#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4); 

#define LED_PIN 2
#define POTENTIOMETER_PIN A0
void setup()
{
 lcd.init();
 lcd.init();
 lcd.backlight(); 
  pinMode(LED_PIN, OUTPUT);
}
void loop()
{
  float potentiometerValue = analogRead(POTENTIOMETER_PIN);
  float motor_speed = potentiometerValue / 4;
  analogWrite(LED_PIN, motor_speed);
  lcd.setCursor(0,0);
  lcd.print("brightness:");
  lcd.setCursor(10,0);
lcd.print(motor_speed);
 }