DIY fan controller

wozzsta · 4 Jan 2016 at 18:06

Hi guys, i got a NZXT H440 for xmas and 3 extra fans for it. so this thing has a total of 7 case fans plus 1 CPU fan and 2 GFX card fans.

That's a lot of freaking fans!

Now the case has a fan hub so i can just connect all my case fans to that which i have done, however it just sets them all at max speed, and its pretty dam loud not to mention unnecessary.

What i would like to do it be able to control all the case fans at once with a variable resistor.

Something like this.

** No Hotlinking **

https://static.bax-shop.nl/image/pr...Yellow_Parts_potmeter_volume_lineair_500k.jpg

Can anyone offer any help as too how i could do that?

Thanks.

Tealc · 4 Jan 2016 at 18:24

You'd need a few more components than just a potentiometer I'm afraid. The pot shown looks to be a low current one and might possibly handle a low speed fan. Ideally you'd use a transistor fed off the output of the potentiometer and use its current handling capability to drive your fan. The transistor would be in emitter followerr amplifier configuration.

Alternatively rheostats are high current versions of the pot above. They are expensive though and waste energy.

wozzsta · 4 Jan 2016 at 20:32

Yeah the pot i posted was just as an example.

But from what you said this little project seems a little more complicated than i first thought.

Ill see if i can find some info online i guess.

Thanks.

Tealc · 5 Jan 2016 at 07:31

It is only a little more complicated.

I'm sure I built one of these a few years ago, or at least something similar.

With a transistor, in this case 2N2222 (worth about 5p) 'follows' the voltage that you set with the potentiometer. The current you have on the potentiometer is amplified somewhat to provide enough power to drive your fan. It's not perfect though. Having a potential 1k on the base of the transistor may not provide enough current to drive the fan at max speed. By adding additional components you can improve current handling and set low speed limits and things though, for which there are plenty of ideas online.

Even though I built one it wasn't what I was looking for so I experimented further and what I came up with was much better, a DIY fan controller, able to control 4x 3 pin fans off the motherboard PWM signal. This uses about 8 components and is represented in my signature.