So in researching air filters for my room I was very disappointed to find that not only did most of the units cost $50 or more but the annual filter replacement costs were way too much. So I made my own small quiet one on the cheap.
- Cardboard box of some sort. Just big enough to fit the fans. I chose an Optorite DVD burner drive box I had lying around. - Fans. I chose 2 blue LED 120mm fans I you can pick up at www.svc.com or www.newegg.com on sale from $10-15. - Filter. I first tried cutting a whole house filter but it is wavy and has a metal guard so I went back to home depot and found Vent filters for about $8 for a 12 pack of 4 in X 12 in filters. - Box Cutter or x-acto knife - Screw Driver and included fan screws
Improvements for my next version. - Add a switch to turn it on and off. - Add a Fan speed control. - Add a LED kill switch or use fans with no LEDS (Hard to fall asleep sometimes but is good for a night light) - hook to a 12 volt DC to AC power adapter so you don't need to run a wire from the computers power supply.