Re: Re: Mains activated extension socket

["Tim Hawes" <timsyahoo@xxxxxxxxxxxxxx>]

You could do this a couple of ways, I think.
Have a relay in the saw circuit start the extract fan, a second relay
in the extract circuit latches-in the fan supply. An off button turns
the fan of manually, or you could include a timer for delayed-off.
I've knocked-up a circuit diagram for this one, let me know if you'd
like it sent off-list.

2nd way would be to have the relay in the saw circuit as before, but
contact-closure is wired to the powerflash (I think). Powerflash turns
on the extract fan but you turn it off via a minitimer, or whatever.

HTH,

Tim.

On 11/5/07, Peter and Jane <pandj.munnoch@xxxxxxx> wrote:
> Chris
> PIR appeals to me as really the extractor needs to start before the
saw or whatever.
> FYI Axminster tools use a magnetic sensor on the motor of the
woodworking machine.
> Other part of pir logic that appeals is the delay before off. Some
tools start and stop a lot (eg chop saw). PIR timer would leave the
extractor running.
> Still open to better ideas.
> There is no indicator light any of the woodwoking machines, so the
photodetector idea is difficult.
> What I really need is an inductive proximity sensor...but then the
timing circuit is beyond me.
> Good 'ol x10..not good but not bad!
> Rgds
> Peter