Seven-segment display control in Arduino - Mini Project: Build & Apply

Seven-segment display control

📖 Scenario: You have a seven-segment display connected to an Arduino board. Each segment is connected to a specific digital pin. You want to control the display to show numbers from 0 to 9 by turning on and off the correct segments.

🎯 Goal: Build a program that controls a seven-segment display by turning on the correct segments to show digits 0 through 9.

📋 What You'll Learn

Create an array called segmentPins with the exact digital pins connected to segments a to g: 2, 3, 4, 5, 6, 7, 8

Create a two-dimensional array called digits that holds the on/off pattern for each digit 0 to 9 for the seven segments

Write a function called displayDigit that takes a digit and lights up the correct segments

Use setup() to set all segment pins as outputs

Use loop() to display digits 0 to 9 with a 1-second delay between each

💡 Why This Matters

🌍 Real World

Seven-segment displays are common in clocks, counters, and simple numeric displays in appliances.

💼 Career

Understanding how to control hardware components like displays is essential for embedded systems and electronics programming jobs.

1

Set up segment pins array

Create an integer array called segmentPins with these exact values: 2, 3, 4, 5, 6, 7, 8 representing the Arduino pins connected to segments a to g.

Arduino

# Create the segmentPins array with pins 2 to 8
// Your code here

Hint

Use an integer array with the exact pin numbers in curly braces.

2

Create digit patterns array

Create a two-dimensional integer array called digits with 10 rows and 7 columns. Each row represents a digit 0 to 9. Each column is 1 or 0 to turn a segment on or off. Use this exact pattern:
{1,1,1,1,1,1,0}, {0,1,1,0,0,0,0}, {1,1,0,1,1,0,1}, {1,1,1,1,0,0,1}, {0,1,1,0,0,1,1}, {1,0,1,1,0,1,1}, {1,0,1,1,1,1,1}, {1,1,1,0,0,0,0}, {1,1,1,1,1,1,1}, {1,1,1,1,0,1,1}

Arduino

int segmentPins[] = {2, 3, 4, 5, 6, 7, 8};
// Create the digits array with patterns for 0 to 9
// Your code here

Hint

Use a 2D array with 10 rows and 7 columns exactly as shown.

3

Write displayDigit function

Write a function called displayDigit that takes an integer digit. Use a for loop with variable i from 0 to 6 to set each segment pin HIGH if digits[digit][i] is 1, else LOW. Use digitalWrite(segmentPins[i], HIGH) or digitalWrite(segmentPins[i], LOW) accordingly.

Arduino

int segmentPins[] = {2, 3, 4, 5, 6, 7, 8};

int digits[10][7] = {
  {1,1,1,1,1,1,0},
  {0,1,1,0,0,0,0},
  {1,1,0,1,1,0,1},
  {1,1,1,1,0,0,1},
  {0,1,1,0,0,1,1},
  {1,0,1,1,0,1,1},
  {1,0,1,1,1,1,1},
  {1,1,1,0,0,0,0},
  {1,1,1,1,1,1,1},
  {1,1,1,1,0,1,1}
};

// Write the displayDigit function below
// Your code here

Hint

Use a for loop from 0 to 6 and digitalWrite to control each segment.

4

Complete setup and loop to show digits

Write the setup() function to set all pins in segmentPins as OUTPUT using a for loop with variable i. Then write the loop() function to display digits 0 to 9 in order using a for loop with variable digit. Call displayDigit(digit) inside the loop and add delay(1000) to wait 1 second between digits.

Arduino

int segmentPins[] = {2, 3, 4, 5, 6, 7, 8};

int digits[10][7] = {
  {1,1,1,1,1,1,0},
  {0,1,1,0,0,0,0},
  {1,1,0,1,1,0,1},
  {1,1,1,1,0,0,1},
  {0,1,1,0,0,1,1},
  {1,0,1,1,0,1,1},
  {1,0,1,1,1,1,1},
  {1,1,1,0,0,0,0},
  {1,1,1,1,1,1,1},
  {1,1,1,1,0,1,1}
};

void displayDigit(int digit) {
  for (int i = 0; i < 7; i++) {
    if (digits[digit][i] == 1) {
      digitalWrite(segmentPins[i], HIGH);
    } else {
      digitalWrite(segmentPins[i], LOW);
    }
  }
}

// Write setup() and loop() functions below
// Your code here

Hint

Use loops in setup() and loop() to set pins and show digits with delay.