I found my first hardware bug! Can you spot it? It's the big red circle:
The mmwave sensor was mounted too close to either the screen, or the power source (something I thought was a brilliant idea yesterday). Turns out that mounting it so close has an affect on this sensor: when the display is on, it blocks the sensor (and reads it as no-presence). When the display is off, for some reason the sensor picks it up as someone being present. This is bad, because on presence I turn the display on, and on vacancy off. I guess my living room put on a light show for my cats last night.
I suspect I could fix this in the firmware of the sensor, but that's pointless because I can't reverse engineer the sensor protocol anyway. What's the next best fix?
I moved the sensor out of the way, while I think of a better placement.