"Brian-Gaff" wrote in message
...
Well says it all. I have a little door phone and after about 6 months
trying to keep the call/bell button has been abandoned in favour of an old
bell push I found in a drawer with a Woolworths price tag on it. This is
wired so it shorts the intercom cable as the original failed one which
consisted of some tacky little push switch on a pcb glued in with heat
glue. the Woolies on is your basic two brass bits sprung apart and a
plastic button to short them together.
Tis worked fine till one of two things happened. Firstly, its not
waterproof and when its really wet, it shorts enough to make the bell
sound or make silly whining noises leaving the amp running with clicks and
groans. Or, the local cold caller or whoever who seems to have been
studying finger karate, squishes it so much the prongs stay shorted out
when the finger is removed.
Most bell pushes seem to still be of this type. I had no idea of the
stringent needs of a bell push in this environment before, so wondered if
anyone else had any bright ideas?

Use a proper hall effect switch so that it can be completely waterproof
and it doesn’t matter what anyone pressing it does with the magnet
on the button short of attacking it with a hammer.