SOLVED Problem using LCD 20x4 IDE 1.8.7.

Other Hardware Displays
1

I guess this is not the first post about solving issues with the LCD display.

I've passed two days trying to make the LCD 20x4 bluedark display working properly. I've checked and used all libraries and codes related without exit.

I've attached photos of my Arduino connection and the libraries from my folder. I've removed all used libraries about LCD to understand with the default one LiquidCrystal is enough. The address of my LCD is 0x3F with SDA to SDA and SCL to SCL (for MEGA version).

The closest to success was two lines with black squares, however, turning the potenciometer it did not show anything. I'm using Arduino IDE 1.8.7.

Please, could you guide me?

Thanks

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REM14:
I guess this is not the first post about solving issues with the LCD display.

You are dead right there!

REM14:
I've passed two days trying to make the LCD 20x4 bluedark display working properly. I've checked and used all libraries and codes related without exit.

I do not see the HD44780 library in that list. That - Bill, bperrybap's library - is the only one you should be using, installed via the IDE library manager and you do not need to alter or remove any others. It includes full examples on how it is to be used.

REM14:
I've attached photos of my Arduino connection and the libraries from my folder. I've removed all used libraries about LCD to understand with the default one LiquidCrystal is enough. The address of my LCD is 0x3F with SDA to SDA and SCL to SCL (for MEGA version).

How do you know the address then?

REM14:
The closest to success was two lines with black squares, however, turning the potentiometer it did not show anything.

Was the backlight on? Check that you are getting 5 V to the correct two pins on the backpack. If connected, the contrast potentiometer should always change something.

REM14:
I'm using Arduino IDE 1.8.7.

Not particularly relevant. AFAIK

3

I know the address because I've installed the I2C scanner previously. Among all the options in that library, which one should I use?

There is a short code to test?

4

SOLVED! I've used the HelloWorld from hd4478io Class/I2exp.

5

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

LiquidCrystal_I2C lcd(0x27, 20, 4); //use 0x27 address, if this address will not work, use this 0x3f.

void setup()
{
lcd.init();
lcd.backlight();
}
void loop()
{
lcd.setCursor(0, 0);
lcd.print("Hello, world!");
}

// download this LiquidCrystal_I2C.zip library.

LiquidCrystal_I2C.zip (19.4 KB)

6

Don't think we need your library (which would not solve the problem anyway as you do not know which backpack is in use and do not actually comprehend the problem)! :astonished:

As I explained, Bill "bperrybap" who posts here routinely, has done a substantial body of work with these displays and produced a library which is simply and reliably installed through the Arduino IDE itself as "HD44780", which facilitates accurate and easy detection of hardware configuration as REM14 has found and is thus the only sensible way to drive these displays, with due respect and credit to the past work of fmalpartida.