Introduction: USB Desktop PC Fan


In this instructable I'll explain you how simple is to make a cheap desktop fan from:
- 1 12V PC Fan
- 1 broken laptop mouse

The result will be estetically nice. The fan will run at 5V: something less the half of the original rpm at the maximum voltage. The airflow won't mess your hair, but it's pleasing in hot days, especially when working on the laptop. You can simply use a pencil as a kickstand!


- welder and solder;
- clippers;
- heatshrinks or insulating tape;
- lighter;
- screwdrivers.


You can find tutorials on how to solder and use heatshrinks everywhere. You can learn it, for example, here.

1- Unmount the mouse, you'll see a circuit board like this, with 4 USB wires attached to it.
Very simple: 2 wires are used for data, and they are indicated on the board as D+ and D-. 2 wires are used for Voltage (indicated as V) and Ground (G). Take note of the color of V and G wires. In this case, they are respectively Yellow and White. Clean the cable then strip these two wires.

2- Prepare the fan.
If there is a 3 pin header on the fan, cut it. Then cut the white wire. Strip the two left wires. Usual scheme: red positive, black negative.

3- Prepare 3 heatshrinks on the wires as shown in the link.

4- Let's solder!
Positive wires: Red to yellow. Negative ones: Black to white.

5- Heat the heatshrinks and... Enjoy! ;-)