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Display on dot matrix

What is dot matrix?

Dot matrix is a matrix of LEDs in which the LEDs are arranged in rows and columns.

<<<<<<< HEAD dotmatrix

Connection of dot matrix on the turtle robot

======= dotmatrix

Connection of dot matrix on the turtle robot

f0e5d95e7252cafd0009fd2b6c30ba4fb767e43c

Control LED matrix

  1. Install the Adafruit LED backpack library <<<<<<< HEAD

    Sketch > Include Library > Manage Libraries...

    Search for "adafruit led" > Install "Adafruit LED Backpack Library" > Install all libraries

  2. Include the necessary libraries in the code and create an object to control the dot matrix.

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    #include <Wire.h>
#include "Adafruit_LEDBackpack.h"   
#include "Adafruit_GFX.h"
Adafruit_LEDBackpack matrix = Adafruit_LEDBackpack();

  3. Initialise the dot matrix by notify the address of the dot matrix.

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    void setup() {
    matrix.begin(0x70);
}

  4. The dot matrix is controlled with the displaybuffer array. Each item in the array represents a column counting from right to left starting from 0.

    We use binary code for each item in the array with 1 being on and 0 being off for the LEDs. To set the middle two columns to light up, we will have

    void loop() {
    matrix.displaybuffer[0] = B00000000;
    matrix.displaybuffer[1] = B00000000;
    matrix.displaybuffer[2] = B00000000;
    matrix.displaybuffer[3] = B11111111;
    matrix.displaybuffer[4] = B11111111;
    matrix.displaybuffer[5] = B00000000;
    matrix.displaybuffer[6] = B00000000;
    matrix.displaybuffer[7] = B00000000;
    matrix.writeDisplay(); //(1)
}
    1. Send the display pattern to the dot matrix

  5. We can create different patterns as custom functions. With this we can directly call the function if we want a certain pattern to show on the dot matrix.

    Info

    These functions should be declared outside the setup and loop functions.

    void dm_startup() {
    matrix.displaybuffer[0] = B00000011;
    matrix.displaybuffer[1] = B10000000;
    matrix.displaybuffer[2] = B00010011;
    matrix.displaybuffer[3] = B00100000;
    matrix.displaybuffer[4] = B00100000;
    matrix.displaybuffer[5] = B00010011;
    matrix.displaybuffer[6] = B10000000;
    matrix.displaybuffer[7] = B00000011;
    matrix.writeDisplay();
}
void dm_forward()
{
    matrix.displaybuffer[3] = B11111111;     
    matrix.displaybuffer[4] = B11111111;
    matrix.displaybuffer[2] = B00000001;
    matrix.displaybuffer[1] = B00000010;
    matrix.displaybuffer[0] = B00000100;
    matrix.displaybuffer[5] = B00000001;
    matrix.displaybuffer[6] = B00000010;
    matrix.displaybuffer[7] = B00000100;
    matrix.writeDisplay();
}
void dm_backward()
{
    matrix.displaybuffer[3] = B11111111;
    matrix.displaybuffer[4] = B11111111;
    matrix.displaybuffer[2] = B00100000;
    matrix.displaybuffer[1] = B00010000;
    matrix.displaybuffer[0] = B00001000;
    matrix.displaybuffer[5] = B00100000;
    matrix.displaybuffer[6] = B00010000;
    matrix.displaybuffer[7] = B00001000;
    matrix.writeDisplay();
}
void dm_right()
{
    for(int i=0;i<8;i++)
    {
    matrix.displaybuffer[i] = B00001100;
    }
    matrix.displaybuffer[6] = B00011110;
    matrix.displaybuffer[5] = B00101101;
    matrix.displaybuffer[4] = B11001100;
    matrix.writeDisplay();
}
void dm_left()
{
    for(int i=0;i<8;i++)
    {
    matrix.displaybuffer[i] = B00001100;
    }
    matrix.displaybuffer[1] = B00011110;
    matrix.displaybuffer[2] = B00101101;
    matrix.displaybuffer[3] = B11001100;
    matrix.writeDisplay();
}
void dm_stop()
{
    matrix.displaybuffer[0] = B11000000;
    matrix.displaybuffer[1] = B00100001;
    matrix.displaybuffer[2] = B00010010;
    matrix.displaybuffer[3] = B00001100;
    matrix.displaybuffer[4] = B00001100;
    matrix.displaybuffer[5] = B00010010;
    matrix.displaybuffer[6] = B00100001;
    matrix.displaybuffer[7] = B11000000;
    matrix.writeDisplay();
}

    Then in the loop function, we can call the functions to display the patterns on the dot matrix.

    void loop() {
    dm_forward();
    delay(1500);
    dm_backward();
    delay(1500);
    dm_left();
    delay(1500);
    dm_right();
    delay(1500);
}


    Sketch > Include Library > Manage Libraries...
Search for "adafruit led" > Install "Adafruit LED Backpack Library" > Install all libraries

  6. Include the necessary libraries in the code and create an object to control the dot matrix.

    #include <Wire.h>
#include "Adafruit_LEDBackpack.h"   
#include "Adafruit_GFX.h"
Adafruit_LEDBackpack matrix = Adafruit_LEDBackpack();

  7. Initialise the dot matrix by notify the address of the dot matrix.

       void setup() {
   matrix.begin(0x70);
   }

  8. The dot matrix is controlled with the displaybuffer array. Each item in the array represents a column counting from right to left starting from 0.

    We use binary code for each item in the array with 1 being on and 0 being off for the LEDs. To set the middle two columns to light up, we will have to send the display pattern to the dot matrix

       void loop() {
   matrix.displaybuffer[0] = B00000000;
   matrix.displaybuffer[1] = B00000000;
   matrix.displaybuffer[2] = B00000000;
   matrix.displaybuffer[3] = B11111111;
   matrix.displaybuffer[4] = B11111111;
   matrix.displaybuffer[5] = B00000000;
   matrix.displaybuffer[6] = B00000000;
   matrix.displaybuffer[7] = B00000000;
   matrix.writeDisplay(); //(1)
   }

  9. We can create different patterns as custom functions. With this we can directly call the function if we want a certain pattern to show on the dot matrix.

    !!! Info These functions should be declared outside the setup and loop functions.

       void dm_startup() {
   matrix.displaybuffer[0] = B00000011;
   matrix.displaybuffer[1] = B10000000;
   matrix.displaybuffer[2] = B00010011;
   matrix.displaybuffer[3] = B00100000;
   matrix.displaybuffer[4] = B00100000;
   matrix.displaybuffer[5] = B00010011;
   matrix.displaybuffer[6] = B10000000;
   matrix.displaybuffer[7] = B00000011;
   matrix.writeDisplay();
   }
   void dm_forward()
   {
   matrix.displaybuffer[3] = B11111111;     
   matrix.displaybuffer[4] = B11111111;
   matrix.displaybuffer[2] = B00000001;
   matrix.displaybuffer[1] = B00000010;
   matrix.displaybuffer[0] = B00000100;
   matrix.displaybuffer[5] = B00000001;
   matrix.displaybuffer[6] = B00000010;
   matrix.displaybuffer[7] = B00000100;
   matrix.writeDisplay();
   }
   void dm_backward()
   {
   matrix.displaybuffer[3] = B11111111;
   matrix.displaybuffer[4] = B11111111;
   matrix.displaybuffer[2] = B00100000;
   matrix.displaybuffer[1] = B00010000;
   matrix.displaybuffer[0] = B00001000;
   matrix.displaybuffer[5] = B00100000;
   matrix.displaybuffer[6] = B00010000;
   matrix.displaybuffer[7] = B00001000;
   matrix.writeDisplay();
   }
   void dm_right()
   {
   for(int i=0;i<8;i++)
   {
   matrix.displaybuffer[i] = B00001100;
   }
   matrix.displaybuffer[6] = B00011110;
   matrix.displaybuffer[5] = B00101101;
   matrix.displaybuffer[4] = B11001100;
   matrix.writeDisplay();
   }
   void dm_left()
   {
   for(int i=0;i<8;i++)
   {
   matrix.displaybuffer[i] = B00001100;
   }
   matrix.displaybuffer[1] = B00011110;
   matrix.displaybuffer[2] = B00101101;
   matrix.displaybuffer[3] = B11001100;
   matrix.writeDisplay();
   }
   void dm_stop()
   {
   matrix.displaybuffer[0] = B11000000;
   matrix.displaybuffer[1] = B00100001;
   matrix.displaybuffer[2] = B00010010;
   matrix.displaybuffer[3] = B00001100;
   matrix.displaybuffer[4] = B00001100;
   matrix.displaybuffer[5] = B00010010;
   matrix.displaybuffer[6] = B00100001;
   matrix.displaybuffer[7] = B11000000;
   matrix.writeDisplay();
   }

Then in the loop function, we can call the functions to display the patterns on the dot matrix.

    void loop() {
        dm_forward();
        delay(1500);
        dm_backward();
        delay(1500);
        dm_left();
        delay(1500);
        dm_right();
        delay(1500);
    }

f0e5d95e7252cafd0009fd2b6c30ba4fb767e43c

Bring it further

  1. How can we display an animation of arrow moving?