Adding 433MHz DSC security sensors using an RTL-SDR antenna:

As I mentioned earlier, my house came with an ADT DSC Impassa security system using a bunch of 433MHz DSC Door/Window and Motion Sensors. I spent a lot of time trying to figure out the best way to use these in HA, and settled on RTL-SDR. There is definitely a learning curve with this and I recommend anyone intending to use it read the docs carefully.

I used this RTL-SDR dongle with this antenna. I installed the Mosquito and rtl_433 add-ons, and the MQTT integration. I followed the directions in the documentation to get these up and running, and did not need use an rtl_433 config file. But there are a lot more in-depth options if you do. I tried the auto-discovery add-on but it turns out it doesn't have profiles for the "Closed" topic for DSC security sensors, so I ended up getting a bunch of devices with battery state and cover state entities (and some TPMS tire sensors), but not the door closed entity I wanted, so I rolled back and got rid of that.

I read and tinkered a lot. And then I added MQTT-Explorer (thanks, Thomas Nordquist!) and was able to actually see my topics. That was the last piece f the puzzle I needed in order to actually publish topics for testing, and see what my topics were publishing on their own. In short, once the rtl_433 topics are publishing in MQTT you can make entities based on the topics in your configuration.yaml. that's one thing that held me up. There was a lot of old information out there that was no good since the update to how MQTT works in HA, so I'll share part of my yaml here in case anyone needs it. I started with just editing in my config.yaml, but later split the configuration out to a mqtt_binary.yaml file. Here's what it looked like:

mqtt:
  binary_sensor:
    - name: "Garage Entry Door"
      state_topic: "rtl_433/9b13b3f4-rtl433/devices/DSC-Security/3006353/closed"
      payload_on: "0"
      payload_off: "1"
      device_class: door
    - name: "South Patio Door"
      state_topic: "rtl_433/9b13b3f4-rtl433/devices/DSC-Security/2480377/closed"
      payload_on: "0"
      payload_off: "1"
      device_class: door

Payload let me set what 0 and 1 means, so it reads as "on" when the sensor says 0, which is the expected input for a door device being open. There's a whole list of device classes you can use for binary sensors. Since these can't be edited in the UI, you need to set parameters here so you get the right behavior and icons. But the Motion Sensors held me up for a bit. For motion sensors, it only sends when sensing motion, so there's no "event=0" or "cleared" signal. For this I had to add a shutoff or the retained state is always "detected." At first I used "expire_after: 30" which cleared the state after 30 seconds, but the downside is the motion sensor device shows "detected" or "unavailable," but never "cleared." Later I got some help here and learned that setting "off_delay" to 30 seconds would flip the payload back to off, giving me a retained off state that remains present even after reboot.

here is the example section from my mqtt_binary.yaml:

# DSC Door Sensor:
- name: "Front Entry Door"
  state_topic: "rtl_433/9b13b3f4-rtl433/devices/DSC-Security/3130841/closed"
  payload_on: "0"
  payload_off: "1"
  device_class: door
# DSC Door sensor on a Window:
- name: "SE Office Window"
  state_topic: "rtl_433/9b13b3f4-rtl433/devices/DSC-Security/2747986/closed"
  payload_on: "0"
  payload_off: "1"
  device_class: window
# DSC Motion sensor:
- name: "Stairway Motion"
  state_topic: "rtl_433/9b13b3f4-rtl433/devices/DSC-Security/3783986/event"
  payload_on: "1"
  payload_off: "0"
  device_class: motion
  off_delay: 30

​

In my configuration.yaml file I link to this in my config splits:

# configuration split references:
automation: !include automations.yaml
script: !include scripts.yaml
scene: !include scenes.yaml
# manual set groups like the family presence groups:
group: !include groups.yaml
# ios events for watch and iphone: 
ios: !include ios.yaml
# rtl_433 and mqtt sensors setup:       
mqtt:
  binary_sensor: !include mqtt_binary.yaml