#define LED 4
#define BUZZER 2
#define PIN_TRIG 12
#define PIN_ECHO 14

void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
}

void loop() {
  // Start a new measurement:
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  // distance in CM
  int distance = pulseIn(PIN_ECHO, HIGH) / 58;
  distance = map(distance, 2 , 203, 2, 201);

if(distance <= 200){
  digitalWrite(LED, HIGH);
  tone(BUZZER, 262, 250); // Plays 262Hz tone for 0.250 seconds
  Serial.print("the obstacle is detected at distance: ");
  Serial.println(distance);
}
else{
  digitalWrite(LED, LOW);
  Serial.println("no obstacles detected! (no obstacles within range 200)");
}

delay(1000);

}