The rfxtrx platform support binary sensors that communicate in the frequency range of 433.92 MHz. The rfxtrx binary sensor component provides support for them.

Many cheap sensors available on the web today are based on a particular RF chip called PT-2262. Depending on the running firmware on the RFXcom box, some of them may be recognized under the X10 protocol but most of them are recognized under the Lighting4 protocol. The rfxtrx binary sensor component provides some special options for them, while other rfxtrx protocols should work too.

Setting up your devices

Once you have set up your rfxtrx hub, the easiest way to find your binary sensors is to add this to your configuration.yaml:

# Example configuration.yaml entry
binary_sensor:
  platform: rfxtrx
  automatic_add: True

Open your local home-assistant web UI and go to the “states” page. Then make sure to trigger your sensor. You should see a new entity appear in the Current entites list, starting with “binary_sensor.” and some hexadecimal digits. Those hexadecimal digits are your device id.

For example: “binary_sensor.0913000022670e013b70”. Here your device id is 0913000022670e013b70. Then you should update your configuration to:

# Example configuration.yaml entry
binary_sensor:
  platform: rfxtrx
  devices:
    0913000022670e013b70:
      name: device_name

Do not forget to tweak the configuration variables:

• automatic_add (Optional): To enable the automatic addition of new binary sensors.
• device_class (Optional): The type or class of the sensor to set the icon in the frontend.
• off_delay (Optional): For sensors that only sends ‘On’ state updates, this variable sets a delay after which the sensor state will be updated back to ‘Off’.

Binary sensors have only two states - “on” and “off”. Many door or window opening sensors will send a signal each time the door/window is open or closed. However, depending on their hardware or on their purpose, some sensors are only able to signal their “on” state:

• Most motion sensors send a signal each time they detect motion. They stay “on” for a few seconds and go back to sleep, ready to signal other motion events. Usually, they do not send a signal when they go back to sleep.
• Some doorbells may also only send “on” signals when their toggle switch is pressed, but no “off” signal when the switch is released.

For those devices, use the off_delay parameter. It defines a delay after which a device will go back to an “Off” state. That “Off” state will be fired internally by Home Assistant, just as if the device fired it by itself. If a motion sensor can only send signals once every 5 seconds, sets the off_delay parameter to seconds: 5.

Example configuration:

# Example configuration.yaml entry
binary_sensor:
  platform: rfxtrx
  automatic_add: True
  devices:
    091300006ca2c6001080:
    name: motion_hall
    device_class: motion
    off_delay:
      seconds: 5

Options for PT-2262 devices under the Lighting4 protocol

When a data packet is transmitted by a PT-2262 device using the Lighting4 protocol, there is no way to automatically extract the device identifier and the command from the packet. Each device has its own id/command length combination and the fields lengths are not included in the data. One device that sends 2 different commands will be seen as 2 devices on Home Assistant. For sur cases, the following options are available in order to circumvent the problem:

• data_bits (Optional): Defines how many bits are used for commands inside the data packets sent by the device.
• command_on (Optional): Defines the data bits value that is sent by the device upon an ‘On’ command.
• command_off (Optional): Defines the data bits value that is sent by the device upon an ‘Off’ command.

Let’s try to add a new PT-2262 sensor using the “automatic_add” option and have a look at Home Assistant system log.

Have your sensor trigger the “On” state for the first time. Some messages will appear:

INFO (Thread-6) [homeassistant.components.binary_sensor.rfxtrx] Added binary sensor 0913000022670e013970 (Device_id: 22670e Class: LightingDevice Sub: 0)

Here the sensor has the id 22670e.

Now have your sensor trigger the “Off” state and look for the following message in the Home Assistant log. You should see that your device has been detected as a new device when triggering its “Off” state:

INFO (Thread-6) [homeassistant.components.binary_sensor.rfxtrx] Added binary sensor 09130000226707013d70 (Device_id: 226707 Class: LightingDevice Sub: 0)

Here the device id is 226707, which is almost similar to the 22670e we had on the “On” event a few seconds ago.

From those two values, you can guess that the actual id of your device is 22670, and that e and 7 are commands for “On” and “Off” states respectively. As one hexadecimal digit uses 4 bits, we can conclude that the device is using 4 data bits.

So here is the actual configuration section for the binary sensor:

platform: rfxtrx
automatic_add: True
devices:
  0913000022670e013b70:
    name: window_room2
    device_class: opening
    data_bits: 4
    command_on: 0xe
    command_off: 0x7

The automatic_add option makes the rfxtrx binary sensor component calculate and display the configuration options for you in the Home Assistant logs:

INFO (Thread-6) [homeassistant.components.rfxtrx] rfxtrx: found possible device 226707 for 22670e with the following configuration:
data_bits=4
command_on=0xe
command_off=0x7
INFO (Thread-6) [homeassistant.components.binary_sensor.rfxtrx] Found possible matching deviceid 22670e.

This automatic guess should work most of the time but there is no guarantee on that. You should activate it only when you want to configure your new devices and leave it off otherwise.

Known working devices

The following devices are known to work with the rfxtrx binary sensor component. There are too many other to list.

• Motion detectors:
  • Kerui P817 and P829.
  • Chuango PIR-700.
• Door / window sensors:
  • Kerui D026 door / window sensor: can trigger on “open” and “close”. Has a temper switch.
  • Nexa LMST-606 Magnetic contact switch.