The I2C 20x4 LCD repeatedly turns on and off, indicating voltage or current drops due to using power supply from the laptop. This is necessary as I want to run the program and monitor its output on the Arduino IDE serial monitor. When I switch to using a 5V 3A adapter, this issue does not occur. However, using another microcontroller like the ESP32 with the same LCD, there are no issues whether powered by the laptop's USB or an adapter.
Here is a video demonstrating the issue I'm experiencing. I just want to try running a simple "Hello World" or something similar to see the different responses from this LCD. Please help me with how to address this issue.
Sure. Here's my attempt to measure the voltage on the 5V - GND pins going to the 20x4 Blue Light I2C LCD. I tried this on three microcontrollers, but for some reason, this issue only happens with the Arduino when I connect it to the laptop via USB to run the program. However, when I use an adapter, this issue does not occur.
The video can be found in sections 4, 5 - 5.1, and 6.
It is easier for us if you just tell what the voltage is.
The 4.5 or 4.6V is too low.
Suppose that the voltage will not drop below 4.6V, then you can add a capacitor (100µF to 1000µF) to 5V and GND. But that would still not be reliable.
By measuring "on" the display, I meant on the pins of the display. Circled in red:
The Arduino Uno might still work at 3.5V, but those cheap displays need at least 4.5V.
When I say that the display should have at least 4.5V, then I say that on basis on my own experience and by others on this forum. It can be 4.0V for one display or 4.8V for another display. I don't know, the 4.5V is just an average guess.
Have you seen other displays ? I wonder if the backlight is too bright.
