/*
LiquidCrystal Library - Hello World
Demonstrates the use a 16x2 LCD display. The LiquidCrystal
library works with all LCD displays that are compatible with the
Hitachi HD44780 driver. There are many of them out there, and you
can usually tell them by the 16-pin interface.
This sketch prints "Hello World!" to the LCD
and shows the time.
The circuit:
* LCD RS pin to digital pin 12
* LCD Enable pin to digital pin 11
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* LCD R/W pin to ground
* LCD VSS pin to ground
* LCD VCC pin to 5V
* 10K resistor:
* ends to +5V and ground
* wiper to LCD VO pin (pin 3)
Library originally added 18 Apr 2008
by David A. Mellis
library modified 5 Jul 2009
by Limor Fried (http://www.ladyada.net)
example added 9 Jul 2009
by Tom Igoe
modified 22 Nov 2010
by Tom Igoe
modified 7 Nov 2016
by Arturo Guadalupi
This example code is in the public domain.
https://docs.arduino.cc/learn/electronics/lcd-displays
*/
// include the library code:
#include <LiquidCrystal.h>
// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
void setup() {
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");
}
void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset:
lcd.print(millis() / 1000);
}
Some LCDs have a contrast potentiometer at the back and if it's set to very low contrast, you won't see anything on the LCD.
If that's not it, then please share a link to the exact LCD you are using, which arduino, which LiquidCrystal.h library you picked (there are multiple with the same name) and a quick drawing on how you wired things up and how your system is powered.
Breadboard with split power rails.
Potentiometer not wired correctly or other wiring error.
Using a board other than a Uno where the pin markings are not usable GPIO pins.
Header pins badly soldered on LCD with bridged or missing contacts.
Bad hardware.
Software not correctly loaded on MCU.
Show some good photographs of the circuit you have actually created yourself.
