power control (OT)

From: Shawn T. Rutledge <ecloud_at_bigfoot.com>
Date: Mon Jun 25 18:19:47 2001

On Mon, Jun 25, 2001 at 11:41:34PM +0100, Tony Duell wrote:
> > I have half a dozen printers scattered all over the house, and they are
> > rapidly being connected to my home network. It would be real nice to leave
> > them all off until printing needed doing, then to be able to turn on any
> > printer remotely from any computer followed by powering down after some

Yes I've wanted to do this too.

> > reasonable interval. Laserprinters are right at the edge of what X10 will
> > handle.
> I believe there used to be an X10 'appliance module' with a relay (not
> triac) output. Connect the (120V switched) output of that to the coil of
> a large 120V-coil relay or contactor (those are made with _very_ high
> contact ratings, at least 100A if you need them!). Then use that to
> switch the mains to the laserprinter.

Actually the 3-prong appliance module ought to be enough for a printer.

My experience is that the X10 toys aren't long-term reliable. Since
1997 when I got started, I have had 2 light switches fail (one liked to
oscillate instead of switch on or off; the other was for the bathroom,
and got used enough that its pushbutton contacts failed), an X10 switched
outlet failed after only a few months, another outlet sometimes switches
itself on with no input like some kind of poltergeist (but it has been
a while since that happened...) and some others are just generally flaky
(don't receive the commands sometimes).

A couple weeks ago I set up a relay controlled by a Dallas Semiconductor
1-wire switch chip (well, actually a small one-wire relay from PointSix,
controlling a bigger relay) to control the booster pump for my pool cleaner.
That's working OK so far, we'll see about the long term. For now a computer
in the house is controlling it (a cron job) but I want to put a TINI in
the garage one of these days. The 1-wire stuff could potentially be
more reliable than X10 but you do have to have extra control wires (one
signal wire for the serial bus, plus a ground). A spare pair in a
telephone cable works OK. Or, you could use CAN bus, that has a long
track record, and there are TINI systems which can use that bus as well.

Next I want to try to build a DC control board using a 1-wire switch
chip and a FET, to control either relays or sprinkler solenoids.

For a serial printer, a TINI could be used both to put it onto the network
and control its power (along with the same sort of 1-wire relay lashup).

  _______                   Shawn T. Rutledge / KB7PWD  ecloud_at_bigfoot.com
 (_  | |_)          http://www.bigfoot.com/~ecloud  kb7pwd_at_kb7pwd.ampr.org
 __) | | \________________________________________________________________
Received on Mon Jun 25 2001 - 18:19:47 BST

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