Steelmate TPMS decode issue on lilygo-rtl_433-fsk

Theengs OpenMQTTGateway Radio frequencies gateways 315mhz, 433mhz, 868mhz
1

I’m using lilygo-rtl_433-fsk on a LILYGO TTGO board. I can see Ford TPMS sensors being decoded succesfully but it’s not decoding my external Steelmate sensors. Looking at the code for each device the Steelmate is FSK but has FSK_PULSE_MANCHESTER_ZEROBIT modulation. Is there anyway to get the Lilygo to decode this? I’m successfully decoding them with rtl_433 and an SDR.

r_device const steelmate = {
.name = “Steelmate TPMS”,
.modulation = FSK_PULSE_MANCHESTER_ZEROBIT,
.short_width = 50,
.long_width = 50,
.reset_limit = 120,
.decode_fn = &steelmate_callback,
.fields = output_fields,
};

r_device const tpms_ford = {
.name = “Ford TPMS”,
.modulation = FSK_PULSE_PCM,
.short_width = 52, // 12-13 samples @250k
.long_width = 52, // FSK
.reset_limit = 150, // Maximum gap size before End Of Message [us].
.decode_fn = &tpms_ford_callback,
.fields = output_fields,
};

2

This might be due to the not so long ago updated Steelmate rtl_433 decoder not yet having propagated to the rtl_433_ESP library, which does seem underway though.

3

I think the latest steelmate fix in rtl_433 is just to correct the pressure formula so I should get it decoded with the older code in v24.10. I’m wondering if its to do with the FSK_PULSE_MANCHESTER_ZEROBIT modulation. I don’t know my way around the code enough to check whether that’s enabled or not.

4

I didn’t look too closely as to what the exact recent changes were.

Shouldn’t really require looking at the code, but on the rtl_433_ESP page it does state that this modulation is supported

Another issue could be the exact frequency, which might need adjusting in the WebUI, for which you might get a hint when receiving with your SDR and rtl_433 in verbose mode. And I assume your LilyGo is the correct frequency version for your Steelmate TPMS.

5

Still no joy with this. I’ve check on an SDR trace and the Ford and Steelmate sensors are both transmitting at 433.9Mhz. The Lilygo is a 433MHz model so that’s correct and its picking up the Ford TPMS signals.

I’m going to try and enable debug or trace logging on OMG next. Hopefully I’ll see if the Steelmate decoder in been loaded and if it’s receiving any data.

6

Back looking at this issue again.

I’ve set this flag in the build. ‘-DPUBLISH_UNPARSED=true’

and when I see the Steelmate getting decoded by a raspberry pi running rtl_433 I see the following debug output.

rtl_433_ESP(6): Unparsed Signal length: 6001, Signal RSSI: -42, pulses: 56
rtl_433_ESP(6): RAW (6001): +0-80+48-51+51-59+47-51+52-51+51-51+51-51+52-51+59-106+102-47+52-51+51-48+51-51+51-53+57-44+51-114+43-51+53-50+110-106+47-48+51-51+48-51+110-106+106-47+121-115+57-58+110-48+51-51+51-48+51-51+52-53+56-44+59-47+51-52+51-51+51-110+47-51+48-51+110-48+51-109+107-43+70-62+55-58+59-55+55-47+51-52+51-53+46-51+51-51+59-47+51-52+47-51+110-106+106-106+48-325+0-0
T: isAdupl?
T: no pub. dupl
rtl_433_ESP(6): Unparsed Signal length: 6000, Signal RSSI: -57, pulses: 56
rtl_433_ESP(6): RAW (6000): +51-44+51-51+59-47+52-51+51-51+51-52+51-51+59-43+51-52+58-106+103-47+51-48+51-51+59-44+51-51+59-44+51-113+44-52+50-52+109-106+48-48+51-51+51-48+110-105+106-48+121-113+59-54+110-55+48-51+51-48+51-51+58-44+52-51+58-44+51-59+48-51+51-109+48-51+51-54+104-47+52-109+106-44+69-63+55-58+59-55+47-59+50-48+52-51+47-51+52-51+58-48+51-51+52-51+109-107+106-47+62-0
T: isAdupl?
T: no pub. dupl
rtl_433_ESP(6): Unparsed Signal length: 6000, Signal RSSI: -58, pulses: 56
rtl_433_ESP(6): RAW (6000): +0-45+59-48+51-51+51-48+51-51+51-59+47-52+51-51+51-51+51-110+106-48+47-52+51-52+50-51+51-53+50-51+51-110+48-51+53-49+110-106+44-51+48-51+51-51+110-106+106-44+121-117+54-63+106-47+59-47+48-51+51-52+51-51+51-61+41-52+58-48+49-49+52-113+48-49+49-52+109-48+51-110+106-44+69-55+66-55+58-55+47-59+47-53+46-52+51-51+51-52+58-47+51-52+48-58+106-102+111-101+44-0
T: isAdupl?

Seems the Steelmate isn’t getting decoded with my OpenMQTTGateway and rtl_433_ESP build.