Problem with 4x20 Char Display

Using Arduino Displays
1

Hi,
i've bought a display and wired all up like there:

this won't work and i tried the 8 Bit mode. dont work.

here is my wiring:

2592×1456 1.1 MB

can you see what i've done wrong?

here is a shot, while it should display "Hello World":

1456×2592 1.35 MB

Thanks!

2

Did you remember to change lcd.begin(16,2) to lcd.begin(20,4)?

3

are you certain it's a 20x4 display and not a 12864 display

4

i've bought a display and wired all up like there:

We have to be able to unambiguously follow each wire from the LCD module to the Arduino. With wires that are the same colors you must spread them out. We also have to see the actual code that you are using, not the code that you think you are using.

here is a shot, while it should display "Hello World":

That's a classic result when the LCD controller is not being initialized properly. This can be due to improper or defective connections and/or incompatible code. If you cant give us a better picture then we need a description of where each of your LCD connections goes.

Don

EDIT: It looks like you may have a 'cold' solder joint on pin 4.

5

Did you remember to change lcd.begin(16,2) to lcd.begin(20,4)?

That will have no effect on whether the 'hello, world!" message will be displayed or not.

Don

6

are you certain it's a 20x4 display and not a 12864 display

There are not enough pins for a GLCD, and the screen has the wrong proportions for a 128x64.

Don

7

johnwasser:
Did you remember to change lcd.begin(16,2) to lcd.begin(20,4)?

Yes

abrookfield:
are you certain it's a 20x4 display and not a 12864 display

No
Where can i find out?

floresta:

are you certain it's a 20x4 display and not a 12864 display

There are not enough pins for a GLCD, and the screen has the wrong proportions for a 128x64.

Don

What do you mean exactly?

Thanks for your help!

8

What do you mean exactly?

I mean that the other poster is wrong and that you do have a 20x4 display.

If you really want to get your display working you should consider my reply #3?

Don

9

floresta:

What do you mean exactly?

I mean that the other poster is wrong and that you do have a 20x4 display.

If you really want to get your display working you should consider my reply #3?

Don

okay, i resolder all pins and try it again. Is there another reason for this error? - i've copy & pasted the code from the tutorial and changed the constructor for the 8 bit mode, cause it wont work in the 4 bit mode. Should it work in 4 bit mode too?

10

do you have one of the blue wires in the tx pin? looks like maybe you do

11

i've resoldered all pins - still not working.

abrookfield:
do you have one of the blue wires in the tx pin? looks like maybe you do

the RX & TX Pins are unused.

i've wired the data-pins:
Display pin 7 => Arduino pin 9
...
Display pin 14 => Arduino pin 2

other pins:
Display pin 1 => GND
Display pin 2 => 5V
Display pin 3 => Poti (Contrast, works)
Display pin 4 => Arduino pin 12
Display pin 5 => GND
Display pin 6 => Arduino pin 11

Display pin 15 => 5V
Display pin 16 => GND (with resistor for LED Backlight, works)

my code:

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 9, 8, 7, 6, 5, 4, 3, 2);

void setup() {
   // set up the LCD's number of columns and rows: 
   lcd.begin(20, 4);
   // Print a message to the LCD.
   lcd.print("hello, world!");
}

void loop() {
   lcd.setCursor(0, 1);
   // print the number of seconds since reset:
//   lcd.print(millis()/1000);
}
12

I've made a video:

duration: 14s

The Display displays nonsense :s

13 
Display pin 4 => Arduino pin 12
Display pin 6 => Arduino pin 11

That's not what I see in your photograph or your video.

Don

14

floresta:

Display pin 4 => Arduino pin 12

Display pin 6 => Arduino pin 11




That's not what I see in your photograph or your video.

Don

WOW! yeah!

thanks!
that was the problem!

i <3 you!

15

The solution to your problem emphasizes the reason for this:

"We have to be able to unambiguously follow each wire from the LCD module to the Arduino. ... We also have to see the actual code that you are using ..."

Don

16

I don't know about you guys but MY Crystal Ball Broke when I asked it if I was the most handsome guy in the world...

Doc