Where to get power for external fan?

TimTim Southwest PA Icrontian
edited November 2007 in Hardware
I plan to set up a laptop computer to be a webcam server for my website ( www.loudmouthtim.com ) It will be on all the time.

I had to take the laptop apart to change keyboards. It's a Dell Latitude CPi-A366XT laptop, so I got to see the cooling / heat sink setup.

The heat sink for the processor seems to be minimal at best, given the space limitations in a laptop design.

I've been using the computer for occasional internet stuff, and when the tiny stock fan comes on, it's blowing some HOT air.

So when I get this laptop set up and it's on all the time, I'd like to rig up a small (2 inch diameter or so) case fan with a plastic or cardboard funnel to force air into the air intake all the time to keep it cooled down in there.

Only problem is, where do I draw power for the extra fan? You can't just plug it in to the motherboard like on a desktop. I bought this laptop in the first place because I don't want my desktop system to be turned on all the time.

I thought about tapping into the power adapter wires to power the extra fan, but which 2 of the 3 wires would I need? And how to tap into them without chopping the main wire all up? And besides that, the power supply says it outputs 20 volts to the laptop. Wouldn't that burn out a 12 volt case fan?

Since the power supply switch on my desktop computer stays on even when the system it turned off, can I draw power from a USB connector, like I've seen done with USB lights and fans?

The webcam I'm getting runs through the USB on the laptop, could I tap into its power wires of the USB to supply the fan with electricity? Which 2 wires of the USB provide power, and are they 12 volts?

Comments

  • ThraxThrax 🐌 Austin, TX Icrontian
    edited October 2004
    Laptops are designed to precise thermal specifications, which means the cooling they have is perfectly adequate for the contents of the laptop. The air may seem hot to you, but it's not dangerous to your PC. The warmer the air being expelled, the more efficient the laptop is in moving heat away from itself.

    I would personally suggest you abort your idea.
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited October 2004
    USB is only 5v
  • TimTim Southwest PA Icrontian
    edited October 2004
    Hmmm... I knew this extra fan idea would have complications.
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited October 2004
    bah. use an ac fan. problem solved.
  • Straight_ManStraight_Man Geeky, in my own way Naples, FL Icrontian
    edited October 2004
    Or, look at SVC.COM and PCToyLand.com and Ebuyer.com. All have dual fan Laptop coolers that go UNDER laptop adn blow air into it through vents. Kinda like a short HD cooler with stubby feet on its top and bottom. BUT, the ones you set laptop on get plugged into an outlet, and can have their own transformer power. Radio Shack sells 12V transformers adequate for a small fan like you want, try a an IDE hot swap bay carrier fan, about 50-60 mA and you can get a trasnformer power adapter that will handle two of those just fine.

    Thrax is right, probably not needed, but for a fairly long-term-high-load 24\7 application (which most laptops were NOT REALLY designed for, they are designed for SOME off time typically), I would in fact use an aux cooler or at least raise laptop .5" with big feet under it to make airflow in easier for fan to force.
  • TimTim Southwest PA Icrontian
    edited October 2004
    I looked in the Radio Shack catalog online, and they have an adapter that plugs into a wall outlet and has a 12 volt cigarette lighter adapter. They say it's so you can use your laptop power adapter or car phone charger in the house. So with little effort I can run 2 wires into it and get 12 volts. It'll cost $25.00 .
  • Your-Amish-DaddyYour-Amish-Daddy The heart of Texas
    edited November 2007
    Me and a friend of mine just ripped the fan off of a video card and powered it over USB since it started on 5v.
  • RyderRyder Kalamazoo, Mi Icrontian
    edited November 2007
    :necro:
  • MAGICMAGIC Doot Doot Furniture City, Michigan Icrontian
    edited November 2007
    Holy thread resurrection, Batman!
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited November 2007
    Oldie but goodie. There have got to be so, so many old threads that are just begging for updates. (Yes, I mean that.) Maybe we could have an informal contest to see who dredges up the oldest, but still pertinent thread.
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