I want to deploy a RPi 3 in quasi-headless mode, i.e. no display attached, with an application running that takes time-lapse photos (with the standard camera module). Power is supplied through a battery pack, so I want to minimise energy consumption.
I have installed regular Raspbian, i.e. with XFCE, and I would like to avoid having to re-install a headless Jessie lite just for this application. (As I might use some
javax.imageio API, I'm not even sure that I can technically run in headless)
I read this article, and one thing that seems recommended is to turn off HDMI. I also suppose that not starting the X Server but remaining in text mode might save energy.
So my idea is that I temporarily disable the HDMI output, and I temporarily might also be able to avoid booting into XFCE. I take it that I should connect the Pi via SSH and perform these steps.
Which are the steps necessary to deactivate HDMI and stop before the X Windows login, and which are the steps to revert to previous behaviour ("desktop computer")? Any additional things I should disable (e.g. on-board audio)?