Hardwire an ATX system to be always on

[sleddog]

Okay, I'm configuring a Celeron 300 ATX system to run 24/7 unattended. It runs a webcam, captures images and passes them along a network. The machine will be stuck in a difficult to access place. Here's the problem: after a power failure the machine won't power back on -- I've got to press the front soft power switch. Other systems I have have a BIOS setting that tells it what to do after a power failure, this system doesn't.

How can I get it to automatically power back up after a power failure?

Is there any way I can hardwire it to bypass the front switch, so it's always "on"?


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sleddog
[sleddog.f2s.com] (http://www.sleddog.f2s.com)

[Randy_tx]

My forays into electricity are well documented nightmares so I'll just offer the only thing I know of ....which you know too....a Battery Backup system.....usually cost about $165 or so.

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"As hard as a rock & dumb as a brick"...Windows CEMeNT

[bassman]

hey Sledd,
Have you concidered a solar setup? I know it might seem like more money then you want to spend, but for about $300 you could have all you need to be stand alone. With solar you have no power spikes, never affected by power failures, and you can set it up anywere.
Also if you hardwire the switch, when the power comes back on, wont the machine be stuck on the "Windows not properly shut down" screen?Here is a link to check out, and you can do a search for "Solar" and look for something geared for minor homeowner applications. Brandnew blemished batteries can be had for as little as 50% off regular price at most dealers. inverters (http://www.basspro-shops.com/servlet/catalog.TextId?hvarTarget=search&hvarSearchString=12-600-805-02&x=13&y=10)

Hope this helps
http://www.PCGuide.com/ubb/cool.gif

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If a book about Failures doesn't sell, is it a success?

[This message has been edited by bassman (edited 03-24-2001).]

[sleddog]

Randy: a battery backup isn't the answer... if the power is off long enough for the battery to die, then the machine won't come back up when power is restored. If it's a smart UPS that shuts the machine down on a power failure, I still can't get it back up.

bassman: what if it's foggy for a week http://www.PCGuide.com/ubb/smile.gif Thanks for the link I'm certainly going to have a look.

But there *must* be someway around this silly problem. What would happen if I pulled the power switch wire off the motherboard and put a jumper in its place? Snap, crackle, pop?


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sleddog
[sleddog.f2s.com] (http://www.sleddog.f2s.com)

[This message has been edited by sleddog (edited 03-24-2001).]

[Randy_tx]

May not work ALL the time....but it sure beats SNAP, Crackel ...POP http://www.PCGuide.com/ubb/biggrin.gif

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"As hard as a rock & dumb as a brick"...Windows CEMeNT

[Reid]

Here is something I found in a newsgroup:

"The Problem: There are a variety of ATX motherboards that have not
implimented "return to prior state" after power failure, or some other
means of auto restart after a power loss.

I work for a small ISP in Chicago and am in the process of rebuilding
one of our special purpose machines into an ATX motherboard/case. As
many of you have described, after a power failure, it will not boot
back up. This particular machine, if it crashes, can be reset
remotely by a power relay kicking out for 30 seconds. It must come
back up in the powered on state:

Solution (1)
==========

First, several motherboards while not supporting a BOIS solution will
power up if the power button is held in when power returns. Micronics
is an example of this. TO test, unplug the PC ( pull the power cord,
etc.)

HOLD the power on button in. While holding, plug it back in. If it
powers up, your done. Remove the front panel switch cable and put a
jumper on the 2 pins on the motherbaord and your ready to rock.


Solutoin (2) The next step
=========================

At this point, the next step is to get the ATX power supply to turn on
no matter what. This can be accomplished by cutting pin 14 on the ATX
power supply ( small guage green wire) and on the power supply side,
take this wire to GROUND. This will force the power supply to come on
and you will hear the fan running.

Hopefully this will take care of your problem.

If not, now try the power reset described in Solution 1 and see if it
will start. If it works, again, put a jumper on the 2 pins on the
motherboard and your done.


Solution (3) The last resort:
========================

This is where I ended up. From reviewing other messages, I looked in
by BIOS settings and it had a function to control what the power
button did ( on/off, hold for 4 secs prior to action, suspend, etc.)
This I had to set to ON/OFF. I wanted immediate action.

I had already modified the power supply to stay on. The power light
was blinking on the case and if I pressed the power on button, up it
came. Only problem is that no one would be there to do it.

So I needed a space monkey to push the button when the power light
came on. NASA didn't have any and I was afraid of what it might have
done to the working systems... so.....

A little electrical work:

Goto to Radio Shack.

Buy:

- a small project curcuit board: mine was about 1x2 "

- 5VDC relay - mechanical. p/n 275-240A about $2.49
(You can use any other small relay. It needs to be normally open with
a momentary close when energized.)

Specs on the above: current draw 89.3mA, 5.0-6.5V coil voltage, pick
up voltage 3.5V, drop .25V, ciol resistance 56 ohms .. specs in case
you have one at home/office) Low current and low hold volatage are
important.


- a 330uf electrolytic capacitor ( 100uF up to ???? will also work..
this is where you may need to match the uF size to the amount of delay
you need. If your MB is not ready for the power up signal you will
need a larger cap. I don't know where the max value is but if it is
too high it might never get fully charged or put to big of a strain on
the power supply and overdraw it)

Now pop the relay on the board. Wire as follows to a floppy power
supply connector - male ( I cut mine off an old 3.5" floppy power
adapter used to hook up to a HD power plug)


[-----
| +5V ------side 1 of coil
|
| side 2 of coil ----- POS(+) leg of capacitor
|
| GND ------ NEG(-) leg of capacitor
|----

The normally open contacts of the relay get wired to a 2 pin
motherboard connector. You can either cut the wires from the POWER ON
connector you currently have or use any other. I took mine from a LED
used for converting old 3.5 drives into 5.25 carriers so you could see
the drive activity on the front face.


Connector Pin1 - - - - - - - - - - - (relay leg)

Connector Pin 2 - - - - - - - - - -^ (relay leg)


SIMPLE THEORY
================

The power supply comes up. Now you want to push the power on button.
When +5V starts to come out of the power supply it will flow through
the relay coil and start charging the capacitor.

This will throw the relay causing it to look like the power on button
was pushed (closed)

When the capacitor is fully charged, the current stops. When the
current stops, the relay no longer is getting current through it
suffient enough to hold the field and the relay opens. The power on
button was just released.


YOU JUST PRESSED AND RELEASED THE POWER BUTTON !!!!!!

YOUR ATX COMPUTER HOPEFULLY JUST TURNED ON !!!!!


CONTEMPLATED ADJUSTMENTS:
================================
- a high resistance 10Meg Ohm resister could be put across the
capacitor to drain it very slowly if the PC was shut off.
Theoretically, there could be a quick power drop that could shut off
the PC yet not be long enough for the capacitor to drain. The effect
would be that it would not "push" the button for you.


WHAT IF YOU STILL HAVE A PROBLEM OR NEED A LONGER PUSH OF THE POWER ON
BUTTON??
================================================== ===========================

I didn't have to go here so you are on your own to design this, but
the following were my thoughts as I was approaching this. There is a
venerable chip out there called a 555 timer. It can do some
unbelievable timing type things.

It will also act as a "one shot" time delay timer. You " push a
button" and it will then wait X seconds and then hold a line down for
Y seconds.

You would probably have to take the output to a transistor using it to
take the power on motherboard signal to ground. This would give you
the 4+ second ATX "hold the power button in" timing needed, if you
couldn't get around it

The top circuit can provide the "push the button" on the timer.

A search of " 555 timer" or "555 circuits" ( no quotes) on Yahoo will
return a wealth of knowledge. I'm provding the bookmarks to several
that I found when I was looking into this method. Some even have the
simulations set to choose the R-C network you need to set the timing
you desire.
http://www.74.co.uk/lizard/555/frames4.html

There is more at this site, forward and back from this bookmark.

FINALLY
========

This worked for me. It may not work for you. Your milage may vary.
If your not good with a soldering iron, etc. don't mess with it. No
guanantees, warranties, implied or expressed warranties or anything
else.

If you have a question, I'll try to answer it.

AND IN CONCLUSION
====================

If you end up doing this and it works, let me know.

Mike Shartiag
NorthShore.Net

shartynospamplease@ccbs.com"

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reido@my-deja.com

Friends don't let friends install Windows ME

[This message has been edited by Reid (edited 03-24-2001).]

[sleddog]

Reid: marvellous! Thanks so much for your effort. I'll be experimenting later today and let you all know how it goes.

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sleddog
[sleddog.f2s.com] (http://www.sleddog.f2s.com)

[Reid]

I read here in PCGuide that some power supplies have an auto-restart feature, but couldn't easily locate them. I have built electronics gear since "way back", so I started to look at the do-it-yourself aspect.

The few ATX supplies I have worked with apply power for about 2 seconds when the input is energized and that may be long enough for the relay to pull in momentarily. If not, you could get the power from a small DC power adapter. You may need to experiment with different size capacitors to get the right momentary closures.

I have built timer circuits with 555's, but I'd try the cap/relay first if I were doing it because of its simplicity.

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reido@my-deja.com

Friends don't let friends install Windows ME