Open Door Beeper

["robboll" <robboll@xxxxxxxxxxx>]

I put a combination lock on a supply room that I know will remain
unsecure much of the time.  People who use the supply room will simply
forget to lock it as they leave.   What I would like is an audible --
non irritating -- alarm, or an intermittent beep (like a lot of
microwaves have when you forget to remove your food after one minute
or so).  Oh yea -- I just about forgot about my hotdog.

The alarm or periodic beep happens only when the door is open, and
turns off when the door is closed.  The switch can't be that
complicated, but works essentially in reverse of what you would
think.  I couldn't find anything of the nature at Home Depot or Lowes,
so I thought I'd see if someone in internet land might know of such a
switch, or product that has this functionality.

Thanks for any suggestions!

RBolling