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low tech multiple fan speed controller

Discussion in 'Cases, Modding & Electronics' started by coodiggy, Apr 2, 2009.

  1. coodiggy

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    Had some old motherboards leftover that had plenty of 3 pin fan headers on them so I desoldered em all (7 total) and used them to build a 12v/5v multiple fan header switch.

    Standard 4 pin molex power IN with fuses on the 12v and 5v lines, fused power wires lead out to the switch, and one power line leading from the switch to the fan header bank.

    I salvaged the 4 pin molex connector from a old CDROM drive power board. Also using the old cdrom drive metal case as a switch bay, to hold my custom power/reset buttons, and fan doohicky. The case is open in the back, with a hole in the bottom, near the middle. I can route my main power cables through the back and down through the hole, to the back side of the drive cage, as well as all the fan power plugs up through the hole, to the fan doohicky. Should help with cable management, although, the motherboard main connector barely fits through.. May have to open the hole up a little more. No RPM monitoring through the doohicky, however, I can always take the fan rpm wire out of the fan power plug, then plug them into the motherboards chassis fan headers to keep track of my Radiator/chassis fan RPM if I need.

    Got the breadboard and fuses from radio shack :)
     

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  2. Assassin48 New Member

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    Very intresting

    nice work
     
  3. Saakki

    Saakki New Member

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    nice work & sexy black and white pictures :toast:
     
  4. Bokteelo New Member

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    If I knew how to do this kind of stuff I'd save myself a lot of money. Gj.
     
  5. coodiggy

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    Thanks for the comments, B/W for the win :)

    If you look at the two pics with the fans spinning, you can sorta see the difference in fan speed between 12v/5v. At 5v, the light reflections off the blades appear closer together, due to the frequency of light, and the slower spinning blades. I made this so that I can use the computer in quiet mode, with all the fans spinning at 5 volts. There's still enough cooling/airflow, but it's MUCH quieter. The fuses are just incase. I doubt my 120mm radiator fans will draw too much juice while everthing is spinning up from a power off state, but I'd rather pop a fuse than have a wire get hot and short to ground somewhere.
     
  6. crtecha

    crtecha New Member

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    Great little project. I was thinking of making something similar. Did you run into any issues during the project?
     
  7. coodiggy

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    Yeah, a few little issues. The clad bread board from radio shack was really crappy, or my soldering iron was too hot..

    When I touched the solder pad to the tip of the solder iron, the pad pulled right off the bread board and stuck to the tip of the soldering iron. I had to dremel off all the solder pads and use pre tinned length of wire as circuit bus wire.

    I was tryin to build up a nice blob of solder to wrap around the bus wire and slump down onto the pin of the fan header ground leg, then one of the other solder joints got too hot and unsoldered itself and left the wire stuck to the soldering iron.. I got around that by waiting longer for the other solder joints to cool off before trying to solder up the next header.. Could probly use some stainless hemostat clamps or something like that to wick the heat out of fresh solder joints while keeping the heat from the other work from desoldering previous work, save some time too.

    Since the switch was from an older project, I had forgot what the internal connections were in relation to the legs of the switch. Had to double check using an ohmeter to see what the posissions were, turned out (a/off/b) or HI/OFF/LOW and legs were going to be A possitive +5v IN and the common out center leg, for possitive out to the fan header possitive bus, and B +12v IN. I Also double checked to see if the metal body of the switch, and the metal toggle would have any ground or grounding issues with any of the solder/connection legs, in any position.. Don't want to short to ground..

    I used a dab of hot glue on the bottom/edge of the fan headers to fix the fan headers onto the breadboard before soldering..

    To salvage fan headers, use a heatgun, or heat spreader soldering iron tip that will heat all the legs/soldered pins of the fan header at once, then gently pull em out from the other side of the mobo with some plyers or your fingers, if your fast enough to not get burned. I'm not sure how well the PC deals with line/switching noise, but since it's "OFF" and "ON in either direction, I think the PSU's internal regulator and noise filter should be able to handle any fluctuations if switching fan modes while the PC is booted up etc,
     
  8. crtecha

    crtecha New Member

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    I used to do some light board repair and I cant tell you how many times I wanted to scream when I would heat up the wrong part causing things to detach.
     
  9. coodiggy

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    OR like when you just pulled your crust ball out of the fridge after chilling for 4 hours. Rolled crust into the shape of the dish, transfered to the dish, got a nice edge on the crust and go to put the dish in the fridge to chill a little prior to baking and have the damn thing bounce off of something and knock the dish out of your buttery fingers and fall on the floor messing up the nicely constructed pie crust that took literally several hours to construct!!! Not including the time to go to the store and buy ingredients, and not including the time to pre-chill the ingredients.. Mixing everything just right, waiting for the ball to chill, so you get that nice flaky crust..... Yeah, I tend to laugh when stuff like that happens to myself, n specially at other people, then start over, but that last one with the pie crust, I let a choice word fly...
     
  10. crtecha

    crtecha New Member

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    Coodiggy thats quite the story hahahaha im sorry but your misfortunes with the pie was really funny. Im going to just think of that the next time im frustrated. ill post my most irritating moment once I get home from work. That way we can laugh at each others expenses :roll:
     
  11. coodiggy

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    If you have any "instances" that are frustrating, keep in mind the little issues you had, or what the title/name of the item was that you were frustrated with, then go get an adlib book! Put the above mentioned "instances" or "titles" from your recent experience in the blanks. Just don't use it as a weapon against the other person/people that you work with, it's not meant to be hurtful. Mostly allows you to think of the instance in a different way, by not being "frustrated" when you are thinking about the issue, you can come up with different ways of dealing with the issue. Instead of bashing away at it with a hammer till you're tired :O
     
  12. crtecha

    crtecha New Member

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    I printed out your last post. I think that thats some of the best advice I've been given thus far. I actually posted a thread on "How do you handle stress". I think that that can be really helpful for me.


    Thank you Crtecha
     
  13. coodiggy

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    Cool Beans!
     
  14. Sir_Real

    Sir_Real New Member

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    I've used 7 volt in the past 5 volt hardly turns some 12 volt fans.

    Heres how to get 7 volt. & yes this is safe !
     

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  15. coodiggy

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    Nice diagram! I haven't had any trouble with fan speed/air flow with them running on +5v, but I usually start them up on the +12v then switch them to +5v. Any idea if the +5v reg's/caps would get over worked?
     
  16. Sir_Real

    Sir_Real New Member

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    It wont put any load on the 5 volt line running a fan this way. But with +5 volt already running through the line i said to use as the fans neg & 12 volt to the pos then the voltage to the fan will be 7
     
  17. coodiggy

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    yeah cause the potential is different between +5 and +12
    I've been reading about it a little between posts. Sounds like it's OK in practice, I think it's too easy though ;) I'd like to get a pwm hooked up on the 12v line eventually, something that can interpret an analogue POT as a trigger to change the pulse width, or like those capacitive touch switches on old TV's or lamp dimmers where you touch the lamp post to dim the light.
     

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