8x8 LED matrix, one column not working?

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  • Hello

    I have been playing around with my 8x8 LED matrix and for some reason when I use Espruino my 4th column (from the left) does not work, I know it is not a hardware issue because if I use the matrix with Arduino it works just fine.

    SPI1.setup({mosi:D14, sck:D13});
    var disp = require("MAX7219").connect(SPI1,D15);
    var arr = [255,255,255,255,255,255,255,255];

    Here is the code I use to test the display, also I'm not sure if the MAX7219 module is the best to use?

    My board is the Wemos d1 mini


  • Do you have a link to the actual 8x8 matrix you're using?

  • Can you try removing disp.intensity(0); ? I guess that could be doing something strange.

    Also, you're sure that the GND pin is connected?

  • Removing the intensity didn't help and it works just the same with ground connected or disconnected.
    Can I somehow check if the ground on the LED matrix is broke? I think I remember that all columns used to work

  • Testing out the LED matrix (disconnected from MAX7219 driver board) w/ a 5V source and a 470 ...1K Ohm resistor will tell you... and then you do the same with a single LED and the driver board... that will tell you what is broken... or it may just have been a cold soldering point... had those duds when working w/ flip-dots... it just did not want to work, and that's the procedure I used to get to the bottom of the issue.

  • Haven't been able to test it yet but I was thinking, since it works with an Wemos d1 mini running Arduino code, shouldn't that indicate it's something to do with the software?

  • Have you tried the arduino code recently as there might be a hardware issue since the last time you tried it?

  • Got time to test it today and indeed the column of LED's did not light up... So it seems like there is a problem with my LED matrix or the MAX7219 driver board. Also I wanna say thanks for all the help guys! Really appreciate it!

  • Problem found! Seems like one of the soldering's on the driver board was bad :) thanks for all the help once again!

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8x8 LED matrix, one column not working?

Posted by Avatar for Hapseleg @Hapseleg