Hi, thanks in advance for the immediate help.
I'm doing a project with the Arduino Uno and a tactile screen nextion 7 "which when pressing any of 3 different buttons will turn on 3 leds in a protoboard (these leds are only indicators because then they will serve to activate other things through an optocoupler).
I've done all the tests correctly by connecting the arduino one to my laptop via a usb cable and connecting the NEXTION 7 "screen to the respective pins on the Arduino, and it works perfectly !!!, but the detail is that now I want to have a source External power supply for the Arduino (no longer my laptop) where the Nextion 7 screen will be connected, at first I tried connecting a Arduino to a cell phone charger (5v DC - 1A) but the Nextion was blinking, then I tried with a charger Tablet (5v DC - 2A) where the Nextion turned on but could not communicate with the arduino (TX and RX) did not respond when I pressed the buttons the same thing happened when I connected another source (5v DC - 3A) and (12v DC - 3A) I hope you can help me.
Note: For external source tests only use only the source, arduino Uno and Nextion 7 "screen.
Attachment: Arduino code and nextion program
Are grounds tied together between Nextion and Arduino?
Yes, I am using the 5v pin and arduino gnd to feed the screen, plus the tx and rx.
I don't have your tech specs for your UNO but perhaps the UNO is not supplying sufficient power via its 5V pin. What happens when you supply the Nextion via the 5V charger and tie grounds.
When the Arduino Uno is powered by the USB cable of the laptop, the screen works perfect, but when the connector with the 5v -2Ampere charger, the screen and the operation correct but it seems as if it does not communicate with the arduino, the orders That sends the screen without arduino (the led of TX and RX in the Arduino does not blink)
PLEASE check your power plug ...
The fact, that ALL runs when you use a reliable PC USB connection shows that ALL hardware is doing well, the error is on your side ...
In the time you post unimportant code or wait for "immediate help", you already could use a simple multimeter and check things by yourself ...