Oregon Scientific Weather sensors in Home Assistant

The only trouble with getting the RFXtrx 433MHz transceiver is that it tempted me to look for other devices to use with it…

My second device is an Oregon Scientific weather sensor. Most of my indoor ZWave sensors are multi-purpose. I got them for the door sensors, but they also provide temperature data as a bonus. I thought it would be good to have an outdoor sensor as well. Oregon Scientific are one of the big names in weather sensors and their sensors are compatible with the RFXtrx transceiver.

I picked up a kit with a base station and sensor, but you don’t actually need the base station if you’re planning to use the RFXtrx and Home Assistant – the sensor alone is enough. I just thought it would be good to have the base unit to see the data at a glance – and it’s also a handy way to see that the unit is actually working as expected.

The first step to getting it working with Home Assistant is to configure the RFXtrx transceiver to listen for the Oregon Scientific protocol. That has to be done with the RFXmngr Windows application. Plug the transceiver into a USB socket and fire up RFXmngr. Press the connect icon and select the USB port to use – there will only be one in the list unless you have other USB serial devices attached.

If you get an error at that point telling you that the FTD2xx DLL could not be loaded you’ll need to ensure that the USB to serial driver is installed. Go into device manager and find the RFXtrx device. Right click on it and select install drivers – this should automatically install the USB to serial drivers, and at this point the RFXtrx device will disappear from the device manager and you’ll see the USB to serial device instead.

Once you get the manager application working, select Oregon Scientific and click on “Set Mode”. All being well within a few minutes you should see the data coming from the sensor. Make sure you click on the “Save” button at this point – “Set Mode” alone does not make the setting persistent (and yes, I’m mentioning it because I forgot to save first time round and then wondered why it wasn’t working…)

Plug the RFXtrx back into your Home Assistant server and configure the RFXtrx sensor platform. This is documented pretty comprehensively on the Home Assistant website, but I’ll summarise it here for completeness. Basically the idea is to set the automatic_add parameter to find the ID of the device and then hardcode it so that you can configure it further. On the initial run your initial setup will be:

  - platform: rfxtrx
    automatic_add: true

That will give you an automatically generated entity:

You can now take that ID and add it into your configuration:

  - platform: rfxtrx
        name: outside

As it says in the documentation, by default you’ll get one sensor as an individual entity – in this case temperature. The other readings, such as humidity, will be shown as attributes.

Adding the data_type parameter allows you to track both sensor readings as individual entities:

  - platform: rfxtrx
        name: outside
          - Humidity
          - Temperature

So it’s a pretty straightforward setup and another cheap way to add additional sensors to your Home Assistant setup. The hardest part for me was finding a suitable place in my garden for the sensor that didn’t get direct sunlight at any time of day… luckily I bought it at the end of June and we got enough sunny days for me to make that assessment!

in Home Automation


  1. David Worton 21st August 2017
  2. seanbAuthor 21st August 2017
  3. Alberto 23rd January 2019

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