Twitter QR Code

By using the highest level of error correction permissable in QR Code generation it is possible to obsucure a part of the code and still have it readable. The code below is version 4-H, contains a twitter icon and resolves to my twitter page.

QR Code with a twitter icon

5 thoughts on “Twitter QR Code”

  1. Can you explain what you mean by “the highest level of error correction permissible? I don’t see an option in most QR code generating services. Also, what does 4H refer to?

  2. @Aaron – Sure – You are correct that most QR Code generators do not have an ‘error correction level’ option. There are however some that do, like Raco (in the QR Code Generators list) and the Google Chart API for example.

    The QR Code specification allows for four levels of error correction and these are referred to as L, M, Q and H. H allows for 30% of a QR code to be restored (the maximum error correction level).

    Hence the H in 4H. The 4 is the version number and there are versions 1 to 40. Version 1 has 21 rows and 21 columns, Version 2 has 25 rows and 25 columns, Version 3 has 29 rows and 29 columns and so on up to Version 40 which has 177 rows and 177 columns.

    I hope that helps.

  3. Thanks, Roger.

    That does help. I’m going to have to look into this further. In the US, most phones can barely register a QR code, so I wonder if error correction level is something that requires a phone with a more advanced scanning ability or not.

  4. For what it’s worth, I used the Bee Tagg iPhone app – lousy camera and shot the R code on my laptop screen – it still brought me to your Twitter profile. Very cool.

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