LCD display turns on, but doesn't display anything.

Projects General Guidance
1

Hello everyone,
I am currently working on a university project where I have to build a Digital Alarm Clock. I started today and after 3 hours of programming I have stumbled upon the LCD display problem. I have connected the wires and written the code to display "Hello World" on the LCD screen. However, it is not displaying that. I am guessing it has something to do with the resistance in the potentiometer and the resistor which is connected to the display.

Here is the code :-

#include <LiquidCrystal.h>

int Celcius_Temp = 0; 
int Fahrenheit_Temp = 0; 
int RS_Pin = 12; 
int Enable_Pin = 11; 
int DB4_Pin = 5; 
int DB5_Pin = 4; 
int DB6_Pin = 3; 
int DB7_Pin = 2;

LiquidCrystal lcd(RS_Pin, Enable_Pin, DB4_Pin, DB5_Pin, DB6_Pin, DB7_Pin);




void setup()
{
  Serial.begin(9600);
  lcd.begin(16,2);
  lcd.print("Hello World!");
  pinMode(A0,INPUT); //Pin for the temperature sensor 
}

void loop()
{
  //Celcius_Temp = ((analogRead(A0) * (5.0/1024)) - 0.5)/0.01;
  //Fahrenheit_Temp = (Celcius_Temp * 9/5) + 32; 
  
  
  //Serial.println(Celcius_Temp);
  delay(3000);
  
  lcd.clear(); 
  
}

I have attached the circuit as well. Let me know what I did wrong. I have been pulling my hair out on this problem for a long time. Your help will be much appreciated.
Thank You

Digital Clock project .png
Digital Clock project .png1920×908 90.5 KB

2

Looks like you're missing a ground on R/W. Also, looks like you need to power VDD and ground VSS. I'm not personally experimenting with the effects of leaving those off, so I can't promise that's your problem. Here's the link to the recommended pinout: https://www.arduino.cc/en/Tutorial/LiquidCrystalDisplay

Also, once you get the hardware working, your code is set up to display something and then wait for 3 seconds and never display it again. You may have been aware of that already, but I just thought I should point that out in case you weren't.

3

You can try and turn the potentiometer on the display. That sets the contrast. It's a very usual issue.
Run the code and then turn the pot.

4

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Digital Clock project .png
Digital Clock project .png1920×908 90.5 KB

Expand<](LCD display turns on, but doesn't display anything. - Project Guidance - Arduino Forum)

A little hint to make it easier. Do not connect the potentiometer to 5 V. If it is a 10k potentiometer, connect both ends of the potentiometer to ground.

Obviously unless you connect pins 1, 2 and 5 correctly, it can never work. :grinning: