mini LCD + button tester v.01

/*
  Reddit menu example - May 8, 2019
  Displays a multi-level menu on a 20x4 LCD screen, with 5-button navigation.
  Board = Uno
  Other hardware: 20x4 I2C LCD
                  5 series-resistive buttons


  Button 1 should be left, button 2 down, button 3 up, button 4 right. 5 = select.
  buttons, resistors, pin levels:
  1   220Ω  394
  2   470Ω  329
  3   1KΩ   264
  4   2.2KΩ   194
  5   4.7KΩ   114

*/

#include "Wire.h" // For I2C (standard Arduino IDE library)
#include "LiquidCrystal_I2C.h" // Library location --- https://www.arduinolibraries.info/libraries/liquid-crystal-i2-c
LiquidCrystal_I2C lcd(0x27, 20, 4); // 0x27 is -usually- the default I2C bus address of the backpack

bool use_serial_messages = true; // general prototyping messages (allows disabling them for speed reasons)

int buttonInput_pin = A0;
int button_pressed = 0;
const int button_pressed__left = 1;
const int button_pressed__down = 2;
const int button_pressed__up = 3;
const int button_pressed__right = 4;
const int button_pressed__select = 5;


void setup() {
  Serial.begin(9600);
  lcd.init();
  // buttonInput_pin is analogRead(), doesn't require declaration
  // I2C pins A4, A5 are fixed and don't require declaration
  lcd_clear_all_lines();
  Serial.println("Exiting setup()");
}

void loop() {

  lcd_clear_line1();
  delay(500);
  button_pressed = analogRead(buttonInput_pin);
  if (button_pressed > 50 && button_pressed < 130) {
    // select button = 114
    lcd.setCursor(0, 0);
    lcd.print("button = select");
    Serial.println("button = select");
  }
  else if (button_pressed > 180 && button_pressed < 220) {
    // right button = 194
    lcd.setCursor(0, 0);
    lcd.print("button = right");
    Serial.println("button = right");
  }
  else if (button_pressed > 230 && button_pressed < 290) {
    // up button = 264
    lcd.setCursor(0, 0);
    lcd.print("button = up");
    Serial.println("button = up");
  }
  else if (button_pressed > 300 && button_pressed < 360) {
    // down button = 329
    lcd.setCursor(0, 0);
    lcd.print("button = down");
    Serial.println("button = down");
  }
  else if (button_pressed > 370 && button_pressed < 430) {
    // left button = 394
    lcd.setCursor(0, 0);
    lcd.print("button = left");
    Serial.println("button = left");
  }
  else {
    // no button pressed.
    lcd.setCursor(0, 1);
    lcd.print("button = none");
    Serial.println("button = none");
  }
  delay(2000);

} // end of main loop




void lcd_clear_all_lines() {
  lcd_clear_line1();
  lcd_clear_line2();
  lcd_clear_line3();
  lcd_clear_line4();
}

void lcd_clear_line1() {
  lcd.setCursor(0, 0);
  lcd.print("                    ");
}

void lcd_clear_line2() {
  lcd.setCursor(0, 1);
  lcd.print("                    ");
}

void lcd_clear_line3() {
  lcd.setCursor(0, 2);
  lcd.print("                    ");
}

void lcd_clear_line4() {
  lcd.setCursor(0, 3);
  lcd.print("                    ");
}