Binary to BCD Converter for Car project

Discussion in 'The Projects Forum' started by bluebrakes, Oct 17, 2009.

  1. bluebrakes

    Thread Starter Active Member

    Oct 17, 2009
    245
    7
    Hi Everybody,

    this is my first time on this forum. Probably a younger one of the forum at 22. I've been into electronics since I was a toddler, where I nearly killed myself unscrewing a mains wall socket when I was about 18months old, i've built many things over the years, everything from robots controlled by the computer to rewiring a car's engine management system.

    I was wondering if you could help me with a project of mine.
    I'm trying to fit a navigation unit from a newer car into an older car, but the communication bus from the navi unit to the instrument cluster speak to each other in a slightly different manner.

    I've been told the navigation unit communicates in Binary Coded Decimal and the the instrument panels speaks in plain binary.


    They talk to each other using a twised pair. It has been done before, but I can't for the life of me find out it was done. All I know is that it was done using a PIC.

    Would the basic stamp be suitable in converting the signals?

    Any advice would be great.

    Thanks,
    Dominic
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    No reason you couldn't use a Basic Stamp. However, the uC's themselves are quite expensive compared to a PIC that would do the job.

    You can buy 40-pin PIC16's for under $3 US. 8-pin PIC12's are available for well under $1 ea.
    Basic Stamps start out at $30, and go up from there.

    Nothing wrong with using them if you already have them. Just remember your cost per project will be rather high.

    Also, since the Basic Stamps use tokenized code with a Basic interpreter on the module, their performance will be considerably slower than a PIC.

    Not knowing the data rate coming out of your twisted pair, it's hard to say what speed you'll need.
     
  3. bluebrakes

    Thread Starter Active Member

    Oct 17, 2009
    245
    7
    I believe the speed is around 250kbps.

    Certainly if I can use a cheaper PIC that would be much better.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, for starters you'll need some kind of differential line receiver IC, to convert the twisted pair signal to TTL/CMOS levels.

    Do you know what EIA standard the signal might be?
     
  5. bluebrakes

    Thread Starter Active Member

    Oct 17, 2009
    245
    7
    I believe it is ISO11519. 11bit identifiers. thanks.
     
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