int trigPin = 16;
int echoPin = 4;
long duration;
int distance;

int ledRedPin = 14;
int ledYellowPin = 27; 

void setup() {
  pinMode(14, OUTPUT); 
 
  pinMode(27, OUTPUT); 

  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

if (distance < 100) {
      digitalWrite(14, HIGH);
      digitalWrite(ledYellowPin, LOW);
      Serial.print("Distance Danger: ");
      Serial.print(distance);
      Serial.println(" cm");
    }else if(distance>=100 && distance<200){
      digitalWrite(14, LOW);
      digitalWrite(ledYellowPin, HIGH);
      Serial.print("Distance Warning: ");
      Serial.print(distance);
      Serial.println(" cm");
      digitalWrite(14, LOW);
      digitalWrite(ledYellowPin, LOW);
      delay(1000);
    }else{
      digitalWrite(14, LOW);
      digitalWrite(ledYellowPin, LOW);
      Serial.print("No Object detected.");
    }
  delay(100);
}