Shahbaz75sb
Published © LGPL

8x8 led matrix interfacing with arduino

I use 788bs, a common anode 8x8 led matrix Modules for this project. Learn how to identify matrix pinout, how to interface with Arduino.

IntermediateFull instructions provided13
8x8 led matrix interfacing with arduino

Things used in this project

Hardware components

Arduino UNO
Arduino UNO
×1
LED Dot Matrix Display, Green
LED Dot Matrix Display, Green
×1
Solderless Breadboard Full Size
Solderless Breadboard Full Size
×1
AA Batteries
AA Batteries
×1
Jumper wires (generic)
Jumper wires (generic)
×1

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Mastech MS8217 Autorange Digital Multimeter
Digilent Mastech MS8217 Autorange Digital Multimeter
Multitool, Screwdriver
Multitool, Screwdriver

Story

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Schematics

Pin connection led matrix

8x8 led matrix connection diagram

Code

Led matrix display running

INI
To display as you like, I display a moving a Person.
// Pins connect as per define
// Fill in the pins you used on your own setup.

#define ROW_1 2
#define ROW_2 3
#define ROW_3 4
#define ROW_4 5
#define ROW_5 6
#define ROW_6 7
#define ROW_7 8
#define ROW_8 9

#define COL_1 10
#define COL_2 11
#define COL_3 12
#define COL_4 13
#define COL_5 A0
#define COL_6 A1
#define COL_7 A2
#define COL_8 A3

const byte rows[] = {
    ROW_1, ROW_2, ROW_3, ROW_4, ROW_5, ROW_6, ROW_7, ROW_8
};

// The display buffer
// It shows a walking steps (1 = ON, 0 = OFF)
byte star1[] = {B00000110,B11000010,B10100100,B00011000,B00011000,B00100101,B01000011,B01100000};
byte star2[] = {B00110000,B00100000,B00100111,B00011001,B10011000,B11100100,B00000100,B00001100};
byte star3[] = {B00000110,B10001000,B10010000,B01011100,B00111010,B00001001,B00010001,B01100000};

float timeCount = 0;

void setup() {
    // Open serial port
    Serial.begin(9600);
    
    // Set all used pins to OUTPUT
    // This is very important! If the pins are set to input
    for (byte i = 2; i <= 13; i++)
        pinMode(i, OUTPUT);
    pinMode(A0, OUTPUT);
    pinMode(A1, OUTPUT);
    pinMode(A2, OUTPUT);
    pinMode(A3, OUTPUT);
}

void loop() {
  // This could be rewritten to not use a delay, which would make it appear brighter
delay(5);
timeCount += 1;
if(timeCount <  20) {
drawScreen(star1);
} else if (timeCount <  80) {
drawScreen(star2);
} else if (timeCount <  100) {
drawScreen(star3);
} else if (timeCount <  120) {
drawScreen(star1);
} else if (timeCount <  140) {
drawScreen(star2);
} else if (timeCount <  160) {
drawScreen(star3);
} else {
// back to the start
timeCount = 0;
}
}
 void  drawScreen(byte buffer2[]){
     
    
   // Turn on each row in series
    for (byte i = 0; i < 8; i++) {
        setColumns(buffer2[i]); // Set columns for this specific row
        
        digitalWrite(rows[i], HIGH);
        delay(2); // Set this to 50 or 100 if you want to see the multiplexing effect!
        digitalWrite(rows[i], LOW);
        
    }
}


void setColumns(byte b) {
    digitalWrite(COL_1, (~b >> 0) & 0x01); // Get the 1st bit: 10000000
    digitalWrite(COL_2, (~b >> 1) & 0x01); // Get the 2nd bit: 01000000
    digitalWrite(COL_3, (~b >> 2) & 0x01); // Get the 3rd bit: 00100000
    digitalWrite(COL_4, (~b >> 3) & 0x01); // Get the 4th bit: 00010000
    digitalWrite(COL_5, (~b >> 4) & 0x01); // Get the 5th bit: 00001000
    digitalWrite(COL_6, (~b >> 5) & 0x01); // Get the 6th bit: 00000100
    digitalWrite(COL_7, (~b >> 6) & 0x01); // Get the 7th bit: 00000010
    digitalWrite(COL_8, (~b >> 7) & 0x01); // Get the 8th bit: 00000001
    
    // If the polarity of your matrix is the opposite of mine
    // remove all the '~' above.
}

Credits

Shahbaz75sb

Shahbaz75sb

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