LED matrix + MAX7219 strange behavior

Hi,

I’ve just bought an 8x8 LED matrix with a MAX7219 (Link) an hooked it up to my Arduino UNO R3, but somehow the LED matrix doesn’t do what it should supposed to do.

I copied the follwing code

#include "LedControl.h" //  need the library
LedControl lc=LedControl(12,11,10,1); // 
 
// pin 12 is connected to the MAX7219 pin 1
// pin 11 is connected to the CLK pin 13
// pin 10 is connected to LOAD pin 12
// 1 as we are only using 1 MAX7219
 
void setup()
{
  // the zero refers to the MAX7219 number, it is zero for 1 chip
  lc.shutdown(0,false);// turn off power saving, enables display
  lc.setIntensity(0,8);// sets brightness (0~15 possible values)
  lc.clearDisplay(0);// clear screen
}
void loop()
{
  for (int row=0; row<8; row++)
  {
    for (int col=0; col<8; col++)
    {
      lc.setLed(0,col,row,true); // turns on LED at col, row
      delay(25);
    }
  }
 
  for (int row=0; row<8; row++)
  {
    for (int col=0; col<8; col++)
    {
      lc.setLed(0,col,row,false); // turns off LED at col, row
      delay(25);
    }
  }
}

from this site and uploaded it to the Arduino, but I only get some wierd animations (I’ve uploaded a video here).

After that I wrote a new program which only purpose is to show a blank screen, but even that doesn’t work, there are still four LEDs turned on :’(

//we have to include the library 
#include "LedControl.h"

//and create the LedControl 
LedControl lc=LedControl(12,11,10,1); 

void setup() {
   //leave the MAX72XX from power-saving mode 
   lc.shutdown(0,true);
}

void loop()
{
  
}

What am I doing wrong? Can someone help me?

Thanks,

digger955

I have ten of those and bought ten more.

You need to insert the 8x8 LED matrix upside down.

When you do that you will see that row 1 is at the bottom and column 1 is at the right.

Hi

Same here.
I got a few of them from same ebay seller as digger955 and got same issue.
What I could understand so far: as I bought some of theses kits from another seller and they are working fine. It’s the specification of the led modules. From this seller they are labelled 1088BS ( from schematics, it stand for common anode ) and the ones from the other seller are labelled 1088AS ( stand for common cathode ).
So ieee488, should I invert the side of soldering for the led module? at the opposite side of the max72xx chip ?

This is how I soldered both of them, with 1088AS is working fine, but not for 1088BS.

arssant: Hi

Same here. I got a few of them from same ebay seller as digger955 and got same issue. What I could understand so far: as I bought some of theses kits from another seller and they are working fine. It's the specification of the led modules. From this seller they are labelled 1088BS ( from schematics, it stand for common anode ) and the ones from the other seller are labelled 1088AS ( stand for common cathode ). So ieee488, should I invert the side of soldering for the led module? at the opposite side of the max72xx chip ?

This is how I soldered both of them, with 1088AS is working fine, but not for 1088BS.

The DIY kits that I bought on eBay came with the 1088AS. So, they are the right type, but the MAX7219 are wired to different pins. These PCBs have label FC-16.

If you DIY kits came with the 1088BS, you won't be able to use the 1088BS without a lot of re-wiring. I bought ten these row anode column cathode 8x8 but not with the PCB. To use them I rotated them 90 degrees. I hope that makes sense.

Basically, with these DIY kits, your seller needs to send you the [u]row cathode column anode[/u] 8x8 LED matrix and the MAX7219 connected to the correct pins on the 8x8. I am worried now, because I also bought some 8x8 LED matrices from your seller. If he sends me 1088BS, I will be mad, and I will have to file a claim on eBay.

I hope this makes sense.

ieee488: I hope this makes sense.

Thanks, and yes it makes sense.

I came to same conclusion yesterdays after looking at the data-sheet, and just ordered 5 1088AS from another seller for 3$. I hope for OP, he didn't received 1088BS as I.

Ps. can you send a PM with your seller, I wanna try yours. :) Talking about your 1st one, not mine as digger955.

Hi,

Thanks for your replies. I've looked at the matrix, and ieee488 was right. It's a 1088BS :slightly_frowning_face: At least I know why it didn't worked.

Thanks again,

digger955

arssant: I came to same conclusion yesterdays after looking at the data-sheet, and just ordered 5 1088AS from another seller for 3$.

I have already sent a message to my seller asking him to send me the 1088AS.

His auction says common cathode and he has very good feedback on eBay, but obviously they are clueless about electronics.

I PM'd you the other seller's listing.

digger955:
Hi,

Thanks for your replies. I’ve looked at the matrix, and ieee488 was right. It’s a 1088BS :slightly_frowning_face:
At least I know why it didn’t worked.

Thanks again,

digger955

You can use these 1088BS, but you’d have to do your own wiring with your own MAX7219.
I have gotten lazy and that is why I bought these kits with the PCB + MAX7219 + 8x8 LED matrix all in one.
But these eBay sellers are driving me nuts. :confused:

ieee488: I have already sent a message to my seller asking him to send me the 1088AS.

Lotsa luck! As per below.

ieee488: His auction says common cathode and he has very good feedback on eBay, but obviously they are clueless about electronics.

Well, of course they are (clueless!). When you sell both bras and Arduinos (do they?), something has to give.

The term "common cathode" is in the first place, quite meaningless when applied to matrix displays.

ieee488: I have already sent a message to my seller asking him to send me the 1088AS.

I PM'd you the other seller's listing.

Thanks, I got it, at least this ones is labelled 1088AS.

And as you, I sent a message to him 3 days ago, and got answer: " Sorry for inconvenience"

Paul__B: Well, of course they are (clueless!). When you sell both bras and Arduinos (do they?), something has to give.

That the point. :)

Paul__B: Well, of course they are (clueless!). When you sell both bras and Arduinos (do they?), something has to give.

The term "common cathode" is in the first place, quite meaningless when applied to matrix displays.

But this seller strictly sells electronics, if you look at his auctions.

Yes, "common cathode" is meaningless, but that is the verbage as opposed to "common anode".

This is what they understand.

arssant: And as you, I sent a message to him 3 days ago, and got answer: " Sorry for inconvenience"

That answer won't do.

I will file a SNAR against him on eBay.

ieee488: But this seller strictly sells electronics, if you look at his auctions.

Oh! I was being general. Yes, gc_supermarket (and his alter egos - but I hadn't initially looked) is generally a good vendor; this should not happen.

Even so, I wonder to what extent they could - or might - actually test the junk they are purchasing. In this case, it would not be difficult as they have all the stuff on hand.

Hi.

Now I'm p... with this seller. I just receive a reply from a guy who bought 5 of them at gcc_ some days before me, and wrote a comment over the gcc_ seller store, and guess what ? he got 5 1088AS.

ieee488 you could be the lucky one too :)

arssant: Hi.

Now I'm p... with this seller. I just receive a reply from a guy who bought 5 of them at gcc_ some days before me, and wrote a comment over the gcc_ seller store, and guess what ? he got 5 1088AS.

ieee488 you could be the lucky one too :)

I hope that I am a lucky one too. :)

How were able to contact the other buyer? eBay doesn't let you do that as far as I know.

Is the seller going to send you the 1088AS ? If not, you definitely need to file a SNAR with eBay.

ieee488: I hope that I am a lucky one too. :)

How were able to contact the other buyer? eBay doesn't let you do that as far as I know.

Is the seller going to send you the 1088AS ? If not, you definitely need to file a SNAR with eBay.

The buyer just wrote a review for this product at the vendor store, so I could saw his name ( ebay user ). I asked to tell me about his kit, he confirm that he received a 1088AS labelled.

Sending a new 1088AS ? I just wrote to the seller about this long story.. :)

I contaced gc_supermarket yesterday regarding the wrong matrix and they offered me a full refund:

dear customer sorry almost it is no problem

would like to refund for you of it if you can not use it

is this ok ?

we seek for long term

regards

The other things I ordered (e.g. LCD display) are working fine, so I can't be mad. Maybe you're also a lucky one, ieee488 ;)

digger955: I contaced gc_supermarket yesterday regarding the wrong matrix and they offered me a full refund: The other things I ordered (e.g. LCD display) are working fine, so I can't be mad. Maybe you're also a lucky one, ieee488 ;)

Nope. Not lucky. Got 1088BS. >:(