#define TRIGGER_PIN 2
#define ECHO_PIN 4
#define MAX_DISTANCE 200
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
int buzzerPin = 12;
int ledPin = 5;
void setup() {
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(115200);
}
void loop() {
  delay(500);
  unsigned int distance = sonar.ping_cm();
  Serial.print(distance);
  Serial.println(" cm");
  if (distance <= 15) {
    digitalWrite(buzzerPin, HIGH);
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(buzzerPin, LOW);
    digitalWrite(ledPin, LOW);
  }
}