed]

Anonymous 0 Comments

Oversimplified: a QR code is really just a compact and complicated font. The different patterns of squares make no sense to us, but the font can be read by our phones. So when your phone associates them with a link, it’s a font that says www.[whateverrandomwebsite].com. For convenience, your phone sees that website and offers to take you there.

Anonymous 0 Comments

Oversimplified: a QR code is really just a compact and complicated font. The different patterns of squares make no sense to us, but the font can be read by our phones. So when your phone associates them with a link, it’s a font that says www.[whateverrandomwebsite].com. For convenience, your phone sees that website and offers to take you there.

Anonymous 0 Comments

Oversimplified: a QR code is really just a compact and complicated font. The different patterns of squares make no sense to us, but the font can be read by our phones. So when your phone associates them with a link, it’s a font that says www.[whateverrandomwebsite].com. For convenience, your phone sees that website and offers to take you there.

Anonymous 0 Comments

You’re sort of familiar with the idea of Morse code, right? The long-short-long pulses they’d send over telegraph wires in the olden days?

Imagine taking a string of text, like a website URL, and converting it to some kind of Morse-like code. You could write it down as a sequence of dots and dashes on some notebook paper.

Those dots and dashes are kind of hard for a computer to read using a camera. Perhaps instead of dots and dashes, we can use light and dark. Those are pretty easy to pick out. Let’s swap out our notebook for a graph paper notebook, so we can use the little graph squares. Instead of writing dots and dashes, we can instead create a sequence of filled-in squares and blank squares to represent our message.

If you took that string of squares and extended them up and down so it became a series of lines (which makes them even easier for a computer to see), you will have essentially invented the barcode. Just like the ones the scanners at the store use.

So, what if the thing you’re trying to write out is really long? That would create a looong barcode. What could you do? Well, if you were writing that long URL in regular text in a notebook, and you ran out of room, what would you do there? Snap it off somewhere and start writing it on the next line, right? You can do that with your barcode, too. Once your run out of squares on your graph paper, just start writing on the next line, and keep going until your whole message is encoded. If you’re really clever with this, you can even do it in such a way that the final result looks kind of square-ish.

And that’s it. You’ve essentially invented the QR code. A computer can take a picture of that, use scanning software to pick out the light and dark squares, convert it to a string of Morse-like code, and decode it into plain text. It can then recognize it as a URL (if it is one) and may even open that URL right away without needing to be asked. The computer is so quick at this that it all happens basically instantly.

There are nuances that I glossed over, of course. QR codes are more complex than that. For instance, the funny square patterns in only three of the corners. Those markers are essentially the same thing as the “THIS SIDE UP” marking on a cardboard box. It tells the computer which part of the code is the starting point. With that info built-in, you can photograph a QR code sideways, right side up, upside down, or any other orientation and the computer can just figure it out and read it anyway. There’s also some clever error-correction stuff crammed in there so that even if small bits of the code are obscured, or blurry, the computer can still correctly guess the message.