Help needed please, designing a home security system

Hey folks,

Want to add a security system to my house. I don’t need professional monitoring (but if it was cheap I’d be open to signing up). I know there are various diy systems out there, but what makes my situation a little unique is I already have a various mish-mash of equipment I should be able to utilize.

I have:

  1. 5 Arlo (non-pro) cameras
  2. Nest Hello Doorbell
  3. Smartthings hub (via Shield TV) and 3 multi-sensors
  4. Existing old ADT security system with 3 hard-wired door sensors and 3 hard-wired motion sensors – People have succesfully ported this to ST via Arduino and also integrated with Simpli-Safe by soldering it to their sensors

Ideally I’d be able to add a siren (even if it’s one that I manually trigger).

As far as I know, but please correct me if I’m wrong, to be able to utilize my equipment, my only option is to go the SmartThings route, correct? Particularly the arlo cameras and the nest doorbell. My concern with going the ST route is that their multi-sensors often report themselves as off-line and/or show an incorrect status of open vs closed. If I don’t use the ST multi-sensors would everything else be reliable? My second concern with going the ST route is that their phone sensor often reports me as being away when I’m home and vice-versa, which will affect arming/disarming.

Anyone have any ideas/thoughts of the best way I should go about this to help me design this?


Most smartthings models are simply not suited to being a primary security system because they are too cloud-based. You can’t even get a notification on your own phone even if you’re at home on the same Wi-Fi network unless the SmartThings cloud is operational. You can’t arm or disarm the security system if your Internet is out, a time when you might most want to.

If you follow any of the links about security on the SmartThings website now, they all take you to the ADT/SmartThings Model line, which looks like a decent competitor for a low-cost DIY system. It has a completely separate line of sensors which are definitely more reliable. It does have cellular communications to the monitoring center, but I don’t think that works for self notification on your phone, so it might not be a good fit for you.

The people in the following thread are using that model and should know the details:

But I couldn’t recommend any of the other ST hub models as the basis of a primary security system.

Also, ST is in the middle of a major transition right now: new hub, new platform, new app. And the new app has many fewer features than the classic app did: for example, in the new app you are not allowed to arm/disarm on the basis of anything other than time of day. You can’t arm based on Geopresence when you leave the house, or with a different button, or anything else. You also can’t automate unlocking your smart locks. So I would definitely wait until all of those changes finish happening before investing a lot more cobbling together a security system based on it.



Yeah, my issue with the ADT/ST one was that you had to use their sensors and I was trying to utilize mine. I don’t care as much about the multi-sensors, but the rest… I’ll look more into the limitations including how well it’s phone presence sensors work.

I think i’m ok with occasional outages as even pro systems have those and I have the original arlo app to fall back on. Weekly outages would be annoying though. Maybe though I could do something like HomeAssistant on a Raspberry Pi (although I haven’t researched it’s reliablilty yet).

Smartthings has had at least one outage in every month for the last 20 months or so except I think for January 2017. Not every customer is affected every time, and the amount of time varies, but it’s just nowhere near the standard of a pro security system.

Also smartthings can and does push out hub firmware updates which can either be denied nor delayed, and which will take your system off-line. Maybe only a couple of minutes, maybe a couple of hours. These have historically happened at least once a month. Again, just doesn’t fit with a security system.

Yeah, that level of unreliabilty is acceptable to me. I live in a very safe neighborhood, just want extra protection for my family. But again I have the arlo app to fall back on for the once a month outage. What’s not acceptable is how reliable the multi-sensors have worked. They’re correct and online less than 25% of the time for me, which is relatively useless.

I guess, taking the full outages out of the equation, could I expect that with arlo cameras and nest hello doorbell and hardwired alarm sensors feeding into ST, could I expect good reliability (when ST is online) or should I expect that those become as reliable as the multi-sensors once fed through ST?

I would start a new thread title specific to Konnected and ask people for their experiences, I just don’t know.

As you probably know, this is a very busy forum with a lot of posts, and you will tend to get more responses if the thread title refers to specific device models or a very specific use case. A lot of people just skip what look like general discussion topics.

Sounds good. I’ll do a little more research on it first. Thanks!

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