Mnewman

I've been put in charge of designing and implementing a mobile unit which can provide surveillance for our construction sites over the internet. Has anyone ever built anything like this? Right now my primary concern is how to power the DVR in areas where power might not be available, or running power cords might be dangerous (think heavy construction equipment). I've looked at units like the Nuvico NVDV3-16250 16 channel DVR, a color unit with a 250GB hard drive and internet support, but haven't yet seen a spec listing how much current they draw. Right now I'm thinking about by-passing whatever internal power supply it might have and run it off of a several dozen lithium-ion batteries. Buying a big Honda generator that can run 14 hours on a tank of gas seemed like a good idea at first, but I doubt this system would draw anywhere near the 1400 Watts that that 14 hour number comes from, not to mention how inefficient it would be to generate DC electricity, just to be inverted to AC, and then back to DC in the DVR itself. The final concern is getting internet access in the middle of nowhere.. Cell service is an attractive option, but there is no gaurentee of service in any given random location. HughesNet satallite service has a plan with 500Kbps upstream. Does anyone know about how much bandwidth would be needed on a unit like to to monitor 16 channels? I doubt it sends all of them full resolution in a grid or what not. Any suggestions or similar experiences would be greatly appreciated.

It's been alluded to me that for this project the final/monthly cost isn't really a concern. But as for WISP, I still don't think that's an option since we're talking like AR for a few weeks, WA for a few weeks, KY for a few weeks.. That sort of thing, hopping states. If they could give me some concrete locations I'd look into EVDO coverage, we've had great success with that in some of our other mobile operations.

The issue of people carting off with the system itself was one of the first things I mentioned when my boss told me he wanted something mobile. I was thinking of going the ATM route and encasing the entire thing in a locked steel enclosure and then weighting it down with a few hundred pounds of something, rather than enclosing the whole thing in a trailer. The idea was to have a 'package' that could be freight shipped to any location we knew we were going to be at ahead of time. As for the WISP, that's probably not going to be an option since these are jobs that run anywhere from a few days to a week or two at any given location among several states.. Trying to setup some sort of access in a time frame of 3-4 days with a different ISP each time probably isn't going to be feasible... though if it were I would happily take that over satallite. The satallite plan I've been looking at so far provides 500Kbps upstream for $180 a month (after buying equipment). Based on your 4Mbps figure for 16 cameras, I assume I should be able to monitor any two simultaneously assuming perfect conditions. Further comments on that would be appreciated. Another area I've started researching are wireless cameras. It was suggested that a useful extension of this system (and thus the 16 camera unit instead of my originally proposed 4) was to put a wireless camera on most of the bits of equipment next to the driver. I've seen camera systems that allow you to select among 4 channels. Can you suggest a system which would provide for more? I assume most of the wireless camera run off of around 12V, which could be provided by an invertor or something similar on each of the pieces of equipment.. perhaps even a solar cell-battery combination.