DIY USB KVM selector using audio selector. (1 keyboard -> 2 computer)

    The simplest hardware solution to control 2 computers with 1 set of mouse and a keyboard.

For this project, you would need.

• 4 pole 3-way rotary selector.
• 2x USB Cable (Printer cable)
• Female USB connector. (from old USB Hub)
• Small plastic box (I use dental floss box).
• A working USB Hub for connecting Mouse and Keyboard.

     The reason you will need a 3-way selector while only use 2 of them is that this kind of selector will momentary short between adjacent position while turning so you should use a 3-way selector while leaving the center position unconnected.
    I use twist-pair cat5 wire for connection.

Wiring diagram

    USB female connector can be harvested from a dollar store USB Hub.

Finished product.
Two USB cables (white) are connected to both computers, PC or Mac.
Connect a USB hub to the female USB connector.
Connect mouse & keyboard to the USB Hub.

    If you are using a USB 2.0 hub you can also plug a USB Flash drive to share between computers as well, Just remember to eject the flash drive before switching.