Add LED's to Your Computer Fans




About: I love to build things. My love affair with destructing, constructing and reconstructing stuff began when I was very young. When I got a new toy the first thing I did was take it apart to find out how it wor...

Like those fans with lights in them? Today I'm going to show you how simple it is to add LED lighting to your fans.  This will be short because it is a really easy project.  Take a look at your fan.  You may be surprised to find that there are already holes for LED's.  That's because the manufactures use the same shrouds for the lighted and non-lighted fans.  That holds down their cost since the factory only has to make one production run of shrouds instead of two.  Another place this is obvious is in printed circuit boards.  Take a look at a few and notice all the empty holes.  Look inside the front of the DVD, there are lots of empty holes in the pcb.  I always wondered what features I was missing in those spots?!  Anyway, if you don't have holes in the shroud already, you can simply drill some, just make sure your LED's will not hit the blade of the fan.

Step 1: Parts and Tools

This is a very simple project and should only take you an hour or so.  All you need is a soldering iron, solder, clip-on heat sink (for the LED's), four LED's, two resistors, wire and some hot glue. Oh yes, of course, a fan to light!

Step 2: Wiring the LED's

The wiring,is simple and strait forward, it is a series-parallel configuration. Wire two LED's and a resistor is series the wire them together in parallel. Look at the wiring diagram to see how this works. The LED's are rated at 3..3v -3.8v 20ma. each. The resistors are 1/8 watt 220 ohm. You resistor size will depend on several things, Input voltage, LED's voltage and the mA requirements, and the number of LED's you want to use. You can figure this out mathematically a formula like this:
Wikipedia quote:

Resistance in ohms(R) = ([power supply voltage(Vs) - LED voltage drop(Vf))
                                                         LED current rating(If)

* Power supply voltage (Vs) is the voltage of the power supply e.g. a 9 volt battery.
* LED voltage drop (Vf) is the voltage drop across the LED (typically about 1.8 - 3.3 volts; this varies by the color of the LED) 1.8 volts for red and its gets higher as the spectrum increases to 3.3 volts for blue.
* LED current rating (If) is the manufacturer rating of the LED (usually given in milliamperes such as 20 mA)


or you can simply do a search for "LED calculator" and pick one.  Orrrrr you can use Led Calculator from The last picture shows how I routed the wires around the outside of the fan shroud.

Step 3: Testing the Connections

I always like to test things as I go along to make sure everything works before I button it all up.  After wiring the first set hook the wires to your power supply and make sure they light. If so your ready to wire the second set.  Check once more, to make sure all four light, then place the LED's in the holes on the shroud.  Now it's time to get out the hot glue.  Put just a dab over the back of the LCD's to hold them in.  Also secure the wires along the outside of the shroud with a couple dabs to hold them in place.

Step 4: Ready to Install

To finish off your fan, and to make it custom, use some cable sleeving on the power wires, some shrink wrap to cover the wire channel and your own custom lable for the center.   My personal fan was mounted under the top window I put in my case.  I cut my window with a scroll saw and gave it some dimension.  If you want to know how I achieved this affect just leave me some comments and I'll post an Instructible on how to do it.

Hope you all find this useful and thanks for lQQking!



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    14 Discussions


    3 years ago on Introduction

    Nice one...if the fan with led light is 5V and runs easily with 5V power source. Can i connect extra 1 single red led light of 5V ? will 5V power be enough run all ? ...


    6 years ago on Step 4

    Wow! Awesome Instructable! I'm going to try this right now!


    8 years ago on Introduction

    Your title says LCD's but these are LED's, just letting you know because I was wondering how (and possibly why) you were going to put an LCD screen into a fan.

    3 replies

    8 years ago on Introduction

    awesome! this is a instructable every diy pc modder should have a look at. im using 2 green leds, a red and a yellow. the average is 2.4v, so using the led claculator, it said a 120 ohm(i think) resistor. (it was brown red brown gold) i ended wiring the leds like in the picture, since thats how i wired them in the first place. or instead of all that do i just use 5 volts?

    5 replies

    It really depends on how you wire the LED's, in series or parallel. You don't show what you've done with the 12v Neg. If you wire them using the configuration above you should not have any problems. I use 12v CCFL's so I just used the same voltage for the LED's. I think your better off using 12v, especially with 4 LED's. Just my opinion.

    the -12v is just connected the same way the +12v is, i was wondering, do i still need the resistor? or is it okay on 12v?

    alright! i'll go to "the source" once i get back into the city. also, i painted the fan blades gun metal, it looks really awesome! i will post pics once i get the resistors