I know Xiaomi / Aqara are not fully supported by HE but they do work great with the occasional fall off.
So I have modified a Piston that I found a while back and used with SmartThings to send alerts when a sensor falls offline. Since HE doesn’t report if a device is offline but the new drivers report presence I modified it so if the Presence changes to Not Present it’ll alert.
In order for this piston to work you need to be using Xiaomi / Aqara devices and using the latest drivers that check presence…
