I buy new lcd 1602 but it dont work

Other Hardware Displays
1

Hi, I bought an lcd 1602 display in a store where the seller connected it to his board (connected via a bus), he connected it according to the following scheme:

#include <Wire.h>
#include <LiquidCrystal.h>
 
LiquidCrystal lcd(0);
 
void setup() {
  lcd.begin(16, 2);
  lcd.print("hello, world!");
}
 
void loop() {

  lcd.setCursor(0, 1);
  lcd.print(millis()/1000);
 
  lcd.setBacklight(HIGH);
  delay(500);
  lcd.setBacklight(LOW);
  delay(500);
}

gnd-gnd vcc-5V SDA- A4 SCL-5A and displayed text through this code
the display worked when I came and connected the same circuit with this the display did not respond with the code

#include <Wire.h> // библиотека для управления устройствами по I2C 
#include <LiquidCrystal_I2C.h> // подключаем библиотеку для QAPASS 1602

LiquidCrystal_I2C LCD(0x27,16,2); // присваиваем имя LCD для дисплея

void setup() {
   LCD.init(); // инициализация LCD дисплея
   LCD.backlight(); // включение подсветки дисплея
   
   LCD.setCursor(1, 0);     // ставим курсор на 1 символ первой строки
   LCD.print("I LOVE");     // печатаем сообщение на первой строке
  
   LCD.setCursor(8, 1);        // ставим курсор на 1 символ второй строки
   LCD.print("ARDUINO");  // печатаем сообщение на второй строке
}

void loop() {
   LCD.noDisplay(); // выключаем и включаем надпись на дисплее
   delay(1000);
   LCD.display();
   delay(1000);
}

its backlight did not turn on, while the board was serviceable and everything worked on the other display. maybe someone knows what the reason is?

2

Your topic has been moved to the Displays category of the forum

More details please

  • What sort of interface does the dispaly use to connect to the Uno R3 ?
  • How did you test it in the store ?
  • What does "not work" mean ?
  • What sketch are you running ?
3

If you have supplied all the information, and the LCD was connected and works on another Arduino, but does not work when connected on your Arduino, then you have a bad Arduino.

Run some basic sketches on your Arduino, including this pin check sketch that will tie all your DIO pins HIGH, showing a "1" in the Serial Monitor, and when you short a ground pin to any DIO pin, it will show as 0 in the Serial Monitor:

//**********************************************************************
// 1. Connect a jumper wire to GND
// 2. Upload the sketch
// 3. Touch the jumper wire to a pin 2 through 12 and A0 through A5
// 4. The output will show the pin(s) you are touching
//
// This shows pin D3 sensing ground through jumper...
// 12 11 10 D9 D8 D7 D6 D5 D4 D3 D2 A0 A1 A2 A3 A4 A5
//  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1
//**********************************************************************

int pin[] = {13, 12, 11, 10, 9, 8,  7, 6, 5, 4, 3, 2, 14, 15, 16, 17, 18, 19};
int size = sizeof(pin) / sizeof(pin[0]);

void setup() {
  Serial.begin(115200);
  Serial.println("Pin State Reader");

  for (int i = 0; i < size; i++) {
    pinMode(pin[i], INPUT_PULLUP);
  }
}

void loop() {
  int size = sizeof(pin) / sizeof(pin[0]);
  Serial.println(F(" 13 12 11 10 D9 D8 | D7 D6 D5 D4 D3 D2 | A0 A1 A2 A3 A4 A5"));
  for (int i = 0; i < size; i++) {
    int state = digitalRead(pin[i]);
    if (i == 6 || i == 12)
      Serial.print(" |  ");
    else
      Serial.print("  ");
    Serial.print(state);
  }
  Serial.println();
  delay(1000);  // to allow jumper to be moved
}
4

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