8x8 LED Matrix Using a MAX7219 Arduino Module

8x8 LED Matrix Using a MAX7219 Arduino Module

In this tutorial, we will learn how to control an 8x8 LED matrix using a MAX7219 module with an Arduino. The MAX7219 simplifies the control of multiple LEDs, allowing us to display characters and patterns easily. By the end of this project, you will be able to display the word "ROBOJAX" on the matrix.

To achieve this, we will utilize the LedControl library, which is specifically designed for interfacing with the MAX7219. This library allows us to send data to the LED matrix with minimal effort. If you want a clearer understanding of the wiring and code, be sure to check the associated video (in video at 0:30).

Hardware Explained

The primary components of this project include the MAX7219 module and the 8x8 LED matrix. The MAX7219 is an integrated circuit that manages the display of the LEDs, handling the communication and control signals from the Arduino. It utilizes a serial interface, which means we can control many LEDs with just a few pins from the Arduino.

The 8x8 LED matrix consists of 64 individual LEDs arranged in a grid. Each LED can be turned on or off by sending the appropriate commands through the MAX7219. This allows for the display of various characters and graphics on the matrix.

Datasheet Details

Manufacturer	Maxim Integrated
Part number	MAX7219
Logic/IO voltage	3.3V to 5.5V
Supply voltage	4.0V to 5.5V
Output current (per channel)	40 mA max
Peak current (per channel)	100 mA max
PWM frequency guidance	100 Hz
Input logic thresholds	2.0V (high) / 0.8V (low)
Voltage drop / R_DS(on) / saturation	0.2V typ.
Thermal limits	150°C
Package	16-DIP
Notes / variants	Common anode configuration

Ensure proper power supply (4.0V to 5.5V).
Use current-limiting resistors for each LED to prevent damage.
Keep wiring short to avoid interference.
Monitor heat dissipation; use a heatsink if necessary.
Double-check pin connections to avoid miscommunication.

Wiring Instructions

To wire the MAX7219 to the Arduino, connect the following pins:

Connect the VCC pin of the MAX7219 to the Arduino's 5V.
Connect the GND pin to the Arduino's ground.
Connect the DIN pin (Data In) to Arduino pin 12.
Connect the CLK pin (Clock) to Arduino pin 11.
Connect the CS pin (Chip Select) to Arduino pin 10.

Make sure to check that all connections are secure before powering on the circuit. The wiring is straightforward, but if you encounter issues, review the connections carefully (in video at 1:45).

Code Examples & Walkthrough

In the code, we start by including the LedControl library, which is essential for communicating with the MAX7219. The following excerpt initializes the LedControl object:

LedControl lc=LedControl(12,11,10,1);

This line sets the data pin, clock pin, chip select pin, and the number of devices (1, in this case). Next, in the setup() function, we wake up the MAX7219 and set the display intensity:

lc.shutdown(0,false);
lc.setIntensity(0,8);
lc.clearDisplay(0);

This ensures the display is active and ready to show characters. The main function that drives the display is writeArduinoOnMatrix(), which sequentially lights up the rows of the matrix to display letters.

Demonstration / What to Expect

Once everything is wired and the code is uploaded, the LED matrix should display the word "ROBOJAX". If the display does not work, check for issues like loose connections or incorrect pin assignments. Additionally, ensure the power supply is adequate (in video at 2:30).

Chapters

Introduction (0:00)
Hardware Overview (0:30)
Wiring Instructions (1:45)
Code Walkthrough (2:15)
Demonstration (3:00)

4-8x8 LED matrix using a MAX7219 Arduino module

Language: C++

/*
 * This video shows you how to use the MAX7219 module with an 8x8 LED matrix to display text or any characters on the LED.
 * Watch YouTube video: https://youtu.be/AAiDwBKs9uE
 * 
 * Written by Ahmad Shamshiri for Robojax.com
 * on February 26, 2017 in Ajax, Ontario, Canada
 * Get this code and other Arduino codes from Robojax.com
 * Learn Arduino step by step in a structured course with all materials, wiring diagrams, and libraries
 * all in one place. 
 
 ****************************
 * Get early access to my videos via Patreon and have your name mentioned at the end of every 
 * video I publish on YouTube here: http://robojax.com/L/?id=63 (watch until the end of this video for a list of my Patrons)
 ****************************
 
 * Or make a donation using PayPal http://robojax.com/L/?id=64
 
 * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.
 * This code has been downloaded from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
 
 
// We always have to include the library
// Based on a project posted https://github.com/wayoda/LedControl
#include "LedControl.h"
 
 /*
  Now we need a LedControl to work with.
  // Customized for RoboJax.com on February 26, 2017 in Ajax, Ontario, Canada.
  ***** These pin numbers will probably not work with your hardware *****
  pin 12 is connected to the DataIn 
  pin 11 is connected to the CLK 
  pin 10 is connected to CS
  We have only a single MAX72XX.
  */
 LedControl lc=LedControl(12,11,10,1);
 
 /* we always wait a bit between updates of the display */
 unsigned long delaytime=600;
 
 void setup() {
   /*
    The MAX72XX is in power-saving mode on startup,
    we have to do a wakeup call
    */
   lc.shutdown(0,false);
   /* Set the brightness to a medium value */
   lc.setIntensity(0,8);
   /* and clear the display */
   lc.clearDisplay(0);
 }
 
 /*
  This method will display the characters for the
  word "Arduino" one after the other on the matrix. 
  (you need at least 5x7 LEDs to see the whole characters)
  */
 void writeArduinoOnMatrix() {
   /* here is the data for the characters */
 
   // K
   byte R[8]={B11111100,B10000100,B10000100,B11111000,B10100000,B10010000,B10001000,B10000100};
   byte O[8]={B00011000,B00100100,B01000010,B01000010,B01000010,B01000010,B00100100,B00011000};  
   byte B[8]={B11111100,B10000100,B10000100,B11111000,B10001000,B10000100,B10000100,B11111100};
   byte J[8]={B00011110,B00000100,B00000100,B00000100,B10000100,B10000100,B01000100,B00111000};
   byte A[8]={B00111000,B01000100,B10000010,B11111110,B10000010,B10000010,B10000010,B10000010};     
   byte X[8]={ B10000001,B01000010,B00100100,B00011000,B00011000,B00100100,B01000010,B10000001};
   byte love[8]={ B00000000,B01100110,B10011001,B10011001,B10000001,B01000010,B00100100,B00011000};  
 
 
   /* Letter R */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,R[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter R ///////
 
   /* Letter O */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,O[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter O ///////
 
 
   /* Letter B */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,B[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter B ///////
 
   /* Letter O */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,O[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter O ///////
 
   /* Letter J */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,J[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter J ///////
 
   /* Letter A */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,A[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter A ///////
 
   /* Letter X */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,X[i]);
 
   }
    
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter X ///////
 
 
 
   /* love */
   for (int i=0; i<8; i++){
   lc.setRow(0,i,love[i]);
 
   }
    
   delay(delaytime);
   delay(delaytime);
   for(int i=0; i<8; i++){
       lc.setRow(0,i,0);// this is for blank
   }  
 //////////////// END of Letter love ///////
 
 }// writeArduinoOnMatrix()  end
 
 
 void loop() { 
   writeArduinoOnMatrix();
 
 }

5-8x8 LED Matrix using a MAX7219 Arduino Module

Language: C++

/*
 * This video shows you how to use the MAX7219 module with an 8x8 LED matrix to display text or any characters on the LED.
 * Watch YouTube video: https://youtu.be/AAiDwBKs9uE
 * 
 * Written by Ahmad S. for Robojax.com
 * on February 26, 2017 in Ajax, Ontario, Canada
 * Permission granted to share this code, given that this
 * note is kept with the code.
 * Disclaimer: This code is "AS IS" and for educational purposes only.

 */

// We always have to include the library
// Based on a project posted on https://github.com/wayoda/LedControl
#include "LedControl.h"

/*
 Now we need a LedControl object to work with.
 // Customized for RoboJax.com on February 26, 2017 in Ajax, Ontario, Canada.
 ***** These pin numbers will probably not work with your hardware *****
 pin 1 is connected to the DataIn 
 pin 4 is connected to the CLK 
 pin 53 is connected to CS
 We have only a single MAX72XX.
 */
LedControl lc=LedControl(1,4,53,1);// this line determines if this code can work with Arduino Mega or Arduino UNO

/* we always wait a bit between updates of the display */
unsigned long delaytime=600;

void setup() {
  /*
   The MAX72XX is in power-saving mode on startup,
   we have to do a wakeup call
   */
  lc.shutdown(0,false);
  /* Set the brightness to a medium value */
  lc.setIntensity(0,8);
  /* and clear the display */
  lc.clearDisplay(0);
}

/*
 This method will display the characters for the
 word "Arduino" one after the other on the matrix. 
 (you need at least 5x7 LEDs to see the whole characters)
 */
void writeArduinoOnMatrix() {
  /* here is the data for the characters */

  // K
  byte R[8]={B11111100,B10000100,B10000100,B11111000,B10100000,B10010000,B10001000,B10000100};
  byte O[8]={B00011000,B00100100,B01000010,B01000010,B01000010,B01000010,B00100100,B00011000};  
  byte B[8]={B11111100,B10000100,B10000100,B11111000,B10001000,B10000100,B10000100,B11111100};
  byte J[8]={B00011110,B00000100,B00000100,B00000100,B10000100,B10000100,B01000100,B00111000};
  byte A[8]={B00111000,B01000100,B10000010,B11111110,B10000010,B10000010,B10000010,B10000010};     
  byte X[8]={ B10000001,B01000010,B00100100,B00011000,B00011000,B00100100,B01000010,B10000001};
  byte love[8]={ B00000000,B01100110,B10011001,B10011001,B10000001,B01000010,B00100100,B00011000};  


  /* Letter R */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,R[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter R ///////

  /* Letter O */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,O[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter O ///////


  /* Letter B */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,B[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter B ///////

  /* Letter O */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,O[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter O ///////

  /* Letter J */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,J[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter J ///////

  /* Letter A */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,A[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter A ///////

  /* Letter X */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,X[i]);

  }
   
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of Letter X ///////



  /* love */
  for (int i=0; i<8; i++){
  lc.setRow(0,i,love[i]);

  }
   
  delay(delaytime);
  delay(delaytime);
  for(int i=0; i<8; i++){
      lc.setRow(0,i,0);// this is for blank
  }  
/////////////// END of love ///////

}// writeArduinoOnMatrix()  end


void loop() { 
  writeArduinoOnMatrix();

}