Barcode scanner

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faultman
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Barcode scanner

Post by faultman » Tue Sep 09, 2003 5:52 am

I have a project coming up and I'll need to detect a barcode. 3 of 9 is prefered but for now any barcode will do and I'll need it to provide or drive a set of dry contacts. I'm not interested in the barcode information itself at this time but only to make sure one is there. I'm trying to stay away for using a computer if at all posible. Any sugestions would be greatly appreciated. Thanks,<p>Frank

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Chris Smith
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Re: Barcode scanner

Post by Chris Smith » Tue Sep 09, 2003 9:16 am

Behind every scanner, is a computer and its needed software?

desterline
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Re: Barcode scanner

Post by desterline » Tue Sep 09, 2003 11:30 am

I can imagine bypassing the scanning engine and collecting the raw on/off from the pickup (phototransistor / photodiode / whatever) then just checking that you have several transitions of some length....<p>Don't see the advantage though, it would require consistant feed rates and environment etc...<p>Lots of barcode scanners are what's called a "keyboard wedge". They plug in between the computer and keboard and barcode data looks just like it was typed. <p>Add that to availible plans for various keyboard interfaces from PIC micros, and the basic building blocks are there to connect a scanner to a PIC without a computer.<p>One other thought, I have a scanner that beeps after it reads a barcode. It might be possible to pick a signal off the beeper instead of the data lines. I guess this would depend on weather or not the scanner needs "handshaking" with a pc.<p>Good luck
-Denny

faultman
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Re: Barcode scanner

Post by faultman » Thu Sep 11, 2003 10:43 am

Thanks Denny, that works fine. The scanner that I'm trying has an accept and reject lamp. That provides plenty of signal to drive a detector and that allows me to drive a relay. From there it's a piece of cake. Thanks for the ideas.<p>Frank

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