Windows 7 - Fan Speed Controller - Build your Own

Nice tute LordBob

A Guy

Thanks for the updated tutorial Lordbob... The pics make things 10 times clearer and easier to follow!

Thanks. It is a lot easier now that I realized there was no need to cut any wires to make it

~Lordbob

Thanks , nd looks koool

Hey Lordbob75

Sorry to bump an old thread.

Wanted to say thanks for the great tutorial, the formulas helped me heaps. Fanstatic stuff
But with this tutorial i was wondering if one 12v line would power say, 6 fans?
something like this image

Cheers,

Silvion,

I can't see the picture but I'm pretty confident in saying yes. Though there are many variables that would determine if it could(amps available to the 12v rail, how many other things are on the rail, etc) I can't fathom a pc fan that could saturate a 12v rail even if you ran 10 of them.

My phone isn't letting me edit the post but I do want to add that my post only applies to PSUs bigger than 300W

Hey,
thanks for the reply,
I am happy to run just the fan controller off say one molex, nothing else running off that wire. Doesnt matter there.
the image is like this

Hey Silvion, don't worry about it. It is a tutorial for a reason.

As to your last post, that would not work how you want it to.

I don't think that it would power 6 fans well. I would go with no more than 3 each, so you would only need 2 controllers.

You want the LED directly after the switch (so that if the switch is off, the LED is off, and if the switch is on the LED is on). If it is after the pot then it won't work so well.
Keep in mine that LEDs use around 1-2 volts. Anything more will blow them out. So you will need a resistor big enough to protect the LED.

I would wire it like this:
12V from PSU
-> Switch
-> Resistor to LED in parallel to the potentiometer
-> Fan

Basically, when you wire it up it will work like this:
Have the switch plug into the molex connector from the PSU.
From the switch, run 2 wires. One connects to the resistor and LED, the other goes into the potentiometer.

~Lordbob

Hey thanks for the reply!
Yeah, i understand that. The resistor on the LED won't affect the potentiometer at all?
Or did you mean have a "Y" section? splits to resistor/led and to potentiometer?


I can make two seperate circuits to have two 12v inputs, no worries there..
Also, would you know where i went wrong with these calculations?
12 = 12(85.71/(Rr+85.71))
1 = 85.71/(Rr+85.71)
1(Rr+85.71) = 85.71
Rr + 85.71 = 85.71
Rr = 1???
My fan is drawing 0.14amps on a 12v line:/