Can I have two HDD activity lights on the same circuit?

Associate
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Hi all sorry not been on a while illness got the better of me.
I’ve searched all over for this info. Most want to remove the lights and I want to add another

My plan is to have two hard drive activity lights on the same circuit powered by the motherboard (msi z97s krait edition) which then feed into some acrylic tubes which will then light up as the light passes through it.

Can I run two orange 5mm single bulb led’s and run in either series or parallel (open to suggestion) and power them both from the usual motherboard connection to flash when active.

Do I need a resistor or will the bulbs have them built in these days.
Any suggestions will help me please.
Many thanks
 
Man of Honour
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LEDs won't normally have a built in resistor (they are also polarity sensitive) - IIRC the HDD activity connector on most motherboards is 5v with a 330Ohm current limiting resistor built in and generally OK for about 20ma draw but I'm not 100% on that.

For advanced use beyond just the normal chassis LED it would be better to connect the output of the front panel connector to a transistor or optorelay and use that to drive the output of whatever illumination which sourced its power from another output.

If you want to power 2 LEDs I'd start with a 10K resistor on each and wire them in parallel then adjust the resistors up or down from there until you get the level of brightness you want.
 
Associate
OP
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LEDs won't normally have a built in resistor (they are also polarity sensitive) - IIRC the HDD activity connector on most motherboards is 5v with a 330Ohm current limiting resistor built in and generally OK for about 20ma draw but I'm not 100% on that.

For advanced use beyond just the normal chassis LED it would be better to connect the output of the front panel connector to a transistor or optorelay and use that to drive the output of whatever illumination which sourced its power from another output.

If you want to power 2 LEDs I'd start with a 10K resistor on each and wire them in parallel then adjust the resistors up or down from there until you get the level of brightness you want.
Thank you pal that is all the info I needed there, it’s been a nightmare finding similar info online.

The purpose was to have two acrylic rods light up orange and work as the HDD light would. It may be simpler to just do the one or not as an HDD light.
Can’t for the life of me find someone who supplies a pre wired orange hard drive light now. But il be able to put one together.
Many thanks
 
Soldato
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LEDs in series would need increased source voltage to draw any current, which is very likely impossible to get directly.
While two in parallel would need increased current.
Like said mobo likely has fixed resistor in parallel, which would make LEDs dimmer if using two in parallel.
Though there are differences in amount of current needed by LEDs and likely not just from light output but also from efficiency differences.
So using some low current LEDs it might be possible have two in parallel.
But would better to use some "buffer" or what ever you want to call it circuitry using mobo's HDD LED header only as controlling input.

Once did voltage measurements from mobo connector for small circuit connected also to HW RAID card's outputs.
(feeding comparator configured opamps)
IIRC that board had controlling transistor on ground side.
 
Man of Honour
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LEDs in series would need increased source voltage to draw any current, which is very likely impossible to get directly.
While two in parallel would need increased current.
Like said mobo likely has fixed resistor in parallel, which would make LEDs dimmer if using two in parallel.

Series also potentially reduces the number of parts required but can be a little more complicated for troubleshooting for someone with basic electronics experience.

It would be far better to use the header as the controlling input to something else but that does increase complexity significantly for anyone not familiar with electronics.
 
Associate
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Just buy an HDD led y-splitter cable and plug 2 normal HDD led cables into it and see what happens. The motherboard will likely be able to supply sufficient current to power the 2 leds. LED’s take minimal current to light up. A basic orange led will draw in the region of 20-40mA … not a lot.
 
Associate
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Always mused a the idea of using the HDD led signal to control a strobe, to get a case lightning or disco effect.
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Man of Honour
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83,147
Just buy an HDD led y-splitter cable and plug 2 normal HDD led cables into it and see what happens. The motherboard will likely be able to supply sufficient current to power the 2 leds. LED’s take minimal current to light up. A basic orange led will draw in the region of 20-40mA … not a lot.

Even fairly bright, in terms of indicator rather than illumination level, LEDs can be as little as 2-3mA - in theory the headers should be able to supply way more than a couple of LEDs need but I'm a little cautious as I've encountered boards before where they've been specced up with the cheapest parts which will do the bare minimum.
 
Associate
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Or buy 2 of these


And splice together into a 2 pin panel connector and be done. At 60p each, what’s to lose?

I know it’s linking a competitor but I’ve searched ocuk and can’t see and equivalent product.
 
Soldato
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If you want to power 2 LEDs I'd start with a 10K resistor on each and wire them in parallel then adjust the resistors up or down from there until you get the level of brightness you want.
I've done that with the power led on my case, I added a few resistors to dim the led a bit.
 
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