Ayushman Gupta Toll gate project APS Ambala Cantt.

 #include <Servo.h>

const int trigPin = 6;

const int echoPin = 7;

Servo myServo;

void setup() {

  pinMode(trigPin, OUTPUT);

  pinMode(echoPin, INPUT);

  myServo.attach(9);

  myServo.write(0); // Gate closed position

}

void loop() {

  long duration, distance;

  

  // Send ultrasonic pulse

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  

  // Read echo time

  duration = pulseIn(echoPin, HIGH);

  

  // Calculate distance in cm

  distance = duration * 0.034 / 2;

  

  if (distance < 20) { // If object is within 20 cm

    myServo.write(120); // Open gate

    delay(3000);        // Keep gate open for 3 seconds

    myServo.write(0);   // Close gate

  }

  

  delay(500); // Wait before next measurement

}