Building a simple fan controller

Discussion in 'The Projects Forum' started by amoeba1126, Dec 20, 2008.

  1. amoeba1126

    Thread Starter New Member

    Dec 20, 2008
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    Rather than buy a crappy fan controller (that's right companies, you can take your 6-7 watt fancy POS and shove it), I am trying to save money and build a fan controller that achieves the following:

    - Switch fans between 12V and 5V (I do not need OFF or 7V for fans)
    - Draw power directly from the PSU and not to worry about anything between 5V and 12V, thus avoiding the need for resistors
    - Avoid using a circuit board unless I can make one out of plexi and a conductor pen
    - Not to blow up my computer :D

    That is all very nice and awesome until I realized one very important disadvantage; I am a circuit virgin. Sure I dabbled with making a light bulb turn off or on in elementary school, but lets face it, that is the equivalent of say self-love. Here is what I have come up with as my initial plans. Afterwards, a couple of acquaintances informed me that the 2 middle ground wires for molex connectors were the same thing and I can wire all the POS 1 and POS 2 grounds to the same source. Anyways, here is what I have come up with, not including the change for ground wiring.

    [​IMG]

    Can you guys review this and tell me if it is correct? Any advice, suggestions, or constructive feedback will be greatly appreciated. Also, the DPDT toggle switch I am looking at appears to be ON-OFF-ON. Are there any switches that are just ON-ON where it switches between 2 different actions? I think it is a DPST switch but I am not sure.
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    The circuit looks fine but you can use a SPDT switch and connect all grounds together. You don't need a switch on the ground wire but only on the 5V and 12V wires.
     
  3. amoeba1126

    Thread Starter New Member

    Dec 20, 2008
    4
    0
    So daisy chain fan ground, to molex ground?
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Yes, connect the fan ground to molex ground and use the SPDT switch to switch between 5V and 12V.
     
  5. amoeba1126

    Thread Starter New Member

    Dec 20, 2008
    4
    0
    oh boy...thats gonna be a lot of daisy chaining...
     
  6. amoeba1126

    Thread Starter New Member

    Dec 20, 2008
    4
    0
    Here is the revised version. Is this what you are talking about?

    [​IMG]
     
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