const int trigger=14,echo=12,green=21,orange=5,red=4,buzzer=25;
float distance=0;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(green, OUTPUT);
  pinMode(orange, OUTPUT);
  pinMode(red, OUTPUT);
}
int ship(){
  digitalWrite(trigger,HIGH);
  delay(1000);
  digitalWrite(trigger,LOW);
  float eh=pulseIn(echo,HIGH);
  distance=eh*0.034/2;
  return distance;
}
void loop() {
  int sensor=ship();
  if(distance>=300){
  digitalWrite(green, HIGH);
  digitalWrite(orange, LOW);
  digitalWrite(red, LOW);
  Serial.println("You are safe!!");
  noTone(buzzer);
  } else if(distance>=200 && distance<300){
  digitalWrite(orange, HIGH);
  digitalWrite(green, LOW);
  digitalWrite(red, LOW);
  Serial.println("You are unsafe!!");
  noTone(buzzer);
  } else{
  digitalWrite(red, HIGH);
  digitalWrite(orange, LOW);
  digitalWrite(green, LOW);
  Serial.println("You are danger!!!!!!");
  tone(buzzer, 10000);
  }
  delay(10); // this speeds up the simulation
}