What This Reference Design Is
Fall detection that runs entirely on the edge device.
A fixed indoor camera, per-person tracking, and a temporal decision on whether someone went down.
A fall publishes one MQTT JSON message. Home Assistant, a nursing-call system or your own service subscribes. One event per fall, not repeated while the person is on the floor.
No video leaves the device. What crosses the network is a JSON message of a few hundred bytes, so it works offline.
Limits: the fall has to happen inside the frame. Started on someone already lying down, it reports the posture and raises no event. This is an assistive alert, not a certified medical or life-safety system.