in the meantime, i did some tests.
although the design is not yet finished (the main part is always to get
such things in a  box ;-)
i'm quite sure that this will work:

on the controlling pc:

to turn the printer on, a small tool is started, knowing the mac address
of the power switch, as well as the ip address of the printer.
this tool sends a magic packet to the switch once a minute, and pings
the printer to check if it is on.

to turn the printer off, this tool is terminated.


at the printer:

a network card with a wol connector is required. this nic gets it's 5v
controlled by a pic.
whenever the wol signal goes high (once in a minute, when the tool on
the pc is running), a timeout on the pic is set to 10minutes, and the
nic is powered down for 1 sec, to clear the wol signal.
as long as the timeout counter has not counted down to zero, a relais is
activated, powering the printer.
as soon as no magic packets arrive anymore, the printer is turned off
after 10minutes.


a nice thing is that no sw or driver has to be 'installed' on the pc.
the tool on the memory stick or somewhere on the net does it all.
another nice thing with this solution is, that i can activate the
printer from different pc's (i have several users, using this printer),
and it stays on as long as any pc is sending the magic packets. 

sw for the pc and the pic is done. now waiting for a fairy putting it
all in a box ;-)

tino

************************************************************************
******************************


>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>On Behalf Of Howard Winter
>Sent: Thursday, September 29, 2005 9:09 PM
>To: Microcontroller discussion list - Public.
>Subject: Re: [EE] PC Network Adapter as IP Power Switch
>
>
>On Wed, 28 Sep 2005 08:50:05 -0300, Gerhard Fiedler wrote:
>
>> PicDude wrote:
>> 
>> > Why not just timeout like an auto-shutoff?  You can monitor the 
>> > busy/ready light or a power line to the print-head, etc.
>> 
>> Good idea! The busy light is probably better, because you 
>can monitor 
>> it without modifying the printer (and losing warranty). But 
>this still 
>> wouldn't turn it on...
>
>Well turning it on needs the "magic packet" which others have 
>referred to, which will cause the network card 
>to set the WOL signal.  After that, you're on your own!  :-)  
>You need to power the network card using the 
>"standby" power (5V and/or 3V3) at all times, so that it can 
>receive and respond to the magic packet.
>
>Remember it's designed to operate in a PC, so the machine 
>wakes from its suspended state and the software 
>takes over, doing whatever it was supposed to.  The shutdown 
>is caused by a period of inactivity according to 
>whatever parameters are set, which may have nothing to do with 
>networking, and can be instigated by the BIOS, 
>the operating system, or both.  That's why the network card 
>takes no part in the going to sleep, only the 
>waking up - it's not its job to decide, because all sorts of 
>things could be happening that it knows nothing 
>about - so a higher power which does know, makes that decision.
>
>Cheers,
>
>
>Howard Winter
>St.Albans, England
>
>
>-- 
>http://www.piclist.com PIC/SX FAQ & list archive
>View/change your membership options at 
>http://mailman.mit.edu/mailman/listinfo/piclist
>

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist