Connecting 16x4 lcd to arduino

[FutureEngineer]

Hi,

I am trying to connect 16x4 lcd to Arduino.
I used hello world code, but the lcd does not display any text

[stefankersten]

Can you upload the code you used

[ledsyn]

You have to add more information. Looking at a photo to figure out how the wires are connected is hard - a schematic / circuit diagram is direct and easy to follow.

Also include your code formatted as code.

Edit: Include what display you use.

[FutureEngineer]

I used the same connection with another 16x2 LCD and it worked
This is the code

#include <LiquidCrystal.h>

const int rs = 12, en = 11, d4 = 4, d5 = 5, d6 = 6, d7 = 7;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 4);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis() / 1000);
}

[david_2018]

Can you post a link to the display, or a picture of the back of the display board? I see connection points for an I2C interface, are you sure it should be driven directly by the LCD connections?

[ledsyn]

@FutureEngineer

I used the same connection with another 16x2 LCD and it worked

This information isn't useful. Can you please provide a schematic how you have wired LCD and Arduino? Even a hand drawn schematic will do if you don't have the possiblity to make a digital one.

Just help us help you by providing necessary information. We're not mind readers.

[FutureEngineer]

Hello,

I followed the schematic shown in Arduino website. Please find link below.

Liquid Crystal Displays (LCD) with Arduino | Arduino Documentation

[ledsyn]

Now we're getting somewhere, and what display do you got there? The model that is, just 16x4 isn't good enough.

[groundFungus]

Have you tried adjusting the contrast pot. If it is set improperly it can blank out the characters.

Is the LCD RW pin connected to ground?

[camsysca]

@ledsyn

Looking at a photo to figure out how the wires are connected is hard

To illustrate this issue, please, without looking at your circuit, just that photo, tell me what wire is on pin 4 of the LCD, and what pin it connects to on the Arduino. You can't. So, although the photo is nice for giving us a hint about your circuit, a wiring diagram would be so much more useful.

[david_2018]

Are you certain the display is not suppose to be controlled by I2C instead of the parallel interface?

[camsysca]

At this point, a link to the design information, or product page, of the item in question would be helpful. Otherwise, random speculation will continue.

[xfpd]

Disconnect the potentiometer (I have not yet needed one)

[mikedb]

There is Serial pins on the LCD also , look at the back of the LCD if there is a jumper or small solder pad to select Serial or Parallel.

I have never seen a Alpha numeric like this one.

[bperrybap]

Guys,
There is nothing wrong with the pot or its adjustment.
Just look at the display. You are seeing pixels on two rows but not on the other two
rows. This indicates a good contrast setting for the pot and also indicates a 4 row LCD that is in its power up state and has not been initialized.

This is likely due to the Arduino not being able to properly communicate with the LCD.
The typical cause of this is a wiring issue.
Either bad wires, bad connections, or wired incorrectly.

Its hard to tell, but it looks to me like the LCD may not be wired up to match the constructor in the sketch.
i.e. the pin wiring specified in the sketch may be the way the Arduino pins are wired up to the LCD in the actual circuit.
This is just from my looking at the wires in that appears that there are wires going to Arduino pins 11 and 12 and it looks like there are some wires going to some low number pins like Arduino pins 2 or 3.
But it ishard to tell exactly where the wires are going from the photo.

@FutureEngineer I would say verify your wiring.
But as a few others said it could be the LCD jumpered/wired for i2c.
Can you post a photo of the back of the LCD?
And/or post a link to the LCD datasheet.

Also, could you post another photo that more clearly shows the wiring between the LCD and the Arduino where were can clearly make out all the wire connections on both ends so we can verify that the wiring is correct.
i.e. we need to be able to trace each connection between the LCD and the Arduino board to be able to verify that each Arduino pin specified in the sketch is connected the expected LCD pin.

-- bill