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Topic: 16x2 lcd with UnoR3 probs (Read 7 times) previous topic - next topic

mysqo

Hi!

It seems I got the famous problem with the lcd. The letters wont appear.
Its a 16x2 blue lcd.

Have checked the cables over and over again and I find it correct.
The LCD starts and the backlight shows, but not the letters.
Sometimes the white boxes flashes a millisec or so, then disappears.

Im followed the Hello world guide wich comes with the arduino.
I got the 10K potentiometer. And I have tried with and without it, same result.
I also cant change the contrast with the potentiometer coupled on. Ive
checked the outputvoltage on it,and it works!
Anybody that got an idea? Can link a video if someone want a look.

floresta

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Have checked the cables over and over again and I find it correct.

I have heard that before.

Quote
The LCD starts and the backlight shows, but not the letters.
Sometimes the white boxes flashes a millisec or so, then disappears.

Are you using a current limiting resistor with your backlight?

Quote
I got the 10K potentiometer. And I have tried with and without it, same result.
I also cant change the contrast with the potentiometer coupled on.

You must use the potentiometer and you must get the contrast working before you proceed any further.  
If you can't get a row of boxes to appear then you are wasting your time trying to display any text.


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Ive checked the outputvoltage on it,and it works!

Explain what voltage(s) you measured and why you think it works.  When it really works you will be able to see a row of boxes on the screen.

We really can't give more help without more information.


Don





tuxduino

Quote
We really can't give more help without more information.


Like code and schematics.

liudr

Video would be fine as long as its quality is high enough to tell how the connection is made.

mysqo

When I checked the potentiometer,I used a voltmeter and looked at the output voltage when the arduino was running and only coupled in the voltage from the arduino.I think the potentiometer works because it gives diffrent voltage to the LCD. It also changes the contrast a liiiiiitle liiiitle bit.
Little bit hard to see it in the video tho.
Here is the video: https://vimeo.com/54703995

Here is a clearly pic of how I wired everything, and a pic I got from the manual to compare with.
http://tinypic.com/view.php?pic=2ldubtt&s=6

Here is a video showing how the white boxes flashes when I turned the potentiometer with everything wired:
https://vimeo.com/54704282

Here is the manual for the LCD from the manufactor:
http://www.kjell.com/.mvc/Document/File?id=b6e33422-63ff-48be-b140-a04a0114d7ef

And here is the code I was runnning with everyting coupled in the pic:

#include <LiquidCrystal.h>

LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

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

void loop() {
  lcd.setCursor(0, 1);
  lcd.print(millis()/1000);
}



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