WTB: USB Mains switch

[Vortex]

I'd better explain:

I am looking for some kind of mains switch that I can use to automatically power down computer peripherals that are unnecessary when my PC is "sleeping".

For example I have a scanner, printer and powered USB hub, all of which (if not manuallly turned off) have warm "wall warts"....and use expensive Watts during the 20+ hours per day my PC sleeps.

My first thought was to build something using a relay

and DIN rail bits and bobs from TLC

....BUT this must be a common requirement and somebody must have thought of this before. Casual "Googling" has not turned up any commercial products. It's the sort of thing that you might expect to be able to obtain from MAPLIN...but their infuriatingly crappy search engine has turned up nothing (as well as causing me anger issues).

Any suggestions?

David

[Trevor Smith]

Why not use a remote control socket, B&Q do them, and a 4 way extension socket for the peripherals. Trevor Smith

[Andy Dee]

How about this?

[Pete Verdon]

Looks like the answer. But the copywriter clearly has a problem with logical thought - apparently "[t]his energy-efficient 6-way mains panel even comes fully equipped with a power surge protector which can wreck an entire system and prove very costly"

Pete

[nog]

[Dave Plowman (News)]

I'd be slightly concerned about the power you can take from a USB outlet - as they are electronically switched and not just straight off the PS rail. Most PCs have a pretty meaty 12 volt rail - if you really want it switched with the PC itself why not fit a socket for that to the case and drive a relay off that? 12 volt coil high power relays are easy to come by.

I fitted a switched FCU on the wall close to the PC which switches a socket which feeds the computers and peripherals so use that to power everything down.

I tried one of those sensing multi-outlet strips but found it not 100% reliable in operation. Perhaps they've improved them.

[Andrew Gabriel]

I quite often build PC peripherals which I power from spare USB ports rather than using extra wall-warts. It would be quite easy to simply run a relay from the 5V USB power output. You shouldn't draw more than 100mA, which means you should consider driving a small relay which in turn drives a larger mains relay. You might also have to adjust the BIOS to disable PC switchon from USB devices, which might other keep them powered when the PC is off.

You should be able to drive the following relay directly:

?sku=SW02480Use a reverse diode to absorb back EMF from the relay coil.

[Harry Bloomfield]

You can buy a ready made 13amp strip socket (one of those multi outlet things with a short flex and 13amp plug on the end) - which has one socket where if current is drawn the rest of the sockets turn on and when no current is drawn they are turned off. Use that socket for your PC and Robert is your auntie.

[Dave Liquorice]

Looked in Tesco? Ours had 'em before Christmas... They normally operate with the controlling device being switched off but one assumes that below a certain power level it will consider the controlling device to be "off". What that power level is I don't know or if your sleeping PC will be above it.

They are very common these days the DIY shed and PC stores all stock them but finding the right google words is tricky...

[Andy Wade]

Lovely! They also suffer from the all too common failure to understand the difference between power and energy: "[...] and a USB hub on standby wastes an average of 20 watts per hour, with some laser printers or games consoles wasting a staggering 80 watts per hour"

[Vortex]

On paper that looks like just the ticket....but I agree the copywriting is shocking.

Just found this alternative:

guys do a special one for laptops as well.

david

[Vortex]

> These guys do a special one for laptops as well.

better still:

[John]

In article , Andrew Gabriel writes

I have found that my PC still powers the USB port even though it is shut down - obviously designed to enable the PC to be awoken by a remote device - you might find that the relay was always up!

[Roger Mills]

Try this:

magic search word on the Maplin site is "intelligent"]

They also have a smaller version which looks like a multi-way adaptor, with integral 13A plug.

I have a couple of 6-way Intelligent Extension Leads (no surge protection - no longer available) which turn off the peripherals on my 2 computers quite happily. Whether they would respond to a computer which is simply "sleeping", I don't know.

[Roger Mills]

>>> These guys do a special one for laptops as well.

of these are also available at Maplins (see my other post) - but yours are cheaper, unless you live near to a Maplins branch and can thus avoid paying for postage.

[Vortex]

Well spotted!

AND local Maplin has one. If it's still there tomorrow I may well go and buy it!

Will report on it's efficacy.

[Andrew Gabriel]

As I said, check for the BIOS setting. Also check all the USB ports as it's sometimes only one of two with continuous power.

[Dave Plowman (News)]

The one I have is adjustable for the switching load so should be able to be set for the quiescent current draw. Except it's not reliable enough.

[Mike Faithfull]

(snip ...)

Intelligent? Maplins? ;-)

[Roger Mills]

Quite!

It doesn't apply to them though, but to the device. I spent ages trying to find it on the Maplin site - trying various options with "smart" and "mains extension" etc. - and in the end I had to dig out my 3 1/2 year-old invoice (too old to still be in my on-line order history!) to find out what the bl**dy thing was called, and there it was - "Intelligent Ext lead" - BINGO!!