nicholas.seward Wrote:
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> I am going for cheap so I will use a cheap webcam.
> The bowden tube flexes very gracefully. I was
> thinking about getting an 8 conductor ribbon and
> spiraling in just like I do it now. We will see.
An 8-conductor ribbon is going to give you horrible signal-integrity problems. I expect you'll see fallback to USB 2.0 Full Speed, or even USB 2.0 Low Speed. Honestly, is the high-flex USB cable for $10 so bad? Another option would be to see if you can find one of the flat USB cables and coil it.
The thing about USB is that it needs shielding. If you open up a USB cable, you'll see that it's got a shielded signal pair (white & green), then the power pair (red & black) then a shield around everything. That's why you can push such high speeds, but it's also what kills the flex.
What I tried (and failed) to find was a flex cable with a USB plug on one end and a USB socket on the other. Because a flex cable is like a circuit board, you can route differential traces over a ground plane and have the same effect as a shielded cable. Sadly, it seems that those do not exist at the moment. You could probably contract someone like Samtec to make them and it would probably be cheap, but the setup costs would be terrible.
-------------------------------------------------------
> I am going for cheap so I will use a cheap webcam.
> The bowden tube flexes very gracefully. I was
> thinking about getting an 8 conductor ribbon and
> spiraling in just like I do it now. We will see.
An 8-conductor ribbon is going to give you horrible signal-integrity problems. I expect you'll see fallback to USB 2.0 Full Speed, or even USB 2.0 Low Speed. Honestly, is the high-flex USB cable for $10 so bad? Another option would be to see if you can find one of the flat USB cables and coil it.
The thing about USB is that it needs shielding. If you open up a USB cable, you'll see that it's got a shielded signal pair (white & green), then the power pair (red & black) then a shield around everything. That's why you can push such high speeds, but it's also what kills the flex.
What I tried (and failed) to find was a flex cable with a USB plug on one end and a USB socket on the other. Because a flex cable is like a circuit board, you can route differential traces over a ground plane and have the same effect as a shielded cable. Sadly, it seems that those do not exist at the moment. You could probably contract someone like Samtec to make them and it would probably be cheap, but the setup costs would be terrible.