Arduino Examples

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7-Seg Display Program

Description

7-Seg Display is a more complex Arduino program that will allow you to display different numbers on a properly configured seven segment display. Code is provided to display a basic countdown, but functions are provided that will allow you to easily implement other ideas.

Materials

• Arduino
• Breadboard
• Seven Segment Display
• Jumper Wires
• Resistors

Instructions

1. Paste the code below into the Arduino IDE
2. Set up the breadboard and Arduino in the same configuration as the diagram below
3. Compile and upload the code to the Arduino
4. Start the Arduino

Circuit Diagram

Code

// This 2d-boolean array tells the display which sections to light up.
bool leds[10][8] = {
  {1,1,1,0,0,1,1,1}, // 0
  {0,0,1,0,0,0,0,1}, // 1
  {1,1,0,0,1,1,1,0}, // 2
  {0,1,1,0,1,0,1,1}, // 3
  {0,0,1,0,1,1,0,1}, // 4
  {0,0,0,0,0,0,0,0}, // 5
  {0,0,0,0,0,0,0,0}, // 6
  {0,0,0,0,0,0,0,0}, // 7
  {0,0,0,0,0,0,0,0}, // 8
  {0,0,0,0,0,0,0,0}, // 9
};

// This function sets pins 2 to 9 to an array of boolean values.
void setSevenSeg(bool ledArray[]) {
  for (int i = 0; i < sizeof(ledArray); i++) {
    digitalWrite(i+2, ledArray[i] ? HIGH : LOW);
  }
}

// This function makes sets the display to a certain number.
void setSevenSegDigit (int number) {
  setSevenSeg(leds[number]);
}
  
// The setup function runs once when the Arduino starts.
void setup() {
  // Sets pins 2 through 9 to output.
  for (int i = 2; i <= 9; i++) {
    pinMode(i, OUTPUT);
  }
}

// The loop function runs over and over.
void loop() {
  // Counts down from 10.
  for (int i = 9; i >= 0; i--) {
    delay(1000);
    setSevenSegDigit(i);
  }
}