NodeMCU not printing text on 16x2 LCD using I2C

Projects Programming
1

I am using a 16x2 LCD to display some data for my project. I am using I2C for interfacing NodeMCU 1.0
Code is compiling and uploading successfully but it's not displaying text.

Circuit:

576×646 44.9 KB

Library used: LiquidCrystal_I2C.h
The project I referred to NodeMCU 16x2 LCD on Arduino IDE - Robo India || Tutorials || Learn Arduino || Robotics

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

LiquidCrystal_I2C lcd(0x3F);  // updated the address after scanning the I2C

void setup(){
  Wire.begin(2,0);
  lcd.begin(16,2);   // initializing the LCD
  lcd.backlight(); // Enable or Turn On the backlight 
  lcd.print(" Hello Makers "); // Start Printing
}
void loop(){
  // Nothing Absolutely Nothing!
}
2

What does the i2cscanner.ino sketch tell you? That is part of the project you reference. Does it show the LCD present?

3

blh64:
What does the i2cscanner.ino sketch tell you? That is part of the project you reference. Does it show the LCD present?

I used this sketch to find the address: NodeMCU i2c Scanner on Arduino IDE - Robo India || Tutorials || Learn Arduino || Robotics
It gave me 0x27
I updated the address but it was not fruitful.

4

Have you tried adjusting the contrast control that is generally located on the display's I2C board?

5

david_2018:
Have you tried adjusting the contrast control that is generally located on the display's I2C board?

Yes, I have adjusted it and set it to the maximum level.

6

Yes, I have adjusted it and set it to the maximum level.

Contrast post should be set at the level where the blocks are illuminated on only one row of the display.

7

You may have a problem with the display running at 5 volts while the nodemcu runs at 3.3 volts, you should be using a level shifter.

Might be a problem with the library, there are a lot of LiquidCrystal_I2C libraries using the same file names, so hard to tell whether the one you have is compatible with a nodemcu.

Try using the hd44780 library (it should be in the library manager in the IDE), and run the FIle > Examples > hd44780 > ioClass > hd44780_I2Cexp > I2CexpDiag sketch. That will give you a lot of info in the serial monitor as well as on the LCD display.

8

david_2018:
You may have a problem with the display running at 5 volts while the nodemcu runs at 3.3 volts, you should be using a level shifter.

Might be a problem with the library, there are a lot of LiquidCrystal_I2C libraries using the same file names, so hard to tell whether the one you have is compatible with a nodemcu.

Try using the hd44780 library (it should be in the library manager in the IDE), and run the FIle > Examples > hd44780 > ioClass > hd44780_I2Cexp > I2CexpDiag sketch. That will give you a lot of info in the serial monitor as well as on the LCD display.

I tried changing parameters in Wire.begin() to D2 and D1 for SDA and SCL connections instead of 2 and 0.
It worked for me now!

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

LiquidCrystal_I2C lcd(0x27, 16, 2);  // updated the address after scanning the I2C

void setup(){
  Wire.begin(D2,D1);
  lcd.begin(16, 2);   // initializing the LCD
  lcd.home();
  lcd.backlight(); // Enable or Turn On the backlight
  lcd.print("Hello World"); // Start Printing
  delay(1000);
}
9

chauhannaman98:
I tried changing parameters in Wire.begin() to D2 and D1 for SDA and SCL connections instead of 2 and 0.
It worked for me now!

I didn't even notice the Wire.begin, generally that is done by the LCD library and defaults to the hardware I2C.

10

D1 and D2 are the default pins for an NodeMCU. Using 2 and 0 was never correct.

11

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.