7 segment LED display by Jose Ojeda

Shows how to drive a 7 segment LED display. The display shows the numbers from 0 to 9 over and over. Those displays can be common anode (the segments will be ON by turning the pins LOW) or common cathode (the segments will be ON by turning the pins HIGH).

int number = 0;  // variable to keep the number in the display

void turn_all_off()    // function to turn off all the segments
{
  for (int i = 8; i < 16; i++)
  {
    digitalWrite(i, LOW);
  }
}

void setup()
{
  for (int i = 8; i < 16; i++) // set pins 0-7 as outputs
  {
    pinMode(i, OUTPUT);
  }
}

void loop()
{
  turn_all_off();  // turns off the display segments
  if (number == 0) // set pins ON for drawing number 0
  {
    digitalWrite(13, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 1) // set pins ON for drawing number 1
  {
    digitalWrite(10, HIGH);
    digitalWrite(15, HIGH);
  }
  if (number == 2) // set pins ON for drawing number 2
  {
    digitalWrite(15, HIGH);
    digitalWrite(12, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
  }
  if (number == 3) // set pins ON for drawing number 3
  {
    digitalWrite(12, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 4) // set pins ON for drawing number 4
  {
    digitalWrite(13, HIGH);
    digitalWrite(12, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 5) // set pins ON for drawing number 5
  {
    digitalWrite(12, HIGH);
    digitalWrite(13, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 6) // set pins ON for drawing number 6
  {
    digitalWrite(12, HIGH);
    digitalWrite(13, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 7) // set pins ON for drawing number 7
  {
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 8) // set pins ON for drawing number 8
  {
    digitalWrite(12, HIGH);
    digitalWrite(13, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(8, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  if (number == 9) // set pins ON for drawing number 9
  {
    digitalWrite(12, HIGH);
    digitalWrite(13, HIGH);
    digitalWrite(14, HIGH);
    digitalWrite(15, HIGH);
    digitalWrite(9, HIGH);
    digitalWrite(10, HIGH);
  }
  delay(1000);  // wait for a second
  number = number + 1;  // increment the number
  if (number > 9)   // range check, if greater then 9 go back to 0
  {
    number = 0;
  }
}