LCD 1602 con retroiluminación azul con I2C pre-soldado

/*
 * ==================================================================
 *  Generated by Codey.online  —  https://www.codey.online
 * ==================================================================
 *  Project   : 1602 I2C LCD Display Demo
 *  Board     : Arduino UNO (arduino:avr:uno)
 *  Parts     : 1602 LCD I2C DISPLAY
 *  Libraries : LiquidCrystal I2C 1.1.2
 *
 *  Codey Online is an AI-powered browser IDE for Arduino and ESP32.
 *  Describe your project and Codey writes the code, draws the wiring
 *  diagram and uploads it to your board, straight from the browser.
 *  This code is free to use, modify and share, without warranty.
 * ==================================================================
 */

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

// Set the LCD address to 0x27 for a 16 chars and 2 line display
// (If your display stays blank, try address 0x3F)
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(115200);
  Serial.println(F("Starting 1602 I2C LCD demo..."));

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print(F("Hello, World!"));
}

void loop() {
  // Display the running uptime in seconds on the second line
  unsigned long seconds = millis() / 1000;

  lcd.setCursor(0, 1);
  lcd.print(F("Uptime: "));
  lcd.print(seconds);
  lcd.print(F("s   "));

  Serial.print(F("Uptime: "));
  Serial.print(seconds);
  Serial.println(F(" s"));

  delay(1000);
}

/*
 * ==================================================================
 *  Generated by Codey.online  —  https://www.codey.online
 * ==================================================================
 *  Project   : ESP32 1602 I2C LCD Display Demo
 *  Board     : ESP32 DEVKIT V1 (esp32:esp32:esp32doit-devkit-v1)
 *  Parts     : 1602 LCD I2C DISPLAY
 *  Libraries : LiquidCrystal I2C 1.1.2
 *
 *  Codey Online is an AI-powered browser IDE for Arduino and ESP32.
 *  Describe your project and Codey writes the code, draws the wiring
 *  diagram and uploads it to your board, straight from the browser.
 *  This code is free to use, modify and share, without warranty.
 * ==================================================================
 */

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

// Set LCD I2C address (commonly 0x27 or 0x3F) and dimensions (16 columns, 2 rows)
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize I2C with ESP32 default pins: SDA (GPIO 21), SCL (GPIO 22)
  Wire.begin(21, 22);
  
  lcd.init();
  lcd.backlight();
  
  lcd.setCursor(0, 0);
  lcd.print("ESP32 LCD Demo");
  lcd.setCursor(0, 1);
  lcd.print("Uptime: ");
}

void loop() {
  // Update uptime counter in seconds
  lcd.setCursor(8, 1);
  lcd.print(millis() / 1000);
  lcd.print("s  ");
  delay(500);
}