Questions

[jdonnerstag]

Hi Henry,

I coundn't find any email or other ways of contacting you. Hence this way.

I have an electrical engineering background, though many years, ago, and no experience with SDR yet. We have a Somfy shader at home and I'd like to use it to learn and apply SDR. Hence my interest in your project and the information provided.

In your explanation you're suggesting "RTL_SDR by Radioddity". Am I right to assume this is still your suggestion? With or without an additional antenna (the link doesn't work anymore)?

I'm a little uncertain after reading several blogs about SDR kits. They're all talking about receiving and analysing. Is transmitting - like simulating a Somfy hand device - always included and possible, or something to explicitly watch out for? You'r providing a Somfy transeiver script, assuming that your recommended SDR does support transmitting.

Which tools are you using to visualize the data? Like the graphs in github.

Any other recommendations?

Thanks a lot for your help Juergen

[henrythasler]

Hi Jürgen,

thanks for your interest in this project. I haven't played around with it for a while and even have some difficulties understanding it again myself...

Hardware

I would still suggest the RTL-based sets. They are cheap and work well for a hobbyist. Make sure you buy one with a metal case, for obvious reasons. The Radioddity set workes well and I'd buy it again.

The Radioddity set is shipped with an antenna. If you need a smaller antenna for more portability I recommend buying a NRF905 module. It's shipped with a really small (50mm) antenna that can be re-used with the RTL_SDR.

The HackRF is probably much better but most likely overkill for simple tasks. And 10x more expensive.

The RTL-based sets are not capable of transmitting! They can only be used to passively read IQ-Data for processing.

Transmitting

I use a RFM69HCW module connected to a raspberry pi. See my rfm69 repository (docs-folder for schematic). There are several versions of that transmitter. Make sure you get the HCW-version which has a PA_BOOST-mode for significantly increased output power. Use a self-made 433-MHz-Coil-loaded-antenna.

Please also have a look at the berner remote control folder for an example. I use node-red to connect a Smartphone over an MQTT-Server with transmitter.py.

The Hack-RF is capable of transmitting but most likely too expensive for simple home automation tasks.

additional equipment

If you start playing around with your own setup (RFM69), make sure you have some means on measuring stuff with an oscilloscope. I use a Bitscope Micro. The software is not very good but at least it's cheap...

Somfy

I haven't finished the project to control the unit with another transmitter. Let me know your experience.

Analyzing, Visualizing

I recommend inspectrum. I did my analysis with it. An alternative is baudline which, imho, is more complicated to use.

Let me know if you have other questions. Maybe I'll even restart my experiments over christmas holidays :-)

[jdonnerstag]

Hi Henry,

I never said thank you. I bought this one and the Bitscope Micro that you recommended. I did not yet buy a transmitter. I thought I start with the receiver side, trying to read the signals. It's fun playing with it, but I've not had much time.

Juergen

[ruedli]

@jdonnerstag I managed to get it to work from and ESP8266 and a CC1101 transceiver, see https://github.com/ruedli/SomfyMQTT . I didn't have to do much, just the Somfy library, CC1101 driver and a standard mqtt server. The Somfy library came with an example that already allowed to operate the Somfy sunshade, so all I did was integration to allow it to understand the position of the shade and add the logic for operating it through MQTT. This offers nice remote clients for operating your blinds. Let me know if there is still demand for that, or did I just reinvent the wheel? ;-)