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Relay Switch For 5vSB?

F

FireDemon

Limp Gawd
Joined
Feb 10, 2006
Messages
256
OK guys I could really use some help here.

What I have for my porject is to make the two front intake fans change color when the PC goes into standby (S3). I have already rewired the fans, thrown on the red led's, and sleeved everything accordingly.

My motherboard PWR_LED header has the ability for a dual color LED, but obviously does not supply sufficient amperage for 8 LED's. What I plan here is to run the hot line for the red LED's directly from the 5vSB rail on the power supply. But the ATX power supply still gives off this voltage when the PC is powered on.

What I was wondering is this: Is it possible to create a relay switch which can tell when the PC is powered on and powered off. When the PC is powered on, it breaks the circuit thus not giving any power to the red LED's and the fans stay blue. When it senses the lights go out it bridges power from the 5vSB and presto the fans change color to red.

So can it be done?
 
Hardly 10mA. Try either 2.5A or 3A. 2.5A is the ATX standard while several PSU manufacturers have moved to 3A. If you doubt it look at your PSU label.
 
Uhhh yeah I was about to say WTF components that still spin in my PC and light up off the 5vSB use WAY more than 10ma.

So, back on subject. These LED's take about 20ma a piece. Do you guys know of any good guides for building relays? I have a 5VDC relay sitting not 20 feet from me.
 
I dont mess with standby or sleep so I have to assume some things. If I am wrong just correct me and we can take another crack at it.

Assume the +12 ( or +5) becomes inactive when in standby.
Assume SPDT single pole double throw relay

power the coil of a 12V (or 5V) relay with +12 (+5) from a molex connector.

run a wire from the 5V standby power to the relays NC (normally closed /connected contact)

run wire from the other side of the relays NC contact to the leds.






computer on, relay energized NC contact is OPEN no current flows - no red leds.

computer SB, +12 drops, relay de-energizes, NC contacts CLOSE and standby power is sent to the leds Red Leds .

if this is feasible you need to consider a dropping resistor depending on the LEDs and a diode across the coil to prevent emf spike being sent back into your +12.
 
BTW I did a bit of research.

My current Raidmax Volcano outputs a maximum of 2.5A on the 5VSB rail. However, my 1000w enermax galaxy I have stashed in the closet and will be plugging up in just one months time is more than doubled at a whopping 6A.

Maybe that last guy was thinking of the minimum 5VSB current, which is typically .1A
 
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