Tutorial: Adding multiple LEDs to a basic case fan.

[Tealc]

Tutorial: Adding multiple LEDs to a basic case fan.--New 80mm fan pics.

In this tutorial I will be adding 16 Orange LEDs to a Xilence Red Wing 120mm case fan.

So the fan in question, all basic and boring.

I used several tools, bits and bobs. Some were required, some just to tidy things up.

16x Super Bright Orange 3mm LEDs.
4x 100 ohm resistor 1/4w
Soldering Iron and thin solder.
Scrap wire Thin.
Insulation tape - Black
Hot glue/glue gun (Cheapo off the bay)
12v Power Source
Molex connector and a bit of wire (off an Antec Tri-Cool)
Switch
Drill, 3mm drill bit.
Post-it Yellow
Cable Ties
Heatshrink Black

A few pics of my equipment.

Deciding which Resistor and shape of array.

I always wanted to use Orange LEDs and built my design around this. An Orange LED has a typical voltage of 1.8-2.2v and a current draw of 20mA to 30mA (Max).
I can safely string up to 5 in a line as the max voltage would only be 11v, which is fine in a 12v application. I could possibly do 6 but they might be underbright, only getting a max of 2v each.

Using V = I R transposed to R = V/I because we know Volts and Current and wish to determine resistance.

Our voltage is 12v-(2.2 x 4) because of the 4 LEDs in series. This gives is a required voltage drop of 3.2v.

We know the current is 20-30mA, so I picked 25mA.

Now the formula R=
Gives me R = 128 ohm

I dropped it down to 100, because I had some available and I fancied them just a little bit brighter.

Measuring up and deciding where to put the holes.

My fan is 119mm in diameter and therefore has a circumference of 374mm
I wish to place 16 LEDs so worked out that the pitch between LEDs is 23.375



I drew equally spaced crossed on a post-it so that my holes would be more or less perfect. I made a small hole at the crosses and used a felt tip marker to make a mark on the fan. A hole punch would also work.

[IMG]http://i959.photobucket.com/albums/ae72/Tealc_wii/Sums.jpg

Drilling

I am using 3mm LEDs so chose a 3mm drill. I purposefully offset the angle of the drill by about 15-20 degrees for added effect.

Here's the holes all nicely drilled. I needed to clean up some burrs on the internal side of the fan with my fingernail. Biters, use a knife blade or something

Take note that the holes are not in the dead centre but positioned slightly towards the front face of the fan. The reason for this is that the fan blades do not extend all the way to the back of the fan and using this off centre method gets the LEDs closer to the centre of the fan hub.

Install some LEDs just to see how they fit. Nice.

So now we are ready to start loading in LEDs and soldering up.

I kept the same convention, always placing the LED in with Anode to the left and Cathode to the right. The first LED needed a bend or two on the Anode to receive the positive wire and cut on the Cathode because the leg was too long. The second LED needed both legs cut.

I bent the legs directly out of the housing so at not to encroach upon the surround of the fan too much. Added the next two LEDs, forming the Cathode of the fourth on to receive the future ground wire.

It was particularly happy as the rigidity of the legs allowed me to ensure that the LEDs pointed where I wanted and it also made it much easier to solder them in place.

So easy to solder, just applying some heat to the joint and pushing some solder into the joint. The tight fit of the LEDs in the holes held them in place beautifully.

Then adding the resistor the Anode on LED one.

LED branch removed from fan.

Testing one string of 4 LEDs. Hooking up to my 12v power source and spinning the fan manually.

Adding a bit of hot glue to hold them in place. Some LEDs needed holding away from the fan while the glue cooled. I found the 3mm LEDs just a tad long through this particular frame.

Repeat the same process so that you have 4 individual strings of 4 LEDs on each side of the fan.

Wiring up the common Positive and Ground wires.

We must provide 12v goodness to all resistors so that each string of LEDs can receive the proper amount of voltage.

I used the thinnest insulated wire I could find, some telephone installation wire that I had kicking about. I removed the black and red from the insulation.

Wiring a red wire from the unattached side of the resistor to the one on the next side in a clockwise rotation. I started this at the wire inlet for the fan's standard wiring so that it can be bundled up in the same place. Then repeating the process with a black wire, starting on the negative side to the left of the standard wiring and moving counter clockwise from final cathode to final cathode

Do not join the red back up with itself, only 3 sides needed to be spanned.

Then adding a couple of wires for external power. I run out of thicker red wire so used blue wire. I hot glued the wires onto the fan here as the solder joints aren't particularly strong. A cable tie gathers things.

Wiring in a switch

I can't imagine ever wanting to turn this off but I thought I'd wire in the capability anyway.

Here's my switch. It's a '1 off 2' type switch so one side will be unused. I may use a different switch later. The 12v source is wired to the centre pin, the LED array to the top/bottom post as desired.

Wiring up to a Molex for Power

I could have patched the wires directly into the existing fan wiring after the switch but I like to have separation with things like this, it also allows me to route the cables to a different location if needed.

Donor Molex, a chopped power Molex for an Antec Tri-cool which now runs off my fan controller using a 3 pin fan header.

Soldering the wires to the Molex, with heatshrink on the wires before I join them.

So we are all done.

Looks awesome I think.

The profile of the wiring on top of the fan could short out against a case.

So added some tape to insulate the wiring from my case.

And finally some other pictures.

I'm extremely happy with the way this turned out and feel it is so much better than my first attempt at this type of mod, whether this is due to the increased number of LEDs (16 vs 12) or learned techniques or just that the Red Wing reflects Orange better than a Antec TC Black does. http://i959.photobucket.com/albums/ae72/Tealc_wii/OrangeLEDBlackfan.jpg

 

[Tealc]

Here's a couple of diagrams to visualise the way the wiring is working.

Calculation and considerations for your own array of LEDs.

Very useful website that allows you to plug in your LED values and it outputs a visual representation of your array, along with resistor values you could use. In the case of complicated circuits it'll even give you options.

http://led.linear1.org/led.wiz

Do NOT wire too many LEDs in parallel. This is where a single resistor feeds several branches of LEDs, it puts a big current draw on the resistor and the resistor will fail. Each branch of LEDs needs it's own current limiting resistor. Or buy a heavy duty resistor if you must.

Always wire in series where possible. Make a string of LEDs from a resistor as long as you can while staying under 12v.

LEDs have different operating voltages. Here are some typical values.

Red - 1.8 to 1.9v
Yellow - 1.8 to 2.1v
Orange - 1.8 to 2.2v
Green - 2.8 to 3.2v
Purple - 3.2 to 3.6v
Blue - 3.2 to 3.8v
White - 3.2 to 3.8v

When wiring LEDs in series make sure that when their voltages when added together is less than 12v.

Calculations are done using V = I x R. Volts = Current x Resistance.

Don't forget that LEDs are polarized and will only work one way around. Most LEDs have the Anode (positive side) as the longer leg and the Cathode (negative leg) as the shorter leg. The other way to differentiate is to check the inside of the LED. The smaller element inside the LED is the Anode and the larger element is the Cathode.

Night shots (had to be done)

And a couple of videos showing the fans and other LEDs I've added to the case..

In the daytime..

At night..

 

[Tealc]

Muel -It's not recommended to wire LEDs in parallel like that. You are right though, it would be much easier to have one big resistor at the start to take all 16 LEDs but electronics is never as easy as that. Besides 16 LEDs on a 12v line would only get 0.75v each and wouldn't even light up even with a 0 ohm resistor.

Azza - Good old Volt = Current x Resistance (V = I x R) stuff. We know Voltage and we can get current from the LED spec.

In this example.

V = 12v - (2.2v x 4) = 3.2v
I = 0.020-0.030A
R = ?

3.2v /0.025A = 128 ohm.

I wanted it a little brighter so I chose 100 ohm

I will add this sort of stuff to the second post in due course.

 

[Tealc]

Haven't installed it yet. No side panel window/fan mount either. I will probably install it in the front along with the other one I made with 12LEDs but if it looks odd I will make another to go with it. It only took an hour or so if I take away the photographing time, which was considerable as the camera I have us pants.

 

[Tealc]

I'd probably go for 150 ohm resistors for a Red LED circuit. I think Reds have a forward voltage of 1.9v or so, where my Oranges were up to 2.2v

Check the spec of your chosen LEDs

The common positive and ground is a part of the guide which I had some trouble describing, which wasn't helped by the fact that I didn't take that many photos of that part if the build.

Just think of the commons as two bits of wire that run almost all the way around the fan that provide 12v goodness to each string of 4 LEDs. The positive or red wire will join up the resistor side of each LED series but not touch any other parts. The ground or black wire will join up the negative side of the last LED on each side.

Having a single string of 16 LEDs just wouldn't work so we need to make 4 strings of 4.

There's a wiring diagram in post 2 with the wiring all laid out in a line.

Perhaps I need a fan shaped outline and have the wiring running around that as well. I did think of this but could only locate coloured images or 3D models of fans so didn't bother.

I'm thinking of modding a Noctua fan or two next.

 

[Tealc]

12v -2 -2 -2 -2 = 4v

Current = 0.018A

4 / 0.018 = 222 ohm. ?

The wizard I use gives me 270ohm but I'd come down from that to get better brightness.

You have sourced ultra bright LEDs haven't you? 20mA seems to be customary for ultra heights and I usually go 25mA as they have max if 30mA.


On my iPod so don't have a good way to calculate.

Yes that can be different wires if you wish but you could also bare a section in the insulation, what we used to call a window strip. Tricky to do but neat. You can hook the resistor leg around the window strip and solder in place. Or run 3 bits around all joined together. You don't want to join it back up and form a loop, that would be bad.

 

[Tealc]

Maybe you could copy and paste the spec for me?

You will need to solder. Irons arte cheap as chips on the bay and I'd imagine so is solder. Do some practise solders first. Remember also to tin all legs for best results.

Are we talking Molex or Fan connector? Anyway what I would do is to cut the wires somewhere on the fan's own wires and join in my own wires to form a sort of Y joint. Best place would be close to the fan itself I'd imagine, with less wiring to hide it would be neater. Cover the exposed wires with heatshrink or insulation tape.

 

[Tealc]

I'd go with 200 ohm then. This will drive them to about 22mA which will be fine. 150 ohms would drive them up to 27 mA which might be bad for them.

I'm sure you must have some spare Molex -Molex to fan converter like I have imaged in Post 1 (Image 4).

Just cut the fan connector off (leave a few inches of wire for a possible future use) and join to your LED common wiring.

Make sure you post some pics of your end result.

If you have any more questions feel free.

 

[Tealc]

The Yellow and Black wires in a 4 pin Molex are +12v and Ground, so you could wire to those pins. The Red and Black wires heading to a fan connector are also +12v and Ground.

You don't want to connect to the 5v line on the Molex so just watch for that.

 

[Tealc]

15000mcd? I think that seller might be inflating that figure somewhat. That resistance should be ok I'd imagine.

The first fan I modded was done with 12 LEDs. It looks great but I did find that the middle LED sticks out of the fan a little more and prevented me fitting in the rear fan spot on my case. My second fan was a lot neater though and may have fitted. I haven't even installed the one from this tutorial yet.

Good luck with the Mod. Green is a cool colour for a fan.

 

[Tealc]

You can use any Molex, provided it has the two wires you need.

Here's a selection of options.

Molex to Fan cable.

Molex to PCI-E cable.

Molex to Sata cable.

You don't need to destroy a fan to do this mod.

You must have some spare cables from your PSU, Motherboard, drives?

 

[Tealc]

As long as you didn't intend using them again then it's all good.

I just want to see the end result in green, or whatever colour you decide to do..

 

[Tealc]

So I finally installed the second attempt at doing this to my case. I can't believe I'm so lazy, but anyway.

Top fan is the 16 LED version on the Xilence fan, much neater work. The bottom fan is the 12 LED version done on a Tri-cool, a little haphazard I think.

Day shots, one with filters closed and one open.

Night shots, one with filters closed and one open.

I wish I'd removed the grille of these before I installed the hardware instead of rushing to fit everything the day the case arrived.

 

[Tealc]

Initially I did use the same kind of thing as is pictured in post #31, but as I added more and more led strips, led fans etc to my case I found it was getting a little tricky to squeeze the two molexes and the wires into the case.

So I bought a couple of terminal blocks from the pound shop, wired it up and hot glued it into my case as pictured. The bloody front panel wires get on my nerves, they make them so bloody long that they just get in the way of everything.

I now have 4 spots for wiring anything 12v up, and I can double or even triple up wires to each terminal. I also wired a switch up so I could flick it off for any reason, although I can't see that I would need to.

I didn't take any pictures as I was wiring it up though so this quick schematic may help someone.

 

[Tealc]

So had a message in trust today from schizo3177 asking about 80cm fans and the potential for adding white LEDs to them. He's going to try it himself but seeing as I had a few minutes spare today and a spare never used fan I'd thought I'd give it a quick whirl.

Anyway here's the fan. Xilence 80cm redwing.

I won't bore you with the procedure again but slight changes were made to fit the 80cm size and reduced LED count. I used two 510 ohm resistors in parallel to give me an overall resistance of 255ohm. 12v - (2.3v x 3) = 5.1v to drop at 20mA = 5.1 / 0.02 = 255 ohm. Perfect.

Here's one side lit up. Decided on 3 per side as 4 might have made it too busy.

And all lit up. A gloomy day enhances the colour.

A bit messy but was rushing to get it done before the wife got home with the kids.

And overall shot. Used a two wire old modem lead for the LED power supply, this would just hook right into my 12v terminal block on the rear side of the motherboard.

Makes me wonder how well 4 per side would look, it'd be a bit of a fiddly job to wire up the LEDs due to the cramped space but might work out well enough.

The LEDs seem to stick out the side of this design a great deal and would cause problems if the fan were to be fitted in a restrictive space. Probably will add insulation tape to the sides to protect it from the case.

Also chopped off the Molex and just joined the fan header wires up to make that neater.

Here's a more shots just for fun.

Comments, questions, advice, just ask.

 

[Tealc]

How much was that magnifier contraption you have there mate?

Only 4 LEDs? What resistors did you get for the job?

 

[Tealc]

The resistors were specified based on a 3 per circuit arrangement so wouldn't work so well on 4 wired in series. You could probably just wire the 4 in series without a resistor, or possibly 2 White LEDs per circuit with 2 of the resistors in series (to make 112ohm) for full LED brightness. We were initially talking about 12 LEDs per fan and the 56ohm resistors were specced for that configuration.

Hope that doesn't confuse you.

I use a fire lighter thing I picked up from the pound shop, a cigarrette lighter would be the same. I've also used the soldering iron to radiate heat into the polyolefin shrink but it takes ages to go down.

 

[Tealc]

If you go for 8 on a single 80cm fan you'll have a few choices.

1) 2 sets of 4 LEDs per string.

+ve ------LED------LED-------LED-------LED------ -ve

Each LED would share the 12v and receive 3v each. This may not be desireable as the LEDs I showed were...

Forward Voltage : 3.2v – 3.8v

..and may not achieve full brightness.

So you'd need..

2) 4 sets of 2 LEDs per string.

+ve ----resistor------LED------LED------ -ve

Now each LED is 3.5v typical, so that's 7v total string voltage needed. 12v - 7v = 5v to drop by resistor at 20mA which would require a 250 ohm resistor.

3) Or individually resistor each LED.

12v - 3.5v = 8.5v to dissipate at 20mA. 8.5/0.02 = 425 ohm or nearest standard value.


Or go for 12 LEDs per fan by having 4 strings of 3 LEDs each for the perfect solution given the parts you have purchased.

3.5v x 3 = 10.5v, leaving only 1.5v@20mA to dissipate by resistor. 1.5/0.02 is 75 ohm, so I dropped it to 56 ohm which was a nearby standard value.

And would end up looking something (but better than) like this (quick photoshop colour change)

With resistors you can combine them to make different resistances.

eg.
in series
--resistor---resistor--resistor--
has the effect of adding together. 56 + 56 + 56 = 168ohm.

or in parallel
_/--resistor--\____
..\--resistor--/

which just gets complicated.

 

[Tealc]

Sorry I'm trying to give you all the options.

If you are set on 8 LEDs per 80cm fan then you could combine 4 of your 56ohm resistors to make 224 ohm which is close enough to 250 ohm as laid out above.

You will need to have 4 circuits in total, each with two LEDs and a chain of resistors on it.

Please excuse the crudeity(sp) of this drawing.

So that would need 16 resistors and 8 LEDs per fan.

Or get some 240ohm resistors and keep the 56ohm for a future project and use just 4 per fan.

 

[Tealc]

Or if you fancy 12 LEDs per fan.