You can use a MS14A motion sensor mounted on the inside of the door.
I have a socket rocket in mine at address A11 and the motion sensor set to trigger on A11. The motion sensor then turns off depending on the delay set in the motion sensor. In my application the RF from the motion sensor has no problem reaching the transceiver but you may need to test your setup to see if range will be a problem.
I use the same setup in a few location and all works great. In my laundry room if you stand still long enough the lights go out but then all you need to do is move a bit and it comes back on. I have also noticed that if the washer is set to use a straight hot water rinse the heat coming up from the washer will trigger the motion sensor now and then. (this could have some potential as a heat detector in an attic to trigger a fan if you could get the setup just right
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