As of late, my smoking habits have increased and I've used my computer fan to pull the smoke away from me. I hate having the smoke that I don't inhale in my face, it burns my eyes. I understand the dangers of smoking, but then again, I don't want my computer filled with the smoke or anything tobacco produces. As I've been told after asking a question in the answers section of Instructables, build an air filter. As some searching and browsing through others Instructables on air filtration and purification I realized I have a strict budget of $0.00USD. So I needed something cheap, home-made and what would keep the smoke relatively filtered, or at least pulled away from my computer, and me.

Step 1: Materials/Parts

I didn't want to spend an money. So, I used parts from around the house and old computers in the basement to build my filtration system.

First off, a FAN to pull in the smoke is highly recommended. I used an old CPU fan and it's mounting screws.
Second, I used a small CPU packaging box for the support.
Third, some sort of filter. I used a thin piece of a napkin.
Fourth, a power supply. I used a 9V battery and its corresponding(matching) plug.
Fifth, something to hold it all in place. I chose electrical tape, since it was all I had around at the time.

You will also need tools:
Wire cutter/stripper(not pictured)
Knife(not pictured)
Screwdriver(not pictured)

Step 2: Mounting the Fan

This is quite simple, decide which hole of the box the fan covers entirely. Next, line it up and take your knife and put tiny holes where the screws can be mounted in the cardboard.
NOTE: Make sure the fan pulls air IN!
Then take the screws and slowly screw them in, making sure not to strip the holes out.

Step 3: Connect the Power Supply

Wire the CPU fan to the plug for the 9V battery.
Black=ground
Red=positive

The extra wire on the fan is useless, unless you know what to use it for. Cut it off making sure not to damage the fan itself.

Use the electrical tape to wrap it up.
Next, take the battery and make a tape loop on it, sticky side out. This is useful for mounting it inside the box.

Step 4: Just Add a Filter

Cut the napkin(or whatever you choose) large enough to cover the exit hole, tape it down making sure to not leave holes where it will leak.

Step 5: Plug It Up, and Close the Box

Simple, plug in the battery, mount it to the inner wall and there you have it. A free(cheap?) second hand smoke filter.

Step 6: Closing Arguements

Being the hypocrite that I am, I understand smoking is bad on my health. In NO WAY do I suggest anyone ever pick up a cigarette, it is worse than weed, as far as my experiences have shown. This is my simple way of (hopefully) filtering out some of the smoke, so my gaming computer doesn't suck it all up.