Servo Trigger - GoPro Hero 4 Session

I wanted to experiment with those cool time-lapses you see of prints, where a picture is taken after each layer. Because I only a Go Pro Hero 4 Session as usable camera, and I couldn't find any way of triggering it over a wire from my printer, I designed a mount that uses a SG90 servo to trigger the camera.

I'm still figuring out how to connect my servo and configure it in the Marlin firmware to take a picture after a M280 command in the G Code.
Any help is welcome!

Edit 10/02/2019:
I ad