Barcode label orientation

Discussion in 'General Electronics Chat' started by Dritech, Aug 7, 2016.

  1. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    Hi all,

    I want to use a barcode scanner to obtain the item information and the orientation of the item while being scanned.
    I did some research on barcode format CODE_128 and found that it consists from a Start and Stop pattern so the system will know from where to start the pattern decoding. I was planning to achieve this by implementing a barcode pattern as shown in the attached image, where a pattern which indicates the orientation if the item is followed by a CODE_128 barcode format. How can this be achieved?

    Any help would be highly appreciated.
  2. AlbertHall

    Distinguished Member

    Jun 4, 2014
    Are you trying to recognise the orientation of the item by the directon of the barcode?
    Most (all?) barcode scanners are designed to work whichever way round the barcode is and they don't include a direction indicator in their output. So I believe that to recognise the orientation you will need to make your own scanner (or your own app for a mobile phone).
  3. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    My guess is that with a purchased barcode scanner, you probably will not get the orientation as part of the output. Somewhere deep inside its firmware it must know the orientation, but with lowcost USB gun and wand scanners, only the data field is brought out as if it were typed on a keyboard.

  4. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    Yep, I recently printed a bar code for a "store rewards" card with my label printer using the numbers printed on the bottom of the tag.
    The printed bars actually came out in reverse.

    I was basically trying to match the bar code with the tag's code so I could put the tag on a piece of stainless steel instead of the cardboard plastic junk that attaches to your key ring. It worked out well.
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    yep.. by default a scanner will output the correct code regardless of orientation..
    You might be able to program the scanner to not do so (but I kind of doubt it)..
    I just looked through the programming manual of one of our "fancy" barcoders and I didn't see a way to have it not spit out the code in the proper start to stop direction regardless of orientation..

    A vision sensor can easily output rotation though.. I picked up a Sick PI50 for dirt cheap ($99) on ebay the other day and had a lot of fun playing with it.. Rotation is simple there along with a load of other quality/position,etc.. checks..
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
    The bar code scanner is called a "scanner" for a reason. The way I understand it, the laser beam reflected as a scan, repeating in many different rotational directions using mirrors. This is a "dumb" illumination process - nothing smart/programmed here, the scan just repeats over and over with hopes of reading a valid bar-code when a barcode wand is passed over one (or a bar code is passed over a stationary scanner area). Just a well designed spinning mirror and 5 or more stationary mirrors to make sure the beam covers 8, 10, 12 or 16 different angles so that one of them scans across the code at approximately 90 degrees +/- 22-degrees from beginning to end. This is why you see some sort of a star-burst or array of laser lines when you put your hand under the bar-code reader (light source).

    The smart part of the barcode "scanner" is the receiver. The receiver is constantly looking for patterns (kind of dots and dashes) - patterns reflected by the lack of absorbing black bars and gaps from the light-absorbing black bars. The start pattern (narrow-wide-narrow) - a bunch of long and short - and a finish pattern (wide-narrow-wide). Any data streams that do not coincide with the data bridged by the appropriate start and stop series, is noise and ignored. Data with an appropriate start and stop series is good. The wand also has an appropriate windows (gates) encoded with the spinning mirror to let the receiver know when a new direction/angle is started with hopes to to hope to pick up a signal if the last one was crap (lacking appropriate start/stop signals).