// Pin Definitions
int segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 9};  // a, b, c, d, e, f, g, DP
int digitPins[] = {10, 11, 12, 13};            // Digit select pins
int potPin = A0;                               // Potentiometer connected to A0

// Number Encoding for 7-segment (common cathode)
byte numbers[10] = {
  0b00111111,  // 0
  0b00000110,  // 1
  0b01011011,  // 2
  0b01001111,  // 3
  0b01100110,  // 4
  0b01101101,  // 5
  0b01111101,  // 6
  0b00000111,  // 7
  0b01111111,  // 8
  0b01101111   // 9
};

void setup() {
  // Set all segment and digit pins as outputs
  for (int i = 0; i < 8; i++) pinMode(segmentPins[i], OUTPUT);
  for (int i = 0; i < 4; i++) pinMode(digitPins[i], OUTPUT);
}

void loop() {
  int value = analogRead(potPin);              // Read potentiometer value
  int displayValue = map(value, 0, 1023, 0, 9999);  // Scale to 4-digit range
  displayNumber(displayValue);
}

// Function to display a number
void displayNumber(int number) {
  for (int digit = 0; digit < 4; digit++) {
    int digitValue = number % 10;              // Extract digit
    number /= 10;

    // Light up the corresponding digit
    for (int i = 0; i < 8; i++) {
      digitalWrite(segmentPins[i], (numbers[digitValue] >> i) & 0x01);
    }
    digitalWrite(digitPins[digit], LOW);       // Activate current digit
    delay(2);                                  // Small delay for multiplexing
    digitalWrite(digitPins[digit], HIGH);      // Deactivate digit
  }
}