Thanks!
Just to clarify, do you mean leaving the batteries out of the ST Hub? So will the ST Hub automatically send an alert when it loses communication or do I have to put in code somewhere? Iāve seen a number of code/program posts, but I donāt know how to use them ā¦ yet.
Yup, if you have a V2, just leave the batteries out. If you have a V1, you have literally zero steps to take. No code necessary with either hub, when the cloud canāt reach your hub, it will tell you itās inactive. Easy.
Cool ā¦ thanks again!
Right, if you donāt need the ST hub to be operational, then its losing connection with the cloud account will cause a notification to be sent. So as always, it just comes down to the details of what you need.
As for the link to the thread that discusses the V1 motion sensor, that device is no longer sold. Which is unfortunate, because it was one of the few that would send a notification when it shifted from mains power to battery power. It was very popular in 2014 for this kind of purpose. But thereās been two more generations of that device since then, and itās really hard to find the v1 motion sensor to buy now.
Actually Iād prefer both approaches ā¦ the batteries out method and one of the wellness check SmartApps.
Would this Wellness Check SmartApp work with my sensors? If so, how do I ādownloadā or use the app? ā¦ https://github.com/erocm123/SmartThingsPublic/blob/master/smartapps/erocm123/device-monitor.src/device-monitor.groovy
Thanks again!
Custom code FAQ. 
Another option is the following:
If you have an android phone or tablet that you are planning to use as a main controller, install tasker and sharptools. Then set Tasker to toggle a virtual switch when the power goes out which can trigger a notification.
Alternatively you can use core and tasker to do the same thing and bypass the virtual switch completely.
Thank you!
Cool idea ā¦ Iāll try to do that too. I actually use Automagic Premium instead of Tasker, but hopefully it will work.
Iām happy to see all these good ideas.
Thanks!
Tasker is pretty powerful. You can even use it and a few other plugins together to control your home. Case in point:
Very cool ā¦ it sure is going to take me a while to absorb all this. It sure it fun, though!
Well ā¦ I got the "Device Monitor - Get Notified if Devices Stop Reporting " working, but noticed it only alerts me after the device has been inactive for an hour. So Iāve been trying to figure out the solution which uses a relay with a door/window sensor. I think I get the basic concept, but was wondering if anyone has any specifics of how to wire the relay to power and then how to wire the relay to the z-wave window sensor so it will send an alert.
Thanks for any help!
I have AT&T Digital Life - they use z-wave for their devices, but some of their devices have a battery backup - I have integrated that into ST (I can see all window and door contact sensors in ST) - and some of the devices (keypad, repeater, siren, DLC) will let me know if the power is off of mains or battery. But Iām a special case 
Perhaps one could find a device that has a battery backup - maybe the wired Nest Protect, for example? and use that to figure out power status.
Thanks ā¦ That soundās like a good solution. Although, Iām wondering if it will have the same delay as the wellness check SmartApp. It probably will depend on what device I find, so Iāll do more searching to see if thereās something what would send an immediate alert.
Thatās why Iām leaning toward a relay with an open/close sensor. It sounds like it sends a quick alert ā¦ that is if I can figure out how to do it and what sensor to get.
The Aeotec siren has a battery backup. Check the DTH to see if it provides information on the power supply, whether mains or battery - you should get an immediate warning, if the siren reports that.
BTW, I tried this yesterday and it worked great! Thank you for the suggestion. It has a 10 minute delay, though, to get a notification. Is that a factor of the ST Hub?
It looks like I still have a ton to learn, since I didnāt know what a DTH was. Now I know itās a Device Type Handler. I think I found the Aeotec Siren DTH at ā¦ https://graph-na02-useast1.api.smartthings.com/ide/device/create. How do I tell, from reading the DTH, whether it has a power supply alert function? Or should install the DTH and see what choices it give me? Sorry for the ignorant newbie questions.
I donāt see any power related thing in there 
Are you looking at the Metadata to figure that out? Based on Metadata, it looks like the Aeon Multisensor 6 might have the capability for power supply, if Iām reading it right ā¦ https://graph-na02-useast1.api.smartthings.com/ide/device/create
capability "Motion Sensor"
capability "Temperature Measurement"
capability "Relative Humidity Measurement"
capability "Illuminance Measurement"
capability "Ultraviolet Index"
capability "Configuration"
capability "Sensor"
capability "Battery"
capability "Health Check"
attribute "tamper", "enum", ["detected", "clear"]
attribute "batteryStatus", "string"
attribute "powerSupply", "enum", ["USB Cable", "Battery"]
Thatās the multisensor, not the siren. Yeah, that powerSupply would be it. The multisensor canāt be powered by both, unfortunately, so it wonāt serve your purpose.