Article by : SpotTheCat
I made this, it's better than a rheostat/baybus because those produce heat, cost more money, and can't handle big fans. I went to my hardware store and bought a 3way lightswitch for $1.20, cut a hole in a 5.25" bay, and mounted it. The wiring is slightly complex, Here's how I made it :
Yellow - always +12V
Black - either ground or +5V, depending on switch position
Black - always ground
Red - always +5V
Here are some pics I whipped up, click on the image for a bigger picture
How it works: when the switch has the negative fan lead at ground, the total voltage is 12-0=12V
when the negative fan lead is at +5 you get a resultant of 12-5=7V
You can have fans always 7 or always 12 by moving the pins on the molex connecters to the always 5 or always ground leads
Thanks go out to SpotTheCat for providing us with this howto and pictures!
