USB - Switching between machines

S

Splash

New Member

• Dec 14, 2006

• #1

Hey all,
Very quick question for you all. Im making an item that allows a friend of mine to share a printer between 2 computers. I know a network would be a far simpler system to achieve this but because of a lack of network ports I offered to try and make a manual device that achieved a printer sharing result.

Im pretty sure that its as simple as the diagram i've attached, however it would be great if someone could just confirm for me that this will work and wont cause any damage

 

Attachments

• USB Switcher.jpg

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justDIY

Active Member

• Dec 14, 2006

• #2

yea, it'll work just fine

make sure your switch is "break before make" (most are) ... as far as the devices are concerned, it would be no different than unplugging and re-plugging the device.

 

ivancho

New Member

• Dec 14, 2006

• #3

It will most likly work as long as you keep very short leads and maintain the shield. Nevertheless if it is a USB2.0 device, you might encounter problems and the device might not be recognized.

Keep in mind that there is a limit in the length of the cable to 5 meters total. The shorter the cable the better.

 

Sceadwian

Banned

• Dec 14, 2006

• #4

Cable length problems can be mitigated by using USB repeaters. Depends on how much capactiance that switch you're going to use adds. Even if it doesn't work at USB 2.0 speeds it should automatically fall back to 1.0 speeds.

 

evandude

New Member

• Dec 14, 2006

• #5

It's guaranteed to be in violation of the USB specs, but that's not hard to do, and often doesn't mean it won't work. You could probably directly wire all the ground wires together, and switch the other three. That would provide a more solid ground connection which should help avoid issues. And, of course, keep your wires as short and neat as you can, do a good job soldering, etc. etc. And you will probably be fine.

 

Sceadwian

Banned

• Dec 14, 2006

• #6

Why not split them up? Say 4 SPDT switches mechanically ganged, or 4 SPDT relays with a common drive signal? The issolated switches/relays would likley satisfy USB specs. The problem with a massive muli pole multi position switch like the one in the original post is the very large parasitic capacitances between all of the lines.

 

justDIY

Active Member

• Dec 14, 2006

• #7

or get a digital switching IC, maxim makes some easy to use ones.

 

Sceadwian

Banned

• Dec 14, 2006

• #8

Hopefully they work at 480mbit (USB 2.0) or 12mbit (USB 1.x) ?

 

S

Splash

New Member

• Dec 15, 2006

• #9

Hey,
well ok, these are the USB sockets I've purchased
**broken link removed**

I cant find any datasheets for them anywhere.. and have become very confused as to which pin is which. Does anyone here have enough eperience to tell me, which pin is ground? I assume I connact all the other pins in the order shown in my diagram?

oh one more thing, do i need to connect all three sockets cases together?

 

justDIY

Active Member

• Dec 15, 2006

• #10

this says it all

https://pinouts.ru/Slots/USB_pinout.shtml