/* LCD_I2C_UltraSonic_distance2.ino

*/

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,4);

const int trigPin = 6;
const int echoPin = 4;
const int redLED = 13;
const int yellowLED = 11;
const int greenLED = 8;


void setup(){
  // Initialize serial communication
  //Serial.begin(9600);

  //LCD setup
  lcd.init();
  lcd.backlight();

  //Ultrasonic & LED setup
  pinMode (trigPin, OUTPUT);
  pinMode (echoPin, INPUT);
  pinMode (redLED, OUTPUT);
  pinMode (yellowLED, OUTPUT);
  pinMode (greenLED, OUTPUT);
}

void loop(){
  //Send pulse to ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  //Calculate the duration it takes for pulse to return
  long duration = pulseIn(echoPin, HIGH);
  
  //Calculate the distance in cm
  int distance = duration * 0.034 / 2;

  //Output the distance to the Serial Monitor
  //Serial.print("Distance: ");
  //Serial.print(distance);
  //Serial.println(" cm")


  //Lightup LED based on distance
  if (distance > 2 && distance <= 50) {
    digitalWrite(redLED, HIGH);
    digitalWrite(yellowLED, LOW);
    digitalWrite(greenLED, LOW);} 
    
  else if (distance > 50 && distance <= 100 ) {
    digitalWrite(redLED, LOW);
    digitalWrite(yellowLED, HIGH);
    digitalWrite(greenLED, LOW);}
    
  else if (distance > 100 && distance <= 150) {
    digitalWrite(redLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(greenLED, HIGH);}
  
  else if (distance > 150) {
    digitalWrite(redLED, HIGH);
    digitalWrite(yellowLED, HIGH);
    digitalWrite(greenLED, HIGH);}

  //Display the distance in LCD
  
  lcd.setCursor(0,0); // Set cursor to the first line
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");

  }