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Barcode

Hi all,

Has anyone got any ideas about where to get some C code to read a barcode?

Ive got a pen but dont know what to plug it to.

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  • "I think Erik is trying to be funny?"

    Not really: several contributors have told you that this is not a trivial exercise, and yet you continue to ask to be given free, complete code!

    "very sarcy and not helpful!"

    Your request looked more like a demand for a freebie than for "help".

    "I think polling might not work well, and I think I must use an interrupt."

    Now you're getting somewhere!

    Whether polling is workable depends on what else your processor has to do - since a barcode swipe is only relatively brief, it might be possible to stop everything else and poll the input during a swipe...

    "But should it be edge or level?"

    Probably edge: what you want is to detect the start of a bar - which would be an edge.
    You then need to time the width of the bar.

    As already mentioned, this just gives you the raw bar timings - you then have to process that to allow for irregular and skewed scanning, poor-quality printing, etc, then decode that, etc, etc,...

    Barcode scanners are relatively cheap on ebay - do you really need to do this from scratch for yourself?

    Have you tried looking on the Agilent site, or others?

Reply
  • "I think Erik is trying to be funny?"

    Not really: several contributors have told you that this is not a trivial exercise, and yet you continue to ask to be given free, complete code!

    "very sarcy and not helpful!"

    Your request looked more like a demand for a freebie than for "help".

    "I think polling might not work well, and I think I must use an interrupt."

    Now you're getting somewhere!

    Whether polling is workable depends on what else your processor has to do - since a barcode swipe is only relatively brief, it might be possible to stop everything else and poll the input during a swipe...

    "But should it be edge or level?"

    Probably edge: what you want is to detect the start of a bar - which would be an edge.
    You then need to time the width of the bar.

    As already mentioned, this just gives you the raw bar timings - you then have to process that to allow for irregular and skewed scanning, poor-quality printing, etc, then decode that, etc, etc,...

    Barcode scanners are relatively cheap on ebay - do you really need to do this from scratch for yourself?

    Have you tried looking on the Agilent site, or others?

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