#include <LiquidCrystal_I2C.h>
#include <Wire.h>

int blue = 8;
int green = 9;
int red = 10;


const int pingPin = 11;
const int echoPin = 3;

LiquidCrystal_I2C lcd(0x27,  16, 2);

void setup() {
  // put your setup code here, to run once:
pinMode(red, OUTPUT);
pinMode(green, OUTPUT);
pinMode(blue, OUTPUT);
Serial.begin(9600); // Starting Serial Terminal

lcd.init();
lcd.backlight();


}

void loop() {
   long duration, inches, cm;
   pinMode(pingPin, OUTPUT);
   digitalWrite(pingPin, LOW);
   delayMicroseconds(2);
   digitalWrite(pingPin, HIGH);
   delayMicroseconds(10);
   digitalWrite(pingPin, LOW);
   pinMode(echoPin, INPUT);
   duration = pulseIn(echoPin, HIGH);
   inches = microsecondsToInches(duration);
   cm = microsecondsToCentimeters(duration);
   

 // lcd.clear();
  lcd.setCursor(0,0);
  lcd.print(cm);
  lcd.print(" ");
  lcd.setCursor(4,0);
  lcd.print("cm");
 // delay(1);




  if(cm <= 10)
  {
    digitalWrite(green, HIGH);
    digitalWrite(red, LOW);
    digitalWrite(blue, LOW);
    lcd.setCursor(0,1);
    lcd.print("zelena");

  }
  else if(cm <= 30)
  {
    digitalWrite(green, LOW);
    digitalWrite(red, LOW);
    digitalWrite(blue, HIGH);
    
    lcd.setCursor(0,1);
    lcd.print("modra  ");
  }
  else if(cm <= 50)
  {
    digitalWrite(green, LOW);
    digitalWrite(red, HIGH);
    digitalWrite(blue, LOW);
    
    lcd.setCursor(0,1);
    lcd.print("cervena");
  }
  else
  digitalWrite(green, LOW);
  digitalWrite(red, LOW);
  digitalWrite(blue, LOW);



}

long microsecondsToInches(long microseconds) {
   return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds) {
   return microseconds / 29 / 2;
}