Updates delayed due to me being dumb and bricking an Arduino and sensor shield. Good times.
I have, however, gotten the 12V trigger working. I stepped down the 12V to ~3V using a DC-DC converter. This worked great, though I had to plug it in an analog pin instead of a digital pin to get it to work properly.
Once the projector is on, switching to an anamorphic mode seems to keep the 12V trigger switched on until you explicitly turn it off. So if you turn on the projector without turning on any input sources, you can immediately switch to the anamorphic mode to trigger anything connected to it. You can then turn on a source that initially outputs to 4k60, like the UB820, and have the anamorphic mode works when this source switches to playing 4k24 content. Obviously, the anamorphic processing won't turn on until the switch, but the trigger remains active.
To integrate into my Harmony hub, I'll simply put in a delay so that the receiver and UB820 don't switch on until after the projector has changed over completely.
JVC RS-520, Elite Screens 16x9 100", XY Screen 2.4:1 115"
Klipsch RP-8000F, RP-450C, 2xRP-240S, 2xRP-402S, 2xSVS PB-1000
Denon AVR-X3200W/HDFury Linker/MiniDSP 2x4 HD
Panasonic UB820/PC/PS3/PS4 Pro/Switch/WiiU/Xbox One X/Original Xbox
Logitech Harmony Hub
Last edited by evanft; 10-31-2019 at 06:49 AM.