MQTT guidance on 433mhz SDR via MQTT. Unsure how to annotate and then which trigger for automations

[blazing escarp]

New to this discord, rule 3 is describe the problem.

Problem: An elder needs a life alert/alarm system, but not full blow LTE/4G modem. Too expensive for monthly service. They now make 433mhhz alert systems for elderly - it's really just a remote doorbell. Perfect, cheap and long range. Problem is if they are home alone and nobody to hear the Alarm sound going off. I want to use SDR/433mhz to "hear" the button broadcast and then do SOMETHING. In this case - long term will be text/voice call via cloud provider, but that's not where I'm stuck.

I got the hardware working up until doing the alerts/triggers.

Hardware:
Button --> RTL-SDR USB --> USB RasPi 3b+ --> rtl_433 plugin --> MQTT --> HA

Ideally, ONE of the 3 buttons is a "test" and will just test connectivity and send a text to ONE phone number. The others, will do the real call list/911/emergency/etc. This is just a simple API/endpoint modification, not concerned with how to do this part too much.

I've read most of the docs 1 level deep, used the discord search. Hope this hasn't been answered.

I'm pretty sure I could cobble together SOMETHING that triggers this behavior. But wanted the HA Discord take on how I can put a little more effort or setup now, so that it's much more flexible in the future. Is reddit a better choice? I don't like posting much online.

Each of the buttons/alarms in the picture is like $8.

Ideally, this would be extensible enough that I could onboard a "new" button that just toggles the garagedoor/light/etc. In the MQTT Message, I think device ID is enough to use. CMD and Tristate seem vaguely random. The button has no config to change. Internally, the Alarm unit has a "pair" button but that's it. Have to crack the case to get it open.

Checkout the attachments please.

I'm stuck on what "MQTT Component"(Alarm control, button, event, notify, sensor, ???, etc.) to use.

After which MQTT Component to use -- which HA Trigger(Event,MQTT,Template,Device,???, etc.) to use?

Apparently I've hit the length limit.. sorry! Just wanted to explain all of it at once.

This is my current MQTT config yaml... but just for reference on what topic I'm looking at.

mqtt: sensor: - name: "Generic Alarm" unique_id: "generic_remote_60376" state_topic: "rtl_433/9b13b3f4-rtl433-next/devices/Generic-Remote/60376"

Triggers added for clarity

[rare sonnet]

They're just buttons, so that's the mqtt component to use
It will create an entity that (similar to an input_button) has a state that is the last time it was pressed, the easiest trigger is therefore just a state trigger as this will change every time the button is pressed