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What encoding method should I use?

Discussion in 'Electronic Design' started by Maddy, Feb 11, 2007.

  1. Maddy

    Maddy Guest

    I need some advice on the following- what encoding method should i
    use to meet the following requirements-
    1. The process, magnetic or optical should be capable of encoding a
    number between 0 and 5000 in an area 1mm by 1cm.
    2. It should be possible to print/encode these data bits on a long
    1cm wide strip with each discrete data bit right next to each other
    without any interference/degradation of data read.
    3. The sensor should be small, probably 2cm by 2cm by 4cm.
    4. It should not involve any radio transmission.

    Would really appreciate any help i can get. Thanks a lot
    Maddy
     
  2. Guest

    Search on "bar codes".
     
  3. Maddy

    Maddy Guest

    Search on "bar codes".
    But arent barcodes very wide. I need something just 1mm wide.
    Maddy
     
  4. Rich Webb

    Rich Webb Guest

    Barcodes are (typically) wide in order to relieve the reader of the need
    for precise alignment with the printed code. The track under the read
    head is probably a good bit narrower (no pun intended) than 1 mm.
     
  5. mkaras

    mkaras Guest

    0-5000 requires 13 binary bits to encode. It is a fact of life (and
    also physics) that there will always be issues with bit cell to bit
    cell distortion so you will need SOME type of redundancy built into
    your code to permit reliable readback. Lets guess at full 100%
    reduncancy and you get up to 26 bits of information to encode into
    your stamp.

    Now it also sounds like to me that the selection of 0 to 5000 as a
    range is tied to some present tense application need. I would include
    more bits for further expansion or flexibilty. Why not pick another
    batch of bits and move up to 64 bits total.

    I think you would be better off looking at a small square type bar
    code like a Datamatrix code. See this link for a quick description of
    such codes:
    http://www.mecsw.com/specs/datamatx.html
    or
    http://www.idautomation.com/datamatrixfaq.html

    It is possible to make small bar code readers which can image a
    Datamatrix bar code. For example check out this link:
    http://www.omnica.com/What's New/Miniature barcode reader.htm
    or
    http://www.jadaktech.com/products/product.cfm?prod=1068

    - mkaras
     
  6. Cauzin SoftStrip?
     
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