Log in

View Full Version : Cheap way to adjust fan speed?


ownaginatious
08-12-2009, 11:27 PM
Hey guys,

I recently installed two fans in the new case I'm almost done making that I took from an old Apple G5.

Anyway, the fans work really well, but they're also super loud! Both are connected together directly to one of the outputs of the power supply, so I can't adjust the speed with the motherboard (all those fan spots are taken :p).

So I was wondering, is there some kind of switch I can buy that will adjust maybe the resistance of the electricity to the fans (like a dial to go on the outside of the case)? I remember using one of these in my physics labs at university last year, and the TA said they were super expensive :(. Also, would it be safe (i.e. I don't want the switch going to a million degrees when the fans are on low speed)? There is a bulk electronics component store near my house, and they just ignore me whenever I ask them questions like this :(.

I don't want to have to buy a full out fan speed controller.

Thanks,

Dillon
Zephik
08-12-2009, 11:43 PM
From $10 to $110.

http://www.amazon.com/s?ie=UTF8&tag=mozilla-20&index=blended&link_code=qs&field-keywords=fan%20controller&sourceid=Mozilla-search

They're about as safe as being trapped inside a giant plastic bubble. Not much can go wrong here, if anything at all.
ownaginatious
08-13-2009, 12:00 AM
I know fan speed controllers can be cheap, but the case I made is really compact, and I don't think I would have room for something like that. Plus, I only need one fan controlled by a knob (the others are still very quiet even in their maximum settings). I think what I need is a potentiometer.
Zephik
08-13-2009, 12:59 AM
Why not buy the $10 Silverstone controller and dismantle it? We support cannabalizing products to better suit our needs here. :)

http://img44.imageshack.us/img44/9489/tnsilvercontrol69471750.jpg

Looks like three individual controllers already nice and wired up for you!
ownaginatious
08-13-2009, 01:06 AM
Why not buy the $10 Silverstone controller and dismantle it? We support cannabalizing products to better suit our needs here. :)

http://img44.imageshack.us/img44/9489/tnsilvercontrol69471750.jpg

Looks like three individual controllers already nice and wired up for you!

I may end up doing that. I'm first going to check my local random cannabilized electronic parts store, since their's always the possibility of getting one for cheap. If not, I guess I'm going to be spending $10.
msmrx57
08-13-2009, 08:06 AM
I think what I need is a potentiometer.

That was the first thing that came to mind. Put it somewhere so the knob works with the design, adn tap it into one of the leads.
Spawn-Inc
08-13-2009, 05:34 PM
http://www.thebestcasescenario.com/forum/showthread.php?p=238910#post238910
ownaginatious
08-13-2009, 08:58 PM
Well, I got a couple variable resistors (50k and a 5k), and it didn't work out so well. They worked great when the resistor was set to max or set to 0 ohms. The problems occurred when I put it to a setting that was anywhere between there. The resistors started burning.

I think I'm probably safer to just connect the fans to the 5-Volt line instead of the 12-Volt and live with it.
Spawn-Inc
08-13-2009, 11:30 PM
if the 5 volt isn't enough for you you can do 7 volt with the 12 volt line feeding the red wire to the fan and the 5 volt line feeding the black wire to the fan.