Here's an idea. Pictures!

Here's the vault of the living room ceiling. Not likely to have any
crawl space above it, right?

http://www.morris.umn.edu/~webbrl/Sm...ngRoomVault.jp
g


Here's the location of the smoke detector on that ceiling, circled in
red. Sorry it's a little hard to see. I shot this pic from the other
side of the main support beam. The room I'm shooting from is also
vaulted, but in a different direction (90 degrees perpendicular).

http://www.morris.umn.edu/~webbrl/Sm...eDetectorLocat
ion.jpg


Here's what I call the wiring, which I thought of as just sitting in
dark air above the ceiling. I see now it seems to be contained in some
sort of dome-shaped metal casing? Anyway, this is where the chirping is
coming from, not from the removable plastic part. Does that seem
feasible? And if I could find a way to remove the metal casing and
everything contained in it (red white yellow black wires, little round
blue thing that looks like a phillips screw but which I think might be
the actual sensor), the chirping would stop, yes?


http://www.morris.umn.edu/~webbrl/Sm...eDetectorInnar
ds.jpg

RW