Turn case fan into usb fans?

[Deathhorse]

Can i take a basic 3 or 4pin case fan and make it into a usb powered fan? Or is there a adapter i can purchase to turn 3 or 4 pin into a usb device?

I have multiple fans that i could try it on so i dont mind messing up.

 

[Automata]

As long as you don't exceed the port's capacity and the fan can run at 5v, then it should work fine. I don't know of any 3 pin fan headers to USB. You could always make one by sacrificing a cable.

 

[Deathhorse]

ok ill find out what the capacity is. I have plenty of usb cables and fans. How would i got about this?

 

[Automata]

Cut the cable of a USB cable, strip back the protective cover. This should leave you 3-4 wires (depending on how they do the ground). Use the pinout of USB to find what wires/pins you need to use. You will be using pins 1 and 4 for power. Solder the proper wires together and put something protective over it (heatshrink, electrical tape).

 

[Deathhorse]

oh i think i got it

1 VCC +5 VDC Red
4 GND Ground Black

then connect those to the red and black of the fan (if the fan lets me do 5volts)

does that sound right?

 

[Automata]

If the 5v on the USB cable is red and the ground is black, then it will be "red to red" and "black to black"; correct.

 

[petteyg359]

A USB 2.0 port can only supply 500mA at 5V. Make sure your fan doesn't draw more than 0.5A. If you're sure its power requirements are low enough, and it still doesn't start, try flicking it Most fans require a bit more juice to start than they do once they're already running.

 

[Deathhorse]

^^ very cool i will pay close attention to the MA

 

[Deathhorse]

ugh i made one and its the slowest ca ca fan ever. back to the drawing board.

 

[randomwhiteguy]

just curious since you said that a usb 2.0 can only do 5v, can a usb 3.0 do more?

 

[Bobnova]

I think USB3 is still 5v, but can cough up more amps, I don't remember how many offhand.

For this basic plan to work well you'll need a fan designed to run at 5v, running a 12v fan at 5v results in a mighty slow fan.

 

[petteyg359]

just curious since you said that a usb 2.0 can only do 5v, can a usb 3.0 do more?

No. All USB is 5V. USB 2.0 goes up to 500mA, while USB 3.0 goes up to 900mA.