#define trigPin 7
#define echoPin 6
#define LEDlampRed 15
#define LEDlampYellow 10
#define LEDlampGreen 5

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LEDlampRed, OUTPUT);
  pinMode(LEDlampYellow,OUTPUT);
  pinMode(LEDlampGreen, OUTPUT);  
}
void
  loop() {
    long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  duration = pulseIn(echoPin, HIGH);

  distance = (duration *0.0344/2) ;
 
  if (distance < 50) {

      digitalWrite(LEDlampGreen, HIGH);
}
  else {
      digitalWrite(LEDlampGreen,
  LOW);
  }
  
  if (distance < 20) {
    digitalWrite(LEDlampYellow,
  HIGH);
}
  else {
    digitalWrite(LEDlampYellow,LOW);
  }
  if (distance < 5) {
    digitalWrite(LEDlampRed, HIGH);
}
  else
  {
    digitalWrite(LEDlampRed,LOW);
  }
  
  delay(100);
}