For context, I am using a raspberry PI 4 connected with it's charger (edit : I meant power supply, not charger). I wish to be able to turn it on when it receive a high value on a pin (for example,using another raspberry).
I have zero experience with circuits and don't want to fry mi PI so I want to make sure I don't do anything stupid.
from what I understand, it is possible to turn on and off the PI by shorting GPIO pin 3 and GND but in my case, I dont want to short the pins physically but use a software on another PI.
My current settup consist on 2 Raspberry, RA and RB, both have a battery (edit : I meant power supply here too) to have enough power. RA boot normaly and I set one of it's pin High or low with a script. this pin on RA is connected to a pin on RB and I want RB to only boot when this pin is High.
From the documentation I found, (https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README) I can edit my config.txt to set any pin to be used for shutdown but only GPIO3 can be used for boot.
So in the end, can I just add : dtoverlay=gpio-shutdown,gpio_pin=3 to the config.txt of RB and have RA turn it on (and maybe of) by only connecting the pin from RA to GPIO3 on RB ?
Thank you for your attention