My needs are the same as every other person looking to implement a surveillance system - a reliable monitoring system that I hope never to have to use beyond seeing who is at my
front door. Like an airbag in a car, though, I wanted something I could trust enough that if it becomes critically important, it will work without snags.
This was not as huge of a project, but still presented some interesting challenges. There are pre-configured systems out there that are more "user friendly" than the route I went with,
but from having worked with several over the years, and researching many more, I don't like the lack of configuration and scalability that most of them offer. Also in many cases you're
vendor locked on hardware, which I avoid as a matter of principle. In the end, I decided that a computer running a software surveillance system would be the best option for my needs.
The biggest hurdle on this project was figuring out what hardware to buy. I know all too well the effects on a wallet a power hungry server can use, so I wanted to keep this one
to an absolute bare minimum on power draw. The biggest advantage I could see was to have the most recent version of Intel's QuickSync, with the lowest possible TDP CPU I could find.
This wound up being the Pentium Gold G7400. This is a 12th Gen processor with a 46W TDP and NO turbo frequency. Normally I avoid Intel processors because their TDP ratings are [in my
opinion] very, very misleading. A 65W TDP CPU under full load will easily use over 200W (source).
This processor, however, has no turbo boost (or whatever Intel's terminology is for it), so 46W is the maximum it'll consume, ever. Running under stress tests at 100% load, the highest
usage I observed was 40W, which is GREAT!
The other big decision was cameras. I didn't have too much in the way of requirements, my only stipulations were 1) compatibility with PoE/BlueIris, and 2) reasonable build
quality and resolution. I wound up going with Amcrest cameras because they seemed to fill the requirements at a reasonable price. The only thing I'd warn of with these is that Amcrest
uses rebranded Dahua cameras - whose use is actually banned in several US government agencies. I put up a firewall blocking them from accessing anything outside my local network, since
they should only be connecting with the NVR anyway. But the same principle applies no matter which camera manufacturer you use - in a local, DIY solution, any surveillance camera
has no reason to access the WAN.
Other than the CPU and cameras, the other components were pretty much decided by what the cheapest option at the time was. This is a list of components I bought and their costs:
I should mention that I had a spare case and PSU laying around, so the costs above don't represent a full ground-up build out (though, if we were to do a "from zero" build, it would include pricing for cable runs, a PoE switch, etc). I also record all data straight to my NAS, so HDDs aren't a factor as well (it also takes out the headache of data redundancy, within reason).
Building the system was a breeze compared to running the cable needed for the cameras (not my strong suit). In setting up BlueIris itself, I found 2 settings that were critical for good
power/storage performance - the first was to set both cameras as "Direct to disk", so that the CPU wouldn't re-encode the signal coming from the camera. This drops average CPU usage to
11% in total for the system. The second was to use the setting
for variable bitrate rather than constant bit rate; because both of my cameras are in locations that have sparse activity, using a variable bitrate has huge storage savings - rather than
using 8-10Mbps or so, variable bitrate will use only 2-3Mbps.
The ultimate question when all is said and done is this: how power effecient is it? The cameras themselves are quite effecient, both of them using up only about 4W each according to my
PoE switch. The entire NVR build draws an average of 39W at the wall. I would have loved a solution that uses under 35W total, but coming in under 50W is almost as good.
By my calculations, my electricity cost (including taxes, fees, etc) is $0.13/KWh. That means that this system costs me $4.40/month to run. That cost would be more reasonable with the
addition of more cameras - the NVR wouldn't use too much more power with additional cameras, and with cameras using 4W each, I could scale to 10 cameras without breaking 100W total.