The Sound agent lets your house speak up through the loudspeaker of a Mac: a doorbell, a gong at dinner time, a dog that barks when somebody comes to the door while nobody is home. It comes with twelve sounds (buzzer, church, dingdong, dogbark, dogwhoo, gong, hello, knocking, laser, scream, thunder and xylophone) and announces itself and its sounds to the Engine as soundmachine, so a rule needs no definition at all: sound dingdong on soundmachine.
It is a small Mac app (macOS 10.14 or later) without settings: start it, and the Engine finds it. An old Mac in the hallway or the study makes a fine doorbell. There is no Linux version yet. The example "Somebody at the front door" shows it at work.
How to download and install: see the Introduction.
Download here: