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Re: multiple webcams via one linux box

Hello Bernie 

On 26 Aug 2002 at 9:56, Bernie Berg wrote:

> > I have tested two "Dexxa" webcams (compatible with Logitec Quickcam 
> > Express), on the same USB bus. I set it up to take alternating snap 
> > shots from each camera. This works well and could be expanded to more 
> > camera's.
> That should work, but at 85 cams this could get kinda messy.  How fast 
> can  you alternate?

I ran 1 image every 15 seconds per camera, with 2 camera's, which was 
enough for my requirement.

There is a very real finite limit to the bandwidth on USB. I don't 
think this will scale to 85 cams on one bus.  You could try and split 
them over say 4 buses and aim for a refresh rate of 1 pic per 5 
seconds per camera. It will depend on the resolution of each picture. 

> If I used the wireless x10 cams with usb adapters I don't think I would 
> reach 15m.  The problem I think I would have with the x10's are that one 
> receiver controls a number of cams (3 I think) and you can switch 
> between them (at least that is how the windows software works), but I 
> need them to all act independently.  I've tried contacting x10 to ask 
> some technical questions but the hold times are too long and they don't 
> reply to emails.

I don't see all of those wireless controllers expanding to 85 
camera's. (Do they have enough independent channels and enough 

I am going to try "thin client" boxes on a network, each with say 4 
cameras - the limitation being the USB cable lengths. 2 Boxes and  8 
camera's should meet my requirement.  But each box will need power 
and a place to live so this probably won't scale to 85 cameras 

Your installation will be quite large, have you talked to any 
"professional" companies? I would hate to be running around a site 
chasing 85 "domestic quality" web cams when one or another of them 
keeps dying for unknown reasons and the supplier does not answer the 


Ian Forbes ZSD
Office: +27 21 683-1388  Fax: +27 21 674-1106
Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa

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