When I was little, I remembered my dad telling me that when he was a kid, they used to put buckets of ice in front of a fan and it worked wonders. Well, today while working on my Altoids USB charger (had to wait for my epoxy to dry), it got very hot in the room and I needed to find a place to cool down. Unfortunately my whole-house air conditioner is broken and my landlord is too cheap to fix it. So, I decided to use some common household supplies to make my own, only USB powered.
-Old USB cord. Any kind will due, from any device. Preferably one that you no longer use.
-Container of some sort.
-Knife / scissors / wire cutters.
-Soldering iron. This isn't essential, but recommended.
-Old PC fan. Clean the dust out first.
Let's get started.
Step 1 - Cut holes in your enclosure.
You can use any kind of enclosure you want. RadioShack sells large ones for about $8, however they're strong ABS plastic and are not exactly meant to be opened and closed. I used a Domino Sugar container, which has a soft plastic which is easy to cut.
Start to cut holes around your enclosure, but not TOO large. You want multiple small holes. Trace and cut out an area for your fan. Do NOT trace it too small, leave some area for your fan to sit comfortably on top.
Step 2 - Mount and glue your fan.
You'll want to use a hot glue gun. Superglue and epoxy will work, but it takes forever to dry and does not offer the beast sealant. Put glue around the perimeter. Make sure you leave no areas unsealed. Make sure you test your fan ahead of time to see what side air blows out of. Normally it's label side. Nearly all fans are 12v, but USB only really hits about 5v. The fan will spin somewhat slower, but you will still feel the cold air.
Step 3 - Strip your USB cord.
Find an old USB cord. Cut the top off using wire cutters or snips. Proceed to strip the plastic around the edge off the remaining part, exposing the wires. Do NOT clamp too hard, otherwise you'll cut through the wires.
The green / white wires are not needed, as they are the wires that actually carry data. We only want the positive (black) and negative (red) wires. Cut the green and white wires short.
Step 4 - Twine your wires together.
The reason we do this is to make a secure connection so we can solder it and form our joint. Negative (red) goes with negative (red), and positive (black) goes with positive (black).
Step 5 - Solder OR tape your wires together.
I suggest soldering, but if you do not own a soldering iron or you do not know how to solder efficiently, you can skip to the step below and tape without soldering.
[b]Step 6 - Wrap each joint.[/img]
Do this even if you are not planning to solder. Wrapping the joints is essential to prevent short-circuiting.
Step 7 - Wrap both joints together.
Make sure you wrap them nice and tight, as you don't want the wires slipping out (if you didn't solder them).
Step 8 - Obtain some ice and place it in your container.
I made some cheap ice packs (though you can get ice packs cheap for about $1 a piece) using sandwich bags, water, and tape. I don't suggest using loose ice, as it is a pain to clean up and if you spill it, it can ruin your fan.
Step 9 - Secure your lid.
This part is essential. If you do not properly fasten your lid, you won't notice any cold air.
Step 10 - Plug it in, and enjoy.
If you did it right, your fan should start working when you plug in your USB cable. It works for wall chargers as well. It's been sitting at my video editing PC for the last hour, and is noticeably cold.
A few things. You will NOT notice a difference across the room. This is mainly for a small area. Also, the ice will melt in about two hours, depending on amount of ice. Keep extra packs on hand for hot days. It's 78 in here, after plugging it in, it dropped it down to about 68 degrees in my area.
If you REALLY wanted to get technical, you could add a toggle switch to turn it on / off. All you would need to do is solder it in between the negatives (red).