SMART_HELMET_WITH_MOTOR_DRIVER_12_VOLTS_MOTOR

 // Pin definitions

const int trigPin = 2;   // HC-SR04 trigger

const int echoPin = 3;   // HC-SR04 echo

const int ENA     = 9;   // L298N Enable A (PWM)

const int IN1     = 10;  // L298N IN1

const int IN2     = 11;  // L298N IN2

// Distance threshold (in cm)

const int detectDist = 10;  

void setup() {

  pinMode(trigPin, OUTPUT);

  pinMode(echoPin, INPUT);

  pinMode(ENA, OUTPUT);

  pinMode(IN1, OUTPUT);

  pinMode(IN2, OUTPUT);

  // Motor off initially

  digitalWrite(IN1, LOW);

  digitalWrite(IN2, LOW);

  analogWrite(ENA, 0);

  Serial.begin(9600);

}

long readDistanceCm() {

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH, 30000UL); // 30ms timeout

  if (duration == 0) return -1;

  return duration / 58; // Convert µs to cm

}

void loop() {

  long distance = readDistanceCm();

  if (distance > 0 && distance <= detectDist) {

    // Object detected → Run motor forward full speed

    digitalWrite(IN1, HIGH);

    digitalWrite(IN2, LOW);

    analogWrite(ENA, 255); // Full speed

    Serial.print("Object at ");

    Serial.print(distance);

    Serial.println(" cm → Motor ON");

  } else {

    // Stop motor

    digitalWrite(IN1, LOW);

    digitalWrite(IN2, LOW);

    analogWrite(ENA, 0);

    Serial.println("No object → Motor OFF");

  }

  delay(100);

}