Documentation

// LCD1602 Keypad Shield - Hello World
// Uses the standard LiquidCrystal library.
// LCD pins: RS=8, E=9, D4=4, D5=5, D6=6, D7=7

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup() {
  lcd.begin(16, 2);
  lcd.print("ShillehTek LCD");
  lcd.setCursor(0, 1);
  lcd.print("Press a button");
}

void loop() {
  // Nothing to do — second example handles input
}

// LCD1602 Keypad Shield - Read Buttons via A0 Resistor Ladder
// Prints the active button on the LCD.

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

enum Button { BTN_NONE, BTN_RIGHT, BTN_UP, BTN_DOWN, BTN_LEFT, BTN_SELECT };

Button readButton() {
  int v = analogRead(A0);
  if (v < 50)   return BTN_RIGHT;
  if (v < 150)  return BTN_UP;
  if (v < 300)  return BTN_DOWN;
  if (v < 500)  return BTN_LEFT;
  if (v < 750)  return BTN_SELECT;
  return BTN_NONE;
}

void setup() {
  lcd.begin(16, 2);
  lcd.print("Press a button:");
}

void loop() {
  Button b = readButton();
  lcd.setCursor(0, 1);
  switch (b) {
    case BTN_RIGHT:  lcd.print("RIGHT          "); break;
    case BTN_UP:     lcd.print("UP             "); break;
    case BTN_DOWN:   lcd.print("DOWN           "); break;
    case BTN_LEFT:   lcd.print("LEFT           "); break;
    case BTN_SELECT: lcd.print("SELECT         "); break;
    default:         lcd.print("(none)         "); break;
  }
  delay(100);
}

// LCD1602 Keypad Shield - Simple Menu Skeleton
// UP/DOWN moves the cursor, SELECT triggers the action.

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

const char* items[] = {"Start", "Settings", "About"};
const int itemCount = 3;
int cursor = 0;
unsigned long lastInput = 0;

int readButton() {
  int v = analogRead(A0);
  if (v < 50)   return 1;  // RIGHT
  if (v < 150)  return 2;  // UP
  if (v < 300)  return 3;  // DOWN
  if (v < 500)  return 4;  // LEFT
  if (v < 750)  return 5;  // SELECT
  return 0;
}

void drawMenu() {
  lcd.clear();
  lcd.print("Menu:");
  lcd.setCursor(0, 1);
  lcd.print("> ");
  lcd.print(items[cursor]);
}

void setup() {
  lcd.begin(16, 2);
  drawMenu();
}

void loop() {
  int b = readButton();
  if (b && millis() - lastInput > 200) {
    lastInput = millis();
    if (b == 2 && cursor > 0)              cursor--;
    if (b == 3 && cursor < itemCount - 1) cursor++;
    if (b == 5) {
      lcd.clear();
      lcd.print("Selected:");
      lcd.setCursor(0, 1);
      lcd.print(items[cursor]);
      delay(1500);
    }
    drawMenu();
  }
}