{"product_id":"2004-lcd-i2c-display-20x4-blue-backlight-hd44780-arduino","title":"2004 LCD I²C Display Module — 20×4 Characters, Blue Backlight, HD44780, Arduino","description":"\u003ch2\u003e2004 LCD I²C Display Module — 20×4 Characters, Blue Backlight, HD44780, Arduino\u003c\/h2\u003e\u003cp\u003eThis 2004 LCD module combines a 20-column × 4-row HD44780-compatible character LCD with a PCF8574-based I²C backpack adapter, reducing the connection from 16 pins to just 4 wires (VCC, GND, SDA, SCL). The blue backlight with white characters provides excellent readability. With I²C address 0x27 (or 0x3F depending on variant), it is directly supported by the LiquidCrystal_I2C Arduino library and is the standard multi-line text display for Arduino data loggers, sensor readouts, menu systems, and industrial HMI panels.\u003c\/p\u003e\u003ch3\u003eKey Specifications\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDisplay Size\u003c\/td\u003e\n\u003ctd\u003e20 columns × 4 rows (2004)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eController IC\u003c\/td\u003e\n\u003ctd\u003eHD44780 (or compatible)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInterface\u003c\/td\u003e\n\u003ctd\u003eI²C (via PCF8574 I\/O expander)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eI²C Address\u003c\/td\u003e\n\u003ctd\u003e0x27 (default) or 0x3F (variant)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSupply Voltage\u003c\/td\u003e\n\u003ctd\u003e5V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBacklight Color\u003c\/td\u003e\n\u003ctd\u003eBlue (with white characters)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCharacter Size\u003c\/td\u003e\n\u003ctd\u003e5×8 dot matrix per character\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temperature\u003c\/td\u003e\n\u003ctd\u003e-20°C to +70°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003e2004 LCD vs 1602 LCD\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003e2004 LCD (20×4)\u003c\/th\u003e\n\u003cth\u003e1602 LCD (16×2)\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCharacters\u003c\/td\u003e\n\u003ctd\u003e80 (20×4)\u003c\/td\u003e\n\u003ctd\u003e32 (16×2)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRows\u003c\/td\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003ctd\u003e2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBest for\u003c\/td\u003e\n\u003ctd\u003eMulti-line menus, sensor dashboards\u003c\/td\u003e\n\u003ctd\u003eSimple 2-line status display\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLibrary\u003c\/td\u003e\n\u003ctd\u003eLiquidCrystal_I2C (same)\u003c\/td\u003e\n\u003ctd\u003eLiquidCrystal_I2C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch3\u003eWhy Choose 2004 LCD I²C?\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e4-wire I²C connection\u003c\/strong\u003e — only VCC, GND, SDA, SCL needed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e80 characters (20×4)\u003c\/strong\u003e — display 4 lines of sensor data simultaneously\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHD44780 compatible\u003c\/strong\u003e — LiquidCrystal_I2C library, same code as 1602 LCD\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdjustable contrast\u003c\/strong\u003e — onboard trimmer potentiometer\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBacklight control\u003c\/strong\u003e — on\/off via I²C for power saving\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eCompatible With\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eArduino UNO\/Nano\u003c\/strong\u003e: SDA=A4, SCL=A5, 5V, GND\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArduino Mega\u003c\/strong\u003e: SDA=20, SCL=21\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eESP32\u003c\/strong\u003e: SDA=GPIO21, SCL=GPIO22 (add 4.7kΩ pull-ups to 3.3V)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eESP8266\u003c\/strong\u003e: SDA=GPIO4 (D2), SCL=GPIO5 (D1)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eQ: How do I use 2004 LCD I²C with Arduino?\u003c\/strong\u003e\u003cbr\u003eA: Install LiquidCrystal I2C library. Connect SDA to A4, SCL to A5, VCC to 5V, GND to GND. Code: \u003ccode\u003eLiquidCrystal_I2C lcd(0x27, 20, 4); lcd.init(); lcd.backlight(); lcd.print(\"Hello!\");\u003c\/code\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ: My LCD shows blocks or nothing — how do I fix it?\u003c\/strong\u003e\u003cbr\u003eA: (1) Adjust contrast trimmer on I²C backpack. (2) Verify I²C address with I2C scanner sketch (0x27 or 0x3F). (3) Check SDA\/SCL wiring. (4) Add 4.7kΩ pull-ups if using 3.3V MCU.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ: Can I use 2004 LCD with ESP32 at 3.3V?\u003c\/strong\u003e\u003cbr\u003eA: Connect VCC to 5V, GND to GND, SDA\/SCL to ESP32 GPIO21\/GPIO22. Add 4.7kΩ pull-ups from SDA\/SCL to 3.3V for ESP32 compatibility.\u003c\/p\u003e\u003ch3\u003ePackage Contents\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e1× 2004 LCD I²C Display Module (20×4, blue backlight, PCF8574 I²C backpack)\u003c\/li\u003e\u003c\/ul\u003e","brand":"Keszoox","offers":[{"title":"2004 IIC green","offer_id":46991470919915,"sku":"14:29#2004 IIC green","price":18.76,"currency_code":"USD","in_stock":true},{"title":"LCD1602","offer_id":46991470952683,"sku":"14:201684806#LCD1602","price":4.44,"currency_code":"USD","in_stock":true},{"title":"2004 green","offer_id":46991470985451,"sku":"14:201659810#2004 green","price":16.28,"currency_code":"USD","in_stock":true},{"title":"2004 IIC blue","offer_id":46991471018219,"sku":"14:173#2004 IIC blue","price":18.76,"currency_code":"USD","in_stock":true},{"title":"2004 blue","offer_id":46991471050987,"sku":"14:10#2004 blue","price":16.28,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/1005\/8731\/files\/i2c-2004-blue-backlight-lcd-module-arduino.webp?v=1761633846","url":"https:\/\/keszoox.com\/products\/2004-lcd-i2c-display-20x4-blue-backlight-hd44780-arduino","provider":"Keszoox","version":"1.0","type":"link"}