USB Diverter

[D@rkL0rd]

Hey everyone,

So I undertook a project on which I would like some help.

I want to create a device that will divert a USB channel from one port to another. A crude representation of what I am trying to achieve. (Basic Structure.png)

So far I have created this circuit (Primary Circuit.jpg).

R1 is used to bring the base current down. I have yet to find its value.
B1 is one of the buttons showed on Basic Structure photo.
X1, X2, X3, X4 are the transistors used as a switch. I am not sure that this will work but this is what I could come up with.

I did not complete the second part to avoid confusion but think it will be same as the others.

The first thing I want to know is if this is even possible? Am I on wild goose chase?
If this is possible then will my circuit be able to achieve it or do I have to make other arrangements?

Thank you for your time.

Basic Structure

 

[ramussons]

USB pins 2 and 3 carry the traffic, so only these 2 lines need to be switched. But for complete isolation, all the 4 lines need to be switched.

Why not use a 4 pole 2 way slide switch (or 3 way, or even 4 way)? Is'nt it much simpler?

ps your schematic will not isolate the keyboard from the second computer. It will only parallel it. Further, there is also a danger of paralleling the +5 Volt supplies of the 2 computers, which is very likely to cause a loop current since the 2 power supply units may not be exactly 5 Volts.

 

[D@rkL0rd]

@ramussons Yes, that is much simpler that using BJTs. Can you please explain your last point? The parallel one and the loop current one.

Thanks

 

[flippineck]

I expect you probably want to do this yourself but I had a setup like that once - I used a readymade solution which handled the mouse and monitor as well, it was called a KVM switch. It had a foot pedal to switch between several towers.

https://en.wikipedia.org/wiki/KVM_switch
http://www.ebay.co.uk/sch/i.html?_nkw=kvm+switch

No challenge of design-it-yourself there though I guess. Maybe it's helpful links.

 

[D@rkL0rd]

@flippineck Yes that is exactly what I want to do But I want to build-it-myself. Thanks for the link

 

[ramussons]

@ramussons Yes, that is much simpler that using BJTs. Can you please explain your last point? The parallel one and the loop current one.

Thanks

* If the terminals T1, T2, T3 and T4 as shown is USB2, then it's permanently connected. Switch B1 will connect (I'm not saying that the transistor setup will work) USB3 without removing USB2. That's paralleling I mentioned.

* If the PC1 has 5.1 Volts, and PC2 5.2 Volts, there will be a current flow from PC2 to PC1 on the 5 Volt line - unless you maintain a total isolation.

 

[D@rkL0rd]

@ramussons will the 4PDT switch be able to connect with total isolation.

No, T1, T2, T3, T4 are actually terminators to end the signal line.

 

[ramussons]

@ramussons will the 4PDT switch be able to connect with total isolation.

No, T1, T2, T3, T4 are actually terminators to end the signal line.

Ok, I stand corrected.
Yes, the 4 pole 2 way switch will provide total isolation.

 

[D@rkL0rd]

Okay guys, I am back after my exams and all ready for completing this project. I am sorry for not coming back after for so long.

So does anybody know any good simulator that I can use to simulate the CD4066?

I have tried 123circuits.com and fritzing simulator.

Thanks.