Communicating with 433MHz things

I am trying to control two kind of devices that operate in the 433MHz radio bands:

  1. One Somfy RTS awning
  2. Four power sockets from Silvercrest (LIDL)

Obviously, I would need a hardware peripheral that takes commands form openHAB and converts them to RF signals. Looking around here, I found two potential candidates:

  1. A RFXCom RFXtrx433XL transceiver
  2. A Cc1101 Usb Light transceiver

Looking in the bindings, I saw the URTSI binding, but it’s not clear to me if that page is talking about a physical box bought from Somfy or a “protocol” that both the transceivers above can use.
Also, I could not find any binding specifically for these 433.92MHz power sockets, but I believe they are so called generic remote controlled power sockets and may already have support via something else.

What would you recommend that I look at? Would you suggest another communication dongle?

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I use a Sonoff RF Bridge flashed with tasmota to activate my roller shades, a chime and a few RF outlets. The tasmota software can be integrated with OpenHAB using MQTT or with direct HTTP calls via the HTTP binding. I use the latter in a rules file to replay the POST commands used in the tasmota UI, captured from a web browser.

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Are you sure that LIDL power sockets are 433.92MHz ? In Portugal, Spain, UK and probably other countries the LIDL smart home line is Zigbee.

another option: rflink

broadlink rm pro

Thanks, that’s a great suggestion. However, it seems tasmota cannot do RTS protocol, but I’ll continue looking around. Or maybe I need one adapter for 433.92 and another one for 433.42 (RTS)

Yes, those are the power sockets sold in a pack of 4 right before Christmas time. It’s written 433.92MHz on the remote which has 5 pairs of “on/off” buttons, one for each socket, and one to control them all at once.
The LIDL smart home objects have been launched in France just two weeks ago, and yes, they are zibgee based, but those power sockets I’m interested in controlling are much older than that.

This one looks the most promising indeed, I stumbled across it right after having posted my message above. There a detailed explanation here for instance, and even a specific module for RTS from Nodo.
However, there is no binding for openHAB 3 to be found in the repository accessible via the web interface. The Nodo website mentions this one: GitHub - cyrilcc/org.openhab.binding.rflink: RFLink binding for OpenHAB 2.0
But it seems to not have been updated for a while and appears to be stuck on openHAB 2
But maybe it’s not that difficult to upgrade it, I’ll add that to my “to-do” list.

Thanks, I did not know about that one. For others looking at this, it’s the “plus” version that can do 433MHz. But it appears that it cannot do RTS communication and also that it’s binding is not (yet) available for openHAB 3.

Note that Somfy RTS operates at 433.42MHz.
The RFXtrx433XL operates on multiple frequencies, 433.42MHZ, 433.92MHz and 434.50MHz (MCZ stove)

Yes, I discovered that as well, Somfy is really an annoying provider.
I have also seen this RFXCom transceiver, but to me it has two drawbacks: it’s expensive and it’s out of stock everywhere I look. However, that’s the only one (so far) that has a openHAB 3 binding available.

rflink device plugs straight into your system as a serial connection (via usb). You’d use openhab’s serial binding. I used it on OH2.5 but I no longer use any 433mhz stuff now.

It seems that with RFlink you can only have either 433.92MHz or 433.42MHz but not both in one system? I suppose you can have two devices, one for each frequency.

Ah yes, that’s one possibility indeed. The protocol is described here but I was hoping a binding would make things a bit less error-prone by avoiding repeating the “header” parts of the frames for instance.

That’s what I’m getting at indeed, even if it seems people indicate that sending packets to a 433.42MHz device (the awning) with a 433.92MHz emitter works relatively well.

fyi, I built my own rflink hardware using an arduino mega (already had one lying around) and a cheap receiver from ebay. I never got the transmitter to work but I didn’t need it at the time.

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Related to Rflink on OH3:

There is some work ongoing on github for this. I am running now for approx 2 weeks on the new binding version w/o any issues.
You can find the link here:

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bunding available here

When I was looking around for my Somfy things, the RFXcom wasn’t available anymore. I ended up buying the Arduino RFLink board. But the interface is poorly documented and it was not clear if an OH binding was still operational or being maintained. The extended RTS protocol also didn’t look to be working correctly (extended RTS protocol is needed to control my awning slats and light).
So after some investigation I wrote my own Arduino SW for the RFLink board. I now have the full base+extended RTS protocol operational on the Arduino RFLink and communicating with my own driver software running on PC or Raspberry and controlled using the executeCommandLine in the OH rules.
My future plan is to get rid of the Arduino RFLink and use a RFM69 module connected directly to the Raspberry. It has a programmable frequency and transmitter power so I may also use it to control devices out of my Z-Wave range.
I might even look into modifying an existing OH binding to use instead of the combination executeCommandLine/driver SW, but while I am quite fluent in C development, Java is completely new for me.
A collaboration with someone Java oriented could be an option to accomplish this.

You might want to join efforts with this repository:

It’s basically a revival of the RFLink project, based on the last publicly available sources (R29)
The people behind it are quite active, there is even a discord available here:

The main channel is in French because the two main developers are French, but there is an “English chat” channel for those of you who are not at ease with Molière’s language.

Note that the project advertises the sending/receiving of messages via MQTT, but they kept the “serial port” functionality so that it is usable with the original RFLink binding.

I’m currently waiting for my ESP32 board and RXB6 transceiver to arrive so that I can start playing with this.

Note that there is also support for the RFM69 module, so you should feel right at home for your future project.

OK, thanks, I’ll have a look there (even though my knowledge of French is about the same level as Java :smile:).
I also did find some sites with RFLink release R35 (e.g. tazounet, seahu on Github), but while there are quite some plugins available, the Somfy RTS plugin is missing. Which is why I decided to just write it myself - my OH system is currently mainly Z-Wave so I don’t need all the other RFLink plugins.
Somfy does have a Z-Wave to RTS module, but only for the US market (with a different Z-Wave frequency there so not usable in the EU).

Out of curiosity, is your code available somewhere online? Like in a Github repository maybe?

I use an esp32 with c1101 transmitter and this library. Works perfectly to control my Somfy sunblinds:

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No, not at the moment. Somfy has some patents about RTS; and the disappearing of code on internet and device sellers has made me a bit suspicious. I need to have a chat with a patent attorney I know before doing so. Especially the extended protocol may be problematic since it has an extra patent to protect it.
I took a quick look at the Legion2 library mentioned here and that does indeed contain code for the base RTS protocol.