Odd Question - Will A PC Boot With No Power Switch

[dukeofcrydee]

I'm building a custom PC inside a 50cal. military ammo can. I don't feel like putting an ugly PC-looking power & reset button on the thing. I was hoping I could power the PC on and off via the toggle switch on the power supply.

My question is though, will the PC boot without the power/reset cable on the motherboard attached to anything?

 

[dukeofcrydee]

I wrote that post to quick. Obviously there are no power/reset cables on the motherboard...just on the case *slaps head*.

So basically when I connect everything it might not turn on via the power supply. But if I quickly hook a power switch to the mobo I can flip it "on" and then use the power supply in the future. So my question now is....

When I remove the temporary power switch, will it boot without the cable being attached to the motherboard?

 

[phsstpok]

Use the Keyboard Power-ON function. Just set your motherboard jumper, BIOS and ACPI options appropriately.

<b>[addition]</b>
You could also set the Power Loss Recovery to Enabled. This is intended for automatically restarting your computer after a loss of power but a side effect is that you can turn your computer on with the Power Supply main switch or with a power strip.

A consequence is if you shut down the computer but leave the main switch on, any temporary interruption of power ( perhaps even a spike) may turn your computer on.

<b>[more additions]</b>
Forget the second suggestion. I just tested Power Loss Recovery. The system doesn't reliably turn on with the main power switch. Only works if power is lost during operation (makes sense). Sorry about that.

<b>99% is great, unless you are talking about system stability</b><P ID="edit"><FONT SIZE=-1><EM>Edited by phsstpok on 04/24/03 03:54 PM.</EM></FONT></P>

 

[dukeofcrydee]

Thanks.

 

[soulprovider]

Get one of those trembler switches used on car alarms and hook it up to your motherboards power switch pins.

Then just kick the box to switch it on. Subtle but pretty cool considering the case :tongue:

<b>Vorsprung durch Dontwerk</b>.....<i>as they say at VIA</i>

 

[Teq]

Instead of pounding your powersupply with repeated current surges, why don't you replace the PCish power button with one of these little guys:

<A HREF="http://www.radioshack.com/product.asp?catalog_name=CTLG&category_name=CTLG_010_007_005_000&product_id=275-016" target="_new">http://www.radioshack.com/product.asp?catalog_name=CTLG&category_name=CTLG_010_007_005_000&product_id=275-016</A>

Bend the tip of the lever up 90 degrees and poke it out through a small hole in an inconspicuous spot on your homemade case. A little bracket, solder on the wires and you got a hidden startup switch.

Reset button... same idea.


--->It ain't better if it don't work<---

 

[Crashman]

You really do want some kind of momentary contact switch. Keyboard power on doesn't work for "first boot" after the power is hooked up on many boards. You can use a micro button though, yes even the military uses such devices.

<font color=blue>Watts mean squat if you don't have quality!</font color=blue>

 

[alltaken]

ok get some gattling gun ammon as would have been in the box in the first place. then have it set up so that this is comming out of the case so when you pull on it it also acts to trigger a switch therefore having the coolest looking switch in the world.

so the lid would be permenently open a wee bit(so if thats a problem then just ignor my idea)




Alltaken

 

[phsstpok]

I just noticed you said you are going to use an ammo can. Why not just mount the switch on the inside and just reach under the lid when you want to start the PC?

Last night (Thursday), Yoshi of TechTV's, "The Screensavers", just presented a custom PC. His is a mini-ITX mobo mounted in a 7.62 mm ammo can. It's tiny compared a .50 cal case but it might give you some ideas. See link below.

<A HREF="http://www.techtv.com/screensavers/howto/story/0,24330,3426073,00.html" target="_new">http://www.techtv.com/screensavers/howto/story/0,24330,3426073,00.html</A>

<b>99% is great, unless you are talking about system stability</b><P ID="edit"><FONT SIZE=-1><EM>Edited by phsstpok on 04/25/03 11:06 AM.</EM></FONT></P>

 

[dukeofcrydee]

Funny you should mention Yoshi. I saw his ammo can project in the show notes of that show and that basically ignited my project.

As for the switch, I think I know now that I need a momentary switch (SPDT Switch). Here's my current problem though....

1) Is there something nice looking (black plastic rocker would be fine) available anywhere? I'd mount it to the case since it wasn't a PC-looking push button, or some fugly looking one like the Radio Shack link someone provided (which I'm grateful for...from that I know to get SPDT )

2) Wires. What the hell do I do about wiring it? Cases come with the wires so I'd have to buy them separately and I know NOTHING about electronics.

 

[phsstpok]

Well, a basic case only has wiring for power switch, reset switch, power LED, and HD LED, and PC speaker. Everything else is on the motherboard or power supply.

If you wanted to be really minimal you could just do the power switch and speaker. Leave out the reset switch and LEDs.

I would think the most difficult problem would be organization. I just did a search on ammo cases. I thought .50 cal ammo cases were bigger but they are only 11" long x 7" tall x 5.5" wide (interior sizes). A full sized ATX mobo is 12" x 9.6" and a micro-ATX is 9.6" x 9.6" so these won't fit. You'd have to use something smaller like Yoshi who used a mini-ITX mobo.

<b>99% is great, unless you are talking about system stability</b>

 

[dukeofcrydee]

Way ahead of ya. I have a VIA Epia Mini-ITX on order already. 7"x7".

I also did more research on my switch. I'm getting a key switch. SPST version. I know it's not a momentary switch like normal, but a quick turn of the key on & off should do the trick. And I can hang the keys inside the box like they used to do in some of the arcade machines. Plus it keeps everything organized.

On GideonTech's forums I read the wire could be a simple speaker cable, so I got one from Radio Shack with red/black tips so I knew what the hell was what.

Hopefully my trust in others doesn't get me fried

 

[Teq]

If you want to use a key switch (to simulate the lock on the ammo box) do a little more shopping around... they do make spring loaded key switches that will bounce back to center as soon as you release them.

I can't for the life of me find a link to it right now, I think it was either Allied or Electrosonic... but I did see one a while back that was SPDT with three positions On-OFF-ON and it snapped back to center from either side... This would be handy, use one side for startup and the other for reset...two switches in one.



--->It ain't better if it don't work<---

 

[dukeofcrydee]

It's not so much to simulate anything, but mainly for the rugged look and I like the functionality of it all.

That SPDT keyswitch sounds like the perfect solution, although at Radio Shack the guy was surprised to see they had keyswitches at all....so I know I'm not going to find an SPDT there. I'll look online this weekend and see what I can't dig up. Thanks for the tip.

Although, your suggestion of a dual switch baffles me. How would you wire something like that? Are there 4 connectors on a SPDT switch?

 

[Teq]

It's unlikely you will find this at Radio Shack... Allied Elctronics or Electrosonic are your better bets.

Anyway... You don't need 4 contacts.

Both the power and reset switches go to ground, three pins will do it... Hook the startup+ to the Right-On contact, the Reset+ to the Left-On contact and the grounds to the common contact. For safety, test it with 1K resistors in series with the switch contacts... There's almost no current there, a couple of ma at most.

If I could upload graphics I'd draw you a real nice picture , but I think you can figure it out...





--->It ain't better if it don't work<---

 

[dukeofcrydee]

I get it. We'll pretend the + is the red positive speaker wire & the - is the black negative speaker wire. So the 3 connections would be:

POWER ON+
STANDBY-
RESET ON +

 

[Teq]

Nope...
In a normal PC it works like this:

Startup + == Startup
Startup - == Ground

Reset + == Reset
Reset - == Ground

The Ground wires from both Reset and Startup are actually connected together on the motherboard... so you only need 3 wires (i.e. you only need 1 of the grounds).

Now We've got 3 solder points on the back of the keyswitch itself. The left and right on positions both contact the center common when you turn the key...

Left-On == Reset +
Common == Ground
Right-On == Startup +

Turn Right... Startup (right-on) contacts Ground (common) Computer boots up or shuts down.
Turn Left ... Reset (left-on) contacts Ground (common) Computer reboots.
Let go... both switches are open, Computer stays in it's current state.

Wire colour is unimportant, it's the positions on the motherboard header you've got to get right.



--->It ain't better if it don't work<---