@Eme
Thank you for coming back to report how you solved your problem! Your comments will help other people.
I am a big fan of Frugal Tech and I think MySensors is great for that.
Alas, MySensors is not well supported anymore. Right now I'm having problems linking to the home page It's people like you and me that will keep MySensors going.
Thanks for your help.
OSD
@Vuinne-Ryvmar You seem to be confused about what this forum is. Maybe you just ended up here on a random Google search?
But in our case on an Arduino, D3 is literally the name for one of the metal legs coming off of the little controller, and we call it a pin sometimes. @tbowmo was looking for how to send the command to turn the power on or off to that part of the board, not a code to enable connecting up a controller to their phone.
I see that a D3 game controller is a thing, but I doubt you will have any luck getting help with that here. It's not what this site is about.
This is what we work with:
https://github.com/mysensors/MySensors/pull/1562 switches to using libgpiod instead of the earlier interface. I have not tested it myself but it looks good.
@tnick STM32F1 2019.12.8 (stm32duino) is the version that was active when the latest MySensors release was made. Later versions may or may not work; nobody would know until they tried.