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Add support for LaCrosse TX31U-IT ()

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agspoon 2023-02-19 09:55:34 -08:00 • committed by GitHub
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conf/rtl_433.example.conf
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@ -461,6 +461,7 @@ stop_after_successful_events false
protocol 237 # Flowis flow meters
protocol 238 # Wireless M-Bus, Mode T, 32.768kbps (-f 868.3M -s 1000k)
protocol 239 # Revolt NC-5642 Energy Meter
protocol 240 # LaCrosse TX31U-IT, The Weather Channel WS-1910TWC-IT
## Flex devices (command line option "-X")

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include/rtl_433_devices.h
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@ -247,6 +247,7 @@
DECL(flowis) \
DECL(m_bus_mode_c_t_downlink) \
DECL(revolt_nc5462) \
DECL(lacrosse_tx31u) \
/* Add new decoders here. */

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src/CMakeLists.txt
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@ -150,6 +150,7 @@ add_library(r_433 STATIC
devices/lacrosse_r1.c
devices/lacrosse_th3.c
devices/lacrosse_tx141x.c
devices/lacrosse_tx31u.c
devices/lacrosse_tx34.c
devices/lacrosse_tx35.c
devices/lacrosse_wr1.c

227
src/devices/lacrosse_tx31u.c Normal file
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@ -0,0 +1,227 @@
/** @file
LaCrosse TX31U-IT protocol.
Copyright (C) 2023 Craig Johnston
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
*/
/**
Decoder for LaCrosse transmitter provided with the WS-1910TWC-IT product.
Branded with "The Weather Channel" logo.
https://www.lacrossetechnology.com/products/ws-1910twc-it
FCC ID: OMO-TX22U
FSK_PCM @915 MHz, 116usec/bit
## Protocol
Data format:
This transmitter uses a variable length protocol that includes 1-5 measurements
of 2 bytes each. The first nibble of each measurement identifies the sensor.
Sensor Code Encoding
TEMP 0 BCD tenths of a degree C plus 400 offset.
EX: 0x0653 is 25.3 degrees C
HUMID 1 BCD % relative humidity.
EX: 0x1068 is 68%
UNKNOWN 2 This is probably reserved for a rain gauge (TX32U-IT) - NOT TESTED
WIND_AVG_DIR 3 Wind direction and decimal time averaged wind speed in m/sec.
First nibble is direction in units of 22.5 degrees.
WIND_MAX 4 Decimal maximum wind speed in m/sec during last reporting interval.
First nibble is 0x1 if wind sensor input is lost.
a a a a 2 d d 4 a 2 e 5 0 6 5 3 c 0
Bits :
1010 1010 1010 1010 0010 1101 1101 0100 1010 0010 1110 0101 0000 0110 0101 0011 1100 0000
Bytes num :
----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----N----
~~~~~~~~~~~~~~~~~~~ 2 bytes preamble (0xaaaa)
~~~~~~~~~~~~~~~~~~~ bytes 3 and 4 sync word of 0x2dd4
sensor model (always 0xa) ~~~~ 1st nibble of byte 5
Random device id (6 bits) ~~~~ ~~ 2nd nibble of byte 5 and bits 7-6 of byte 6
Initial training mode (all sensors report) ~ bit 5 of byte 6
no external sensor detected ~ bit 4 of byte 6
low battery indication ~ bit 3 of byte 6
count of sensors reporting (1 to 5) ~~~ bits 2,1,0 of byte 6
sensor code ~~~~ 1st nibble of byte 7
sensor reading (meaning varies, see above) ~~~~ ~~~~ ~~~~ 2nd nibble of byte 7 and byte 8
---
--- repeat sensor code:reading as specified in count value above
---
crc8 (poly 0x31 init 0x00) of bytes 5 thru (N-1) ~~~~ ~~~~ last byte
## Developer's comments
The WS-1910TWC-IT does not have a rain gauge or wind direction vane. The readings output here
are inferred from the output data, and correlating it with other similar Lacrosse devices.
These readings have not been tested.
*/
#include "decoder.h"
#define BIT(pos) (1 << (pos))
#define CHECK_BIT(y, pos) ((0u == ((y) & (BIT(pos)))) ? 0u : 1u)
#define SET_LSBITS(len) (BIT(len) - 1) // the first len bits are '1' and the rest are '0'
#define BF_PREP(y, start, len) (((y)&SET_LSBITS(len)) << (start)) // Prepare a bitmask
#define BF_GET(y, start, len) (((y) >> (start)) & SET_LSBITS(len))
#define TX31U_MIN_LEN_BYTES 9 // assume at least one measurement
#define TX31U_MAX_LEN_BYTES 20 // actually shouldn't be more than 18, but we'll be generous
static int lacrosse_tx31u_decode(r_device *decoder, bitbuffer_t *bitbuffer)
{
// There will only be one row
if (bitbuffer->num_rows > 1) {
decoder_logf(decoder, 1, __func__, "Too many rows: %d", bitbuffer->num_rows);
return DECODE_FAIL_SANITY;
}
// search for expected start sequence
uint8_t const start_match[] = {0xaa, 0xaa, 0x2d, 0xd4}; // preamble + sync word (32 bits)
unsigned int start_pos = bitbuffer_search(bitbuffer, 0, 0, start_match, sizeof(start_match) * 8);
if (start_pos >= bitbuffer->bits_per_row[0]) {
return DECODE_ABORT_EARLY;
}
uint8_t msg_bytes = (bitbuffer->bits_per_row[0] - start_pos) / 8;
if (msg_bytes < TX31U_MIN_LEN_BYTES) {
decoder_logf(decoder, 1, __func__, "Packet too short: %d bytes", msg_bytes);
return DECODE_ABORT_LENGTH;
}
else if (msg_bytes > TX31U_MAX_LEN_BYTES) {
decoder_logf(decoder, 1, __func__, "Packet too long: %d bytes", msg_bytes);
return DECODE_ABORT_LENGTH;
}
else {
decoder_logf(decoder, 2, __func__, "packet length: %d", msg_bytes);
}
decoder_log(decoder, 1, __func__, "LaCrosse TX31U-IT detected");
uint8_t msg[TX31U_MAX_LEN_BYTES];
bitbuffer_extract_bytes(bitbuffer, 0, start_pos, msg, msg_bytes * 8);
// int model = BF_GET(msg[4], 4, 4);
int sensor_id = (BF_GET(msg[4], 0, 4) << 2) | BF_GET(msg[5], 6, 2);
// int training = CHECK_BIT(msg[5], 5);
int no_ext_sensor = CHECK_BIT(msg[5], 4);
int battery_low = CHECK_BIT(msg[5], 3);
int measurements = BF_GET(msg[5], 0, 3);
// Check message integrity
int expected_bytes = 6 + measurements * 2 + 1;
if (msg_bytes >= expected_bytes) { // did we get shorted?
int r_crc = msg[expected_bytes - 1];
int c_crc = crc8(&msg[4], 2 + measurements * 2, 0x31, 0x00);
if (r_crc != c_crc) {
decoder_logf(decoder, 1, __func__, "LaCrosse TX31U-IT bad CRC: calculated %02x, received %02x", c_crc, r_crc);
return DECODE_FAIL_MIC;
}
}
else {
decoder_logf(decoder, 1, __func__, "Packet truncated: received %d bytes, expected %d bytes", msg_bytes, expected_bytes);
return DECODE_ABORT_LENGTH;
}
/* clang-format off */
// what we know from the header
data_t *data = data_make(
"model", "", DATA_STRING, "LaCrosse-TX31UIT",
"id", "", DATA_INT, sensor_id,
"battery_ok", "Battery", DATA_INT, !battery_low,
NULL);
// decode each measurement we get and append them.
enum sensor_type { TEMP=0, HUMIDITY, RAIN, WIND_AVG, WIND_MAX };
for (int m=0; m<measurements; ++m ) {
uint8_t type = BF_GET(msg[6+m*2], 4, 4 );
uint8_t nib1 = BF_GET(msg[6+m*2], 0, 4 );
uint8_t nib2 = BF_GET(msg[7+m*2], 4, 4 );
uint8_t nib3 = BF_GET(msg[7+m*2], 0, 4 );
switch (type) {
case TEMP: {
float temp_c = 10*nib1 + nib2 + 0.1f*nib3 - 40.0f; // BCD offset 40 deg C
data = data_append( data,
"temperature_C", "Temperature", DATA_FORMAT, "%.1f C", DATA_DOUBLE, temp_c,
NULL);
} break;
case HUMIDITY: {
int humidity = 100*nib1 + 10*nib2 + nib3; // BCD %
data = data_append( data,
"humidity", "Humidity", DATA_FORMAT, "%u %%", DATA_INT, humidity,
NULL);
} break;
case RAIN: {
int raw_rain = (nib1<<8) + (nib2<<4) + nib3; // count of contact closures
if ( !no_ext_sensor && raw_rain > 0) { // most of these do not have rain gauges. Surpress output if zero.
data = data_append( data,
"rain", "raw_rain", DATA_FORMAT, "%03x", DATA_INT, raw_rain,
NULL);
}
} break;
case WIND_AVG: {
if ( !no_ext_sensor ) {
float wind_dir = nib1 * 22.5 ; // compass direction in degrees
float wind_avg = ((nib2<<4) + nib3) * 0.1f * 3.6; // wind values are decimal m/sec, convert to km/hr
data = data_append( data,
"wind_dir_deg", "Wind direction", DATA_FORMAT, "%.1f", DATA_DOUBLE, wind_dir,
"wind_avg_km_h", "Wind speed", DATA_FORMAT, "%.1f km/h", DATA_DOUBLE, wind_avg,
NULL);
}
} break;
case WIND_MAX: {
int wind_input_lost = CHECK_BIT(nib1, 0); // a sensor was attched, but now not detected
if ( !no_ext_sensor && !wind_input_lost ) {
float wind_max = ((nib2<<4) + nib3) * 0.1f * 3.6; // wind values are decimal m/sec, convert to km/hr
data = data_append( data,
"wind_max_km_h", "Wind gust", DATA_FORMAT, "%.1f km/h", DATA_DOUBLE, wind_max,
NULL);
}
} break;
default:
decoder_logf(decoder, 1, __func__, "LaCrosse TX31U-IT unknown sensor type %d", type);
break;
}
}
data = data_append( data,
"mic", "Integrity", DATA_STRING, "CRC",
NULL);
/* clang-format on */
decoder_output_data(decoder, data);
return 1;
}
static char const *output_fields[] = {
"model",
"id",
"battery_ok",
"temperature_C",
"humidity",
"wind_avg_km_h",
"wind_max_km_h",
"wind_dir_deg",
"mic",
NULL,
};
// Receiver for the Lacrosse TX31U-IT
r_device const lacrosse_tx31u = {
.name = "LaCrosse TX31U-IT, The Weather Channel WS-1910TWC-IT",
.modulation = FSK_PULSE_PCM,
.short_width = 116,
.long_width = 116,
.reset_limit = 20000,
.decode_fn = &lacrosse_tx31u_decode,
.fields = output_fields,
};