On Tuesday, January 6, 2015 10:51:06 AM UTC, Johny B Good wrote:
On Sat, 3 Jan 2015 09:08:24 -0000, "Andrew Mawson"
wrote:

"Mike Tomlinson" wrote in message ....

En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

I'm surprised that they are just copper - I'd expect them to be a bronze or
brass to give them resilience and springyness.


The last time I looked at such a door bell switch, it was just a
couple of brass strips pushed together by the button press. They had a
decent airgap considering the low voltage and made a sliding/rubbing
contact which bodes well for maintained low on resistance (or even the
option for the operator to find 'The Sweet Spot' when age finally
takes its toll on the switch - crude but effective).
--
J B Good

I'm a +1 to removing the sender from outside. My experience was that it was the contact between the button cells that was the problem due to the weather. I was fortunate in that I had cable already in place to put a decent push button switch, and put the original sender up in the attic where it has a wider range of transmission as well.

Rob