Off light?

[cruzcr]

i'm about to begin my first mod which will involve building a cheapo web browsing computer into my desk. The drawer im using is very tiny, and i need the front for 2 intake fans. my plan is to fabricate a small matching wooden box or palette to hold all my buttons, switches, and LEDS, having them integrated into the desk. i was wondering if there was a way to wire toggle switches(ones with LEDS or using separately wired LEDS) so that the light is visible when the switch is off. Essentially, an off light so i can find it in the dark.

My understanding is limited, but are the only ways to achieve this either using the ground from the psu or an external powersource(be it wall wart or 9v)? or is there some other possible method. I could also use a diagram of sorts if anyone knows of or can draw one up cause i dont understand where the off led could connect in the slightest.

thank you in advance.

[halcyonforever]

this can definately be done
either with a relay or a lighted switch wired to the 12v rail

[Crazy Buddhist]

The 12v rail will be dead when the power is off so that won't do. Will need an external p/s (small battery?) but the circuit will be fairly simple for the electronics chappies to explain.

CB

[halcyonforever]

ok, so maybe my terminology is wrong, but isn't there a live wire from the power-supply all the time. It's what operates the circuit for the powerbutton.

[SgtM]

Isn't the 5v rail on USB always powered? It would be real simple to hack up a USB cable.

[crazybillybob]

The Purple wire coming from the PSU always has 5Vdc on it even when the pc is powered down. So if you tap that wire you'll have a constant 5Vdc supply. The down side is that most of the switches your talking about need 12DC to light up (as they are designed to be used in Automobiles). I'm sure with a little looking you can find one that works with 5Vdc (like the type that take an external resistor to set the voltage). The USB is a good Idea but many mobo manufactures shut down the 5Vdc line on the USB ports when the mobo is in the power off state (unless wake on mouse is enabled).

Good luck!

CrazyBillyBob

[nevermind1534]

On my motherboard, when I have the + for the LED connected to the - on the motherboard and the - connected to the +, the light is on when the computer's off, and not when it's on, assuming that you don't shut off the power to it.

[xmastree]

Try putting the LED directly across the power switch pins. There must be something there or the witch wouldn't work. When you press the switch, it will short out the LED and bring on the computer.
Worst case is either there's not enough current to light the LED or the LED draws enough to tun on the PC.

So, with the computer off, connect the LED to the pins and see what happens. If it lights up without turning the PC on, then it'll work. (If it doesn't light, try it the other way round)

[nevermind1534]

I looked and confirmed what I said in my previous post, that you can wire it the opposite way and it will give you a no-power led. This was pretty much made with the people with the 2 color LED's in mind.

[DonT-FeaR]

night light type thing that plugs somewhere....?

change it to just 1 or 2 leds ?

trying to help