Multicam not working over USB extension?! - General Help and Assistance on using CHDK stable releases - CHDK Forum

Multicam not working over USB extension?!

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Multicam not working over USB extension?!
« on: 26 / August / 2015, 11:40:38 »

I have the following setup:

                                                                                      -> USB Hub -> 4 Kameras
Laptop -> USB 2.0 -> USB Extension (3m) -> USB Hub   -> USB Hub -> 4 Kameras
                                                                                      -> USB Hub -> 4 Kameras

When connecting the USB hub with the 3 connected hubs directly to the computer my script works fine. However if I use the extension wire between the first hub and the computer it has timeouts and doesn't do anything.

Does anyone know why this happens?


Offline reyalp

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Re: Multicam not working over USB extension?!
« Reply #1 on: 26 / August / 2015, 16:59:58 »
It sounds like a hardware problem. CHDK software doesn't know anything about how many hubs or what kind of cables you have.

I would try to use a process of elimination to narrow down the problem. For example, if you just plug one camera into the extension does it work? If it does, then try extension  -> hub -> one camera, then extension -> hub -> 4 camera etc.

There's a lot of marginal USB hardware out there, most manufacturers only care that it works in typical consumer use (if that) so it shouldn't be a surprise if it doesn't meet spec.

Are your hubs externally powered? They should be.

If you post the brand / mode of hubs that you are using, that might be helpful either to you or people trying to do the same thing in the future.
Don't forget what the H stands for.

Re: Multicam not working over USB extension?!
« Reply #2 on: 26 / August / 2015, 18:17:22 »
Here's e.g. previously used

My understanding: the Manhattan variety has been successful in that particular large cam count setting.

I have one - tested successfully with 3 cams so far.

Re: Multicam not working over USB extension?!
« Reply #3 on: 07 / October / 2015, 14:23:58 »
Although i know nothing about multiple cameras, i have used CHDK on a variety of cameras from SX120 to 150 and 510 and in my experience more often than not the culprit is the extension cable. ive found that my cameras are very picky about the extension on which they will work 'reliably' on.

on testing, most of the cables claiming to be V2.0 marked on the packaging but not printed on the cable itself, seemed to be substandard and the cameras failed on these. Most of the cables which had V2.0 printed on the cable itself worked. These cables seemed to be slightly more robust and hard physically and after a time i was able to hold the cable in my hand and determine if the cable would work or not

But that is just my experience and these sub standard cables have given me many a hard time trying to debug long distance. :(


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