#include "Ultrasonic.h"
Ultrasonic ultrasonic(13,12);
int distance;
int led_green=4;
int led_yellow=3;
int led_red=2;
void setup() {
  Serial.begin(9600);
  pinMode(led_green, OUTPUT);
  pinMode(led_yellow, OUTPUT);
  pinMode(led_red, OUTPUT);
}

void loop() {

  // put your main code here, to run repeatedly:
 distance = ultrasonic.read(CM);
 Serial.print("Distance in CM:");
 Serial.println(distance);
 
 delay(1000);
  digitalWrite(led_red, LOW);
 digitalWrite(led_yellow , LOW);
 digitalWrite(led_green , LOW);


 if(distance < 100){
  digitalWrite(led_yellow , LOW);
 digitalWrite(led_green , LOW);
 digitalWrite(led_red, HIGH);}
 else if(distance >= 100 && distance <= 300 ){
  digitalWrite(led_red, LOW);
  digitalWrite(led_green , LOW);
 digitalWrite(led_yellow , HIGH);}

  else {
      digitalWrite(led_red, LOW);

   digitalWrite(led_yellow , LOW);
 digitalWrite(led_green , HIGH);}


}