Can a switch replace my computer's power button?

[javeryh]

On my old cabinet I extended the wires from the motherboard to one of these mini momentary pushbuttons (the top onein this picture):



and it works perfectly.  I push it once, everything comes on.  I push it again, everything shuts off.

Now I'm wondering if I did the same thing but used one of these:



would it still work?  The pushbutton makes contact and opens the circuit immediately but I think the switch would keep the circuit closed until flipping it again.  I like the look of the "on/off" switch instead of just a plain old button...  Any thoughts? 

[SavannahLion]

Usually not as a direct drop in replacement. This would appear to the PC as you holding in the power switch in an "ON" state. Some PC's see this as an error and post as such. Most PC's might misinterpret this as shutdown/sleep/whatever command. Others won't do anything at all (My Aptiva had a sticky power switch and it passed POST just fine). You might need to construct a small simple circuit to give the rocker switch the appearance of a momentary switch.

You have some other options before you though.

I've seen switches like the one pictured there that looks like a rocker switch but is actually a momentary switch internally. They don't stay in an on state though. Rock the "switch" and release it and it moves back into its normal state.

The other, more common method around here, is to configure the BIOS to always power on from a power outage then either extend the master switch from the PSU or modify a power strip for the purpose. The danger here is that you're dealing with 120v AC power levels instead of 5v DC power levels. Mistakes are less forgiving here.

[ratzz]

This is something I've been thinking of as well, but with a lit power switch.

I imagine the principal would be the same -- but I am completely dumb to this side of my project.

Ratzz

[javeryh]

Usually not as a direct drop in replacement. This would appear to the PC as you holding in the power switch in an "ON" state. Some PC's see this as an error and post as such. Most PC's might misinterpret this as shutdown/sleep/whatever command. Others won't do anything at all (My Aptiva had a sticky power switch and it passed POST just fine). You might need to construct a small simple circuit to give the rocker switch the appearance of a momentary switch.

You have some other options before you though.

I've seen switches like the one pictured there that looks like a rocker switch but is actually a momentary switch internally. They don't stay in an on state though. Rock the "switch" and release it and it moves back into its normal state.

The other, more common method around here, is to configure the BIOS to always power on from a power outage then either extend the master switch from the PSU or modify a power strip for the purpose. The danger here is that you're dealing with 120v AC power levels instead of 5v DC power levels. Mistakes are less forgiving here.

That's what I thought.  I'm 99% sure it would be read by my computer as holding down the power button which wouldn't be good.  Any ideas as to where to get one of those "rocker" switches that acts like a momentary pushbutton but looks like the black switch I posted?  I'm sure I've seen them around too.

Thanks!!   

[mountain]

Here is switch that is similar to what you showed above. It is a momentary.

[badkitty]

thats what i did..wired my POWER and RESEST leads from motherboard to arcade buttons.  works fine for me.  i would imagine any MOMENTARY , not OFF/ON  would would.  as this is what is in most cases.  push and turns on...hold (keeps contact) powers off/hibernate ect.)

[Zebidee]

Javery

Currently you turn power on/off using a momentry switch connected to the motherboard (MB).  You can do exactly the same for an always-on switch by connecting onto the ATX->MB power supply connector instead.

if you have an ATX+ style power supply, then one of the pins where the ATX connector goes to the MB is a "Power Supply On" (PSON) trigger.  This works the way you want it to - it will keep the PC on as long as the switch is closed.  If the switch is opened, the PC goes off.  Only 5v runs thru the signal line, so it is quite safe.

For ATX 20-pin connector to MB, PSON at pin 14, ground to pin 15
http://pinouts.ru/Power/atxpower_pinout.shtml

For ATX 24-pin connector to MB, PSON at pin 16, ground to pin 17
http://pinouts.ru/Power/atx_v2_pinout.shtml

The easiest way to test this is by exposing/twisting your wire ends, and inserting it into the back of the ATX->MB connectors so as to make good & secure contact.  Once you test it and are sure that you have the right pins, you can solder the wires to make sure.

[SirPeale]

Try this:

http://www.pealefamily.net/tech/captrick/

[FrizzleFried]

Simply install a power strip in the cab,  then extend the power switch from the strip and mount it (or another switch) to your cab.  Set your BIOS to boot after power outage and you are good as gold.  That is how i have 2 of my MAME cabinets set up.

[btp2k2]

I mount the power strip right inside the coin door on my cabinets.

Just open the door, reach inside, flip the switch and the monitor/marquee light/speakers power up, while I'm in there push the PC power switch and get ready for some Joust!

It may not the greatest solution, but it is simple and even the most un-tech savvy (IE me) person can figure out how to set it up....

[Kevin Mullins]

Those all look like Radio Shack buttons.... I swear I've seen a momentary switch there in that rocker panel style that you want. Might take a look there if you haven't already.

[Malenko]

I mount the power strip right inside the coin door on my cabinets.

Just open the door, reach inside, flip the switch and the monitor/marquee light/speakers power up, while I'm in there push the PC power switch and get ready for some Joust!

It may not the greatest solution, but it is simple and even the most un-tech savvy (IE me) person can figure out how to set it up....

thats how mine is set up as well. I looked into special strips that start up up everything but in the end I have one outlet always on (PC plugged into it) and the rest are hooked up to a power splitter, I flip that button and the marquee, speakers, monitor, and coin doors light up .   simple yet effective!

[Zebidee]

You really can't do it simpler and safer than with the ATX PSON switch, as described above.  It only runds 5v to the switch, and no need to buy anything special or make bits with capacitors etc.

[SirPeale]

You really can't do it simpler and safer than with the ATX PSON switch, as described above.  It only runds 5v to the switch, and no need to buy anything special or make bits with capacitors etc.

That's good, IF it works with your motherboard.  It doesn't work with them all.

[Zebidee]

It doesn't work with them all.

Yeah, if you have a non-ATX it's good to have some sneaky options like Peale's cap-trick up your sleeve

[SavannahLion]

It doesn't work with them all.

Yeah, if you have a non-ATX it's good to have some sneaky options like Peale's cap-trick up your sleeve

That cap trick is specifically for ATX boards, not non-ATX boards. For instance, older AT power supplies use a much more dangerous 120v switch, not a soft-switch.

[Zebidee]

That cap trick is specifically for ATX boards, not non-ATX boards. For instance, older AT power supplies use a much more dangerous 120v switch, not a soft-switch.

 

In that case, I really struggle to understand WHY you would need to use the cap-trick, as every standard ATX power supply connector provides a PSON (5v) at either pin 14 or pin 16 (for 24 pin ATX types).  Every ATX PC has this feature, as far as I am aware.

This will work like an on/off switch, not like a momentary on/off button that only SOME ATX MBs support. 

Peale's cap-trick is clever, but it only works on the MB switch on an ATX PC.  However, one could save the trouble and simply tap into the ATX power connector.

[SirPeale]

Zebidee: because of what I already stated - this does not work with all motherboards!

[Zebidee]

Well, if I ever find an ATX motherboard that isn't to ATX standard then I'll know what to do!

Peale, I'm not sure if you're talking about the same MB connection that I am.  Pls correct me if I am wrong, I'm not looking for an argument.

What you are doing is controlled by the MB connections to the normal power switch at the front of the PC - the PSON switch you show in your pics on your website is connected to the rest of those "front panel" connections.  The PSON I am talking about is different to that - it is where the ATX Power supply itself connects to the MB, and it is in a different place on the MB.  In is more related to the PS itself than the MB.  In function, it is more analogous to the hard on/off switch at the back of the power supply.

[bfauska]

Peale's solution should allow a software driven shut-down, while I don't think that Zebide's would.  If the both work on most ATX motherboards I would say Peale's is the one I'd try first.

[SirPeale]

Zeb: while this will definitely make *any* ATX power supply power up, some motherboards don't like the fact that these have been shorted, and will cause the board to not boot.

[SavannahLion]

Zebidee, from what I understand of the PSON line, it is intended to bring a power supply out of a sleep state. Not bring the motherboard out of a sleep state.

When you send an ATX PC to sleep, it either puts a high impedence on PSON or lets PSON float. This forces the PSU into a sleep state, ie it should bring the power lines, except for Standby, down to 0v. The power button on your motherboard is really a soft switch. From almost any state, the motherboard will ground PSON thereby bringing the PSU up to a full power and allowing the entire PC operate.

When you operate the PSU without a MB, you must ground PSON pin to get the PSU to operate properly. (On some, you even need to have a load on the power rail as well!). This is what you're describing.

Here's the rub, there is nothing that specifies that a MB MUST come out of a sleep state if something other than the MB grounds the PSON line. It's possible for some MB's to remain in a sleep state but the PSU will be powered.

There's also another problem. Some PC's (most notably those from Compaq) have all the appearances of an ATX standard PSU and Motherboard, however, the pinout and circuitry of said boards are not ATX compliant nor compatible. On some models, swapping an ATX PSU into these crap boards will do nothing (at best) or pop a few components (at worst). As far as I know, there is no documentation readily available to determine the pinouts of these faux-ATX PSU's.

This will work like an on/off switch, not like a momentary on/off button that only SOME ATX MBs support. 

No. not some, ALL. In my entire PC building career, I've yet to encounter an ATX complaint board lacking the the MOM power switch.

From reading your previous postings, it seems that there's some confusion on the different board standards there. In one of my posts, I specifically use AT boards as an example. That is not a typo! I'm not writing AT* to include ATX, I'm specifically writing AT exclusive of ATX. There are many many motherboard standards out there. A small handful include XT, AT, Baby AT, ATX, BTX, and LPX. Wikipedia compares some of the more well known form factors. It is a good launching point to learning the more common form factors you're likely to encounter.

[Jack Burton]

You could just mount this switch and when you power on your cab simply rock it back and forth once for turning it on, and again for turning it off.  That is, if you only care about the cosmetic function of the switch.

[Zebidee]

Thanks SL!  That was a fantastic explanation! I appreciate you taking the time to educate me about the sleep-state power-on issue.  I haven't encountered an ATX MB like that yet. 

Looks like Javery has a bunch of good options to choose from.