Constant Live From PSU?

[TrentLane2k]

Evening,

I was wondering if anyone could point me in the correct direction. I have a RF board which I want to use to controll the on / off switch of my computer. My problem is finding a point that provides 12v constantly (ie even when off).

At first I took 12v from a sata power cable and instantly realised that was stupid, it powered the board but only when the PC was on (obviously). So I could turn the PC off but not on.

I then had an idea of taking it from the 24 pin connector, assuming this was constanly live. Seems that I was wrong, I spliced the +12v and a ground but had the same issue, I could turn the PC off but no power was getting to the board when off.

There has to be somewhere that supplies a constant 12v, can someone point me in the right direction?

My PC will only accept WOL when asleep and I don't like using sleep mode hence the wanting to use an RF board.

 

[the nerd 389]

First of all, the only rail that's always on in an ATX PSU is the PS_on pin at +5V. Using this pin will cause your PSU to turn on, and there is no documentation that I'm aware of that says the motherboard will be safe if you turn it on this way.

The other option is to use a rechargeable battery (LiFePO4) that charges when the PSU is on, and provides power to the RF board when off. RF boards should be available that can last years on a very small battery.

 

[TrentLane2k]

First of all, the only rail that's always on in an ATX PSU is the PS_on pin at +5V. Using this pin will cause your PSU to turn on, and there is no documentation that I'm aware of that says the motherboard will be safe if you turn it on this way.

The other option is to use a rechargeable battery (LiFePO4) that charges when the PSU is on, and provides power to the RF board when off. RF boards should be available that can last years on a very small battery.

Thanks for that, makes perfect sence.

With my ignorance of batteries could you provide a link to one?

 

[the nerd 389]

The specific battery will depend on the particular board you intend to use. You'll also need a charging circuit, but those are fairly common.

If you know what board you want to use, I can see if I know where to get the appropriate battery and charger.