Moderators: Random Orbital Bob, nev, Noel, Charley, CHJ

By GrahamRounce
Hi all - I don't know where else to post this.
I want a gadget with a mains socket that switches a (low wattage) load on and off as a machine, eg a lathe, is switched on and off.
It's the same way a dust vacuun works: you switch on the X and the dust collector switches on too, except that I think dust vacuuns come with it built in.
I want it for another purpose, so as a separate module/gadget.
I'm sure they must be available, but I don't know what they're called!
Any help pls?
Thanks, Graham
By Sideways
Theres a thing called an intelliplug you'll pick up for a tenner that will probably do the job.
There's an old thread on the forum about this.
If you need slightly more amps, search for master slave module.
Be wary that these devices don't handle overloads well even for a short time and induction motors can pull much more than their rated current for a few seconds when starting.
By GrahamRounce
Great response, thanks!

I'm feeling a little guilty, because on second thoughts maybe a slave socket's not what I need, sorry. (But I'm glad to know what they're called!) Maybe I should have said what it's for.

I keep forgetting, or not bothering, to pull the curtain across the doorway of the workshop area, so the rest of the house gets covered in dust.

I was musing about a piece of elastic that pulls the curtain shut. It would latch somehow to stay open, but as soon as a machine got switched on, a pulse goes to a solenoid or something which lifts the latch catch, and the curtain whizzes shut, hopefully.

Yes, I can do electronics, and mains stuff. I'm now thinking diy. A relay with a mains coil should come into the design somewhere.......
By sunnybob
burglar alarm type magnetic switch.
fit the main body to the wall and the magnet to the curtain top. wire the switch so that you cant turn on the light untill the curtain is pulled closed.
I'm assuming you need light? that way there is no power load involved.
By MikeG.
Electrickery isn't my thing, but I have a remotely switched socket set up in my workshop, and there are a number in the house (mainly for under-worktop machines such as washing machine, tumble drier etc). Wouldn't this achieve what the OP wants to achieve, (switching machine and extract on together if they're plugged into the same socket) and for nothing more than the cost of a switch and a back-box?
By Sideways
I think Bob's got it. You need something to give you a reminder that isn't easy to ignore.
Some burglar alarm magnetic switches are not rated for mains voltages so take note when selecting. Or for a robust version, there are many configurations of 'limit switch' used in industry. There will be something that you can hook the end of a tensioned curtain line to, or build something using a microswitch (cheap, highly reliable and main rated no problem).
By novocaine
this all sounds rather Rube Goldberg to me. surely it can be done with a 9v battery, an arduino, a microphone and a solenoid. everything in a tiny little box, no mains connection to worry about. hell, it could be done with an LDR so the curtain closes when the lights come on.

you could do it without the microprocessor just an LDR and a solenoid, all low voltage and easy to stick in a small box.

now wheres my mouse trap.
By GrahamRounce
The thing is, my "workshop" is half of my "kitchen". I will need light for making tea and microwaving food.
Maybe when the curtain is in the open position :) it trips a microswitch that will allow power to the electromagnet (via a transformer) when something is turned on (the transformer being wired to the socket). When the magnet gets power, it pulls on a latch which releases the curtain and untrips the microswitch.
Jeez! Nice and simple. IN PRINCIPLE lol.
Simpler ideas? (An Arduino does *not* count as simple! :roll:
By sunnybob
Graham, sharing a kitchen and a workshop has to be one of the unhealthiest things I've heard for a while. Eating sawdust is almost as bad as breathing it. A curtain is just not going to keep dust out of your food. You REALLY need to find somewhere else.
By GrahamRounce
It's not like it sounds! No food or crockery or utensils are left out. If they are, they're rinsed before use.
That being said, I'd like a mega extractor fan if anyone has one going cheep.