Help, LCD Display

Using Arduino Programming Questions
#1

Hi, so I am having problems with my new LCD Display. I haven’t ever used one before, but I got some sample code:

#include "LiquidCrystal.h"

// initialize the library by providing the nuber of pins to it
LiquidCrystal lcd(8,9,4,5,6,7);

void setup() {
lcd.begin(16,2);

// set cursor position to start of first line on the LCD
lcd.setCursor(0,0);
//text to print
lcd.print("    COUNTER");
delay(100);

int a=0;
lcd.setCursor(0,1);
lcd.print("       ");
lcd.print(a);
while(a<=100)
{
  a=a+1;
  delay(1000);
  lcd.setCursor(0,1);
  lcd.print("       ");
  lcd.print(a);
}
}
void loop()
{
  lcd.clear();
}

and wired up my LCD according to this site: Interface an LCD with an Arduino - Projects

however, nothing happens, and it doesn’t appear to work. Is there something wrong with the code or wiring? Also, what does the pot do?

Thanks!

#2

Also, what does the pot do?

If you smoke it, it gets you high.

You didn't post a link to the LCD, so we only surmise that you've been smoking too much pot.

#3

I meant the Potentiometer :) Do you mean a link to where I bought the LCD? I thought they were all the same. Here is the link to where I bought it: https://tinyurl.com/y9pztok6

#4

Character intensity adjustment On LCD power-up , no code yet running ! , you should adjust this pot until you see line(s) on 5x7 dots characters.

#5

I changed the code to this: 

#include "LiquidCrystal.h"

// initialize the library by providing the nuber of pins to it
LiquidCrystal lcd(8,9,4,5,6,7);

void setup() {
lcd.begin(16,2);
}

void loop() {
  lcd.setCursor(0,1);
  lcd.print("Hello World");
}

I then turned the pot slowly back and forth and nothing happened.

#6

Ok, so as I was messing around with it, I accidentally bumped it, and then stuff flickered on. I figured out that if I bend it around, then I can get it to work a little. At one point, I got it just right so that it said the right words and everything. However, I can't get it in just the right bend again. I have it on some male pins out from my breadboard, but I don't know how to get it to connect better.

#7

What arduino board are you using? If its less than 5V display might not have enough power, try a 5V arduino board with example code.

#8

What are you bending? The display? Wires? Are you using a bread board?

#9

There is an old saying - it works better when you plug it in. I guess my comment about NOT running ANY code and then adjusting the pot did not sink in. Just connect the + and grounds to BOTH LCD supply and backlight LED and do you intensity adjustment after the device goes thru its power-on sequence - automatically. . It is possible that your is also controlling the backlight so you are better off not running code until you have working hardware.

Not to worry about how much power you drawing - these LCD been around for few yeas and are not that hungry by itself - its the backlight LED that takes few mA.

#10

I have it on some male pins out from my breadboard, but I don't know how to get it to connect better.

Probably a silly question, but are the pins soldered to the LCD?

#11

Okay guys, thanks for all the question helps, I think I got it mostly figured. So, I was just using some straight male to male pins from my breadboard to each hole in the LCD, and when I gently bent/tipped the lcd display backward or forward, it would sometimes work. So then I knew that it was a problem of bad connectivity. And then, yes, I soldered the pins to the LCD, and now it works great. Will it work to use my IR Remote to change the text on the LCD?

WIN_20180505_10_23_24_Pro.jpg
WIN_20180505_10_23_24_Pro.jpg1280×720 163 KB

#12

Vulcan666: Okay guys, thanks for all the question helps, I think I got it mostly figured. So, I was just using some straight male to male pins from my breadboard to each hole in the LCD, and when I gently bent/tipped the lcd display backward or forward, it would sometimes work. So then I knew that it was a problem of bad connectivity.

Never use loose connections; recipe for problems (as you have figured).

Vulcan666: Will it work to use my IR Remote to change the text on the LCD?

If you code it properly, yes :)

#13

Okay, why doesn’t this work?

//----------------------------Libraries
#include <LiquidCrystal.h>
#include "IRremote.h"
#include "Servo.h"

//----------------------------Servo Pre-Setup
Servo AlarmServo;

//----------------------------Remote Pre-Setup
int receiver = 12;
IRrecv irrecv(receiver);
decode_results results;

//--------------------------------------LCD Pre-Setup
LiquidCrystal lcd(0, 1, 8, 9, 10, 11);

void setup() {  // - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * -Void Setup()

  //----------------------------LCD Setup
  lcd.begin(16, 2);
  lcd.print(" LD Alarm Clock");

  //----------------------------Servo Setup
  AlarmServo.write(5);
  AlarmServo.attach(10);

  //----------------------------Remote Setup
  Serial.begin(9600);
  irrecv.enableIRIn();
  pinMode(52, OUTPUT);
}

void loop() {//- * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * - * -Void Loop()

  //--------------------------------------------Remote Functions/Setup
  if (irrecv.decode(&results))   {
    switch (results.value)  {

      //------------------Button: 1
      case 0xFF6897:
        lcd.write("Howdy");
        digitalWrite(52, HIGH);
        break;

        //------------------Remote Setup Finish
        delay(250);
        irrecv.resume();

    }
  }
}

the led turns on but the lcd display doesn’t change from “LD Alarm Clock” to “howdy”

#14

Why do you use pins 0 and 1 for the LCD? Those pins are also used for the serial port.

Use different pins for the LCD.

#15

Okay, thanks so much, it works now. However, now it says howdyhowdyhowdyhowdy without end, how do I make it say it once? I put it on those pins because I looked up a diagram and that was how it was wired. Guess they didn't have ir remote plans in mind:)

#16

how do I make it say it once?

Move the irrecv.resume() out of the switch/case.

case 0xFF6897:
        lcd.write("Howdy");
        digitalWrite(52, HIGH);
        break;
    }
     irrecv.resume();
  }

Remove the delay from the switch/case for a more responsive sketch.

Guess they didn't have ir remote plans in mind:

pins 0 & 1 are for the Serial port, they have noting to do with IR remote.

I put it on those pins because I looked up a diagram and that was how it was wired.

What you saw was probably the wiring for a LCD to an I2C expander. Not applicable for your LCD.

#17