Homekit critical alarm for security system

Hello, I have set up an alarm system for our house if we are at home. For example: Somebody opens a window or door and we get a acoustic signal via Sonos in our bedroom. I would like to extend the functionality to homekit, but I´m not sure what will be the best way. My approach is to create a kind of a dummy sensor and connect it with the existing automation or similar. In this case I would need a device_class who could use the homekit critical alarm.

Maybe some of you has a smarter way!?

Okay, got it. Sensor template + input boolean :crazy_face: