Making a mains relay pulse - electronics Q

["David Chapman" <david@xxxxxxxxxx>]

Automated Home DiscussionI'm sure this is not too difficult but I
can't
figure out how !

As part of a bit of HA I've got an output (from a PIR exterior light) at
mains level that I think is transistor switched (can't hear a relay)  What
I
want this to do is close a couple of contacts on a switch at 5v level -
that
bit is quite easy, mains relay, but I want it to pulse the relay just for
one second rather than holding it closed and the problem is the shortest
time I can get the PIR to switch for is about 30 seconds.

I guess what I need is a capacitor - somehow - that maybe lets through an
initial pulse ?  Also how do I then protect the output of the PIR ? I think
just a mains rated diode on the output would do the job ?

Any ideas or clues ? I did have a link to a website with loads of little
circuits like this but I can't find it.

David C