search

merbanan / rtl_433

Program to decode radio transmissions from devices on the ISM bands (and other frequencies)
GNU General Public License v2.0
6.04k stars 1.31k forks source link

La Crosse LTV-W1 wind sensor reports as R3 Rain Gauge #1855

Closed BarryMar closed 2 years ago

BarryMar commented 2 years ago

Info on the sensor is found here: https://www.lacrossetechnology.com/products/ltv-w1

LTV-W1 a pretty simple sensor. Just wind speed (and probably a low battery indicator, but I don't have any dead C cells so far).

When rtl_433 branch master at 202110291420 receives a signal from this unit it mistakenly identifies it as a R3 Rain Gauge and spits out garbage.

Sample recording is available in merbanan/rtl_433_tests#404

zuckschwerdt commented 2 years ago

The data shows the wind speed as (dezi)km/h plainly. Strangely that seems the only value transmitted. See this BitBench. The codes with 555 feel like a bit is missing. I'll check the checksum next.

zuckschwerdt commented 2 years ago

I guess it's really the same protocol as the LTV-R3, but with aa aa aa WWW aaa (literal a, W=wind speed) instead of 6 bytes rain value. We could check on that magic aa and switch to show W1 values.

zuckschwerdt commented 2 years ago

Try to get low battery code or sample if you can. Known flat batteries or a variable voltage power supply, if you have one.

BarryMar commented 2 years ago

As luck would have it, I remembered that I found an old flashlight the other day that had some C cells that were at least 10 years old. I still had to burn them for a bit in order to make them weak enough to trip the sensor.

In the sequence below, I first put fresh batteries in. During this time the sensor beeps 4 times and sends 5 * 915 MHz signals out approximately every 10 seconds, of which I only got 3 for some reason.

I then replaced the batteries with the weak ones. Same 4 beeps and 5 * 915 MHz signals every 10 seconds. The La Crosse CA80550 display then showed a Low Battery symbol on the Wind Speed sensor.

rtl_433 -f 915M -s 1M -R 0 -X 'n=LTV-W1,m=FSK_PCM,s=100,l=100,r=9000,preamble=d2aa2dd40fb220'

rtl_433 version 21.05-122-g4bb75b4c branch master at 202110291420 inputs file rtl_tcp RTL-SDR Use -h for usage help and see https://triq.org/ for documentation. Trying conf file at "rtl_433.conf"... Trying conf file at "/Users/barrymarshall/.config/rtl_433/rtl_433.conf"... Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"... Trying conf file at "/etc/rtl_433/rtl_433.conf"...

New defaults active, use "-Y classic -s 250k" for the old defaults!

Disabling all device decoders. Registered 1 out of 200 device decoding protocols [ ] Found Rafael Micro R820T tuner Exact sample rate is: 1000000.026491 Hz [R82XX] PLL not locked! Sample rate set to 1000000 S/s. Tuner gain set to Auto. Tuned to 915.000MHz. baseband_demod_FM: low pass filter for 1000000 Hz at cutoff 200000 Hz, 5.0 us

Wind Speed: 0 km, Good Battery (all samples)

time : 2021-11-10 14:29:20 model : LTV-W1 count : 1 num_rows : 1 rows : len : 120 data : 42aaaaaa000aaa7300000000000000 codes : {120}42aaaaaa000aaa7300000000000000

time : 2021-11-10 14:29:32 model : LTV-W1 count : 1 num_rows : 1 rows : len : 120 data : 44aaaaaa000aaa6700000000000000 codes : {120}44aaaaaa000aaa6700000000000000

time : 2021-11-10 14:29:52 model : LTV-W1 count : 1 num_rows : 1 rows : len : 119 data : 0aaaaaaa000aaaf200000000000000 codes : {119}0aaaaaaa000aaaf200000000000000

Wind Speed: 0 km, Weak Battery (all samples)

time : 2021-11-10 14:30:43 model : LTV-W1 count : 1 num_rows : 1 rows : len : 120 data : c2aaaaaa000aaacf00000000000000 codes : {120}c2aaaaaa000aaacf00000000000000

time : 2021-11-10 14:30:55 model : LTV-W1 count : 1 num_rows : 1 rows : len : 120 data : c4aaaaaa000aaadb00000000000000 codes : {120}c4aaaaaa000aaadb00000000000000

time : 2021-11-10 14:31:02 model : LTV-W1 count : 1 num_rows : 1 rows : len : 116 data : c6aaaaaa000aaa380000000000000 codes : {116}c6aaaaaa000aaa380000000000000

time : 2021-11-10 14:31:08 model : LTV-W1 count : 1 num_rows : 1 rows : len : 120 data : c8aaaaaa000aaaf300000000000000 codes : {120}c8aaaaaa000aaaf300000000000000

time : 2021-11-10 14:31:15 model : LTV-W1 count : 1 num_rows : 1 rows : len : 119 data : 8aaaaaaa000aaa4e00000000000000 codes : {119}8aaaaaaa000aaa4e00000000000000 ^CSignal caught, exiting!

zuckschwerdt commented 2 years ago

That worked out well! As you can see in this BitBench, the Battery Low flag is first, then, I guess, a "Startup" bit. I'll include that in the decoder.

BarryMar commented 2 years ago

I tried compiling the latest sources and it looks good. I'll admit compiling stuff isn't my forte, so this is what I tried:

git clone https://github.com/merbanan/rtl_433.git cd build
cmake ../ make sudo make install cd /usr/local/bin ./rtl_433 -f915M

./rtl_433 -f915M rtl_433 version 21.05-129-gc21d1e13 branch master at 202111111643 inputs file rtl_tcp RTL-SDR Use -h for usage help and see https://triq.org/ for documentation. Trying conf file at "rtl_433.conf"... Trying conf file at "/Users/barrymarshall/.config/rtl_433/rtl_433.conf"... Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"... Trying conf file at "/etc/rtl_433/rtl_433.conf"...

New defaults active, use "-Y classic -s 250k" for the old defaults!

Registered 169 out of 200 device decoding protocols [ 1-4 8 11-12 15-17 19-23 25-26 29-36 38-60 63 67-71 73-100 102-105 108-116 119 121 124-128 130-149 151-161 163-168 170-175 177-197 199 ] Found Rafael Micro R820T tuner Exact sample rate is: 1000000.026491 Hz [R82XX] PLL not locked! Sample rate set to 1000000 S/s. Tuner gain set to Auto. Tuned to 915.000MHz. baseband_demod_FM: low pass filter for 1000000 Hz at cutoff 200000 Hz, 5.0 us

time : 2021-11-11 14:57:58 model : LaCrosse-TH3 Sensor ID : 13efb7 Sequence : 5 unknown : 0 Temperature: 11.5 C Humidity : 59 % Integrity : CRC

time : 2021-11-11 14:57:59 model : LaCrosse-W1 Sensor ID : 0fb220 Battery level: 1 Sequence : 5 Wind Speed: 4.1 km/h Integrity : CRC

time : 2021-11-11 14:59:34 model : LaCrosse-W1 Sensor ID : 0fb220 Battery level: 1 Sequence : 0 Wind Speed: 4.7 km/h Integrity : CRC

time : 2021-11-11 15:00:37 model : LaCrosse-W1 Sensor ID : 0fb220 Battery level: 1 Sequence : 2 Wind Speed: 4.5 km/h Integrity : CRC

time : 2021-11-11 15:01:18 model : LaCrosse-TH3 Sensor ID : 13efb7 Sequence : 1 unknown : 0 Temperature: 11.5 C Humidity : 59 % Integrity : CRC

time : 2021-11-11 15:02:43 model : LaCrosse-W1 Sensor ID : 0fb220 Battery level: 1 Sequence : 6 Wind Speed: 4.5 km/h Integrity : CRC