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elliot
Titel: Advice on setting up a reliable webcam system?  BeitragVerfasst am: 05.12.2007, 18:27 Uhr



Anmeldung: 09. Dez 2005
Beiträge: 10

Hello all,

I've been trying to set up a reliable webcam system for my home for a few years. By reliable, I mean one that won't fail, for different reasons, when in operation for more than a few days at a time. I've just come back from my second trip where I'd set up a system, only to have it fail when in operation partway into my trip. I'm hoping for some design insight from fellow Kanotixers, since I'm using Kanotix as the basis for the two PCs now the backbone of the system. I hope (dream maybe) that someday this will be the backbone of a remotely accessible home automation and control system.

The current configuration consists of a PC from a manufacturer I hesitate to identify, but which we will designate "POS", which describes its general performance. That PC is a Pentium 4 (2.8 GHz) with 447M RAM (512 actually, but some RAM goes to video), 80 GB HD, running the last version of Kanotix 2006 kept more-or-less up-to-date. When overloaded, it tends to crash (overheating, I suspect), so I've been running 2 webcams under Motion using 320x240 resolution, with 1 (security) cam using motion detection and the other one (catcam) just the built-in webserver, with as little as possible otherwise. (I am looking forward to going all Office Space on that POS.) The other, recently added PC is a fit-PC, which is a wonderful little underpowered unit (www.fit-pc.com). Two days of playing with the native Gentoo made me realize that my Gentoo-fu is weak, so I replaced it with Kanotix Thorhammer 6B (I'd love to see some comparative performance benchmarks). Despite 2 USB ports, bandwidth makes only one at a time useful for a standard USB webcam, so I run one cam on 320x240 with just the (catcam 2) webserver. Both PCs are ethernet cabled to a 3COM router, which in turn is connected to a cable modem. The POS has its own UPS, and the fit-PC, router, and cable modem are on another UPS.

The last trip, while viewing my cat sitting in his armchair (fit-PC cam), the system crashed, and no webcam view was possible from either PC. I was unable to SSH into either PC. My cat sitter did not feel capable of following my re-boot instructions, and I wasn't going to trust my cat to try (since I suspect him of crashing the system). When I got home, I surmised that there had not been a power outage (time & date settings on my ancient answering machine were unchanged), but that the POS had crashed, AND the cable modem had reset, although the fit-PC was still running unaffected. The cable modem reset (which also changed the IP address) screwed up the router, so no Internet access was possible. The cron job I had set up on the fit-PC to keep me informed of the system IP (using a bash script, nail, and an IP-checking website) was running properly, although without Internet access, I was receiving internal system mail indicating a failure to resolve the external web address and failure to send the tracking emails.

So, despite having planned against a single system failure (which also happened on the previous trip), and a short power outage, the system overall failed, in part due to the additional cable modem failure. This time, I want to construct a system which will be as crash-proof as possible. I'm hoping for some design insight and practical suggestions from people here.

For example, I figure a quick&easy&inelegant solution to the cable modem/router crash would be to hook up a simple timer that shuts them both down for a few minutes each day; starting them up simultaneously should still allow the router to correctly re-link to the modem. (Separate timers, with the router timer delayed by about 15 minutes, should allow for a slow modem re-connect, but the POS timers can't be counted on to remain in synch.) A more elegant solution would be to employ software that checks the IP connection, and fit-PC serial-port-based hardware that, on loss of connection, shuts down first the cable modem, restarts it, then shuts down the router and re-starts it. I saw something like this on hackaday referencing an article at http://www.evillawngnome.com/2007/06/20 ... onnection/ , but I don't have access to x10 or similar units. While I'd rather pick up something off the shelf, I'm willing to try building the hardware myself, even though I have trouble remembering which end of the soldering iron is the one I'm supposed to hold; I haven't a clue how to safely design such hardware.

I also now realize that I should set the computers up to re-boot when power is lost then re-established, to recover from longer-term power outages. I should set them both up to automatically re-boot and log in to KDE as a restricted user who has very limited rights, restricted to setting up the webcams, running SSH and VNC, and maybe KPF to serve a small custom webpage on a high-numbered port. What is the best, most secure way to do this?

I'm thinking of using Motion only on the security cam, and switching to one of the other image-grabbing programs for the catcams, to reduce system load. I figure setting up a ramdisk to hold the images, and updating them every 2 seconds, should be reasonable for watching the cat on a small custom webpage served off the fit-PC. What software do you recommend? Best way to set up a ramdisk in Kanotix?

What else am I missing? What else should I do?

My thanks in advance for what I hope will become an interesting discussion thread.

--Elliot
 
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ockham23
Titel: Advice on setting up a reliable webcam system?  BeitragVerfasst am: 05.12.2007, 21:12 Uhr



Anmeldung: 25. Mar 2005
Beiträge: 2100

Zitat:
Best way to set up a ramdisk in Kanotix?
The ramdisk already exists, the path is /dev/shm/

No need to change permissons, any user can write data to the ramdisk by default.

_________________
And I ain't got no worries 'cause I ain't in no hurry at all (Doobie Brothers, "Black Water").
 
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