Virtual Heartbeat Presence Sensor
From Hubitat Apps
excuse poor formatting!
A Virtual Heartbeat Presence Sensor is a Virtual Device developed for use with the Maker API. It to be used with external devices (such as ESP8266/32) that send a message when active and indicate that they're not active by their silence!
The Heartbeat concept is basically similar to a Watchdog.
This device responds to "present" and "not present" events as you would expect, but it can be configured to change state X seconds/minutes after the last event was received. There's nothing particularly new about this, Cobra has a similar device, just a switch not a PresenceSensor.
Code at https://github.com/rummyr/Hubitat/tree/master/VirtualDevices