#include <HCSR04.h>
#include <Wire.h>
#include <LCD_I2C.h>

const byte echoPin = 2;
const byte triggerPin = 3;
const byte Red_Led = 6;
const byte Yellow_Led = 7;
const byte Green_Led = 8;

LCD_I2C lcd(0x27, 16, 2);

void setup() {
  lcd.begin();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");

  pinMode(Red_Led,1);
  pinMode(Yellow_Led,1);
  pinMode(Green_Led,1);

  HCSR04.begin(triggerPin, echoPin);
}

void loop() {
  double* distances = HCSR04.measureDistanceCm();
  lcd.setCursor(0, 1);
  lcd.print(distances[0]); 
  lcd.println(" cm");

  if(distances[0] <= 100){
    digitalWrite(Red_Led,1);
    digitalWrite(Yellow_Led,0);
    digitalWrite(Green_Led,0);
    tone(14, 262, 100);
    delay(250);
    tone(14, 262, 100);
  }
  else if((distances[0] > 100) && (distances[0] < 200)){
    digitalWrite(Red_Led,0);
    digitalWrite(Yellow_Led,1);
    digitalWrite(Green_Led,0);
    tone(14, 262, 100);
    delay(500);
    tone(14, 262, 100);
  }
  else if(distances[0] >= 200){
    digitalWrite(Red_Led,0);
    digitalWrite(Yellow_Led,0);
    digitalWrite(Green_Led,1);
  }
}