I'm running OctoPrint 1.8.6 via an OctoPi image on my RPi3B. I'm controlling an Ender3 with a SKR mini E3 v1.2 flashed with Klipper firmware. I have the TFT35 E3 V3.0 flashed with Teeminus v1.3.1 firmware. With this configuration I can monitor and have some control of the printer via the screen and dial/button.
When it comes time to shut down the printer, I can't simply toggle the power button because the RPi is powered by the Ender PSU via a buck converter. I know about other options where I use the RPi and a relay to control the printer PSU. What I was wondering is if there is a way to add an item to the display so that it would tell OctoPrint to shut down so I don't need to go to a computer/phone/tablet?
That's what I had in mind, but I wasn't sure if there was a way to do it. I think you are right that I need to find a way to add a custom menu item that would send that command. I'll try raising an issue on Teeminus' github.
After looking at what that Teeminus was I think you're going to have to enable HOST_ACTION_COMMANDS and CUSTOM_USER_MENUS in Marlin and add a custom menu item to send the shutdown action command (M118 A1 action:shutdown).
Thanks for that, I'll look for documentation and give it a try. I've got an issue with garbled text after trying my first print which has been reported as issue 47. Unfortunately, if I can't fix that, the menu item won't matter. It looks like the author believes there may be a grounding issue which doesn't sound promising.