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

LiquidCrystal_I2C lcd(0x27,  16, 2);

const int upButton = 2;
const int downButton = 3;
const int wiperPin = 5;
const int upLed = 7;
const int downLed = 8;
int wiperValue = 0;

void setup() {
  // put your setup code here, to run once:
  //initialize lcd screen
  lcd.init();
  // turn on the backlight
  lcd.backlight();
  pinMode(upButton, INPUT_PULLUP);
  pinMode(downButton, INPUT_PULLUP);
  pinMode(wiperPin, OUTPUT);
  pinMode(upLed, OUTPUT);
  pinMode(downLed, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  // tell the screen to write on the top row
  lcd.setCursor(0, 0);
  // tell the screen to write “hello, from” on the top  row
  lcd.print("Pot=");
  if (wiperValue < 100) {
    lcd.setCursor(7, 0);
    lcd.print(" ");
  }
  if (wiperValue < 10) {
    lcd.setCursor(6, 0);
    lcd.print(" ");
  }
  lcd.setCursor(5, 0);
  lcd.print(wiperValue);
  digitalWrite(upLed, LOW);
  digitalWrite(downLed, LOW);
  if ((digitalRead(upButton)) == LOW) {
    digitalWrite(upLed, HIGH);
    if (wiperValue < 255) {
      wiperValue = wiperValue + 5;
      lcd.setCursor(15, 0);
      lcd.print((char) 43);
      analogWrite(wiperPin, wiperValue);
      delay(100);
    }
  }
  lcd.setCursor(15, 0);
  lcd.print((char) 0);
  if ((digitalRead(downButton)) == LOW) {
    digitalWrite(downLed, HIGH);
    if ((wiperValue >= 5) && (wiperValue != 0)) {
      wiperValue = wiperValue - 5;
      lcd.setCursor(15, 1);
      lcd.print((char) 45);
      analogWrite(wiperPin, wiperValue);
      delay(100);
    }
  }
  lcd.setCursor(15, 1);
  lcd.print((char) 0);
}