Device Activity Check - "Checking In" activity

[Ranchitat]

Something that might work for you is Simple Idle Alerts, part of the Simple Series.

@dennypage

• Simple Idle Alerts

This application provides a simple alert notification system for devices that have not been updated for a period of time. This is useful for ensuring devices that are expected to periodically report status, such as temperature sensors, do not silently go offline. I also use it to alert me if my weather information goes stale.