How Can I Convert a Barcode Signal to 8-bit Binary Code with LEDs?

[garyman]

I am currently working on a project to build a barcode scanner. I have built the apparatus to detect a signal and am able to view this signal on an oscilloscope, however I am wondering if it is possible to build a circuit to output this signal as a binary code on a series of LED's (or something of that nature...)? You might of guessed I am not very proficent with electronics, so I came here for help! This signal is the same form as on http://www.thekeeser.com/Projects/bar_code_reader.htm" but of a continuous nature. I was thinking of putting the signal through some sort of Analogue to Digital convertor and then using some sort of counter to output this signal on a display, maybe a series of LED's representing a binary code? The readout doesn't have to be that accurate, just as long as it kind of works... Could this be done? How? Any help would be much appreciated!

 

[berkeman]

To decode the barcode signal, you will need to do some signal processing on it. The most straightforward way would be to do as you say, and digitize the signal and then process it with a microcontroller (uC). The uC will need to figure out what the bar frequency is (higher the faster you swipe), and figure out the synchronization and placement of the bars, and then the wide/narrow stuff. The information in 1-D barcodes is stored in the widths and spacings of the lines:

http://en.wikipedia.org/wiki/Barcode

Which encoding will you be using?

 

[garyman]

The only information we were given about barcode is that it would contain 8 bits of information as defined by vertical lines of single and double width. The examples I've got consist of 8 separate lines. As no encode was specified I guess I can just use the simplest one (code 39?)... or even just some sort visual representation of the barcode would do. Like I say I'm trying to keep it as smple as possible for now. Thanks.