Re: Making a mains relay pulse - electronics Q

["c8les" <aaron@xxxxxxxxxxxxx>]

It is possible to get a multi-function timer unit (mains operated),
that can provide a pulsed output of variable duration, or other
types of output.
There will usually be change over relay contacts, that can switch
high or low voltage.

FINDER and OMRON are typical makes

http://www.findernet.com/comuni/pdf/S85EN.pdf

Easily available from most good electrical wholesalers, although one
with some industrial control is better, or there is always RS,
Farnell??

The relays usually require a socket to plug into, allowing simple
wiring.
Not sure if this helps?

Aaron Coles
--- In ukha_d@xxxxxxx, "David Chapman" <david@...> wrote:
>
> 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
>