Scrambled display

Store Forums Digit Shield Bugs/Problems Scrambled display

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    Ive have attempted to make the digitshield on a breadboard to do some testing before ordering one. I have followed the schematic with the only difference being I am not using the same display (I have one 4 digit display) and I am not using any decimal points.

    I have it working partially but I am getting some strange behaviour.

    Here us my sketch


    void setup() {

    void loop() {

    int n = 8888;



    and here are my results (- = digit not on)

    Variable N Output
    8888 8888
    1 -111
    2 -222
    3 to 9 exhibit the same behaviour as 1 and 2
    10 1000
    11 1111
    12 12 backwards 6 backwards 6
    13 1333
    14 1444
    15 1599
    16 1688
    17 1777
    18 1888
    19 1999
    20 2088
    21 21 backwards 6 backwards 6
    22 2222
    23 23 backwards 6 backwards 6
    24 2488
    25 2588
    100 0000
    1000 0000

    Any help would be great

    14 1444


    Are you changing the value of n in your sketch somewhere? I don’t see any change…

    I guess all I can ask is “are you sure you have it wired correctly?” because if you’re using different display hardware, it will have a different pinout… Is it common anode display?


    Hi Michael,

    Sorry I was changing N manually and then re-uploading the sketch. I am using a common anode display with 12 pins (7 segments, colon and 4 digits) and have got each digit displaying correctly in at least one case so I think it might be a software rather than hardware issue (I have double checked the wiring but I will have another look!)
    I will have a poke about the library and see if its something to do with precision or the lack of decimal points.
    One think that is really confusing me is the Backwards 6 (lighting up all segments except the top-left vertical) is this used anywhere as an error code?

    Thanks for you help



    The library is designed to work with the Digit Shield hardware, so if your circuit doesn’t work, then it’s because your circuit/hardware is different from the Digit Shield somehow. How can it be a “software problem”? Obviously the software is working with the Digit Shield — it’s been on the market for almost a year. I’m not sure what you are trying to accomplish with your testing — are you unsure whether the library will work with the Digit Shield? It does!

    It’s not possible to display a backwards 6 with a properly connected 74LS247 chip, so I have no idea how that is being displayed. Have you consulted the datasheet?


    Hi Michael,

    I apologise, I wasnt suggesting your library was at fault merely that perhaps my hardware modifications were incompatible with your library due to the lack of decimal points.

    Ive had a look at the data sheet and I agree a backwards 6 should be impossible so I will continue looking for a mistake in my wiring.

    thanks for you help


    I downloaded the DigitShield zip file and installed the library in my main Arduino libraries folder. When I open the “SetDirectExample” and compile, I receive the following error:


    what error? I don’t see anything in your post.

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