use interrupt pin in arduino

 const int inputPin1 = 2; // Input pin 1

const int inputPin2 = 3; // Input pin 2

const int inputPin3 = 4; // Input pin 3

const int inputPin4 = 5; // Input pin 4

volatile int count1 = 0; // Count variable for input pin 1

volatile int count2 = 0; // Count variable for input pin 2

volatile int count3 = 0; // Count variable for input pin 3

volatile int count4 = 0; // Count variable for input pin 4

void setup() {

  Serial.begin(9600); // Initialize serial communication

  // Set input pins as inputs

  pinMode(inputPin1, INPUT);

  pinMode(inputPin2, INPUT);

  pinMode(inputPin3, INPUT);

  pinMode(inputPin4, INPUT);

  // Enable interrupts on the input pins using rising edge trigger

  attachInterrupt(digitalPinToInterrupt(inputPin1), incrementCount1, RISING);

  attachInterrupt(digitalPinToInterrupt(inputPin2), incrementCount2, RISING);

  attachInterrupt(digitalPinToInterrupt(inputPin3), incrementCount3, RISING);

  attachInterrupt(digitalPinToInterrupt(inputPin4), incrementCount4, RISING);

}

void loop() {

  // Display the count for each input pin on the serial monitor

  Serial.println("Count:");

  Serial.print("Input 1: ");

  Serial.println(count1);

  Serial.print("Input 2: ");

  Serial.println(count2);

  Serial.print("Input 3: ");

  Serial.println(count3);

  Serial.print("Input 4: ");

  Serial.println(count4);

  delay(1000); // Wait for 1 second before updating the count

}

void incrementCount1() {

  count1++; // Increment the count for input pin 1

}

void incrementCount2() {

  count2++; // Increment the count for input pin 2

}

void incrementCount3() {

  count3++; // Increment the count for input pin 3

}

void incrementCount4() {

  count4++; // Increment the count for input pin 4

}