I made my own mass media private that ventilates in the attic of a simple hole in the ceiling of cuts with a cover of enmeshes of wire. It had the hope of which the passive cooling would make the trick, but already has arrived throughout winter seems to me that the system of heating of the furnace, does not allow that the hot air to raise. Thus, to this end, I am studying some 12V assembly ventilators of PC in the hole and have a temperature switch to activate when one is put over certain temperature. I have found several sites that show how to construct one of these switches, but I was hoping that somebody packaging for it could already lay me for the direction of a cheap solution....????