@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: