How to dim a power LED

Phil2008 · 7 Sep 2016 at 20:37

I have the Cooltek W2 case and I haven't got the power LED connected at the moment but I would like it connected. But with it being in my bedroom and having the pc on a lot when Im sleeping, the LED is just too bright.

I had one idea, would a 7V Voltage Reduction fan cable make the LED any dimmer?

Phil2008 · 7 Sep 2016 at 22:49

.Ox. said:
I bought some 'LightDims' for my room. Little stick on dots which go over LED's and come in different sizes. They do different colours, and have ones which block out 80% of the light or completely opaque. £5 from the rainforest, bit much for what it is, but i couldn't be bothered to mess about.

I'm using the 80% ones and they're awesome.

That might be hard to do with my case because the LED shines around the power button, so I would need it stuck onto the LED. I haven't even bothered connecting mine up at all yet, because from pics in reviews the LED lights everything up, not just the power button......

Phil2008 · 8 Sep 2016 at 12:30

I have just looked and theres 1 LED either side of the power button, no wonder its so bright. So Im thinking I will have to use a resistor, but what am I buying as this is unknown territory now? I see I can buy like 50 or so for a few ££s on the bay, so Im guessing I want a pack that goes up in stages, but no idea?....

http://www.ebay.co.uk/sch/i.html?_f...TRC1.A0.H1.Xresi.TRS0&_nkw=resistors&_sacat=0

Phil2008 · 8 Sep 2016 at 14:19

So Im guessing 1k is 1000 and the higher the number the higher the resistance?

Phil2008 · 8 Sep 2016 at 14:34

So I will order the 1k ones and then you guys can let me know what resistor I need depending on the brightness the 1k gives out.

I am guessing its ok to cut the metal wires to make them shorter?

Phil2008 · 8 Sep 2016 at 14:42

ok I bought "Carbon Film Resistors 1/4W 0.25W" 1k Ohm. pack of 20.. Are these correct? http://www.ebay.co.uk/itm/152059712...49&var=451259792618&ssPageName=STRK:MEBIDX:IT

Phil2008 · 8 Sep 2016 at 15:13

Tealc said:
If you buy 1k, a pack of 100 for £1 then if they are too bright with 1 you can put 2 in series for 2k, if they are too dim with 1 then you can put 2 in parallel for 500ohm, or multiples.

So if I connect the resistors on the + lead, it will dim the LED's and if I put them on the - lead it will brighten then LED's. Is that what you mean by saying "series" and "parallel"? Sorry this is all new to me.

Phil2008 · 8 Sep 2016 at 15:47

Tealc said:
No. When I say putting in series and parallel I mean with each other not as to create a new load.

Start by breaking the wire, any will do. Then strip both ends and put one resistor and attach a stripped end to each leg of the resistor. Now the current must pass through the resistor before it gets to your LEDs.

If the LEDs are too dim then get another resistor and sit it on top of the first and attach it by twisting legs over the first. The current is now shared across two resistors and the resistance is lower, therefore a brighter led results.

For a dimmer led you'd have two resistors in a row so the current must pass first through one resistor and then the other. This doubles the resistance and makes the led dimmer. Technically you could out them anywhere in the circuit and break multiple points but that's just messy.

Hope that helps.

Yeah that makes sense, thanks.

Finners said:
Are you using the built in fan controller? If not you have a nice switchable 5v power right there and waiting. Would give you the option of 5v/12v or off

I am using the fan controller and its 7volt and 12volt, but I have got a 7V Voltage Reduction fan cable that I could try?

Phil2008 · 8 Sep 2016 at 16:19

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"

Phil2008 · 8 Sep 2016 at 18:58

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

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 · 12 Sep 2016 at 13:50

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

Phil2008 · 12 Sep 2016 at 17:24

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

Phil2008 · 12 Sep 2016 at 21:29

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

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.

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?

Phil2008 · 15 Sep 2016 at 16:51

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?

Phil2008 · 15 Sep 2016 at 20:49

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.

Phil2008 · 19 Sep 2016 at 01:59

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.

Phil2008 · 19 Sep 2016 at 21:21

Nick1881 said:
Job well done, that looked crazy bright before.

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.