Temporarily hijack existing devices from another managed hub


#1

Hi everyone,
New to the forum but I’ve already learned a ton of stuff, so thanks a bunch to all.

Scenario: I’ve just moved into a house where the leasning company have their own PointCentral ADC-NK-100T smarthub and have two thermostats and a door deadbolt associated to it. The thermostats Building 36’s B36-T10 thermostats OEM’ed by Alarm.com and the deadbolt is a Yale Real Living lock with a YRMZW1-US Z-wave module inside. This setup is pretty lame as one can at most add some lights and that’s all she wrote.

The leasing company charges about 20 bucks a month for a Smarthouse service, giving access to these 3 devices, however one can fortunately cancel the option at any time. I’m 99% sure that they just nuke the PointCentral account and leave the equipment on-site for the next tenant.

Evil intentions: Since I’m now the proud owner of a ST hub and a few devices, once I’ve cancelled the PointCentral service, I want to unplug their hub and then assimilate the thermostats and the lock into my little Z-wave collective and have them talk to my own ST hub instead. (cue nefarious giggle). Having done my homework, it looks like both the thermostats and the lock is SmartThings compatible. However, once I move out, I need to restore everything to previouis working order, so the PointCentral hub talks to the the 3 devices again. It should be said that one doesn’t have full administrative access in the pointcentral solution, i.e. you can’t add

The questions:

  1. Where is the association between the hub and the device stored? On the hub, the device or both? I guess I need to understand the business of inclusion and exclusion a bit better.

  2. What happens when first a hub A and device B are talking, then you power down hub A, then put device B in inclusion mode, connecting to new hub C. Some time later in life you power off hub C. Will device B still reconnect with hub A? Or does all this depend on the device type?

Random thoughts:
I’m presuming the Yale is relatively easy to deal with, provided I spend 70 bucks on some new “brains” (Z-wave module) for it. Then I don’t have to worry about master pin either. I’d then just pop the original module back in at moveout. However I’m not sure what to do about the thermostats. On one hand I would love a pair of shiny learning Nest thermostats, and just rewire a new midplate temporarily. On the other hand if I can hijack the two B36 thermostats to begin with without screwing up the PointCentral system, I’d be a happy camper.

Any thoughts how best to go about this? Any insights would be highly appreciated, thanks!


(Nathan Curtis) #2

The only way to include these ZWave devices into yiur system would be to first do a general exclude to each device. ZWave allows a general device exclude to be issued from any hub. So yiur ST hub could do this and essentially disconnect them from the existing network. Great, you can now include them into your network, right? Kinda…

It’s all great until you move out. They would need to be removed excluded from your ST hub and reset. ST remove commands or another general exclude. So far, so good.

But you don’t have access to the other network, soooo you can’t re-add them to the old hub. Also, the other network might note the devices disappeared… Again you don’t know how it works behind the covers. I’d certainly notice if a bunch of my monitored devices dropped out, but then again I monitor my environment pretty closely.

So in theory yeah, maybe? In practice it’s not as easy. Not to mention a very gray area ethically and you be in a situation where you may have to answer some u comfortable questions.


(Glen King) #3

If they nuke the account and leave the equipment, then you need not worry about re-adding when you leave. Simply perform your general exclude on the way out the door, and let them worry about reconnecting the devices to their network.

But first, I would call them. Tell them you are canceling, and ask what happens to the gear.
If they “just leave it”, then hypothetically the home could be demolished and they would not care about its fate. If that is the case, then do as you wish. But if they wish to come collect it, let them do so.


#4

I think you’ve gotten very good advice in the previous posts, but to answer your specific questions about how the device knows what network it belongs to… (By the way, this is not “association” which has a very specific meaning for Z wave. This is part of establishing the network.)

Z wave only allows a device to belong to one network, and each network can have only one primary controller (hub). The primary controller keeps the full list of all the devices that have been included to its network. Each individual device knows who the primary controller is and then a few of its neighbors.

Any Z wave controller can issue a “general exclude.” This is supposed to take care of the situation where the primary controller itself has been damaged. You can bring in a new controller, and have it issue the general exclude. At that point, if you physically manipulate any nearby Z wave devices, regardless of what network it belongs to, and put it into “exclusion mode” it will accept the general exclude command and clear out its previous network information. That’s all it does. Now it’s a clean slate device again.

You then put the Device into inclusion mode and have the new controller issue the include and the device will then be told its new network ID on the new network, it will recognize its new primary controller, and if necessary there will be an exchange of security keys.

So this is a two-step process. First clear out all the information that tells the end device what network it belongs to. That’s the “general exclude.” Then add the new device to its new network just like any new device.

Since you have cleared out all of the information about the old network, there’s no way to do what you were imagining and put it back on the old network in any kind of surreptitious way when you are ready to move out yourself. You have to go through the normal two-step process: exclude from its current network, and then add it to the other network. But while it’s on your SmartThings network, it doesn’t retain any of its information from the previous network. It would be added as a completely new device if you wanted to put it back again. And it would probably get a different device ID, which would mess up any existing logic. (That’s really the step that’s most likely to trip you up with this unless you have the company’s approval.)

So, to answer your question… The information resides in both places. The hub knows what devices belong to its network. The end devices know which primary controller (hub) owns the one and only Z wave network they currently belong to. In order to move a device to a different network with a different primary controller, you have to first clear out all of the stored information on that device about the previous network.


#5

Gentlemen, thank you very much for some very detailed answers.
In conclusion it would seems an easier and safer approach to replace the thermostats, either rewiring for another midplate or finding a thermostat compatible with the B36’s plate. Any suggestions there? This is the specific device.

Anyway, I at least that way I will own the thermostats and can store all the PointCentral gear, until such time I move into my own home in a year or two, putting things back the way they were.


#6

Just an update on this scenario. Eventually I got around to do something about it. Before I went and bought new gear, I called the leasing company, fessing up to what I wanted to do. As it turns out they do not care what I do with the equipment, as long as it remains in the house at moveout. In other words, they do not care that I break the pairing with the PointCentral hub. I presume they reset everything, before someone else moves in. So now I’ve adopted the two thermostats, and will be working on the lock later this week

Morale of the story: Call your leasing company first :slight_smile: