Some of my brain dump...
One has to have a reasonable expectation of "security" devices/"solutions."
I was engaged in MANY "survivalist" "security" discussions and found that with few exceptions NOBODY mentioned having a dog as a security element. It always seemed to come down to some "mechanical" solution: guns, mostly; with a dog you'd get some time to wake up and get your bearings (people just "think" they can wake from a dead-sleep and deal with any threat!).
Do not put all trust in a single security element. Security is about LAYERS.
I have various animals that can and do alert: I'll leave it at that because I'm not going to give away my "secrets."
Another layer is my fencing, which, though anyone can get through it, is yet one LAYER: one is forced to ingress/egress through my gates (not going to be able to drive through my fence). I have limited access to my home site: with the ditches and whatnot it's like being protected by a moat.
My watchful neighbors are yet another layer. Gotta go by them coming or going.
Now, on to the subject of this thread...
I have a techie "surveillance" system that I built from the ground up (open source software Zoneminder [unless you're a real techno-head I'd say to stay away from it]). System basics are:
- Cameras (Dahua) using POE (hardwired) to a simple POE switch which is connected the gigabit ethernet port on a dedicated server;
- Server is over-spec'd because I figure for a bit more $$ I'd prefer the piece of mind (as camera access goes through the server it's more important to have a robust server- direct streaming to cameras won't require as much CPU capacity);
- Two networks managed by the server, one is the cabled cameras and POE router and the other is a wifi to connect to my WAN router/modem (ISP), which is about 50' away in another building;
- My ISP provided modem/router allows for a DMZ, and this is where access to my server and cameras go through - LOCAL LAN is NOT accessible through the DMZ, which is how it should be done to keep your household computing devices walled off from WAN attacks;
- ALL equipment is connected to UPSes, so should power be dropped there's still some recording possible (I've got a generator that powers everything, so if I have a lengthy power outage I'm good- but, availability of the service provider's equipment is another thing and is outside my control).
Setting up cameras is a bit of work, getting them to cover what you want to cover: if possible have them protected/covered (if you're in a rainy location, such as I am, the views would be akin to the inside of a car wash!) Especially tricky if you're doing motion triggering: it's been noted what kind of hassle this can be with rapid changes in sun condition (clouds) and such, but it's just something that one has to live with. I've got one camera facing a direction in why smoke from my wood stove goes and this tends to trigger alarms (depending on how much smoke; I cannot turn down the sensitivity w/o hampering my ability to catch other motion of interest).
If you're looking at getting pan and tilt cameras (whatever they're called) you might need separate power. Check power requirements: there are POE switches offering different levels of power, though I don't know up to how much. I would have liked playing with such cameras but as I mounted my fixed position cameras to pretty much capture everything I need to monitor there's little need for more capable cameras.
My Dahua cameras are IR, and they actually worked pretty well, but I ended up disabling IR as they'd trigger alarms each time they cycled between day and night modes AND bugs loved to hover around them at night, resulting in more triggering! I have building lights that are activated from motion/IR, and when those lights come on the cameras will then alarm and record.
As has been mentioned, counting on high resolution isn't a good idea. It's nice to see pretty pictures, but masks and such can thwart that. High resolution capturing requires lots of data storage. And speaking of storage, I don't know what the consumer grade systems have, but there are varying grades of drives, with some pretty much targeted toward heavy write cycles. I'm running a higher grade mechanical harddrive for data (system drive is separate and is a non-mechanical/memory type).
One of the bigger hurdles with this stuff has to do with interfacing to the "outside" world. Managing live stream connections, recorded video, and, perhaps, notification alerts (I've kind of struggled with this- more and more ISP require certified/identifiable server connections, and this is a whole nuther bag of worms; it's why many "solutions" come with an extra service fee [I'm too cheap; and, I don't want to load/store stuff up in the "cloud"\]).
My cameras once managed to capture a racoon: keep in mind that we'd had no traces of raccoons in over 7 years!). We'd been losing a lot of eggs and some of our fowl. We have a game camera but where to set that up? The surveillance camera capture was huge in that we then knew for sure what we were dealing with (and were then subsequently able to mitigate the situation).
As I noted above, one of my cameras will pick up smoke from my wood stove. If there's any big issue, house catches on fire, I'll be able to find out fairly quickly!