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Use an empty PC case with a power supply

I experienced problems with hard drive over temperatures in the summer of 2007 with my external USB2 case. The case was using a noisy 40mm fan. I thought a larger PC case with bigger, slower running fans would help lowering the temperature without creating too much noise. So I decided to build my own NAS


  • less cords (power, USB)
  • (maybe) less noise
  • more disk space out of the box
  • impressive look and feel (does not impress spouse really)


  • more physical space used in the room
  • heavier equipment to move around than just a small SLUG and a few USB2 enclosures and power supplies
  • build requires basic electronic and computer skills
  • difficult access to the slug's reset button (unless you route that out as well)

Hardware you need:

An empty PC case with a power supply. Any case will do.
Rip out the entire stuff in it: The board(s), metal plates, whatever bothers you. Keep only what is needed to put in the following equipment:

  • 1x NSLU2
  • 1x USB hub (Belkin four port hub works fine for me)
  • at least one hard drive
  • some switches, some potis (variable resistors) or fan controller
  • some fans 80mm or 120mm
  • some IDE to USB adapters (or any other adapters for your 2.5, 3.5 ATA, SATA ... etc. hard drive
    You can hijack any USB to IDE interface from a not used external case

Tools & skills you need

  • soldering iron
  • soldering tin
  • wires, cables
  • pliers, scissors, screw driver
  • power drill to make some holes, a Drehmel tool is useful as well
  • shrink tube, cable ties, double sided tape


  • Install Unslung 6.8 and unsling to HDD partition /dev/sda1 (USB port 2)
  • Hook up your NSLU2. Use double sided tape to glue it flat on top of the 5.25'' drive bay. That way you have full control over the power switch and still see all four LEDs
  • Install the disk(s), hook up the power, install the USB hub to the bottom of the case with cable ties
  • Wire up the drives to the hub and the hub to port 1 of the slug
  • Wire the 5V power from the PC's power supply directly to the NSLU2. We do not need the slugs power cord anymore. Optional put in a toggle switch into the 5V line to be able to turn off power to the slug completely


  • Modify the power supply to turn on/off with a toggle switch (green cable shortened to ground will turn on power)
    I put the switch into the supply so the back panel of the PC case has a switch sticking out.
  • Install as many fans you like and hook them up to either fan controllers (reduces noise) or simple potis.
    Select value by:

12V 2W fan or 2/12A. With R = U/I = 12V/(2/12)A = 72 Ohm. Putting a 72 Ohm resistor in series to a 72 Ohm fan will
reduce the voltage by 50% and the power by factor 4. The fan will run slow and will consume 0.5W as the resistor.
So a 1W poti with >>72 Ohm will do.I used a spindle 10 turn poti of 1kOhm for each fan.

  • Install potis and or switches into a 5.25' drive bay plastic cover or where you find space
  • Consider making the power supply's fan adjustable as well (requires to open up the supply)

I will try to get more details and maybe some pictures into this page soon.

view · edit · print · history · Last edited by marbordom.
Based on work by marbordom and fcarolo.
Originally by marbordom.
Page last modified on March 22, 2008, at 04:44 PM