Intro: How to Make a Cheap USB Powered Fan
How to make a cheap fan from parts bought at the dollar store. This fan can be made for about $2 (plus tax), unless you can buy a double ended USB wire, then you can make 2 USB fans for $3 (plus tax). That definately beats the $15 or $20 stores tend to charge for these types of devices.
This is my first instructable so I wouldn't mind if people posted their opinion.
NOTE: Pictures will be added at a later date when I make the second fan, the first one (which I am writting this instructable from) was simply a test to see if it would infact work.
Step 1: Preparing the USB Cable
Cut the USB cable to the length you require (long if you need to attach fan to a USB port in the back of your computer). Becareful not to cut the inner wires, use a wire stripper (if you have one) or simply a pair of scissors (be careful not to cut yourself).
Once the protective jacket has been removed, remove some of the shielding such that the 4 wires which make up the USB cable are exposed.
Cut the white and green wires short (to the protective jacket) as they will not be needed for powering the device.
Step 2: Preparing the Power Wires.
CAREFULLY, remove the outter protective jacket from the red and black wires to expose the copper wire underneath. Twist the exposed wire (if not already done) to make your life easier.
Step 3: Taking Apart the Fan.
Remove the battery cover as well as the screw holding the two halves of the fan together (becareful not to loose any small parts such as screws/switches).
Step 4: Connecting the USB Wires to the Fan's Battery Terminals.
This was done through trial and error. I found that while the fan would run both if the red were attached to the positive and black negative or red to negative and black to positive but the second way produced sparks at the negative-to-motor connection so I obviously chose the former hook-up. Wrap the indicated wire around the indicated battery terminal folding the wire over so it stays temporarily. Once this is done, plug the USB wire into your computer (NOTE: Do this instructable at your own risk, I will not take the blame if harm comes to you computer/yourself/etc but nothing bad happened to me/my computer when I connected the fan to the computer) and turn the fan on. If it works, on to the next step, if not, maybe the wires are not connected properly or maybe they are loose, play around with it,m it should work fairly easily (and as long as the fan does not require 3 x 1.5V batteries or more for operation (IE no more than 5 V) ).
Step 5: Making the Conections Permenant.
Now that the fan works successfully, its time to solder the USB power wires to the battery terminals to make the connections more permenant and stable.
NOTE: After completing this instructable, I've discovered that the USB port is too powerful fo the fan I chose so a resistor wired in series before the connection to the fan would help lower the power and therefore not overload the fan/motor. This is as simple as soldering a resistor of high enough resistance to decrease the voltage to around 3 volts (from thew 5 that USB puts out).
Step 6: Personalizing Your USB Fan.
If you find the fan too plain, you can spice it up with paint, decorations, etc, anything you want.
NOTE: this instructable can be used to power practically any device that requires no more than 5.0V.
Enjoy the breeze!