What i want and why i want?
i have an old CNC that only support rs232 and usb for reading and writing data in memory of work. i no like rs232 port so i use USB but every time i have to connect and disconnect my USB flash memory by myself and and lazy so i had to make something to make it easy for me. my CNC controller is unix/linux based os so i have problem to use USB Bridge cable. i try simple 4 contact switch and it was easy (you can find something on Instructables.com too) but i no had any status for operation so i design this simple circuit using two relay and one small switch.
Step 1: Electronics Parts:
1- USB port (male) X 2
2- USB port (female) X 1 ----> i used cable for that
3- Relay 4.5v DC (2 contact = two-pole) X 2 ---> i used Omron G-5V-2-H1 4.5V DC cause it is low cost, small and fast but u can use another relays
4- LED X 2 ( it's better to use 2 color for status of active port )
5- Resistor X 2 ( 380 ohm it's enough for USB voltage and LED current )
6- general Diod X 2 --- i used 1N4001 - u can use anything else too ---
7- (2 pole) or (3 pole) switch X 1
Step 2: Schematic & Test
I use DipTrace Software for design Schematics and PCB for long time but i do not know anyone use it too or no. i just placed screenshot of that and export .dxf file just to checkout if you like that.
in the Schematic you can change the position of GND and V+ or Data+ & Data-, if you see wrong direction of diods it's cause of my feeling (lazy) i just put it in screen to analysed the wire parts.
after that i use my project board to start project and one day that i loose some of my lazy feeling i will put them on real PCB. it will be something look like what i screenshot for PCB but it was just auto trace PCB and i usually make some changes in auto trace to make it smaller PCB size.
if you have any idea to change this design and make it better i will be very happy to hear and learn from you...