I2C scanner No Device Found I2C LCD


I’m currently working on a project that uses 16x2 LCD, and now I’m stuck at determining the address of my I2C using I2C scanner where it always shows “No Devices Found”.

I’m using an Arduino Mega and am very sure that the wires are connected to the right pins. I even bought new I2C and connect it to my LCD (I didn’t buy new LCD because I’m sure it’s working just fine since it’s on). But the same problem still occurs (No Devices Found). I also tried to use my Arduino UNO and it’s just the same as my Mega where the LCD turns on with the I2C connected to it but still can’t find the address of the I2C.

Here’s the pic,

Try this library:

//boolean debug = false;

#include <SoftwareSerial.h>
#include <TinyGPS++.h>

#include <Wire.h>
#include <hd44780.h>
#include <hd44780ioClass/hd44780_I2Cexp.h>

//#define BACKLIGHT_PIN     13

hd44780_I2Cexp mylcd; // declare lcd object: auto locate & config exapander chip

The hd44780.h is super.

To be sure, draw a proper diagram and attache it. Your pic is not precise enough.

When looking at this as a mathematical problem and assuming there is only one thing not working, then there is only one solution: The Mega board and the Uno board are okay, but the display is not.

Can you check the I2C backpack on the back of the display with a magnifier ? Are there broken wires, or solder blobs that shortcut things or pins that are not soldered properly.

Check your wires for continuity.

Use Nick Gammon's scanner.