DIY PC Fan Controller

This instructable should help you build a simple 3 speed fan controller for any 12v dc computer fan. I couldn't find a decent tutorial on fan controllers so i've made this simple one. This is my first Instructable so I hope it's alright :)
Please comment

I can't be held responsible if you break stuff, i have tried to describe things as thouroghly as possible but if stuff breaks it's your fault not mine . None of my stuff broke

The 3 speeds will be off, half speed and full speed
Being able to turn case fans off helps you keep your computer quiet when you don't require the extra cooling, the two fan speeds allow you to turn the fans up when necessary and dow to keep the system quiet while still cooling

You will need:

DC fans - I used 2 i bought on Ebay for about £1.50 each from China, they came with 2 wires for power(+/-) Not PWM 3 pin/wire type and a molex plug so they would run at 12v constantly (Loud)
I don't reccommend LED fans, mine were LED and the change in voltage from changing the speed makes them go dim, not a massive issue but you might not want that
An On/Off Switch
A SPDT switch (3 pins underneath on/on)
Some bits of wire
Soldering iron and solder
Electrical tape or Heat shrink
A computer or computer powersupply to give the fans power
Maybe a screwdriver to open your PC case

Step 1 Chop Chop Chop

First Chop the molex plug off the end of the fan wires,get as close as you can as it will give you more wire to work with later.

So then you should have a fan with a red wire and a black wire coming out and nothing on the end of them.

My fans had pass through molex connectors so you can connect several fans using only one molex outlet on your PSU, if yours does also then clip the end off like in the picture, you want as much wire as possible on the end we're keeping to make soldering easier

Comments

[cool4875]

nice work.... ive done something same but haven't used the 5 volt rails... just running the fans on 12 volt rails.. plus have mounted them on an acrylic sheet.. i also have added some leds... but am not able to power them up without blowing them :(

[cool4875]

here is an image :D its kept upsite down though :P

[g199]

If your LEDs are blowing use a rail with less voltage and/or use a resistor, i hope that sorts your problem :)

[cool4875]

ya i know i need to use resistors.. but idk what rating resistor to use for a particular led... i currently have 10 of each red, green, blue and white....

[g199]

you can work it out quite easily, just google "led resistor calculator", you'll need to know the voltage rating of the LEDs you're using, if you don't know what they're rated to then assume it's 3V, if they're really dim with 3V try 5V, if 12V is blowing them then they probably aren't 12V or above

[cool4875]

hey i got the blue and white leds to work on the 5volt rails :D

[g199]

Looks good, nice work :)

[cool4875]

ty man will do that for sure... btw m using the 5 volt rail for the led :)

[zazenergy]

Interesting. Thanks for sharing!