Mike Barnes wrote:
I've had several freezers with "door open" alarms but they've been all
been f***ing useless. Door wide open when I'm rearranging stuff? Beep
beep bloody beep, yes, thank you, but it's obvious the door's open isn't
it? Door half an inch open because one of the drawers isn't quite
pushed home? Silence.

Thermometer-based alarms are useless because they routinely go off
during the automatic defrost cycle.

The problem with the makers' "door open" alarms are that they work on
the hinge side so they're spectacularly inaccurate. What's needed,
*obviously*, is a switch at the opening edge of the door. But it seems
to be beyond the wit of the manufacturers to understand that or to put
it into practice.

end rant

I did try making my own "door open" alarm many years ago, using a timer
operated by a microswitch stuck on the side of the cabinet with a lever
between the cabinet edge and the door seal. I can't remember why but it
wasn't very successful, probably not robust enough for a kitchen
environment.

I wonder if some sort of magnetic detector might work better - there
are, after all, magnets in the door seal. Or perhaps a low-profile
keyboard-type switch between the cabinet edge and the seal? Or any other
ideas?


Some years ago (prolly about 20), I made one for Mum's freezer. I got
the innards out of a musical birthday card, a miniature microswitch and
a small piece of wood (as an actuator for the microswitch). I glued the
card innards and the microswitch on the side of the freezer and the
wooden block on the edge of the door. OK, you had to listen to the tune
incessantly whilst the door was open, but the problem (of leaving the
door slightly ajar) went away. The battery in the card outlasted the
freezer!

Nowadays, of course, musical birthday cards are bases around digital
samples, so they don't play annoying monophonic tunes that keep going
indefinitely.