//16x2 LCD
#include <LiquidCrystal_I2C.h> //SDA = A4, SCL = A5
LiquidCrystal_I2C lcd(0x27, 16, 2);
/*
 * Bas on Tech - Rotary Encoder and Interrupts
 * This course is part of the courses on 
 https://arduino-tutorials.net 
 * (c) Copyright 2018-2019 - Bas van Dijk / Bas on Tech
 * This code and course is copyrighted. It is not allowed to use these courses commerically
 * without explicit written approval
 * More info about the Rotary Encoder: 
 * https://en.wikipedia.org/wiki/Rotary_encoder
 * 
 * PIN CONNECTIONS
 * GND --> GND black
 *  +  --> 5V  red
 * SW  --> 12  yellow
 * DT  --> 3   green (data)
 * CLK --> 4   blue (clock)
 *
 */

int switchPin = 12;       // button pin
int switchState = HIGH;   // button value

int pinA = 4;          // Rotary encoder Pin A
int pinB = 3;          // Rotary encoder Pin B
int pinAstateCurrent = LOW;  // Current state of Pin A
int pinAStateLast = pinAstateCurrent;      
// Last read value of Pin A

void setup() {
lcd.init();
lcd.backlight();
  pinMode (switchPin, INPUT_PULLUP);       
  // Enable the switchPin as input with a PULLUP resistor
  
  pinMode (pinA, INPUT);  // Set PinA as input
  pinMode (pinB, INPUT);  // Set PinB as input
  
}

void loop() {

  // BUTTON
  switchState = digitalRead(switchPin);    
  // Read the digital value of the switch (LOW/HIGH)

  // If the switch is pressed (LOW), print message
  if (switchState == LOW) {
    lcd.setCursor(0,0);
      lcd.println("Switch pressed");
      delay(500);
lcd.clear();
  }
  
  // ROTATION DIRECTION
  pinAstateCurrent = digitalRead(pinA);    
  // Read the current state of Pin A
  
  // If there is a minimal movement of 1 step
  if ((pinAStateLast == LOW) && (pinAstateCurrent == HIGH)) {
    
    if (digitalRead(pinB) == HIGH) {// If Pin B is HIGH
      lcd.setCursor(0,1);
      lcd.println("Left");   // Print on screen
      delay(500);
    lcd.clear();
    } else {
      lcd.setCursor(8,1);
      lcd.println("Right"); // Print on screen
      delay(500);
    lcd.clear();
    }
    
  }
  pinAStateLast = pinAstateCurrent;
  // Store the latest read value in the currect state variable
  
}