There are many laptop ventilator hacks out there already, this is just another version, which is a little bit more portable and compact.
I took the fan out of my dead power supply (12V, 500mA), remove two locks that hold the grill, then use nuts and bolts to make 2 legs. With the nuts adjusttable, I was able to adjust the angle so that it will fit when my laptop sit on the fan. My laptop does have 2 rubber feet at the front edge so it's not slipping away from the fan. The bolts' heads are kind of sharp so I use a piece of big rubber band to cover it, then secure the big rubber band with small rubber band. The rubber band keep the fan from slipping and damaging the tabletop it's standing on.
Because I carry the laptop with me everyday to work and to school, I want to extract the power directly from my laptop power supply. The laptop PS is rated at 19V, 6.5A so drawing 0.5A out of it hopefully won't be a problem. To get 12V out of this 19V, I use the popular LM317T. The photo below is my first version where I house the regulator and other parts in a small red box (upper part of a toothpick box).
Just on the next day, I found the red box was taking precious space from my backpack. Another problem is the LM317T is kind of getting hot since I don't have any heat sink attached to it (0.5A x (19V - 12V) = 3.5W of heat). I dissassembled it, resoldered the LM317T and resistors on to a plastic sheet (cut out from a plastic cover I found in my recycle bin). My purpose was to put the LM317T attached to the fan grill, with the hope that part of the heat will transfer to the grill, and when the fan operate (only when LM317T produce heat), the heat will be blowed off. The result look like this:
Result: more compact and portable fan for my laptop, I don't know if the weight of the laptop will broke those nuts and bolts someday. The LM317T at that position is always cool, not even warm when the fan runing at full speed. Oh, about the fan speed, this is a bonus feature I didn't expect. My fan turned out to be a Smartfan with a little heat sensor. When putting it under the laptop directly, it can adjsut its speed depend on how hot the laptop is.
I don't know if anybody can proof it right or wrong, but I experienced that if I don't let the fan under the laptop completely, the part of the fan that is outside of the laptop will blow the expelled heat UP, not accumulating behind the laptop, especially if there is a printer or wall behind the laptop.
Comment? Email me at: hoang027 at umn dot edu.