5channel fan controller with one control knob

Discussion in 'The Projects Forum' started by Dulus, Jul 15, 2014.

  1. Dulus

    Thread Starter New Member

    Jul 15, 2014
    Hello everyone,

    i will skip directly to what i need.
    I have 5 pieces of 12 volt 12cm FANs with 0.23A draw each. They are 3 pin fans. I need to have some sort of control for rpm of those fans. Starting voltage of those fans is 5V. the control should be 1 centralized for all 5 fans.

    I have found designs on web but they are either controls for one fan only or separate control for each fan.

    I am not that skilled in electronics design so i need some guidance. I solder frequently so that wont be a problem.

    Is there anyone who can point me to some , or make some design for me ?
    The whole thing should be as small and simple as possible. I need to feed power into it with 5 separate lines (each for one fan, plugged into MB with 3pin male fan connector) and the output should be 5 female 3pin fan connectors. I still need to feed back the rpm readings from fans to motherboard.

    if thats too much, what is the simplest way to decrease the voltage on each of those power lines to lets say 6 volts ?
    i know it can be done using just an inline cca 50 Ohm át least 2W resistor, but thats a little dirty solution to me.
    Last edited: Jul 15, 2014
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    specs/model number of fan? I assume they have an TACH wire..

    Could be as simple as PWMing the fans voltage supply.. But some fans don't like pwm as it screws with the internal commutation/hall sensors so you might simply need to construct an adjustable power supply which could easily be done with an LM317.

  3. DickCappels


    Aug 21, 2008
    One idea is to use a speed regulator for a single fan and use the drive voltage for all the fans. This would work if all of the fans are similar and have similar loads. If the fans and/or loads are not similar you will probably have to resort to one regulator for each fan.
  4. Dulus

    Thread Starter New Member

    Jul 15, 2014
    The fans are AC F12 fans. classic 3 pins.

    Ah, i should have mentioned that. This is not a solution for computers. I am deploying a few cisco routers , but they are located in rooms where people are living. so no bios/sw rpm regulation is possible. They just run at full speed on 12 volts. And they were very loud so i cut the top cover and made holes for those 12 cm fans there. But even at 1400 rpm the aerodynamic noise from those 12cm fans is audible. those routers have classic 3pin connectors so i guess no pwm.