I work as a paintball referee and a chronic problem that I have is my mask fogging up. I consider this the worst thing to happen on the paintball field, whether reffing or playing. As a ref, I can't keep track of players or accurately declare hits. As a player, even if my marker fails or I run out of paint, I can still be a diversion or a flag runner. Nevertheless, I'm pretty useless when I can't see. I've tried various anti-fog sprays, but they only last a game before giving up. The basic idea here is to put a fan in a paintball mask to continuously circulate air and remove humidity. Pretty simple, right?
Step 1: Materials and Tools
1 paintball mask
1 computer fan, 12v
2 slide switches, DPDT
1 resistor, 10 ohm
1 9v battery, preferably rechargeable
1 9v battery holder or connector
4 1" long bolts, must fit through holes in fan
4 matching nuts
4 small zip ties
Step 2: Getting Started
The first thing to do is to REMOVE THE LENS. Also make sure your fan works. You wouldn't want to put all this effort into it for nothing. Just hook it up to a 9v battery. Red goes to the smaller snap. Now make sure it's moving air out of the side with the support structure. Next you'll want to test fit the fan in your mask. The most convenient place for mine was right under my chin. If you put the mask on, you probably won't have enough room in there, so you'll have to trim down the sides.
Step 3: Fitting the Fan
The next step is to cut four corners off of the fan. These should be the corners facing away from where your face would be. Use the dremel with a cutting wheel attachment. You can clean it up with some sanding if you want but this side won't be visible after assembly.