PC Off, Lights On

[reddog418]

I wanted to make a slight mod using a keyswitch. When the keyswitch is turned in the number 2 position (ARMED), I wanted a little red light to shine. The keyswitch allows the powerswitch to be used, and thus the PC can be turned on. What's a way to get the light to turn on without the PC being on? A battery? Or is there a way to get juice from somewhere else?

[Frakk]

battery would be the easiest way. if you turn the psu on, it will turn on the rest of the machine, not to mention you can only turn it on through the 20pin atx powerline which needs to be connected to the mobo.

[Xato]

You could probly rig up a little rechargeable battery... and have it so when the comps on it charges teh batt and powers the light, and when the comps off, the battery can use the new juice it got from the charging... tho i dont know how hard this would be technically, as far as getting the electronics right goes.

[reddog418]

There isn't a lead off the PSU that's always on? there has to be... *grabs his multimeter...*

*Realizes he doesn't remember where it is...*

*Decides to wait for answer...*

[Xato]

There may be, if so its probly in that 20pin ATX connecter.

[reddog418]

I found my multimeter and I found a lead where the power switch, reset switch goes, and it's unused by any of them. It provides a decent 3v and should work fine. Now, however, I've run into another problem. Depending on which position the keyswitch is in, I want either a greed or red light on. Is this possible with a keyswitch? What else might I need to do this?

[reddog418]

Okay, here's what I want to do. When the keyswitch is in position 1, I want the green light to be on. When the switch is in position 2, I want the red light to be on, and the green light off.

Turning the keyswitch into position 2 completes the circuit for the red light.

How might I achieve this?

[Xato]

This way (see below) would work... but it would be easy enough to do it with transistors... which would be much easier and safer, if you know how to use them.

I think my diagram is relatatively the same as your's... but eitherway, using the normal powerlight as the green and adding the red light as the off should work.
Having the common negative will ensure that it is the right voltage.. if necessary...

[Frakk]

i would recomend a 2 color LED. they have 3 pins, one for ground and the other two for each color. now, depending on the key position, it will short out the required pin to give you the effect you want. nice and easy.

[ZeD]

I think the purple line on an an ATX cable is a 3.3v standby always on meant for WOL and stuff

BTW where ya getting your keyswitches?