int trigger =17;
int echo=5;
int green =25;
int orange=26;
int red=27;
float distance;

void setup() {
 
  Serial.begin(115200);
 pinMode(green,OUTPUT);
 pinMode(orange, OUTPUT);
 pinMode(red, OUTPUT);
 pinMode(trigger, OUTPUT);
 pinMode(echo, INPUT);
 pinMode(18, OUTPUT);
 
}

int dist()
{
  digitalWrite(trigger, LOW);
  delay(10);
  digitalWrite(trigger, HIGH);
  delay(100);
  digitalWrite(trigger, LOW);
  distance=pulseIn(echo,HIGH);

  return(distance*0.034/2);
}

void loop() {
  int sonic = dist();
   Serial.println(sonic);

   if(sonic>300){
    digitalWrite(green, HIGH);
    digitalWrite(orange, LOW);
    digitalWrite(red, LOW);
    Serial.println("safe");
  }
  else if( sonic >= 200 && sonic < 300 ){
    digitalWrite(green, LOW);
    digitalWrite(orange,HIGH);
    digitalWrite(red,LOW);
    Serial.println("warning!!!!");
  }
  else if(sonic >0 && sonic < 200){
     digitalWrite(green,LOW);
    digitalWrite(orange,LOW);
    digitalWrite(red,HIGH);
    Serial.println("Danger ahead");
    tone(18,9000);
    noTone(18);
  }

  else{
    digitalWrite(green, LOW);
    digitalWrite(orange, LOW);
    digitalWrite(red, LOW);

}
}