How to dim a power LED

Phil2008 said:

The fan controller on the case uses a sata power connection for its power. on the switch at the rear of the case it says "7v, off, 12v"

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As OK, cheers.

Still think it might be an option to use it as I assume you would slow the fans down at night if it's a bedroom and this would also dim the light.

Seems like if you got a fan splitter or extension you could cut away the plastic and you would have the pins right there to plug the led into

A bit of card will due surely ?

Finners said:

As OK, cheers.

Still think it might be an option to use it as I assume you would slow the fans down at night if it's a bedroom and this would also dim the light.

Seems like if you got a fan splitter or extension you could cut away the plastic and you would have the pins right there to plug the led into

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Ummm so instead of connecting it to the motherboard, just connect it directly to the fan controller, I thought the motherboard sends about 5volts to the power LED?

Phil2008 said:

Ummm so instead of connecting it to the motherboard, just connect it directly to the fan controller, I thought the motherboard sends about 5volts to the power LED?

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It'll be 5v or 3.3v but will certainly not be 12v. If I were at home I'd poke in my PC case to be sure but I'm not.

Connecting to a fan controller will only be an option if you then had some active electronics to switch on the led when the circuit is active. Far too complicated.

I received the resistors this morning and I am going to have a play this afternoon. Im guessing they can be connected anyway?

Ok, Ive had a play, and I have put 4 resistors on but still not dim enough, so I have ordered 10k resistors now, instead of putting loads of 1k resistors on. So hopefully 1 10k will be dim enough

Could stick a variable resistor or a 50K potentiometer or something then you can dial it in for what you want.

Not sure what the setup is but as an aside if the LED is powered off a higher voltage and doesn't have some resistance in there - a pot should be wired with a 200-1000 ohm resistor in series so it doesn't blow the LED when wide open - probably not the case here.

I'm assuming you connected your 1k resistors in series?

A led in the 2-5mA should be fairly dim, maybe you need really dim, an indicator sort of thing. 10k may go too far but you can always parallel them if that's the case.

Rroff said:

Could stick a variable resistor or a 50K potentiometer or something then you can dial it in for what you want..

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I was thinking of one of those or a light sensor one, so as it gets dark the LED gets dimmer,, but that's getting a tad complicated isnt it?

Tealc said:

I'm assuming you connected your 1k resistors in series?

A led in the 2-5mA should be fairly dim, maybe you need really dim, an indicator sort of thing. 10k may go too far but you can always parallel them if that's the case.

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Yeah I connected them together in a line, so the volts goes through each one separately.

I thought the LED was going to be dimmed like 50%, but I only saw a slight difference in brightness when putting the 2nd 1k resistor on?

Im I rightly thinking that a LED will only dim so far and then goes off? If thats the case the 10k might be too much, but as you say, I can always put another one on it in parallel. So 2 10k's in parallel will be 5k, correct?

Received the 10k resistors today, I was expecting the LEDs to not light up,, but amazing the Leds still were fairly bright, so I have put 3 resistors on and at last its fairly dim, but might be too dim now. I'll see how bright things get tonight, and I might remove one of them.

But can you believe it 30k to make the LEDs go really dim? I have seen vids on youtube and in all cases you cant see any light from the LED with a 10k resistor, and Im using 30k and you can still see the light well.

I have taped the metal strands with installation tape and left the resistors showing. Thats ok isnt it, nothing will set on fire or anything stupid like that?

Ummmm, might be a bit too dim now, I think I will remove a resistor tomorrow and see what that does. I dont know why its come up as purple in the camera shot, because its blue.

Looks fine to me, the dimness that is.

As long as no metal is touching other metal then you'll be fine. You shouldn't need to leave the resistors uninsulated though as at 20 or 30k they'll not be dissipating much heat.

Thanks Tealc, I have cut the metal strands shorter and taped it all up with installation tape including the resistor....After a few days of playing, I have only got one 10k resistor on. Its just about bright enough in the daytime and I can only just see it shining on the wall at night and doesn't light the room up.

So thanks everyone for helping me solve this problem, Id say its about 50-75% dimmer with the one 10k, it still slightly lights up the reset button though. The hdd led lights up the reset button, but that can be left disconnected.

Job well done, that looked crazy bright before.

Nick1881 said:

Job well done, that looked crazy bright before.

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Thanks,,, it kind of ruins the effect at full brightness, as the light is only suppose to light up the ring around the power button, but it completely covers the button with the light at full brightness, plus the light shines through the usb ports, reset button(still does with the light dimmed) and audio ports. The finer details on the case are not that great.