Step 1: Materials
You will need:
1 cardboard box (about double the size of your fan) ( width should be triple the width of your fan)
1 case fan
1 USB male header (with about a foot of cord)
1 carbon filter (as big as box or fan holes)
1 ac or dc adapter for power supply(voltage need to should match)
It costed me 0$ because I salvaged it all.
Step 2: Tools Needed
Solder (I use Rausin core because others will deteriorate the electronics you solder)
Step 3: Begin Building!
Prepare your box by cutting out 2 circles on both sides of the box. The circles should be the size of the fan itself and not the outer casing.
Step 4: Mounting The Fan.
Then match up the holes with the fan and the metal screening over each other perfectly. Then screw your screws in.
Step 5: USB Male
Now, you want to take your male header and cut off you desired length. Make sure you cutting off the female side! Inside there may be some wire and foil and a green and white wire. You can get rid of those we don't need them for this project.
Step 6: Soldering
Then solder the red wire from the male header connected to the red wire on the fan same with the black wire.
Step 7: YOUR PRACTICALLY DONE!
If you want you can add electrical tape to the two connections of the fan and the cord. Then a very important thing is to add a carbon filter to the back hole, the carbon filter should be the size of the hole or bigger! You can get carbon filters at a fish or pet store or online. Just accessorize it the way you want! YOUR DONE!