Mary, I've heard enough horror stories about door malfunctions that I will always be careful. Very sorry, by the way, about your sussex girl! They are really super sweet birds. I have 2 and they are wonderful.
Red, mine isn't dependant on the power. It's got a solar battery - so ti works even when the power is out (in theory).
Just about every night, while the dogs are out for 'last call', I wander down there to make sure that everyone is tucked in and the door is closed. It's the only time I can eaisly get my hands on the silver laced whiney-dottes (

) and I like to take a peek at everyone to make sure everything looks right. My easter-egger has a constant case of nasty-butt so her hiney feathers get trimmed often. And since I've had some sort of upper respiratory crud break out, I pick each one up and listen to their breathing and check their eyes.
I like to think that my nightly visits have trained the dogs to go out the door and straight to the coop - since they usually follow me first and then go off to do their business - but that may be giving them way too much credit.
(I think that I might be the only person who has chickens smarter than their dogs...)
But back to gardening - does anyone garden in the dark??? I saw a special once on this guy who had done this whole amazing landscape - working mostly at night with a headlamp. With the heat and humidity... that just seems like an idea worth trying.