Wireless M-Bus protocol signals not getting recived

Compatible devices
1

Hey,

So I got my my LILYGO TTGO LoRa32 V2.1_1.6 with rtl_433-fsk version and after switching to 868.3MHz I started receiving reliable weather station data but when I switched to 868.9 to get water meter data via Wireless M-Bus protocol… nothing.
The reason I know there are signals in the air because I have rtl-sdr dongle right next to it set to 868.9 MHz picking them up. Here is my neighbors water meter from MQTT

time = 2024-06-07 15:11:27
protocol = 104
mode = T
M = BMT
id = 3241463
version = 23
type_string = Warm Water
C = 68
data_length = 37
data = 2244b4096314240317068c00e27a510000000c1357970000046d042e07360f03000000000036b7
mic = CRC
CI = 140
AC = 0
ST = 0
CW = 0
min_volume_flow_min_0 = 342034.868 m3/min
min_energy_wh_0 = 9176599.000 Wh
min_volume_flow_h_21 = 0.000 km3/h
inst_energy_j_0 = 0.000 MJ
max_mass_flow_0 = 1.510 Mkg/h
inst_timedate_0 = 24-06-07T14:04:00
inst_energy_wh_0 = 0.000 Wh
mod = FSK
freq1 = 868.93216
freq2 = 868.97606
rssi = -1.54138
snr = 22.34207
noise = -23.8835
min_volume_flow_min_21 = 0.000 m3/min
min_volume_flow_s_21 = 0.000 Ml/s
min_mass_flow_21 = 0.000 kg/h

I moved the board closer to the meter thinking maybe this is a signal problem… but no nothing. Also, lora32 board is picking up weather station signals more frequently than my rtl-sdr dongle.

rtl-sdr dongle is running full rtl_433 not rtl-sdr_esp so maybe there is a setting that I am missing? However, considering both wmbus protocol and Bresser Weather Center 6-in-1 is under same FSK section it should be working… right?

2

If you are receiving your neighbour’s data on 868 MHz, you should definitely also be receiving your own. Are you sure you’re not receiving your own data?

By the way, is your water meter a Kamstrup flowIQ 2200?

3

The sample is not from OpenMQTTgateway it is from rtl-sdr and sdr dongle. On rtl-sdr I am getting my meter and my neighbors meters I am not getting any of there these meters on OpenMQTTgateway other than “unprocessed” signals.

4

Hm - can you show which command string you’re using to start rtl_433? You should enter it like

$ rtl_433 -F "mqtt://<mqttServerIp>:1833,user=<mqttUser>,pass=<mqttPassword>"

When you start receiving, you should see the messages

MQTT Connected...
MQTT Connection established.
5

RTL-SDR dongles config (I am running it in docker container with USB dongle passthrough hence why it is formatted this way):

    command:
       - "-f868.9M"
      - "-Mprotocol"
      - "-Mlevel"
      - "-Mnoise"
      - "-Mstats"
      - "-Mbits"
      - "-Fmqtt://127.0.0.1:1883"
      - "-Fkv"

TTGO lora32 board connects to MQTT and sends unrecognized signals to MQTT (I see it mqtt explorer) when it is set to 868.95 Mhz (Wireless M-Bus frequency) if I switch to 868.3 Mhz I get weather stations my MQTT.
It is 100% not my connection to MQTT.
I almost certain that it is something to do with rtl_433_ESP modifications it could also be in way rtl_433 is called.
I also compiled a version for firmware enabling all the debuging flags and so in gateway console I see:

T: isAdupl?
N: Send on /RTL_433toMQTT/undecoded signal msg {"model":"undecoded signal","protocol":"signal parsing failed","duration":5000,"rssi":-92,"pulses":19}
T: jsonPubl - ON
T: [ OMG->MQTT ] topic: rtl_433/OMG_lilygo_rtl_433_ESP/RTL_433toMQTT/undecoded signal msg: {"model":"undecoded signal","protocol":"signal parsing failed","duration":5000,"rssi":-92,"pulses":19} 
T: Min ind: 1
T: store code : 0 / 115819386
T: Col: val/timestamp
T: mem code : 0 / 115808287
T: mem code : 0 / 115819386
T: mem code : 0 / 115671544
T: mem code : 0 / 115688240
T: mem code : 0 / 115696560
T: mem code : 0 / 115705260
T: mem code : 0 / 115731748
T: mem code : 0 / 115761731
T: mem code : 0 / 115769580
T: mem code : 0 / 115775879
T: mem code : 0 / 115788906
T: mem code : 0 / 115795620

Have no clue what to do with all of that, gateway can receive the signal not process.

8

he Kamstrup flowIQ 2200 send datas in clear on LoRa at 868MHz, not fsk.

ie “16C0030101070243537461523A303031”

9

To use fsk you need to wire DIO2