How to check this out ? LCD-Display damaged ?

Using Arduino Displays
1

hi this xmas-day,

whish you all nice xmas and year-turn

not all runs as i want ..

have tested a 128x64-lcd-display (20pins-version) on a test board with
arduino nano
all went ok

after mounting this in the final box there is nearly nothing to see on the screen
except a light grid of pointsdependent of contrast-justifiying
sometimes it flickeres a little with running sketch..but no contrast modifying brings was it should do

the sketch seems to run ok as buzzer-tones come in the correct cases
have checked connections serveral times..
might it be the display is damaged by mounting
i.e. platine is broken at any place but no one can see this ?

data of lcd
128 x 64 Pixel LCD Display 12864 Display
Modul kompatibel mit Arduino und Raspberry Pi
lightblue background ilumination
bought at AZ-Delivery in Germany

here a photo what i miss now to see

thermo_monitor_display1
thermo_monitor_display11920×2560 173 KB

who knows further tipps ?

2

Run a sample sketch for the display, I do not think it is damaged.
Random pixels in the lower right corner are an indication of something in the code overwriting the display buffer, usually caused by a lack of dynamic memory (ram).

3

hi davis,
thanks for answer

meanwhile i transported the display out of the final box and back to my testing environment to get shure that all connections are like the successful beginning with it.
Now it shows in a rhytmical order (depending on sketch) lines..but not what the photo shows.
guess the display-platine came under physical tension at mounting
and fixing it with screws..maybe one or more stripes are broken..

as on many of displays on the backsite there are black points ..here 3 of 15mm diameter..what do they hide ?

4

I will take a SWAG and say both your brightness and contrast are not set properly.

5

hi,

may be, but why i cant repeat the situation of the photo ?

6

That is because of the optics and the color sensitive range of your camera. It does not see the same as the human eye,it can see infrared, we cannot.

7

hi,
have made a short sketch like this

/*

  display_short_code1.ino
  Status : 26.12.2023
  Author : W.W.Fietz al lupus51
  Universal 8bit Graphics Library (https://github.com/olikraus/u8g2/)

   please exuse my bad english, thats not my mother-tongue.
*/

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif


/*
  U8g2lib Example Overview:
    Frame Buffer Examples: clearBuffer/sendBuffer. Fast, but may not work with all Arduino boards because of RAM consumption
    Page Buffer Examples: firstPage/nextPage. Less RAM usage, should work with all Arduino boards.
    U8x8 Text Only Example: No RAM usage, direct communication with display controller. No graphics, 8x8 Text only.

*/

// Please UNCOMMENT one of the contructor lines below
// U8g2 Contructor List (Frame Buffer)
// The complete list is available here: https://github.com/olikraus/u8g2/wiki/u8g2setupcpp
// Please update the pin numbers according to your setup. Use U8X8_PIN_NONE if the reset pin is not connected
U8G2_ST7920_128X64_F_SW_SPI u8g2(U8G2_R0, /* clock=*/ 13, /* data=*/ 11, /* CS=*/ 10, /* reset=*/ 8);

void u8g2_prepare(void) {
  u8g2.setFont(u8g2_font_6x10_tf);
  u8g2.setFontRefHeightExtendedText();
  u8g2.setDrawColor(1);
  u8g2.setFontPosTop();
  u8g2.setFontDirection(0);
}

const int pin_buzzer = 9;

const int pin_LED_alarm = 2;

//--const int pin_reset = 3; funcs without any lines here !

String prompt = "";

void setup(void)
{
  pinMode(pin_buzzer, OUTPUT);
  pinMode(pin_LED_alarm, OUTPUT);

  u8g2.begin();
  u8g2_prepare();

  u8g2.setFontDirection(0);

  u8g2.clearBuffer();
  //- senkrechte Alarmlinien malen
  //u8g2.drawLine(10, 1, 100, 60);

  u8g2.setCursor(1, 10);
  u8g2.drawStr(5, 10, "Setup Ready");
  u8g2.sendBuffer();
  delay(1000);
}

void loop(void)
{
  tone(pin_buzzer, 1200); // Send sound signal...
  delay(1500);
  noTone(pin_buzzer);     // Stop sound...
  
  u8g2.clearBuffer();

  u8g2.drawStr(5, 10, "loopz");
  u8g2.setCursor(15, 20);
  prompt = "loopy";
  u8g2.print(prompt );


  u8g2.sendBuffer();
  delay(1000);
}

buzzer works fine, but from the text output there is nothing visable..
only periodical drawing 2 horizontal lines at different positions..
what has nothing todo with sketch..

wonder what that means..

8

hi,
at least here is a wiring-list to arduino nano
with sight on displaysceenabovw the list-line,
counting left to right
display.............................nano
1.......................................GND
2.......................................VCC
6.......................................GND
15.....................................13
16.....................................11
17.....................................10
18.....................................Potentiometer contrast
19.....................................VCC
20.....................................GND

this worked for the scene on the photo.

9

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