how to read data from USB port?

[RavensFan]

As the people who were able to guess digital input pointed out, a USB port won't work for you.  (And neither will an ethernet port.)

What is the physical signal you are trying measure?  Is it a digital voltage high vs. low?  Wheter a switch or relay is opened or closed?  At what frequency do you want to measure this?

[Ranjeet_Singh]

Why you complicating your life. You need to read data from USB then basically you need USB to serial converter and VISA and thats it.

[Intaris]

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@Ranjeet_Singh wrote:

Why you complicating your life. You need to read data from USB then basically you need USB to serial converter and VISA and thats it.

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And how exactly is that supposed to help?

[Ferchu]

Mate, what you have to do so we can help with more ideas is:

- Which device are you using "Model" Slip ring so we can see the datasheet and check what signal format you get through those 4 wires you mentioned?

- What are you looking to read from it (measuring data from a rotating object).

- Is your USB port 1.0, 2.0 or 3.0 (Because some people in the past found issue on USB 2.0 and had to use 1.0 old hub and avoid noisy signal).

Note: The USB to serial converted won’t work if you are not receiving sending serial data across the wires coming out from slip ring....

I have read this threat of answers but we are all guessing because luck of information.

[Ranjeet_Singh]

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@Intaris wrote:

And how exactly is that supposed to help?

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He needs to read the data over USB. I dont think he need anything apart from that. What else he need. Let me know.

[Intaris]

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@Ferchu wrote:

I have read this threat of answers but we are all guessing because luck of information.

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I'm not guessing.  The OP is trying to misuse some port on his PC as a data acquisition device INDEPENDENTLY of the protocol normally sent over the port.

This won't work for USB and it won't work for Ethernet.  End of story.

Depending on the signals you have it MIGHT work on an RS-232 port, but with low speeds and (as suggested) limitations on what type of signal you can detect.

The "USB" in the OPs original post is a red herring.  He wants to read in digital signals over >some port< on his PC.  If I have misunderstood, I am open to more information.

[Intaris]

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@Ranjeet_Singh wrote:

He needs to read the data over USB. I dont think he need anything apart from that. What else he need. Let me know.

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He does not need to read the data "over USB".  That implies that the USB protocol is somehow involved, which it is not in this case.

Again.... He does NOT have a USB device.  He wants to misuse the USB port for digital measurements by somehow accessing the individual pins on the USB port.  This is not going to work.

[Ranjeet_Singh]

Yes this is the case.

[Ferchu]

Guys, I undestand now what he wants to do. As one of you said no matter what protocol is used it wont work connecting this straight to the USB pc port.

The signal needs to be manipulated first before get sent to the pc, it is easy sent it serially in which then you can use what Singh said Serial to USB converter.

If you want to do something fancy you can probably use arduino to decode that signal.

[RavensFan]

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@Ferchu wrote:

If you want to do something fancy you can probably use arduino to decode that signal.

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Or an inexpensive data acquisition device.

I suggest all the conversation in this thread just stop until the original poster decides to get back in and tell us what his real requirements are.