merbanan
TRW TPMS sensor
Hi, I'm trying to read data from a TRW TPMS sensor. In the test report you can find the following information (https://fcc.report/FCC-ID/GQ4-70T/2201538.pdf#subsubsection.3.2.1):
When the transmitter is activated by tire rotation or via encoded LF interrogation, it can, in the worst case,
transmit one 10.5 ms FSK frame or one 22.0 ms ASK frame, or two 10.5 ms ASK frames within any
given 100 ms window. Both ASK frames are Manchester encoded at a 50% duty.
Does this mean I should check two different modulations FSK_PCM and OOK_MC_ZEROBIT?
@testuser7:
From the pdf we can see classic TPMS pulse at 52.5 µs into the graph 5a / 5b page 10.
yes, try this could give you some answers:
rtl_433 -X "n=TRW,m=OOK_PCM,s=52,l=52,r=1000"
rtl_433 -X "n=TRW,m=OOK_MC_ZEROBIT,s=52,l=52,r=1000"
rtl_433 -X "n=TRW,m=FSK_PCM,s=52,l=52,r=1000"
rtl_433 -X "n=TRW,m=FSK_MC_ZEROBIT,s=52,l=52,r=1000"
Other useful information here which describes the use cases / behavior, what, how often transits of signal and signal modulation. Like 4 RF packets, 2 ASK then 2 FSK, when park, drive modes ...
This is what I managed to read:
-
FSK_MC_ZEROBIT
time : 2025-04-23 12:50:14
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a83162124b0e320
codes : {97}7fff5c00f4a83162124b0e320
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -8.3 dB SNR : 16.4 dB Noise : -24.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:50:14
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a83163124b0e240
codes : {97}7fff5c00f4a83163124b0e240
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.8 MHz
RSSI : -7.4 dB SNR : 17.7 dB Noise : -25.2 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:50:14
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a83164124b0e460
codes : {97}7fff5c00f4a83164124b0e460
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -7.2 dB SNR : 18.7 dB Noise : -25.9 dB
-
FSK_PCM
time : 2025-04-23 12:52:17
model : TRW count : 1 num_rows : 1 rows :
len : 194 data : 5555555666a55555aa6599955a5669565a5965a555a959554
codes : {194}5555555666a55555aa6599955a5669565a5965a555a959554
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -0.1 dB SNR : 24.7 dB Noise : -24.8 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:52:17
model : TRW count : 1 num_rows : 1 rows :
len : 194 data : 5555555666a55555aa6599955a5669595a5965a555a956994
codes : {194}5555555666a55555aa6599955a5669595a5965a555a956994
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -0.1 dB SNR : 24.2 dB Noise : -24.4 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:52:17
model : TRW count : 1 num_rows : 1 rows :
len : 194 data : 5555555666a55555aa6599955a56695a5a5965a555a955a54
codes : {194}5555555666a55555aa6599955a56695a5a5965a555a955a54
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -0.1 dB SNR : 24.9 dB Noise : -25.0 dB
-
OOK_PCM
time : 2025-04-23 12:53:42
model : TRW count : 1 num_rows : 1 rows :
len : 178 data : aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
codes : {178}aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 25.0 dB Noise : -25.2 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:53:44
model : TRW count : 1 num_rows : 1 rows :
len : 178 data : aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
codes : {178}aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
Modulation: ASK Freq : 434.0 MHz
RSSI : -0.1 dB SNR : 24.6 dB Noise : -24.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:53:47
model : TRW count : 1 num_rows : 1 rows :
len : 178 data : aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
codes : {178}aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa00000
Modulation: ASK Freq : 434.0 MHz
RSSI : -0.1 dB SNR : 24.4 dB Noise : -24.5 dB
-
OOK_MC_ZEROBIT
time : 2025-04-23 12:55:41
model : TRW count : 1 num_rows : 1 rows :
len : 80 data : 00000000000000000000
codes : {80}00000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 25.6 dB Noise : -25.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:55:44
model : TRW count : 1 num_rows : 1 rows :
len : 80 data : 00000000000000000000
codes : {80}00000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 24.3 dB Noise : -24.4 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : 2025-04-23 12:55:48
model : TRW count : 1 num_rows : 1 rows :
len : 80 data : 00000000000000000000
codes : {80}00000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 24.3 dB Noise : -24.4 dB
Comparing data from few sensors I think it will be like this for FSK_MC_ZEROBIT:
UNK: 7fff5c00f4
ID: a831
COUN: 62 (61, 62, 63, 64, 91, 92, 93, 94, 91...)
PRESS: 12
TEMP: 4b
UNK: 0e
CRC: 32
UNK: 0
There will be a preamble/sync, could be PCM …5556, then the data will read 5c00f4a83161324c0e20.
We expect 7 or 8 chars of ID, likely 00f4a831 here and the leading 5c will be some state indicator.
Grab a series of codes (say 20) and we can check if the last 1-2 bytes are some checksum.
This is what I managed to find out:
- frames are Manchester encoded
- preamble is
0001for OOK modulation and7ffffor FSK modulation - message length is 98 for OEM sensors and 97 for "Chinese OEM" sensors (both sensors work properly in the car)
The message after decoding looks like this:
| UNK1 | ID | UNK2 | SEQ | PRESS | TEMP | UNK3 | CRC? | UNK4 |
|---|---|---|---|---|---|---|---|---|
| 5c | 3e52852e | 6 | 2 | 53 | 4b | 0e | 68 | 4 |
where:
- UNK1: a) 5c - not in motion b) 5c, 5d, 5e - in motion (5c all the time for "Chinese OEM")
- ID: sensor ID
- UNK2: a) 6 - pressure drop (not in motion) b) 9 - pressure increase (not in motion), (the same for pressure drop for "Chinese OEM") c) c, b - alternately (in motion)
- SEQ: a) 0, 1, 2, 3 - OEM b) 1, 2, 3, 4 - "Chinese OEM"
- PRESS: pressure
- TEMP: temperature
- UNK3: a) 0e (not in motion) b) some data (in motion)
- CRC?: crc
- UNK4: a) 4 - OEM b) 0 - "Chinese OEM"
Pressure drop (not in motion) OEM:
time : @18.711489s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -10.1 dB SNR : 16.8 dB Noise : -26.8 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @18.830437s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -10.0 dB SNR : 18.7 dB Noise : -28.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @18.951996s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -10.4 dB SNR : 16.7 dB Noise : -27.1 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.056116s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 00015c3e52852e60534b0e444
codes : {98}00015c3e52852e60534b0e444
Modulation: ASK Freq : 433.9 MHz
RSSI : -10.3 dB SNR : 18.6 dB Noise : -28.9 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.091431s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 00015c3e52852e61534b0e524
codes : {98}00015c3e52852e61534b0e524
Modulation: ASK Freq : 433.9 MHz
RSSI : -10.3 dB SNR : 17.7 dB Noise : -28.0 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.221275s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 7fff5c3e52852e62534b0e684
codes : {98}7fff5c3e52852e62534b0e684
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -10.2 dB SNR : 16.5 dB Noise : -26.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.331179s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 7fff5c3e52852e63534b0e7e4
codes : {98}7fff5c3e52852e63534b0e7e4
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -10.4 dB SNR : 17.8 dB Noise : -28.2 dB
Pressure increase (not in motion) OEM:
time : @14.581908s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 27.3 dB Noise : -27.4 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @14.700374s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 28.2 dB Noise : -28.3 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @14.821671s
model : TRW count : 1 num_rows : 1 rows :
len : 211 data : 00000000000000000000000000000000000000000000000000000
codes : {211}00000000000000000000000000000000000000000000000000000
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 28.2 dB Noise : -28.3 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @14.925456s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 00015c3e49783b90514e0ead4
codes : {98}00015c3e49783b90514e0ead4
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 27.9 dB Noise : -28.0 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @14.960402s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 00015c3e49783b91514e0ebb4
codes : {98}00015c3e49783b91514e0ebb4
Modulation: ASK Freq : 433.9 MHz
RSSI : -0.1 dB SNR : 28.4 dB Noise : -28.5 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @15.090328s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 7fff5c3e49783b92514e0e814
codes : {98}7fff5c3e49783b92514e0e814
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -0.1 dB SNR : 27.4 dB Noise : -27.5 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @15.200256s
model : TRW count : 1 num_rows : 1 rows :
len : 98 data : 7fff5c3e49783b93514e0e974
codes : {98}7fff5c3e49783b93514e0e974
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -0.1 dB SNR : 27.7 dB Noise : -27.8 dB
Pressure drop (not in motion) "Chinese OEM" (only FSK modulation):
time : @19.536581s
model : TRW count : 1 num_rows : 1 rows :
len : 80 data : 00000000000000000000
codes : {80}00000000000000000000
Modulation: ASK Freq : 434.0 MHz
RSSI : -11.9 dB SNR : 16.4 dB Noise : -28.3 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.668951s
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a50e914b460e580
codes : {97}7fff5c00f4a50e914b460e580
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -11.6 dB SNR : 15.6 dB Noise : -27.2 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.784409s
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a50e924b460e620
codes : {97}7fff5c00f4a50e924b460e620
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -11.6 dB SNR : 15.3 dB Noise : -27.0 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @19.940355s
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a50e934b460e740
codes : {97}7fff5c00f4a50e934b460e740
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -11.6 dB SNR : 15.1 dB Noise : -26.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time : @20.070982s
model : TRW count : 1 num_rows : 1 rows :
len : 97 data : 7fff5c00f4a50e944b460e160
codes : {97}7fff5c00f4a50e944b460e160
Modulation: FSK Freq1 : 434.0 MHz Freq2 : 433.9 MHz
RSSI : -11.2 dB SNR : 15.7 dB Noise : -27.0 dB
@testuser7 : I started to check your data, the CRC is a classic CRC-8/SMBUS, poly 0x07, init 0x00, final XOR 0x00.
The last 4 or 0 after the CRC can be ignored, it's trailing bits. I will update / share later my other findings, I'm too busy right now.
@testuser7 : I drafted a decoder, but missing important information about the pressure and temperature.
I need the unit of pressure in PSI or KPa and the temperature in C or F with some sample codes to guess the formula between the raw hexa values and the real values. I'm not able to guess the voltage information. Like we are doing on other sensors, any unknown data will be shown as flags, to let you deep dive.
For the moment, I'm able to extract all your findings, I tested from codes, but missing real rf record to test.
Can you please record few cu8 samples ( option -S unknown ) to let us test the decoder. Advice: remove the antenna of your rtl stick to exclude other sensors, stay around 1 meter from the TPM sensor to record the signal.
@testuser7 : I drafted a decoder, but missing important information about the pressure and temperature.
Thank you, I was just planning to add this decoder.
I need the unit of pressure in PSI or KPa and the temperature in C or F with some sample codes to guess the formula between the raw hexa values and the real values. I'm not able to guess the voltage information. Like we are doing on other sensors, any unknown data will be shown as flags, to let you deep dive.
I will try to provide correlations between values.
For the moment, I'm able to extract all your findings, I tested from codes, but missing real rf record to test.
Can you please record few cu8 samples ( option -S unknown ) to let us test the decoder. Advice: remove the antenna of your rtl stick to exclude other sensors, stay around 1 meter from the TPM sensor to record the signal.
Here you will find samples: https://github.com/testuser7/rtl_433_tests/tree/trw-tpms/tests/TRW_tpms
I think the formula for pressure is pressure_value * 0.4 [PSI].
0 is reported for no pressure at all, 46 for 28 PSI and 52-53 for 33 PSI.
As for the temperature, I don't know yet.
The sensor used in this case is Infineon SP376 (SP376271160XTMA1). But I didn't find any documentation (it's only available for SP370).
With those two values it would be closer to pressure_value * 0.6 [PSI] or pressure_value * 4.25 [kPa].
We need more values to check with a proper linear regression.
Ah sorry, I gave the values in hex and not dec. It should be:
- 82-83 (dec) - 33 PSI
- 70 (dec) - 28 PSI
Hi @testuser7 , thanks, so it's 0.4f (a classic scale of 2.5)
And about the temp, do you have any formula ?
And about the temp, do you have any formula ?
Not yet, because I don't know how much the temperature in the wheels can increase while driving. I have to take measurements at different temperatures after the car has been parked for a while.
For temperature it will be:
- 70(dec) - 20 ℃
I only have one value for now.
For pressure 45 (dec) I have a value 18.24 PSI in diagnostic software. There is information there that the value is altitude compensated. The atmospheric pressure during the measurement was 14.21 PSI - read in the diagnostic software.
Could the 0.24 PSI be the compensation?
@testuser7 : about the temp , looks like a classic -50 offset.
I'm updating my drafted decoder and will create the PR.
@testuser7 : Done, I let you test the PR and let me know if all is ok for you.
