issue with display arduino

hi forum i have problem with my lcd :

Zyscom LCD Display HD44780 4x20 chr 20x4 BLUE neg Backlight
when and on only see white squares even if I turn the potentiometer gives me the same thing.

I connected it as you see in the picture

We have to see a photograph of how you actually connected it, not a picture of how you think you connected it.

We also need to see a copy of the actual program code that you are using to see if the code matches the circuit.

Your drawing seems to be incorrect since, as shown, the module most likely is not powered - without a link to the data sheet for the module we really can’t be sure. Also the resistor is not connected properly.

Don

this immage

Hi.

Are your sure about the schematic of your 1 post ?

Pin 1 : Vss Display power ground
Pin 2: Vdd Display power +5V
Pin 3: Vo Contrast Adjust.

I don't see pin 1 GND connected even pin 2 Vdd to 5v on the arduino.

By your schematic, you connected these 3 pins to the potentiometer.

Hi..

Maybe you are trying to do that:

http://fritzing.org/projects/how-to-connect-a-qy-1602a-lcd-to-arduino-correctly

I use to do this:

http://forum.arduino.cc/index.php/topic,183852.0.html
( different forum language, but schematic is fine )

sketch

LiquidCrystal lcd(12, 11, 13, 10, 27, 25);

Typhon Arduino Sketch.odt (20.6 KB)

OK - let’s start with the sketch… AARRGGHH

Have you ever had your display working? If not then you should start out with a simple sketch that just displays a few words on the display and does nothing else.

Now - about the wiring… AARRGGHH again.

We need to be able to unambiguously follow each wire from the Arduino to the LCD module.

My suggestion is for you to disconnect everything and start again. Here is my generic step by step approach that should work. Many use this in conjunction with the sketch in the Arduino ‘Hello World’ tutorial but the sketch in the troubleshooting section would be a better choice.


(1) If the module has a backlight then get it working properly. This involves only pins 15 and 16 on most LCD modules. Make sure to use a current limiting resistor if there is none on the LCD module.

(2) Get the power and contrast working properly. This involves only pins 1, 2, and 3 on most LCD modules. You should be able to just barely see blocks on one row of a two row display and on two rows of a four row display.

NOTE: The Arduino has not been used yet, except as a possible source for the power needed for the first two steps. Do not try to go any further until this is working. If you don’t see the blocks then no amount of program code will help.

(3) Connect the LCD R/W pin (pin 5) to GND.

(4) Connect the six control and data wires between your LCD module and your Arduino.

(5) Upload your sketch and it should work.

Troubleshooting:

If you have a 16x1 display and there are blocks only on the left half of the row in step 2 then use

lcd.begin(8, 2);

in your sketch.

If you still don’t get a display then make sure that your wiring matches the numbers in the descriptor (or vice versa).

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);      // put your pin numbers here

If you get a display but it is garbled or has some other problems then try again with a ‘static’ sketch, one that displays a simple message on the top row of the display and then stops. All of your code should be in setup() and loop() should be empty between the brackets.

#include <LiquidCrystal.h>

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);      // put your pin numbers here

void setup()
  {
  lcd.begin(16, 2);                          // put your LCD parameters here
  lcd.print("hello, world!");
  lcd.setCursor(0,1);
  lcd.print("it works!");
  }

void loop()
  {
  }

If you are still having problems then we need to see a photograph of your setup that clearly and unambiguously shows all of the connections between your Arduino and your LCD module. We also need a copy/paste version of the code that you are actually using, not a link to the code that you think you are using.

Don

arssant:
Hi.

Are your sure about the schematic of your 1 post ?

Pin 1 : Vss Display power ground
Pin 2: Vdd Display power +5V
Pin 3: Vo Contrast Adjust.

I don't see pin 1 GND connected even pin 2 Vdd to 5v on the arduino.

By your schematic, you connected these 3 pins to the potentiometer.

It is possible (but not likely) that his particular module has pin 1 connected to pin 16 and pin 2 connected to pin 15 which is why I said: "as shown, the module most likely is not powered".

Don

floresta:

arssant:
Hi.

Are your sure about the schematic of your 1 post ?

Pin 1 : Vss Display power ground
Pin 2: Vdd Display power +5V
Pin 3: Vo Contrast Adjust.

I don't see pin 1 GND connected even pin 2 Vdd to 5v on the arduino.

By your schematic, you connected these 3 pins to the potentiometer.

It is possible (but not likely) that his particular module has pin 1 connected to pin 16 and pin 2 connected to pin 15 which is why I said: "as shown, the module most likely is not powered".

Don

Hi.

I saw here:

http://www.zyscom.pl/katalog/ym2004a.pdf

Sound like a "standard" 1602A LCD. Backlight is not connected to main control... but as you say, who knows...

I have try 1,2,3 in lcd i see ??? and i have try also pin 5 and date i see 4 ???, but i dont see char :frowning: , i have upload sketch forum but problem persist now?

Hi.

This last pic, is more elucidative.. The display was not been initialized. Is powered but not initialized.
Check all your wires and connections, and as Don said, start with a basic " Hello Word". to test the code too.

We will not be able to help you any further until you provide us with a picture that permits us to unambiguously follow each wire from the LCD back to the Arduino.

We also need to see the program code (sketch) that you are using and the display that results from running that code on the setup in the photo.

Don

good morning this photo

sketch_sep09a_modificato_alba_tramonto.ino (48 KB)

Is there some part of Reply #6 that you do not understand?

In the photo we should be seeing an Arduino, an LCD, a potentiometer, and a dozen or so wires. The sketch should be similar to the one in that reply.

Don

this immage ok?

No. It looks like a rats nest.

Don

hi my lcd dead :(, i have other problem now with me sketch arduino dont upload :frowning:

codice plafo nuova.docx (79.2 KB)

See reply #13. Until you can get the sketch in reply #6 working there is no sense trying anything more complicated.

Don

i dont understood

marco3020:
i dont understood

In reply #6 I asked a question which you have not yet answered.

I also suggested some steps for you to take but it seems that you did not follow them.

In reply #13 I asked if there was any part of reply #6 that you did not understand and you ignored that question as well.

So let's start over, one step at a time.

Have you ever had your display working?

Don