Re: multiple webcams via one linux box
Greetings! Bernie Berg wrote: Hi, I have a project that could potentialy have 85 webcams. [...] You can get a usb adabpter to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? USB has a device number limit per bus - and a cable length limit: specifications limit it to 3m (9ft) max - usually recommended is to keep the length below half of it. Unless you need realtime video I'd suggest you get small video cams (possible to get them for ~200$ each), relay them via a remote (i.e. computer) controlled switch box and feed them into a standard video-in card (e.g. BTT-based). I've seen switch boxes supporting up to 8 video-ins controlled via parallel port - so you probably will have to build your own controller box. Using the parallel port and a number of layered TTL b2d-decoders to trigger a transistor-boosted relais for each input building that box should not be too complicated. Bye Volker Tanger IT-Security Consulting -- discon gmbh Wrangelstraße 100 D-10997 Berlin fon+49 30 6104-3307 fax+49 30 6104-3461 [EMAIL PROTECTED] http://www.discon.de/
Re: multiple webcams via one linux box
Hello, Am 18:00 23/08/02 +0200 hat Nicolas Bougues geschrieben: On Fri, Aug 23, 2002 at 10:06:40AM -0500, Bernie Berg wrote: to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? USB can't have more than 63 devices per bus. What about USB v2.0 with 127 devices ??? Does Linux support it ??? Nicolas Bougues Axialys Interactive Michelle -- Registered Linux-User #280138 with the Linux Counter, http://counter.li.org. +--+ | Michelle's Internet-ServiceInh. Michelle Konzack| | FunkLAN-Providerin | +--+
Re: multiple webcams via one linux box
Hello Bernie On 23 Aug 2002 at 10:06, Bernie Berg wrote: Hi, I have a project that could potentialy have 85 webcams. The easy thing to do would be to use an Axis network camera and just link to its own webserver from my linux web server (or whatever). But these run about 300 bucks, that would be about 25 grand for 85 cams. X10 on the other hand (I hate their website, it looks like to is from 1994), has much cheaper cameras, and they are wireless. You can get a usb adabpter to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? 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. However the limitation was the USB cabling. With hubs and extension cables and hubs, things start getting unreliable after about 15m. Have fun and let me know what you learn! Ian - Ian Forbes ZSD http://www.zsd.co.za Office: +27 21 683-1388 Fax: +27 21 674-1106 Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa -
Re: multiple webcams via one linux box
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? However the limitation was the USB cabling. With hubs and extension cables and hubs, things start getting unreliable after about 15m. 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. Have fun and let me know what you learn! will do Ian - Ian Forbes ZSD http://www.zsd.co.za Office: +27 21 683-1388 Fax: +27 21 674-1106 Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa - -- Bernie Berg| [EMAIL PROTECTED] Network Administrator | Office:(605)362-6361 Circa Design Company | Cell:(605)201-3891
Re: multiple webcams via one linux box
On Sat, Aug 24, 2002 at 10:51:02AM +1200, Dave Watkins wrote: At 18:00 23/08/2002 +0200, Nicolas Bougues wrote: On Fri, Aug 23, 2002 at 10:06:40AM -0500, Bernie Berg wrote: Hi, I have a project that could potentialy have 85 webcams. The easy thing to do would be to use an Axis network camera and just link to its own webserver from my linux web server (or whatever). But these run about 300 bucks, that would be about 25 grand for 85 cams. X10 on the other hand (I hate their website, it looks like to is from 1994), has much cheaper cameras, and they are wireless. You can get a usb adabpter to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? USB can't have more than 63 devices per bus. FYI 127 is the max for USB, 63 is for Firewire Thanks for the correction. BTW, it's probably cheap and easy to add a few more USB buses, using PCI boards. This would dramatically lower the number of devices per bus, and thus avoid (some) problems when the number of cams increases (bandwidth, latency, etc. caused by hubs chaining). One question is how the USB cams send data to the host. If it is not compressed at all, even a small 320x200x24 bit snapshot will be 192 Kb, and you won't be able to receive more than 3 such pictures on a bus per second. Axis cams send JPEG data, which is far smaller, and on a much higher bandwith bus (100 Mbps Ethernet, which can be further switched/aggregated to Gigabit on the host side), and you can easily capture one picture every few seconds on tens of cameras without problem. Oh, one last thing : I don't know X10 products, but you'll probably have some spectrum management issue when you run 85 wireless cams... -- Nicolas Bougues Axialys Interactive
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 range?) 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 either. 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 phone! Regards Ian - Ian Forbes ZSD http://www.zsd.co.za Office: +27 21 683-1388 Fax: +27 21 674-1106 Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa -
Re: multiple webcams via one linux box
Hello, 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 phone! I think I am just going to go with the axis (or similar) network cams. It will save alot of headaches. Thanks for all the info Regards Ian - Ian Forbes ZSD http://www.zsd.co.za Office: +27 21 683-1388 Fax: +27 21 674-1106 Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa - -- Bernie Berg| [EMAIL PROTECTED] Network Administrator | Office:(605)362-6361 Circa Design Company | Cell:(605)201-3891
Re: multiple webcams via one linux box
On Fri, Aug 23, 2002 at 10:06:40AM -0500, Bernie Berg wrote: Hi, I have a project that could potentialy have 85 webcams. The easy thing to do would be to use an Axis network camera and just link to its own webserver from my linux web server (or whatever). But these run about 300 bucks, that would be about 25 grand for 85 cams. X10 on the other hand (I hate their website, it looks like to is from 1994), has much cheaper cameras, and they are wireless. You can get a usb adabpter to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? USB can't have more than 63 devices per bus. But the main question is, do you want to handle real time video from each of the cams, all simultaneously, in which case you'll have serious bandwidth problems, starting on USB ? If it's just a matter of taking a snapshot every few seconds, or using only one video feed at a time, the usb solution might be ok (as long as you have at least two buses to connect all the cams). There might just be a few nasty constants in the device drivers, which should be fairly easy to deal with. -- Nicolas Bougues Axialys Interactive
Re: multiple webcams via one linux box
USB can't have more than 63 devices per bus. ah, yeah I think I heard that somewhere before, thanks But the main question is, do you want to handle real time video from each of the cams, all simultaneously, in which case you'll have serious bandwidth problems, starting on USB ? It wouldn't need to be real time but one snap every 2-3 secs would be nice. If it's just a matter of taking a snapshot every few seconds, or using only one video feed at a time, the usb solution might be ok (as long as you have at least two buses to connect all the cams). There might just be a few nasty constants in the device drivers, which should be fairly easy to deal with. yeah, the device drivers are my main question. Has any one done this with this many cameras? have you used the x10 cameras? thanks! -- Bernie Berg| [EMAIL PROTECTED] Network Administrator | Office:(605)362-6361 Circa Design Company | Cell:(605)201-3891
Re: multiple webcams via one linux box
At 18:00 23/08/2002 +0200, Nicolas Bougues wrote: On Fri, Aug 23, 2002 at 10:06:40AM -0500, Bernie Berg wrote: Hi, I have a project that could potentialy have 85 webcams. The easy thing to do would be to use an Axis network camera and just link to its own webserver from my linux web server (or whatever). But these run about 300 bucks, that would be about 25 grand for 85 cams. X10 on the other hand (I hate their website, it looks like to is from 1994), has much cheaper cameras, and they are wireless. You can get a usb adabpter to input them into a computer. Ummm, anyone have luck linking 85 usb webcams into one linux box? Anyother sugestions? USB can't have more than 63 devices per bus. FYI 127 is the max for USB, 63 is for Firewire
