Another FSK question

[Scoff123]

Hi @dbuezas

I came here after you pointed me in this direction from the HA community forum - thanks for all your efforts making this esphome-cc1101 available! :)

I have installed ESPHome on an ESP32 DEVKITV1 board

and connected this to a D-SUN CC1101 433 board as follows:
CC1101 ESP32
VCC -> 3v3
GND -> GND
SCK -> D14
MOSI -> D13
GDO2 -> n/a
MISO -> D12
CSN -> D15
GDO0 ->D25

However, am I correct in thinking I don't need to use these specific Hardware SPI pins, as per your answer on discussion #1 "The way this component works is by putting the cc1101 in "dumb mode" and send/receive the information through a single pin (instead of using SPI)"

Will using these hardware SPI pins cause an issue in this scenario - should I use alternative pins instead? My ESPHome yaml code compiles ok and installs fine, but I haven't created any sensors within it using the raw 433 codes yet, as I just want to 'sniff' what I believe to be an FSK transmission first to ensure my hardware and basic code works and picks up the raw data. Currently not seeing any raw data in my ESPHome logs for this board.

[dbuezas]

Hey Scoff!
The custom component does use spi, but only to configure the cc1101, not to transmit the data. This means that the pins should be ok.
Regarding FSK, the trick is that there is one extra parameter apart from the base frequency: FSK works by changing the base frequency. This means that instead of turning the radio on and off to communicate, it jumps between one frequency and another one. The difference between those frequencies is the unknown parameter for you.

Ideally, you can find it out using a "software defined radio" (usually an RTL-SDR), but if you don't want to get one, the only option I see is to change that parameter by hand until you start receiving something.

To do that, I recommend you set up a slider or numeric imput for home assistant. Check the other discussion and also the "advanced" yaml in this repo.

Much luck!

(But srsly, buy an sdr, not expensive and very fun to play with)

[dbuezas]

It will be tricky, you need to:

1. Find the right parameters for the cc1101 to see the signal at all
2. Collect the signal in the esp32 and keep it in a circular buffer with the same format as rtl433 does
3. Call the decoder each time a new "bit" is received
4. Set up a custom component in EspHome
5. Publish the collected data within that custom sensor.

Alternatively, the cc1101 may be able to do the buffering and part of the decoding itself.

If you're not into coding, I think you'll have more fun and success connecting an rtl-sdr directly to HA. I haven't tried it myself, but here's a lead: https://community.home-assistant.io/t/home-assistant-add-on-rtl-433-with-mqtt-auto-discovery/260665.

Since you already wired the cc1101, you could still use it as a 433 gateway for switches and the like :)

[Scoff123]

Thanks for listing out the requirements! Although I am getting better with ESPHome, I think for now the SDR is the way forward like you suggest :) My RTL-SDR should arrive tomorrow :) Looking forward to playing around and getting my head round it all. I've found some beginner guides to using a RTL-SDR with various free software so that should help. Then I can see about picking up my watchman FSK device. The CC1101 and sonof rf bridge will no doubt serve a purpose once I'm more proficient with RF.....

[dbuezas]

My pleasure, wish you much fun with it!

[Scoff123]

I've been having fun with it so far! Started with picking up mainstream FM radio stations to check my SDR works, then running the windows version of RTL_433 to see what I could pick up :)

Picking up what appears to be 2 of my neighbours Oil tank monitors, but not my own! I turned my transmitter off for a couple of hours to try to identify which one was my one, but both of these continued to send readings, so perhaps my transmitter isn't FSK after all. It's definitely 433.92 as this is printed on the case and the transmitter, so I think I will need to do some sniffing to try to identify my transmitter. My plug in Watchman Plus receiver works fine and receives the signal from my transmitter so I know it works, just need to identify the keying I believe..... enjoying playing with it so far though, thanks for the suggestion on the SDR :)

[dbuezas]

👏 👏👏
Here's an idea, download a spectrogram app and tune it around 433Mhz. Then wait until the signal comes and post the waterfall here. With that you may be able to find out if it is fsk and find more clues about what the device transmits