How to change a three pin case fan to a usb plug case fan?

[goheenis]

Hi all, Im making a computer cooler table for my laptop computer and I'm having trouble changing the three pin plug that came with my led case fans to a usable usb plug can anyone help me out? ill try to add a picture of the unit with fans installed.

Please if you can help Thanks...

 

[DiscoDuck]

http://pinouts.ru/Motherboard/MbCpuFan_pinout.shtml for 3 pin fan pinout
http://pinouts.ru/Slots/USB_pinout.shtml for usb pinout.
the voltages are different, 5v vs 12v but it should still spin the fan but about half speed. connect 5v to 12v, ground to ground. get some small butt splice crimps and then can heat shrink tube it to look nice. put tubing on before crimping