set up rflink to respond to 433MHz devices and then integrate them with Home Assistant

in this project we integrate inexpensive 433MHz RF devices with modern smart devices

see also: 433MHz smarter letterbox

how to set up RFlink so that it will read your RF sensors

The easiest ready-to-go device to integrate 433MHz RF devices with smart home kit is the Sonoff RF Bridge. For example, I used it to sense when a door contact sensor reacts. I have 433MHz RF door bell buttons which I use to switch the room lights. And then there’s a water leak sensor which one day might alert me to a leaky pump. In all these cases a sensor transmits a wireless RF pulse which is picked up by a Sonoff RF Bridge. The bridge relays an MQTT message to Home Assistant. And then you can do anything. I have two bridges, the just mentioned one was installed with Tasmota, the other is straight out of the box. The unmodified one reacts to door contact sensors (eg my letterbox project), water sensors and motion sensors so this is the easier idea to start with.

But the examples above are lucky examples of compatibility. The Sonoff RF Bridge only responds to or controls some RF devices. You’d need to modify the Bridge (really hard) and install OpenMQTTGateway on it to give it more capability. (A lack of step-by-step instructions left me for dead). Even then you’d still find RF devices that the bridge didn’t respond to. Luckily I stumbled upon RFlink – an alternative that is capable of recognising Oregon Scientific, HomeEasy and Friedland RF devices – and even switching sockets. My RFlink project took ages because the instructions are all over the place. So the rest of this page aims to put them in one place and take us forward. There’s a lot to do BUT two+ years later it has not needed attention and it has not failed me.

what you need to set up RFlink

  • a Raspberry Pi running Home Assistant
  • an Arduino Mega R3 or clone (£10) to plug into the Raspberry Pi with a USB cable. I bought a clone Mega R3 from China. You just need an Arduino Mega R3 – anything else requires effort just to save £1.
  • an RF transmitter and RF receiver and some wires (as below = under £5). Or you can buy a kit from Nodo webshop
  • a tiny bit of soldering skill to attach the aerials
  • some 433MHz devices eg doorbell, button pushes, alarm, water, PIR sensors, HomeEasy stuff that you want to make use of
  • the RFlink firmware / software to put on the Arduino via a Windows PC. You do this bit once only
the wifi and ESP8266 on this board was unnecessary

install RFlink on the Arduino Mega R3 (in Windows)

Plug the Arduino Mega R3 into a Windows PC with a USB cable. Windows should install the necessary drivers for the CH340 and assign a COM port so that we can upload the software to the board.

You only need the RFlinkloader program and the C++ hex file highlighted. Read the txt files if you want to know more.

Above: download the RFlink firmware/software for the Arduino. Open the zip and launch the RFlinkloader application. Below: when the application launches it should find the COM port.

Notice that the software has a button to scan the available ports, a drop-down to select a COM port and a button to select the firmware file (rflinkloader.cpp.hex). You might need to press one of the physical buttons on the Arduino to wake it up. The firmware file uploads and your Arduino should be ready to go. When you click Serial port Logging you’ll see some signs that the software is working. Disconnect the Arduino so that we can add the RF receiver kit.

add the receiver and transmitter to the Arduino

You need six male-to-female Dupont wires, three for the RF transmitter and three for the RF receiver. Solder the correct aerial to the Antenna hole in each board. Connect them to the Arduino Mega as follows because the firmware is expecting to see things on the pins used here.

reconnect the Arduino to the Windows PC running RFlinkloader

I wondered forever how to upload the firmware. I did the upload before adding the sensors but that’s up to you.

With the Arduino and the RF kit connected to the PC click Serial port logging. Now send a signal from one of your RF devices and you ought see some output on the screen. Make a note of the device and what it’s recognised as. I’d recommend that you now power down everything RF to achieve radio silence. You can now identify the name and code of as much kit as you have. You can copy and paste the log text or write this on paper. The key to-do at this stage is to find out if RFlink senses your sensors. You will waste time later, changing batteries and so on, if a sensor appears dead because RFlink isn’t able to respond because say, the send frequency isn’t right. BTW if you want to use 866MHz sensors use the appropriate RF sensor / aerials.

If you find that some devices aren’t recognised, click Debug in the Rflinkloader window. You’ll at least find that they are working. I had the least success getting a response to piezo RF doorbells. I guess that the reason is to do with them being coded or tied to the receivers. You might contact the RFlink software maker about apparently dead sensors but first read how the protocol works here.

connect the Arduino to the Raspberry Pi running Home Assistant to get the USB port name

Click Supervisor > System > Hardware. If needed reboot the RPi to get the USB serial port. See the official docs

add some code to your Home Assistant configuration.yaml

The following code adds the RFlink integration and sets it to auto remember any RF signals it receives. Devices that are sensors (eg Oregon Scientific weather station) will be set as sensor entities. All other devices are understood as lights. Later on we’ll fix this and more. Right now, check your configuration and then reboot the Raspberry Pi.

  port: /dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0
# this port is shown in the image above. your detail might be different
  default: error
# add the following to the existing logger section
    rflink: debug
    homeassistant.components.rflink: debug

# add the following to the existing light section
  - platform: rflink
    automatic_add: true

# add the following to the existing sensor section
  - platform: rflink
    automatic_add: true

add the entities to your Home Assistant overview and automations

From now on Rflink will store the devices it discovers to Home Assistant. Home Assistant will create an entity for anything new. Of course you can display the state of the entities in the Overview / front page. However you must now do the work of identifying what sensor is what.

check the logs for probs

When the discovery above takes place Home Assistant keeps a log in the background. You can access this in the config folder – it might help you identify which device is which.

configure the light entities, write automations and scripts

When your switches (push switch; remote button) have all been identified (as lights) you can comment out the automatic_add line in your configuration.yaml. Your next step will be to re-configure the lights as switches. Notice the name “newkaku_004c899e_b” (below) which tells you the protocol, the code and the unit number needed to send the switch signal from Home Assistant to your device. I found that my things worked better when I added the switch detail – though it might not be essential.

automatic_add: false
 platform: rflink
     name: heunit1 friendly name

You can now place the entities you found on the Overview of Home Assistant. You can also incorporate the entities into an automation that turns on a light when a button is pressed.

keep a record of your codes!

I now put a label on each item and keep a record of the device RF codes and so on in a Google spreadsheet. Some devices change their codes over time and this is infuriating. If you spot a pattern to the code change you can set up an alias list as shown for the back_PIR below. I’ve included some real working examples below to show how we finally integrate RF devices into Home Assistant. After a reboot devices such as those below will appear as Entities in Home Assistant.

#my binary_sensor section of configuration.yaml for RFlink

  - platform: rflink
        name: back_PIR
        off_delay: 5
          - friedland_672caa6e_1
          - friedland_672caa6e_2

#my binary_sensor section of configuration.yaml for Tasmota Sonoff bridge
- platform: mqtt
    state_topic: "rfsignal/tele/RESULT"
    name: "walllightbutton"
    value_template: '{{value_json.RfReceived.Data}}'
    payload_on: "EFCA61"
    payload_off: "EFCA61off"
    device_class: power
    # device: black round tabletop button
    qos: 1
    off_delay: 3
#my switch section of configuration.yaml
platform: rflink
name: heunit1
name: hesocket3
name: hewhite7
name: hesocket1
name: hewhite9
name: bedroomlight2
name: bedroomlight1
name: pondlights

12 Responses

  1. Miranda P says:

    Hi Roger,
    Thanks very much, great write-up.
    Do you know whether the same/similar process will work with 868MHz devices? I know there’s an 868MHz version of the RF kits.

    • roger says:

      Hi, thanks for your question. Your first requirement is less about the frequency, it is that your devices are named on the list of compatible RF devices. For example many RF buttons and sockets work with RF Link and there are unexpected finds. Several doorbell buttons of mine didn’t work (possibly because they have some secure code to stop them working with the neighbour’s). So do that first. You might find OpenMQTTgaterway claims compatibility with your brand.

      Yes I’d say you were in with a very good chance of using 868MHz devices. Yes, the Nodo shop suggests it is indeed a case of using another transmitter/receiver pair for that frequency. Ebay sell modules too. What you read on this page took research and luck. Good luck

  2. Dave Q says:

    Is it possible to use the Mega+wifi R3 onboard WIFI instead of the USB serial

    • roger says:

      According to this doc Home Assistant can listen over TCP so a likely yes,

      I wanted to do this, to locate my RFlink somewhere central, but I found the RF signals to be quite good.
      Still I’d encourage you to explore your wish.
      While I do own similar kit I have still to understand how to send serial data from the Arduino > wifi.

  3. Kim says:

    Thanks for getting me up and running!

  4. Emile says:

    My turn to start dealing with RFlink ! I should have tonight the Arduino card and at least the RF receiver.
    I will try to get few sensors recognized in HA !

    • roger says:

      Best wishes!

      • Émile says:

        I’ve finished the setup.
        I’m using a real antenna, and condensators top optimize the reception of RXB6, but still very very weak reception…
        With a remote for switches, it’s working only once for 10 tries, and at less than 2 meters..
        Any idea what could be wrong ?

        • roger says:

          Well done for getting this far but Oh dear.

          I would have started with a regular receiver.
          I have never been lucky with aerials of any kind … However the range of my 443MHz signals is at least 50m.

          Best wishes.

  5. Dave says:

    Roger will any R3 mega work ?
    I notice on your list “+wifi”
    Do you have a link to the one you used or one in amazon

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