LCD 1602 Question

Other Hardware Displays
1

I have an LCD, I have PIN 1 connected to GND, PIN 2 connected to 5v, PIN 4 connected to digital input 2, PIN 5 connected to GND, PIN 6 connected to digital input 3, PINS 11-14 into digital inputs 4, 5, 6, 7.

(Edit) I forgot to mention I have a 330ohm resistor on pin 15 which is connected to 5v and pin 16 connected to GND).

The screen does turn on.

Here is my code

#include <LiquidCrystal.h>

LiquidCrystal lcd(2,3,4,5,6,7);

void setup() {
 Serial.begin(9600);
 lcd.begin(16,2);
 lcd.print("hello");
}

Also, if I need to display a constantly changing variable, would I need to use the clear command between each change in the variable to achieve this constantly changing value to be displayed on my screen?

Sorry if this is weird to read, I was trying to be precise.

2

Slow it down with at least .1S between updates. You don't have to clear. It's lots faster just to update the data field with a lcd.cursor() command in a loop with the data being updated.

3

Connect a 1K to 10K potentiometer with one end to ground and the wiper to LCD pin 3 (Vo or contrast pin) and adjust till you can see a row of blocks or the printed text. Or connect LCD pin 3 (Vo) to ground through a 1K resistor to set the contrast.

4

I think you mean you have a "1602" alphanumeric display.

Do you mean the backlight goes on? But nothing actually appears?

You have not mentioned pin 3 of the display. Put another 330 Ohm resistor between that pin and ground.

Of course, you have soldered the header pins to the display board.

Presuming you have a common 1602 display, resistor R8 will be "101" or 100 Ohms; the 330 Ohm resistor in series with pin 15 is unnecessary but halves the illumination; generally does not matter.

Clearing the display causes flicker and should definitely not be done unless you want to alter most or all of the display. Do not update it at all unless some data has changed and no more than five times per second; update only that data using lcd.cursor() and you may need to add leading zeros or blanks if the new data is sorter than the old.

5

Thank you for the precise answer, I now see the boxes, and my text. I removed the resistor from pin 15, added a 1k resistor to pin 3, and connected RW to GND and I now see my text. Lets go.

6

What do you want to say the Backlight does not turn on or the Text is not occurring on the Screen there are a big difference in both of the problem so first pls specify your Exact issue.

It will not work you have to connect at least 1K Resistor to work.

Kindly find code and cicuit

7

The Basic code and basic Circuit

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
lcd.begin(16, 2);
lcd.print("Hello World");
lcd.setCursor(0,1);
lcd.print("How r U");
}


void loop() 
{

  
}

It must be work for you else it is Problem of your LCD Screen

Copy of 16x2_lcdDisplay_221121 (1)
Copy of 16x2_lcdDisplay_221121 (1)1143×603 81.9 KB

8 
#include <LiquidCrystal.h>

LiquidCrystal lcd(2,3,4,5,6,7);


int pinB = 12;
int pinR = 11;
int PinC = 0;
int pinS = 0;
int pinLS = 0;

void setup() {
 pinMode(pinB, OUTPUT);
 pinMode(pinR, OUTPUT);
 Serial.begin(9600);
 lcd.begin(16,2);
 
 

}

void loop() {
  
int wait = random(250,2500);
digitalWrite(pinB, HIGH);
if (pinB != HIGH) {
PinC++;
lcd.print(PinC); }
delay(wait);
lcd.clear();
delay(100);
digitalWrite(pinB, LOW);
delay(wait);
digitalWrite(pinR, HIGH);
if (pinR != HIGH) {
PinC++;
lcd.print(PinC);}
delay(wait);
lcd.clear();
delay(100);
digitalWrite(pinR, LOW);
delay(wait);
9

I got it working, I realized that I have a resistor on pin 15 which was limiting the display. I also figured out that pin 3 is needed in order to show the display at all. I got it working as I intended, it shows the number of times that it has flashed.

10

Why are you doing a quite critical to work with it the person doesn't how to work with Basic he is staring with basic the "Hello world" and you are adding wait HIGH LOW my suggestion is just first he must success on working with basic LCD and then he should try this

11

It is not necessary to use lcd.clear every time the value changes.
Just use lcd.setCursor to re-position the cursor, and then write the new value using lcd.print.
Documentation for setCursor is at this link: https://www.arduino.cc/reference/en/libraries/liquidcrystal/setcursor/
As @Paul_B says, you might need to print leading zeros or blanks before the data. Otherwise, if you try to overwrite 100 with 99, you will get 990 on your display (because the 0 at the end of the 100 is still on the display). Or, you might find it easier to instead print blank spaces after you print the data, in order to get rid of any extra digits.

12

Try a 330 Ohm resistor, or a 470. The resistor always goes from pin 3 to ground. The optimum value is generally between 1k and zero, so a 1k variable resistor can be used to adjust it, or you may just try various values.

Note that it is quite sensitive to the supply voltage and temperature, but given that neither changes much, it should not require any further adjustment.

Care to explain what you meant by that?

Your circuit actually shows pin 3 connected directly to ground, no resistor at all. This will usually work, but will probably tend to show dark boxes behind the characters.

You also show a 1k resistor in series with pin 15. That is OK, but the backlight may be dimmer than necessary. As I explained in #4, no series resistor is actually necessary but you can add one if it is too bright or you need to save battery power.

You can actually drive pin 15 from an Arduino pin to switch the backlight on and off or use PWM.

13

Yes, I removed the resistor from pin 15 and switched stuff up, I got it working how I wanted ,recorded a few videos, as I was asking this question for a project. I made a series of LED's that flash at random intervals, and each time one comes on, LedCount++ using an if statement. I repeated this for each of my 2 LED's and displayed the variable on the LCD. I then realized I needed to add the lcd.clear(); command in order to refresh the screen for each added number so it isn't just a screen filled with numbers. It was a fun project, I took the notes on the modules, code, and then I created it.