Electronics 2000

Hi All,

I would quite like to try and make my own KVM switch (for switching vga and usb between 2 or 3 PCs).

My reason for this project is that I have purchased 2 now and neither of them pass through my screens supported resolutions through to the graphics card well or support usb keyboard/mouse input into BIOS screens ect, I would like to make one which simply passed input/output straight through.

Initially I though of doing this with a number of relays........quite a few of course. But think this would be quite primitive and expensive.

My question is, does anyone know if I could do this using transistors as switches (to switch between the inputs) or could anyone suggest a better way I could do this?

Any suggestions welcome and much appreciated, I look forward to hearing your views.

Thanks

Hi, relays may cause probs, you can do it with TTL's dirt cheap.
I will look it up and get back to you.

Hi, early thoughts... interesting project.

The USB's have 4 wires... earth,+5V, data in and data out. The earth can be perminantly earthed at multiple points data in, data out and +5V can be enabled/disabled by feeding them into 3, 2 input and gates when the other input is enabled with a logic high at the other AND input, data will pass unchanged, multiple 3 AND arrays can be selected with a simple MUX... The +5V line may need trip a transistor to save burning its gate... I will do my home work.

The VGA analogue so will need to be switched using 45 transistors, bidirectional CMOS devices are available but may be expensive... prob transistors are the way ahead... I will do my home work...

Interesting project, could you be a bit more clear on what you want to do, what is running what etc etc. more info pls.

Tar&stuff.

That is not to clear...
The USB's have 4 wires... earth,+5V, data in and data out. The earth can be perminantly earthed at multiple points... data in, data out and +5V can be enabled/disabled by feeding them into 3, 2 input AND gates when the other input is enabled with a logic high, data will pass unchanged... multiple 3 AND arrays can be selected with a simple MUX... The +5V line may need trip a transistor to save burning its gate... I will do my home work.