#define PIN_TRIG 3
#define PIN_ECHO 2 
const int l1 = 7;
const int b1 = 12;


void setup() {
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(l1, OUTPUT);  // Corrected: Set LED pin as OUTPUT
  pinMode(b1, OUTPUT);
}

void loop() {
  // Ensure the trigger pin is LOW before starting measurement
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(2);

  // Trigger the ultrasonic sensor
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);  // Corrected: Send 10µs pulse
  digitalWrite(PIN_TRIG, LOW);

  // Measure the response duration
  long duration = pulseIn(PIN_ECHO, HIGH);

  // Convert to distance
  int distance_cm = duration / 58;
  int distance_inch = duration / 148;

  // Print distances
  Serial.print("DISTANCE IN CM: ");
  Serial.println(distance_cm);
  Serial.print("DISTANCE IN inches: ");
  Serial.println(distance_inch);

  // LED control logic
  if (distance_cm <= 100) {
    digitalWrite(l1, HIGH);
    Serial.println("Led on");
    digitalWrite(b1, HIGH);
    tone(b1,250);
  } else {
    digitalWrite(l1, LOW);
    digitalWrite(b1, LOW);
    Serial.println("Led off");
    noTone(b1);
  }

  delay(1000);  // 1 second delay
}

//code written by vel