Is 12v available when pc is powered down?

Access

I have an old dell optiplex gx620 as a HTPC at the moment and need to find a 12v supply while the pc is powered down from the psu.

I need it for a infared to relay board that i will be using to turn the pc on/off by the htpcs remote control.

I know there is obviously a few volts running all the time in the pc waiting for a physical press of the front power button to power on, but would there by a constant 12v coming from the psu while the pc is powered down and how would i identify what cables supply the 12v.

Thanks.

ZENER

The only rail with voltage present while powered off is Pin 9 which is usually a purple cable on the 24 pin ATX2.2 standard connector. This will have a 5VDC standby supply.

Ken

Access

ZENER wrote: »

The only rail with voltage present while powered off is Pin 9 which is usually a purple cable on the 24 pin ATX2.2 standard connector. This will have a 5VDC standby supply.

Ken

Thanks for the info... Might have to get a relay board that runs on 5 volt so.

Might be a silly question, but if its the purple cable that has 5vdc what colour cable it the negative? Thanks

ZENER

0 volts would be any of the blacks.

Ken

Chet T16

You can get 5v -> 12v boost modules on ebay although relays are pretty current hungry and the standby 5v supply might not be able to deliver much.

What is the relay doing? there might be a better/lower power option

Hitchens

you could use a seperate pc psu for this?

Access

Chet T16 wrote: »

You can get 5v -> 12v boost modules on ebay although relays are pretty current hungry and the standby 5v supply might not be able to deliver much.

What is the relay doing? there might be a better/lower power option

Cheers chet... just the man who could solve this...

(im still to read your page on the tablet heating interface - i have it bookmarked to study it!)

Anyway, the relay board is for this project... i was hoping not to need to add a separate 12vdc power supply for the relay board and was hoping that the pc psu could supply 12vdc when powered down.

http://www.boards.ie/vbulletin/showthread.php?t=2057073388

and here is the infrared learning relay board im going to use...

http://www.ebay.ie/itm/Learn-Botton-Infrared-Switch-Remote-Control-5-Relay-KIT-/130419219120?pt=Home_Automation_Controls_Touchscreens&hash=item1e5d975ab0

Its basically so i can turn on my HTPC by remote control (the board will learn the infra-red signal from a designated button on my HTPC remote that i choose).

I have the HTPC in under the tv on the stand at the moment, but my plan is to eventually place it up in the attic and extend the relay boards infra-red receiver via spare cat 6 cable (using only three wires as thats all it needs) and have the infra-red receiver mounted next to the tv. (long 20m hdmi cable will be between attic and tv too).

It looks like i might have to have a separate 12vdc supply from a wall plug into the relay board like Hitchens was saying.

What do you think?

ZENER

What about wake-on-LAN ? Couldn't that wake it up for you then providing the 12v you need? There are several wifi remote control systems that could do this from a smart phone. The NIC connected to your LAN switch could wake it.

There's also wake on USB ! http://www.yoctopuce.com/EN/article/how-to-turn-on-a-computer-remotely

Ken

Chet T16

Access wrote: »

Cheers chet... just the man who could solve this...

(im still to read your page on the tablet heating interface - i have it bookmarked to study it!)

Anyway, the relay board is for this project... i was hoping not to need to add a separate 12vdc power supply for the relay board and was hoping that the pc psu could supply 12vdc when powered down.

http://www.boards.ie/vbulletin/showthread.php?t=2057073388

and here is the infrared learning relay board im going to use...

http://www.ebay.ie/itm/Learn-Botton-Infrared-Switch-Remote-Control-5-Relay-KIT-/130419219120?pt=Home_Automation_Controls_Touchscreens&hash=item1e5d975ab0

Its basically so i can turn on my HTPC by remote control (the board will learn the infra-red signal from a designated button on my HTPC remote that i choose).

I have the HTPC in under the tv on the stand at the moment, but my plan is to eventually place it up in the attic and extend the relay boards infra-red receiver via spare cat 6 cable (using only three wires as thats all it needs) and have the infra-red receiver mounted next to the tv. (long 20m hdmi cable will be between attic and tv too).

It looks like i might have to have a separate 12vdc supply from a wall plug into the relay board like Hitchens was saying.

What do you think?

To simulate a button press you can use a transistor with the collector and emitter across the button. You could drive that directly from a microcontroller. I would need to check but i reckon I can get an 8 pin attiny ic to do what you need it to do

Access

ZENER wrote: »

What about wake-on-LAN ? Couldn't that wake it up for you then providing the 12v you need? There are several wifi remote control systems that could do this from a smart phone. The NIC connected to your LAN switch could wake it.

There's also wake on USB ! http://www.yoctopuce.com/EN/article/how-to-turn-on-a-computer-remotely

Ken

Im trying to keep it as wife and kid friendly as possible so hence my requirement to have it power up from it by remote control.

I do use my android phone as a control for it, but with my kids my phone would be smashed within seconds if i left it around as a remote for the HTPC.

I use the VRC-1100 remote - which is a cheapy €14 remote that can be replaced if it is broken/dropped easily. And there is a couple of buttons on top, one of which is crying out to be defined as power on/off via something like that infrared learning relay board.



I looked into wake on lan before, but this gx620 doesnt seem to support it as far as i could gather. I think It would also mean the htpc being in sleep mode uses a good bit more electricity (on my gx620 anyways) then if it was off. EDIT: - i dont know if im correct on this.
Dont know if wake on usb would be supported either but i will look into it. EDIT: - the wake on LAN and wake on usb seem to require something along the lines of a tablet or phone to initiate the signal to wake the pc. But in my case, i need to keep it simple (have the solution wife and kid proof) and use the HTPCs infra-red remote which is always there for them to use.

ZENER

The GX620 does do WOL as do most NICs. They also have a history of bad capacitors so be aware of that at some stage down the line.

I'm a bit confused though, you say the RC will trigger this relay board but how does the RC then control XMBC ? Is there a pass through to the USB port on the PC ? Most ATX standard PCs once asleep can be woken by clicking the mouse or hitting a key on the keyboard connected via USB - even in any Linux Distro I've used. What happens when the IR receiver is plugged in to the PC, PC goes to sleep and the RC is pressed, wouldn't that be similar to clicking a mouse or hitting a key ?

Just a thought . . .

Ken

Access

ZENER wrote: »

The GX620 does do WOL as do most NICs. They also have a history of bad capacitors so be aware of that at some stage down the line.

I'm a bit confused though, you say the RC will trigger this relay board but how does the RC then control XMBC ? Is there a pass through to the USB port on the PC ? Most ATX standard PCs once asleep can be woken by clicking the mouse or hitting a key on the keyboard connected via USB - even in any Linux Distro I've used. What happens when the IR receiver is plugged in to the PC, PC goes to sleep and the RC is pressed, wouldn't that be similar to clicking a mouse or hitting a key ?

Just a thought . . .

Ken

That remote i have has a usb ir receiver as pictured above, but what i forgot to say is that i would also be extending that via spare cat cable to tv point too so there will be two ir receivers ay the tv point.

They will be extended about 15 metres from pc to tv point so i dont expect any problems with the cable length.

As for waking the htpc from sleep mode via the remote - which basically executes keyboard and mouse presses, this does work but what i have found is a couple of problems with doing it this way...

Firstly its not always a perfect wake up from sleep mode, sometimes it hangs and needs to be rebooted and sometimes the wifi connection is not re established after wake up.

Secondly, with this pc in sleep mode it seems to be using an almighty amount of watts. Nothing like when its on, but still may more then it would be if it was off completly. I used a plug in watt meter before to check this and i cant remember what exactly it was using in sleep mode but it was high. It would be cheaper in the long run to start it from completely off as this dell is an old power hungry machine, but thats all my budget can afford at the moment.

I will actually test this out tonight and post up what watts it is using running and in sleep mode