Custom fan speed controller using a simple potentiometer with a nice cap

[ForkIt]

I would like to build a super low bugdet fan controller that I could build into one of my front lids.

So I was wondering if the following would be possible:

-buy a simple "infinitely variable" potentiometer for like 10 bucks (as cheap as possible)

-solder all my fans onto it

-drill a hole into one of my frontlids

-hot-glue the potentiometer into position

-buy a nice cap for the potentiometer that fits the casees design (or grab one from an old radio or whatever)

-glue the cap onto the potentiometer

 

 

Would that be as simple as that? Have you done something like that before? What specs would the potentiometer need to control 0-12V?

 

I was thinking about something like this:

Potentiometer with built-in switch + Cap

(yes I'm German)

[BaSkA]

A potentiometer will vary the voltage/tension on a circuit so, in theory, it would work.

The only problem I see here is how you're going to work around the ground wire.

 

And you'd probably have to drill a hole in your case and control the fan(s) manually... isn't it better to spend some more and be able to control it via software or maybe even automatic?

[yttrium]

A potentiometer will vary the voltage/tension on a circuit so, in theory, it would work.

 

I actually did this and yes, it does work. It was a horrible job many years back when I was in high school, so don't hate on me for the terrible solder job, but yes, it worked. I basically cut out holes in one of the empty 5.25" bar covers from my NZXT Gamma, and then used a cheap blank breadboard to prototype it. Here's what it ended up looking like. It controlled around 6 fans. The reason I use so many different adapted headers is simply because I catered to my specific build that used those specific connections for each type. I also used a lot of hot glue because, well, #highschool.

 

Essentially it involved some simple transistors and potentiometers. Unfortunately I don't have the controller anymore, so I can't find the exact kinds of parts you'd need, but it should be easy to calculate. The basic gist though is that you'd use potentiometers to tell the transistors how much power to cut, and let the transistors be the actual ones doing the power cutting. It's not a good idea to use the potentiometer for that because if you do, the actual voltage will decrease. Most fans require 10-12V to operate correctly. Speed should be altered by changing amperage, not voltage, for these fans.

 

Obviously fans with PWM controllers should be FAR easier to manage, but this is a simple hack job that works for even the most basic ground/pos DC fans.

 

For those curious, the switch in that controller is actually a momentary on switch connected to pins 16 and 17 of an old server. Essentially, it's a remote power switch for a second machine.

[BaSkA]

I actually did this and yes, it does work. It was a horrible job many years back when I was in high school, so don't hate on me for the terrible solder job, but yes, it worked. I basically cut out holes in one of the empty 5.25" bar covers from my NZXT Gamma, and then used a cheap blank breadboard to prototype it. Here's what it ended up looking like. It controlled around 6 fans. The reason I use so many different adapted headers is simply because I catered to my specific build that used those specific connections for each type. I also used a lot of hot glue because, well, #highschool.

 

Essentially it involved some simple transistors and potentiometers. Unfortunately I don't have the controller anymore, so I can't find the exact kinds of parts you'd need, but it should be easy to calculate. The basic gist though is that you'd use potentiometers to tell the transistors how much power to cut, and let the transistors be the actual ones doing the power cutting. It's not a good idea to use the potentiometer for that because if you do, the actual voltage will decrease. Most fans require 10-12V to operate correctly. Speed should be altered by changing amperage, not voltage, for these fans.

 

Obviously fans with PWM controllers should be FAR easier to manage, but this is a simple hack job that works for even the most basic ground/pos DC fans.

 

For those curious, the switch in that controller is actually a momentary on switch connected to pins 16 and 17 of an old server. Essentially, it's a remote power switch for a second machine.

 

I did this to a PSU I built for two courses in college. I controlled a fan, one output from the PSU and also the LED brightness, I used a set of resistors, potentiometers, transistors and capacitors if I'm not wrong. However, it wasnt related to a motherboard or a computer, just basic electronic so we didn't really care for shortcuts as we had many fuses for those cases.