int trigPin = 11;
int echoPin = 12; 
int greenPin = 2;
int redPin = 3;
int speakerPin = 6; 
long duration, cm, inches; 


void setup() {
  // put your setup code here, to run once:
    Serial.begin(9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    pinMode(greenPin, OUTPUT);
    pinMode(redPin, OUTPUT); 
    pinMode(speakerPin, OUTPUT); 
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
 

  cm = (duration/2) / 29.1;
  
  Serial.print(cm);
  Serial.print("cm");
  Serial.println(); 

  if(cm > 200)
  {
  digitalWrite(greenPin, HIGH);
  digitalWrite(redPin, LOW);
  noTone(speakerPin); 
  }
  else
  {
  digitalWrite(redPin, HIGH);
  digitalWrite(greenPin, LOW);
  tone(speakerPin, 200);
  }
  // put your main code here, to run repeatedly:
  delay(250);
}