Completely DIY 4X4 LED matrix | Details

This is the first LED matrix iv'e made since i got into Arduino. So i took my own approach to assemble it and to get it working. I did not look up any tutorials and i used stuff i had laying around to built it. It actually took me 3 months to completely understand how it works :).

I used:

1 old prototype board i had laying around.
1 Arduino pro mini.
16 white LED's i got from a chinese headlamp.
4 200ohm resistors (still can't remember why but i can't change them).
1 On/off switch.
1 Reset button.

Then i did the following:

Made 8 LED rows.

Connected the LED rows with the digital pins of the Arduino pro mini.

Made a variable for the delay.

int delayAmount = 1;

Made a variables for each of the rows.

int ledPinLow1 = 10;
int ledPinLow2 = 11;
int ledPinLow3 = 12;
int ledPinLow4 = 13;

int ledPinHigh1 = 6;
int ledPinHigh2 = 7;
int ledPinHigh3 = 8;
int ledPinHigh4 = 9;

Made an imaginary table from 1 to 16 where each LED represents a number in the 4X4 matrix.

1	2	3	4
5	6	7	8
9	10	11	12
13	14	15	16

Made a function for each one of them open and assigned them one table number.

void ledOne() {
  digitalWrite(ledPinLow4, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledTwo() {
  digitalWrite(ledPinLow4, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledThree() {
  digitalWrite(ledPinLow4, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledFour() {
  digitalWrite(ledPinLow4, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
}

void ledFive() {
  digitalWrite(ledPinLow3, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledSix() {
  digitalWrite(ledPinLow3, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledSeven() {
  digitalWrite(ledPinLow3, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledEight() {
  digitalWrite(ledPinLow3, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
}

void ledNine() {
  digitalWrite(ledPinLow2, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledTen() {
  digitalWrite(ledPinLow2, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledEleven() {
  digitalWrite(ledPinLow2, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledTwelve() {
  digitalWrite(ledPinLow2, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
}

void ledThirteen() {
  digitalWrite(ledPinLow1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledFourteen() {
  digitalWrite(ledPinLow1, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledFifteen() {
  digitalWrite(ledPinLow1, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh4, HIGH);
}

void ledSixteen() {
  digitalWrite(ledPinLow1, HIGH);
  digitalWrite(ledPinHigh1, HIGH);
  digitalWrite(ledPinHigh2, HIGH);
  digitalWrite(ledPinHigh3, HIGH);
}

Made a function for all of them closed.

void ledClose() {
  digitalWrite(ledPinLow1, LOW);
  digitalWrite(ledPinLow2, LOW);
  digitalWrite(ledPinLow3, LOW);
  digitalWrite(ledPinLow4, LOW);
  digitalWrite(ledPinHigh1, LOW);
  digitalWrite(ledPinHigh2, LOW);
  digitalWrite(ledPinHigh3, LOW);
  digitalWrite(ledPinHigh4, LOW);
}

Made a simple system that uses these functions to rapidly open and close the LED's so you can create "frames" to run inside a for loop, inside void loop to determine for how long a frame should last.

void loop() {

  for (int i = 0; i < 100; i++) {
    frame1();
    delay(2);
  }
}
  
void frame1() {
  ledOne();
  delay(delayAmount);
  ledClose();
  ledThree();
  delay(delayAmount);
  ledClose();
  ledSix();
  delay(delayAmount);
  ledClose();
  ledEight();
  delay(delayAmount);
  ledClose();
  ledNine();
  delay(delayAmount);
  ledClose();
  ledEleven();
  delay(delayAmount);
  ledClose();
  ledFourteen();
  delay(delayAmount);
  ledClose();
  ledSixteen();
  delay(delayAmount);
  ledClose();
}

Put all those frames together and you can have any animation you like, complete control without any libraries.

I still don't know if this is the right way to make a LED matrix but it works surprisingly well.

Project Details