archilochus said:
Plug it into the wall socket..
If you want to get fancy. Cut a hole in the back of your case and insert an a male IEC AC Plug (The same type you plug you AC cord into your power supply .) in the back of it .
Using insulated spade connectors or solder and heatshrink (Depends on the recepticle you buy.).Connect a length of Black wire to the left connection on the back of the plug. Ensure there is no bare wire showing
Repeat and connect white wire to the right connection.
(The bottom connection is a ground. Since your Case is already grounded through your power supply do not connect a wire to this and attempt to chassis ground it to your case. This can result in a ground loop and cause all sorts of problems.)
Next connect your wires to the plug run a white(neutral) to your fan directly.
Get a SPDT (Single Pull Double Throw) Relay with a 12VDC coil.
and pick a spot to mount it somewhere in your case. Preferably away from the motherboard and your other DC components. Be sure when you are doing the below wiring you leave enough slack in the wire to mount your relay in the desired location.
Take the black wire from your plug and connect it to either terminal number 1 (NEMA Relay) or terminal number 11 (IEC Relay) then take another length of wire and run it from terminal 3 (NEMA) or 13(IEC) and connect the other end to your fan.
Next take a "wye" connector that you normally use in your PC to split the 12VDC connectors and clip the plug off one end (make sure it's the end that you would normally plug into a device. (AKA the Female connector).
Clip the Red wire and adajacent Black wire flush with the back of the plug.
Strip the ends of the yellow and remaining black wires and connect the Yellow to the number 2 Terminal (NEMA) or the "+" (IEC)
Connect the black to the number 7 (Terminal) or the "-" (IEC).
Lastly get some silicon and fill in the holes where the other 2 wires you clipped reside in.
Allow to cure for 24 hours.
Then fire it up. When ever you turn on or turn off the computer the fan will start and stop.
You should be able to pick up all the above parts for less then $30 (US) total.
Unless you want the deluxe model in that case wire in a dimmer switch on the black wire between the relay and the fan for speed control. and add another $10 bucks or so to the cost.
Parts list
6 feet 14 AWG Black wire
6 feet 14 AWG White wire
1 IEC AC Cord
1 IEC AC Recepticle
1 SPDT 12VDC Coil Relay (DPDT will work also doesn't matter you only need 1 contact)
1 115VAC AC Fan
1 tube silicon potting compound
soldering iron solder and heat shrink or Spade connectors (depends on the Reecpitcle).