Arduino nano won't boot when power by batery HELP PLS [SOLVED]

Hi, guys hope you can help me,
I have already read this topic but the way I power my Arduino nano is different from the others.

First, my circuit uses 570mA (that’s the max current used by all sensors). All the sensors are in paralel with the Vin and GND. My external battery (common 9v battery) is connected to a voltage regulator 7805 ( output 5v 1A max), and the voltage regulator is in parallel with the Arduino Vin and GND pins, this means it’s also in parallel with the sensors.

I used a voltage regulator in parallel with the Arduino and the sensors because when I connected the sensors via 5v pin there wasn’t enough current to power all the circuit.

The problem is… Now I have enough current however the Arduino light turns on but the Arduino doesn’t boot…

When I connect a USB it works but when I disconnect it the Arduino stops working with the power led turned on.

Can someone help me pls!

PS: to test I used just a code to send “hello” throw the serial.

Sounds like you are applying external voltage regulator 5V to Arduino Vin?
If so, don't; Vin feeds the onboard 5V regulator, and the Arduino will end up with not enough voltage. Apply the external 5V to the Arduino 5V pin instead, bypassing the regulator.
If you connect via USB to a PC at the same time, the PC may not be happy with that. Mine declares a current surge and shuts down the USB port, requiring a restart to bring the port back online.

Thanks for helping! I've tried the way you said. I've connected to the 5V pin instead...and it's the same thing! Arduino doesn't boot. It turns the led4 on but doesn't do anything.
When I connect the USB it boots but when I disconnect it stops.

Okey problem solved. The problem was not the power but the software.
Arduino nano doesn't start serial if he is not connected over USB, he boots up but it doesn't start a serial communication. This means if I want to connect it to serial by RF e need to use the function "

(Serial.available() > 0)

And then send over RF anything to start the serial communication.

Thank you for helping!

New Update: I don't remember how but I've managed to find a solution for the problem. I guess it was a problem with the software.

A Nano will start serial if it's not connected to USB.

I suggest that you make a drawing how everything is connected.

And converting 9V to 5V using the onboard regulator is OK, but not to power a total of 570mA. The regulator can't handle that.

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