Circuit to power on devices when one other device is turned

N

Noozer

Guest
Does anyone have a simple circuit that would power on a few outlets when the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific outlet
draws under 15 or so watts.

Thanks!
 
"Noozer" <postmaster@127.0.0.1> wrote in message
news:Lioqc.492706$Pk3.183254@pd7tw1no...
Does anyone have a simple circuit that would power on a few outlets when
the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific outlet
draws under 15 or so watts.

Thanks!


Are you trying to turn on a printer and monitor when your PC is off standby?
Click to expand...
I would use a current transformer, and operate a relay when the current
exceeds a certain value,

Tam
 
"Noozer" <postmaster@127.0.0.1> wrote in message
news:Lioqc.492706$Pk3.183254@pd7tw1no...
Does anyone have a simple circuit that would power on a few outlets
when the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific
outlet
draws under 15 or so watts.

Thanks!
Click to expand...
These are around but tend to be more expensive than the usual power
strip with a master switch. I'm not sure what the correct acronym for
this is.

If you want to build one, then you should look for a good, reasonably
high current relay like the ones that are used on a remote controlled
consumer device like a TV or VCR. I recently built a proximity switch
and used a Matsushita relay labeled JR1a-DC12V-TV, whch pretty much sums
up what its ratings are. These relays are reasonably sensitive and
should handle 10 to 15 amps or more.

You also have to remember that the master device may have quite a bit of
variance in the amount of current it draws. So if you set your power
strip improperly, it could shut off during periods of low current draw,
such as when your monitor, for example, shows a screen that is
completely black.

--
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"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:10amfpdjdptbvdf@corp.supernews.com...
"Noozer" <postmaster@127.0.0.1> wrote in message
news:Lioqc.492706$Pk3.183254@pd7tw1no...
Does anyone have a simple circuit that would power on a few outlets
when the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific
outlet
draws under 15 or so watts.

Thanks!

These are around but tend to be more expensive than the usual power
strip with a master switch. I'm not sure what the correct acronym for
this is.

If you want to build one, then you should look for a good, reasonably
high current relay like the ones that are used on a remote controlled
consumer device like a TV or VCR. I recently built a proximity switch
and used a Matsushita relay labeled JR1a-DC12V-TV, whch pretty much sums
up what its ratings are. These relays are reasonably sensitive and
should handle 10 to 15 amps or more.

You also have to remember that the master device may have quite a bit of
variance in the amount of current it draws. So if you set your power
strip improperly, it could shut off during periods of low current draw,
such as when your monitor, for example, shows a screen that is
completely black.
Click to expand...
Thanks for all the help folks, but I was hoping for something a little more
specific.

Engineer I am not, but I can solder and etch a circuit board if necessary. I
know that a 1/8 watt resistor won't do where a 1/4 watt is required, etc.

With the number of external devices used on computers I would have thought
that this would have been a pretty common request.

Basically I want to plug my PC into the controlling outlet, so when the PC
shuts off it will turn off my monitor and USB/Firewire drives.

What would really be nice is a "Consumer Connection Protocol" where anything
could be connected to anything - even just to power on/off the linked
devices. It would be great for PC's, not to mention multimedia centers where
you have a separate tuner, monitor and audio devices.
 
With the number of external devices used on computers I would have thought
that this would have been a pretty common request.
Click to expand...
There are circuits for this out there. I know that I have seen one
and likely two different ones in magazines in the last 10 years.

Basically I want to plug my PC into the controlling outlet, so when the PC
shuts off it will turn off my monitor and USB/Firewire drives.
Click to expand...
You can buy these off the shelf for likely less than it would
cost to make. (And quite likely safer to use.)
 
"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10atps6amipdbbb@corp.supernews.com...
With the number of external devices used on computers I would have
thought
that this would have been a pretty common request.

There are circuits for this out there. I know that I have seen one
and likely two different ones in magazines in the last 10 years.

Basically I want to plug my PC into the controlling outlet, so when the
PC
shuts off it will turn off my monitor and USB/Firewire drives.

You can buy these off the shelf for likely less than it would
cost to make. (And quite likely safer to use.)
Click to expand...
But I've never seen one and trying to find one here in Calgary has been
fruitless.

What are these things officially named?
 
"Noozer" <postmaster@127.0.0.1> wrote in message
news:NGxrc.560870$Ig.205113@pd7tw2no...
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:10amfpdjdptbvdf@corp.supernews.com...

"Noozer" <postmaster@127.0.0.1> wrote in message
news:Lioqc.492706$Pk3.183254@pd7tw1no...
Does anyone have a simple circuit that would power on a few outlets
when the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific
outlet
draws under 15 or so watts.

Thanks!

These are around but tend to be more expensive than the usual power
strip with a master switch. I'm not sure what the correct acronym for
this is.

If you want to build one, then you should look for a good, reasonably
high current relay like the ones that are used on a remote controlled
consumer device like a TV or VCR. I recently built a proximity switch
and used a Matsushita relay labeled JR1a-DC12V-TV, whch pretty much sums
up what its ratings are. These relays are reasonably sensitive and
should handle 10 to 15 amps or more.

You also have to remember that the master device may have quite a bit of
variance in the amount of current it draws. So if you set your power
strip improperly, it could shut off during periods of low current draw,
such as when your monitor, for example, shows a screen that is
completely black.

Thanks for all the help folks, but I was hoping for something a little
more
specific.

Engineer I am not, but I can solder and etch a circuit board if necessary.
I
know that a 1/8 watt resistor won't do where a 1/4 watt is required, etc.

With the number of external devices used on computers I would have thought
that this would have been a pretty common request.

Basically I want to plug my PC into the controlling outlet, so when the PC
shuts off it will turn off my monitor and USB/Firewire drives.

What would really be nice is a "Consumer Connection Protocol" where
anything
could be connected to anything - even just to power on/off the linked
devices. It would be great for PC's, not to mention multimedia centers
where
you have a separate tuner, monitor and audio devices.
Click to expand...

The proper term for these power strips is "Smart Strip". You can buy one at
http://www.smarthomeusa.com/Shop/Hardware-Cable/Item/LCG1 for $27.95 plus
shipping. If you're really interested in building your own, a small current
transformer feeding an opamp with a detector and relay driver should be
fairly easy to design. However, for ~ $30, I wouldn't bother with a
homebrew unit.. the electronic parts would likely cost $10 to $15, adding
the cost of the electrical sockets and a suitable housing, plus the
construction time could easily drive the total cost above the cost of the
Smart Strip.

Cheers!!!
--
Dave M

Good judgment comes from experience, and a lot of that comes from bad
judgement.
 
"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:

Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.
Click to expand...
Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).


--
Regards,
Soeren

* If it puzzles you dear... Reverse engineer *
 
Or you could get a solid state relay, SSR (do not use a mechanical relay
(flyback)) and use the +12V form one of the connectors to the drives or
extra fans. When the +12V comes on the so does the SSR. The SSR is isolated
and has no flyback to destroy your computer and can be bought for 110vac or
220vac.
"Tweetldee" <masondg4499@comcast99.net> wrote in message
news:qSBrc.2739$af3.144331@attbi_s51...
"Noozer" <postmaster@127.0.0.1> wrote in message
news:NGxrc.560870$Ig.205113@pd7tw2no...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:10amfpdjdptbvdf@corp.supernews.com...

"Noozer" <postmaster@127.0.0.1> wrote in message
news:Lioqc.492706$Pk3.183254@pd7tw1no...
Does anyone have a simple circuit that would power on a few outlets
when the
power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet
is
drawing more than 15 watts and to turn off whenever that specific
outlet
draws under 15 or so watts.

Thanks!

These are around but tend to be more expensive than the usual power
strip with a master switch. I'm not sure what the correct acronym for
this is.

If you want to build one, then you should look for a good, reasonably
high current relay like the ones that are used on a remote controlled
consumer device like a TV or VCR. I recently built a proximity switch
and used a Matsushita relay labeled JR1a-DC12V-TV, whch pretty much
sums
up what its ratings are. These relays are reasonably sensitive and
should handle 10 to 15 amps or more.

You also have to remember that the master device may have quite a bit
of
variance in the amount of current it draws. So if you set your power
strip improperly, it could shut off during periods of low current
draw,
such as when your monitor, for example, shows a screen that is
completely black.

Thanks for all the help folks, but I was hoping for something a little
more
specific.

Engineer I am not, but I can solder and etch a circuit board if
necessary.
I
know that a 1/8 watt resistor won't do where a 1/4 watt is required,
etc.

With the number of external devices used on computers I would have
thought
that this would have been a pretty common request.

Basically I want to plug my PC into the controlling outlet, so when the
PC
shuts off it will turn off my monitor and USB/Firewire drives.

What would really be nice is a "Consumer Connection Protocol" where
anything
could be connected to anything - even just to power on/off the linked
devices. It would be great for PC's, not to mention multimedia centers
where
you have a separate tuner, monitor and audio devices.



The proper term for these power strips is "Smart Strip". You can buy one
at
http://www.smarthomeusa.com/Shop/Hardware-Cable/Item/LCG1 for $27.95 plus
shipping. If you're really interested in building your own, a small
current
transformer feeding an opamp with a detector and relay driver should be
fairly easy to design. However, for ~ $30, I wouldn't bother with a
homebrew unit.. the electronic parts would likely cost $10 to $15,
adding
the cost of the electrical sockets and a suitable housing, plus the
construction time could easily drive the total cost above the cost of the
Smart Strip.

Cheers!!!
--
Dave M

Good judgment comes from experience, and a lot of that comes from bad
judgement.
Click to expand...
 
"Soeren" <Look@iNO-SPAMt.dk> wrote in message
news:Xns94F18C3108F94oo8ooLooK4iToo8oo@62.243.74.163...
"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:

Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.

Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).
Click to expand...
That's what I was thinking at this point... but (and I haven't checked) I
don't think USB will work if "wake on USB" is enabled as the 5V will always
be present.

Still... The gameport is a good idea. PS/2 port won't provide enough current
to fire a relay, but maybe enough to trigger something else...

I'll do some digging.
 
"Mark Mcmillan" wrote ...
Or you could get a solid state relay, SSR (do not use a mechanical relay
(flyback)) and use the +12V form one of the connectors to the drives or
extra fans. When the +12V comes on the so does the SSR. The SSR is
isolated
and has no flyback to destroy your computer and can be bought for 110vac
or
220vac.
Click to expand...
Or even better the USB, Firewire(6-pin), keyboard/mouse or even serial
or parallel ports all put out voltages when the computer is turned on and
would likely drive the appropriate SSR. No hacking into the computer
case necessary. Sounds like a product opportunity!
 
Noozer wrote:

"Soeren" <Look@iNO-SPAMt.dk> wrote in message
news:Xns94F18C3108F94oo8ooLooK4iToo8oo@62.243.74.163...

"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:


Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.

Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).


That's what I was thinking at this point... but (and I haven't checked) I
don't think USB will work if "wake on USB" is enabled as the 5V will always
be present.

Still... The gameport is a good idea. PS/2 port won't provide enough current
to fire a relay, but maybe enough to trigger something else...
Click to expand...
The gameport is ok, but the PS/2 port (either mouse or keyboard) should
also be good for 100mA. It shouldn't be too difficult to find a suitable
relay. I would consider it preferable to use a 2-pole relay so that both
poles get cut off. Also, don't forget the flywheel diode.

You could of course build a device that doesn't need the auxiliary power
from the PC. Other have offered their suggestions here, but have
neglected to mention that the extra electronics need to have their own
power supply. The overall design effort for doing this properly isn't
trivial, and probably only justified when you want to manufacture in volume.

Still, it would be interesting to know how the commercial devices are
solving this problem. I've got a few ideas, bouncing around in my head
but haven't tried any yet.

A very simple solution would be to have a relay with a special
high-current low-voltage AC coil that can be operated in series with the
master device. If such a thing existed (and I haven't a clue whether it
does - does anyone know?) it would be the only component needed except
maybe for a fuse.

--
Cheers
Stefan
 
Noozer wrote:



Does anyone have a simple circuit that would power on a few outlets
when the power draw on another outlet is more than 15 watts or so?

Basically, I want to turn on a powerbar whenever a specific outlet is
drawing more than 15 watts and to turn off whenever that specific
outlet draws under 15 or so watts.

Thanks!
Click to expand...
Silicon Chip magazine did a project for exactly this type of application in
July 2003.


http://www.siliconchip.com.au

You can order back issues of the magazine, or just a copy of the article if
the magazine is out of stock.


I just looked through my pile of magazines and the July edition is not
there!!! The following little blurb is from the current Jacar Electronics
catalogue:

Auto Power up Kit for Mains Applications.
Refer Silicon Chip July 2003.
Turn on all your equipment at the flick of a switch. This could include your
PC and all its peripherals, TV and the rest of your home theatre, or even
the workshop appliances.
The kit connects to the main unit and switched on the power to the remaining
units, saving you from powering up the other units seperately.

Specs:
Power level to switch slave:1 to 25 watts adjustable.
Maximum load (master and slave outputs combined) 6 A @ 240V AC or 1440 W
Standby current 18.5 mA


Catalogue number KC-5363 $69.95 Australian.


Jaycar do mail orders.

www.jaycar.com.au




I hope this helps


Pippa
 
You could use a 5V DIP relay to operate the power relay, which would have a
125 VAC coil. Radio Shack sells a double pole 10 A with a 125 VAC 16 ma
coil.

Tam
"Stefan Heinzmann" <stefan_heinzmann@yahoo.com> wrote in message
news:c8o4vf$3v9$06$1@news.t-online.com...
Noozer wrote:

"Soeren" <Look@iNO-SPAMt.dk> wrote in message
news:Xns94F18C3108F94oo8ooLooK4iToo8oo@62.243.74.163...

"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:


Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.

Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).


That's what I was thinking at this point... but (and I haven't checked)
I
don't think USB will work if "wake on USB" is enabled as the 5V will
always
be present.

Still... The gameport is a good idea. PS/2 port won't provide enough
current
to fire a relay, but maybe enough to trigger something else...

The gameport is ok, but the PS/2 port (either mouse or keyboard) should
also be good for 100mA. It shouldn't be too difficult to find a suitable
relay. I would consider it preferable to use a 2-pole relay so that both
poles get cut off. Also, don't forget the flywheel diode.

You could of course build a device that doesn't need the auxiliary power
from the PC. Other have offered their suggestions here, but have
neglected to mention that the extra electronics need to have their own
power supply. The overall design effort for doing this properly isn't
trivial, and probably only justified when you want to manufacture in
volume.

Still, it would be interesting to know how the commercial devices are
solving this problem. I've got a few ideas, bouncing around in my head
but haven't tried any yet.

A very simple solution would be to have a relay with a special
high-current low-voltage AC coil that can be operated in series with the
master device. If such a thing existed (and I haven't a clue whether it
does - does anyone know?) it would be the only component needed except
maybe for a fuse.

--
Cheers
Stefan
Click to expand...
 
"Noozer" <postmaster@127.0.0.1> wrote in
news:eek:dMrc.534720$Pk3.352550@pd7tw1no:


That's what I was thinking at this point... but (and I haven't
checked) I don't think USB will work if "wake on USB" is enabled as
the 5V will always be present.
Click to expand...
I guess you are right.


Still... The gameport is a good idea. PS/2 port won't provide enough
current to fire a relay, but maybe enough to trigger something else...
Click to expand...
The gameport can deliver almost whatever you need, as it is connected
directly to the 5V line (the limiting factor is the circuit board traces
current handling ability).


--
Regards,
Soeren

* If it puzzles you dear... Reverse engineer *
 
"Noozer" <postmaster@127.0.0.1> wrote in message
news:eek:dMrc.534720$Pk3.352550@pd7tw1no...
"Soeren" <Look@iNO-SPAMt.dk> wrote in message
news:Xns94F18C3108F94oo8ooLooK4iToo8oo@62.243.74.163...
"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:

Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.

Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).

That's what I was thinking at this point... but (and I haven't checked) I
don't think USB will work if "wake on USB" is enabled as the 5V will
always
be present.

Still... The gameport is a good idea. PS/2 port won't provide enough
current
to fire a relay, but maybe enough to trigger something else...

I'll do some digging.
Click to expand...
http://www.elspareskinnen.dk/ (in danish)

/Klaus
 
in article c8o4vf$3v9$06$1@news.t-online.com, Stefan Heinzmann at
stefan_heinzmann@yahoo.com wrote on 5/22/04 13:10:

Noozer wrote:

"Soeren" <Look@iNO-SPAMt.dk> wrote in message
news:Xns94F18C3108F94oo8ooLooK4iToo8oo@62.243.74.163...

"Noozer" <postmaster@127.0.0.1> wrote in
news:NGxrc.560870$Ig.205113@pd7tw2no:


Basically I want to plug my PC into the controlling outlet, so when
the PC shuts off it will turn off my monitor and USB/Firewire drives.

Use a 5V relay (with contacts rated for mains voltage at the current you
need) or a Solid State Relay.

Drive it from a USB-port or the game port (which both contains 5V).


That's what I was thinking at this point... but (and I haven't checked) I
don't think USB will work if "wake on USB" is enabled as the 5V will always
be present.

Still... The gameport is a good idea. PS/2 port won't provide enough current
to fire a relay, but maybe enough to trigger something else...

The gameport is ok, but the PS/2 port (either mouse or keyboard) should
also be good for 100mA. It shouldn't be too difficult to find a suitable
relay. I would consider it preferable to use a 2-pole relay so that both
poles get cut off. Also, don't forget the flywheel diode.

You could of course build a device that doesn't need the auxiliary power
from the PC. Other have offered their suggestions here, but have
neglected to mention that the extra electronics need to have their own
power supply. The overall design effort for doing this properly isn't
trivial, and probably only justified when you want to manufacture in volume.

Still, it would be interesting to know how the commercial devices are
solving this problem. I've got a few ideas, bouncing around in my head
but haven't tried any yet.

A very simple solution would be to have a relay with a special
high-current low-voltage AC coil that can be operated in series with the
master device. If such a thing existed (and I haven't a clue whether it
does - does anyone know?) it would be the only component needed except
maybe for a fuse.
Click to expand...
Stefan
It's called a current relay.
A few turns of suitably heavy wire around a reed switch works for DC;
maybe add a bridge (shottky?) around the coil for AC? Or it might work w/o
the rectifier. I must try it sometime.
HTH
DC
 
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