The following document explains how to build a goggle fan. All the parts are available at Radio Shack and can be purchased for $26 + change. (At least that's how much I paid) The goggle fan that you can buy at your local paintball store or thru mail order will cost $70 so you can see the benefits of my design.
This design is nice because it allows you to use rechargable NiCad batteries and recharge them with your car cigarette lighter on your way to the paintball field. Also this design gives you two ways of turning on the fan. You can press and hold the momentary button until the goggles are clear then when you release the button, the fan shuts off and you can get back to painting up the poor saps that sill have fogged up lenses. The other option in to press the push on/push off button to turn the fan on then off. The push on/off switch is nice for hands-free operation. You can turn the fan on when the game starts and off after it's over.
Begin by determining where you are going to mount the buttons, LEDs, connectors and batteries in your project box. Drill the appropriate size holes and mount them using epoxy to hold them in place. Some of these components will come with screws or nuts for mounting, but I would suggest using epoxy just to create a seal that paint will not get in thru.
Using the schematic diagram below, wire the parts together using small conductor wire; preferrably solid conductor rather than stranded because in tight places like a project box, it's easier to work with. Keep the wires as short as possible.When wiring the fan, there are two ways of doing it. The way I did, or the way I would if I could do it again! I would suggest you mount a female plug (like I mentioned before, it doesn't matter what plugs you use as long as they fit together) in the project box, and using your twin lead wire (not antenna wire) or speaker wire, run a wire long enough to reach your pocket or wherever you're going to keep the fan control box while your playing and put a male connector on the end. The way I put the plugs together for the fan was to run a wire that would reach my goggles, and solder on a male connector. I put a female on the fan leads. I used tie-wraps to attach the leads to the inside of the mask.
To make a charging cable to charge the batteries, you will have to buy a cigarette light adaptor cord, without a connector on the end, and put an opposite gender connector on the end that matches the one you installed in the charging assembly of the control box.
This is up to you. I tie-wrapped it to the vent holes on top of my goggles. Some of you may have visors that make it more of a challenge to mount it. You could epoxy the fan in place or come up with your own idea that I haven't thought of yet.
REMEMBER!!! The fan WILL get shot with a paintball!!! You may want to make it removable somehow to get the paint off!!
Press on of the two buttons and the fan will run. (If you've wired everything properly)
The momentary pushbutton will run the fan only while you have it pressed down. Once you let it up, the fan will shut off.
The push-on/push-off button will turn the fan on the first time you press the button, and turn it off the next time.
DO NOT TRY TO CHARGE ALKALINE BATTERIES!!! I WILL NOT BE HELD RESPONSIBLE FOR WHAT HAPPENS IF YOU DO!!! THEY WILL EXPLODE IN AN UGLY MESS POSSIBLY INJURING SOMEONE IF YOU DO!!! SO DON'T DO IT UNDER ANY CIRCUMSTANCES!
Now that I got that out of the way I can tell you how to charge batteries. You must use NiCad or lead-acid rechargable batteries for this to work properly. NiCads are your most popular and easy to find rechargables. Do not try to charge Renewal batteries. Attempting to charge them with this charger will cause potentially hazardous problems.
You're now charging. A full charge could take up to 10 hours. I would charge them overnight on a regular charger the first time so that your guaranteed a good first charge, and after that you should only have to charge it on your way to the field.
If you don't have prior experience soldering or have never put together small components like this before, I would suggest an hour practicing putting small wires together on a wire-wrap board. If you don't want to practice it a little before making a try, you could screw things up by glopping hot solder in a molten mess.
One real pain in the butt about this fan is that if it gets shot, it will blow paint into your goggles. Paint stings your eyes like soap so consider yourself warned.
If you build this fan and it doesn't work, rest assured you did it wrong! I followed this design to the letter and it works beautifully for me and I know of 3 dozen paintball players that can attest to this.
I cannot and will not be held responsible for any damages, expenses or injurys if you build and/or use this project. I personnally think that if you get hurt using this fan, you screwed something up!!!