Materials needed: Altoid mint tin, 9 volt batter and connector, switch, 7812 voltage regulator, 12 volt computer fan, carbon filter and 2 pieces of screen. Wire the battery connectors. Solder all of the following: Negative connector to the switch, wire to the switch, ground wire of the voltage regulator to the middle wire, output for the 7812 to the fan, positive lead on the 9 volt connector to the input on the 7812 and the negative from the 7812 to the negative on the fan. Test. Put all the components into the candy tin. Cut a hole in the front and back of the tin for the fan. Mount the 7812 to the inside back of the case. Place the carbon on the back of the fan. Place the screen on the top and bottom of the tin. Test.