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So this is my first arduino (or embedded for that matter) project. I am trying to power 4 leds with max7219. Max7219 seems easy to use, but for some reason after I upload the code, nothing happens. I've looked over my breadboard, and the connections seem right. My confusion arises from the fact that all the projects I have found on google use matrices for the leds. I am using 4 separate leds. Does this even matter?

Here is the code I use:

#include "LedControl.h"

LedControl ledControl = LedControl(12, 9, 10, 1);

void setup()
{
    //should be waking ledcontrol
    ledControl.shutdown(0, false);
    ledControl.setIntensity(0, 8);
}

void loop()
{
    ledControl.setLed(0, 0, 0, true);
}
  • 2
    Could you add a image of your breadboard wiring and possibly a schematic of how you wired it. – RSM Mar 18 '16 at 9:20
  • Try setting all the leds to on, instead of just the first one. – Gerben Mar 18 '16 at 16:31
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No it shouldn't matter that you are using separate LEDs, but you will have to connect them in a way that is acceptable to the 7219, they will have to share either a common anode or cathode (can't remember which of the top of my head).

I find its always best to check the basics (Based on personal experience)

  • Have you got the LEDs the correct way around?
  • Are you using the correct voltage for everything?
  • Do the LEDs work when controlled directly by the Arduino, try "Blink"?
  • Have you tried changing the intensity?
  • Have you got the required resistors in?
  • Try inverting the index of the LEDs, i.e. led(x=0,y=0) might be wired (x=7,y=7)?

You loop() is not pausing, so all it is going to be doing is calling that one statement repeatedly. Now that might not be a problem or the second call may be blocking the first from completing. So I suggest add a delay for a second or so and see if that changes anything. Also to prove you are running you Loop() code flash the LED on the board (pin13?).

Hope that helps.

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