rtl_433 for this board ?

[Adrien Laveau]

Hello !

I bought my house with an alarm from verisur of which I would like to reuse the door opening sensors (magnets) because I thought they would be the easiest one to deal with. Here is a picture of the board.

I though they would be sending kind of an on/off info with an ID at 433Mhz. But monitoring this frequency with gqrx when activating the sensor nothing happens.

At 868MHz to much happens  (see below)

So at the moment I cannot say what is the frequency I should care for.

The lenght of the antenna is approx 10cm so that would correspond to a 1/4 wavelenght of the 868MHz (I live in spain by the way, I understand this might impact the frequency use).

But now I start to doubt if the sensor uses a BLE protocol. Anythought on that ?

With RTL_433 i cannot find any output when the motion sensor is activated.

Thanks

[Michael Cadiere]

There is a config for a verisur alarm, try adding it to the config file 

https://github.com/merbanan/rtl_433/blob/master/conf/verisure_alarm.conf

[Christian Z.]

The EFR32FG1 is quite capable and can do sub-GHz (i.e. 433, 868, …) and 2.4 GHz

https://www.silabs.com/wireless/proprietary/efr32fg1-series-1-sub-ghz-2-4-ghz-socs

Your 868 MHz band has interference, try to remove that. Could be some power supply. Also remove the antenna on the SDR to be more selective.

[Adrien Laveau]

Hello,

thanks for the tips, removing the antena made a much cleaner signal.

For me to understand a bit more how rtl_433 works, I tried the following command line :

rtl_433 -R 0 -c /home/pi/rtl_433/conf/verisure_alarm.conf

The conf file tells rtl_433 how to decode, but nothing regarding the frequency, right ? So I tried :

rtl_433 -R 0 -c /home/pi/rtl_433/conf/verisure_alarm.conf -f 868M

If the frequency is not stated, does rtl_433 just look for some frequency if it finds things ?

I come back on two questions, is it possible that my sensor works with BLE or 2.4 or 2.5GHz that would make my SDR and rtl_433 impossible to detect it ?

Last question, is there any otherway to use the conf file ? Like copy pasting the conf into a main conf file (I could not locate it).

Thanks for you previous super fast comments.

[Adrien Laveau]

One more thing, when I use the conf file, I do not see anything saying that the file is used :

pi@raspberrypi:~/rtl_433/build (master)$ rtl_433 -R 0 -c /home/pi/rtl_433/conf/verisure_alarm.conf
rtl_433 version 22.11-246-g2a7fe211 branch master at 202311011021 inputs file rtl_tcp RTL-SDR
Disabling all device decoders.
Found Rafael Micro R820T tuner
[SDR] Using device 0: Realtek, RTL2838UHIDIR, SN: 00000001, "Generic RTL2832U OEM"
Exact sample rate is: 250000.000414 Hz
[R82XX] PLL not locked!
Allocating 15 zero-copy buffers

Is there anyway to tell rtl_433, tell me all you catch ? I tried

rtl_433 -S all

rtl_433 -S unknown

But nothing comes up.

[Christian Z.]

Yes, you can copy a conf to the main conf. The help (-h) has info on the main conf.

Use the -v option to see more verbose messages.

rtl_433 will not "search", you need to know the frequency and use -f

It wouldn't be BLE, but it could be 2.4 GHz -- no idea about the freqs used.

Best to skip through freqs with e.g. Gqrx, trigger the sensor and watch for a signal.

[L.C. Kimball]

DANGER -  All the messages from Mikaela Bowdle link to the same address,
a good indication that it's a phishing attempt to get you to download
malware.

Not even to mention that none of the messages relate to the purpose of
the group.

Moderator, can you report this person and delete them from the list?



--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

[Christian Z.]

messages from Mikaela Bowdle it's a phishing attempt

Some message were auto-blocked, the rest are removed now. The user is blocked. Thanks for watching out!

[Christian Z.]

Adrien,

Garbage looking data in frequency domain is just noise.

The .ook contains many different data packets. Open the file as text and cut just one good packet, then drop on pdv.
See if you can cut/copy one good packet.

Re short/long see See https://triq.org/rtl_433/PULSE_FORMATS.html and esp. NRZ / RZ.

Re gap/reset: the longest allowed gap before and new row begins or the decoding is aborted.

The "1 us“ samples are bad demodulation. It’s not the true signal.
Drop the .cu8 on pdv to really check the packets, or upload here for more advice.

The signal looks to be much more than 12 bits. Strange for a simple „doorbell“.

[Adrien Laveau]

Hello,

I used teh cu8 in pdv but i cannot zoom somehow and the bursts are really short. Am i using the tooll in a wrong way?

The file weighs 340Mo so I cannot really share it. In the end I have a doubt if I am looking at teh correct frequency. 

I share the print screen of the output. 

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[Christian Z.]

Try https://triq.org/spectrogram-next/ there is a good zoom. It's only a debug preview, so not working perfectly.