Simple Fan controller

Discussion in 'The Projects Forum' started by hydra504, Jan 6, 2009.

  1. hydra504

    Thread Starter Member

    Oct 18, 2007
    I been wanting to make a simple fan controller for my PC using rotary pot's with knobs on the front panel and some LED's. I have an old AC to DC adapter that outputs 12V DC at 1A, to use as a test bench for my project.

    This is what I have came up with using simple 1k pot's and two 80mm fans that I had from old non working power supplies.

    I have the pots set around 80 ohms, and the I have a red LED running parallel acros the source with a 470 ohm resistor.

    Instead I would like to put an LED for each fan that I want to control with a rotary pot with a built in switch. So when I do turn the switch off, the LED turns off and the rest of the fans remain on.

    This is what I came up with so far...I know it needs more work.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Do you wish to control speed, or is it enough to turn the individual fans on and off?
  3. hydra504

    Thread Starter Member

    Oct 18, 2007
    Well I built this last night, and with a 1k pot I was controlling the speed of the fan.

    Now i have been looking on the net and i know they have some rotary pots with a STDP in them, but I would like to have an LED with each individual FAN to indicate which FAN is turned on and off. How would I go about and wire them?

    When I tried placing the LED after the pot BUT before the fan, the LED brightness changes with the speed of the fan.
  4. SgtWookie


    Jul 17, 2007
    Using a pot in series with a motor to control the speed of the motor is not a good idea. There is a large loss of motor torque. PWM is much better, but much more complicated.