How can I light my Computer Power On Button

[mccoy178]

Big news for me.  I received my power on button from Ponyboy, and I really like the looks of it.  The Block O is about an inch and a half deep, so hitting the button would take some work while playing.  I have included some pics and have a question:

While the machine is off, how can I get that triangle to slowly flash, and when on, stay fully lit like now?  I want to make it impossible to not at least wonder what that mysterious triangle does!  I am using the smart strip, but I could use the usb power couldn't I?  The pulsating is the bigger question.  Thanks for the advice in advance.

[Pik4chu]

should I assume you have an ATX motherboard in there? if so its relatively simple


you take this circuit http://www.satcure-focus.com/tutor/page11.htm

this will give you a flashing LED, or find a simiular one of the appropriate speed you want. best if it runs off 3-5 volts. Now. ATX motherboards(connectors) have what is called 'standby power' where there is one pin that provides power even if the computer is off (for various reasons) This will be pin #9. the only purple cable on the molex connector.

[mccoy178]

Now that is a wonderful answer!   I will check into this over the weekend and post my results.  Thank you very much for the work.  We'll have to see how the soldering goes.

[coinguy]

I'd like to add to the circuit.  Pin 4 of the timer IC is a reset and
if you connect a 2N2222A transistor you can hold the timer IC in
reset when power is on.   Connect emitter to gnd.
 Connect pin 4 instead to the collector pin.  Connect a 4.7K resistor
to the collector and +5 always on voltage. Connect a 10K resistor
to the base pin and the +5 voltage what goes to motherboard.

The LED will flash when motherboard is off and stay on when
powered up.

[Pik4chu]

I'd like to add to the circuit.

[coinguy]

In the example circuit changing the values of R2 and R1 will change
the on/off ratio and collectively the rate.  You can play with
these values to get even on/off or quick on/ long off or what ever
you like.

A larger calue of C1 will slow the flashes and a smaller will quicken.

BTW: at 5V you will need a resistor in series with the LED start
with 1K or the LED will draw too much current and burn out.