Lcd flickering while conected to power outlet

Projects General Guidance
1

Hello i am new here i have LCD display 1.9" 170x320 color TFT SPI ST7789 and when i connect my arduino to my PC usb port it works perfectly fine , but when i connect to a wall outlet it suddenly starts flickering
I dont know how to do chematic but i have it conected :
LCD ARDUINO
GND -> GND
VCC ->5v
SCL->D13
SDA->D11
RES->D8
DC->D9
CS->D10
BLK->3.3V
Lcd chematic i found :

wyswietlacz-lcd-19-170x320-kolorowy-tft-spi-st7789
wyswietlacz-lcd-19-170x320-kolorowy-tft-spi-st7789800×800 20 KB

2

Other information that would be useful:

  • State which Arduino you have
  • Provide details of the power supply you are using
  • Post your code in code tags
  • Post photos of your project, make sure they are clear and show the problem
1 Like
3

I have Arduino UNo R4 wifi
power suply : Input: 100–240 V ~ 50–60 Hz, 0.3 A
Output:5 V ⎓ 1.55 A
code:

#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ST7789.h>

// Define pins connected to the TFT display
#define TFT_CS   10   // Chip Select
#define TFT_DC   9    // Data/Command
#define TFT_RST  8    // Reset

// Create an instance of the ST7789 display
Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);

void setup() {
  // Initialize SPI communication
  SPI.begin();

  // Initialize the ST7789 display (1.9" screen, usually 170x320 pixels)
  tft.init(170, 320);

  // Set screen rotation (0–3, each rotates 90 degrees)
  tft.setRotation(0);

  // Fill the screen with black color
  tft.fillScreen(ST77XX_BLACK);

  // Set text color and size
  tft.setTextColor(ST77XX_WHITE);  // White text
  tft.setTextSize(2);              // Text scale factor

  // Set the cursor position and print text
  tft.setCursor(10, 20);
  tft.println("Test 12");

  // Draw a green rectangle around the screen edges
  tft.drawRect(0, 0, 170, 320, ST77XX_GREEN);
}

void loop() {
  // Nothing happens in loop; the display is static
}

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4

The USB port on the PC can supply a stable 5V with limited current, while many wall adapters, especially cheap ones, may not provide "clean" voltage / current.

Can you try with another power adapter ?

do you have longer wires :innocent: :grimacing:

image
image676×1130 149 KB

5

i tried with another one and it still doesnt work

unnamed
unnamed1920×2560 731 KB

6

What about something simple like genuine "Samsung" phone charger?
Those cheap "65W" 5-port superhyper chargers are often really bad quality in my opinion.
Ps. what is that surface you have your devices on?

7

Schematics are the basic language of electronics!

It is not hard, try this link: How to Read a Schematic - SparkFun Learn By using schematics you make it much easier to follow your circuit then your convoluted word salad. You can load a very good schematic capture program that will go from a blank sheet to the Gerber files needed to make a PCB. It is not a weekend learn but when downloading they may ask for a non required donation.

8

Okay i resolved the issue by plugging it in via the huawei laptop charger it works perfectly fine now .

1 Like