• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Success !! my fan bus controller

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

overdoze

Member
Joined
Jan 12, 2001
Location
Texas
Hearing those noise long term really got to my head. Buy panaflo fan will not help me when I want to OC. I want high speed fan once in a while. So I decided to make a temp sensor fan controller for all of my case fans and also have a way to override it when I want max cooling purpose.

Check around the house I found one of the old broken mobo and unsolder the 5V voltage regulator from there. Check on the web for specification and I found an example circuit for it.
http://www.advanced-monolithic.com/assets/ds1084.pdf

Also I found one of the old 80mm fan that has temp sensor in it. I took it apart and unsolder the thermister from it. Looks like it is a 20K one. When I hold the thermister the resistance decrease. Good, make it R1, so now all I need is a 100K pot for R2. I then went to local radio shack store and get myself a solder board the 100K pot for about $2. Then I solder everything together.
I used the chipset heatsink to cool the VR and solder them together with the 3pin to 4pin fan converters. After all the solder done. I make sure the 100K pot is at max position (100K) before solder on.

Then I used the ohm meter to check for short and open. Power up with a small fan and adjust the pot while holding the thermister to get roughly 34C and max output voltage just start to decrease. It turns out that my max voltage is only 10.8V. I guess there is a 1.2V drop across the VR. I then release the thermister to room temp. Voila! the output fan voltage goes down to 8V. I then hook up all my fans (1 120mm and 2 80mm) to the output of this newly build thermal fan controller. (it can handle 5A). I tape the thermister to the base of my CPU WC.
Been tested it all morning sofar. My comp is extremely quiet now and the good news is when I run the cpu at full load for a while my fans starting to speed up and all run at 10V still very quiet.

The beauty of this is I can turn the pot to to speed up or slow down my fans anytime. Also, the fans automaticly speed up or slow down depends on the cpu WB temp. Cool, this is just what I wanted. I'm a happy one now :)
 
OP
overdoze

overdoze

Member
Joined
Jan 12, 2001
Location
Texas
what do you think. Here it is after assemble together
 

Attachments

  • pic00038.jpg
    pic00038.jpg
    66.4 KB · Views: 141

Mike K

Member
Joined
Nov 22, 2001
Location
Chicago, Illinois
Thats pretty sweet seeing as it is temp controlled when youre not O/Cing and when you are you can turn them all the way up instead of letting the sensor do it. Sensors never let fans run at full speed unless you have 80C temps.