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Add support for Fine Offset WH45 air quality sensor

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This commit is contained in:
anthyz 2022-07-02 10:32:31 -07:00 • committed by Greg Troxel
parent 9cd036e1e0
commit a6c5044c34
3 changed files with 155 additions and 0 deletions

1
include/rtl_433_devices.h
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@ -226,6 +226,7 @@
DECL(ant_antplus) \
DECL(emos_e6016_rain) \
DECL(hcs200_fsk) \
DECL(fineoffset_wh45) \
/* Add new decoders here. */

1
src/CMakeLists.txt
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@ -101,6 +101,7 @@ add_library(r_433 STATIC
devices/fineoffset_wh1050.c
devices/fineoffset_wh1080.c
devices/fineoffset_wh31l.c
devices/fineoffset_wh45.c
devices/fineoffset_ws80.c
devices/flex.c
devices/fordremote.c

153
src/devices/fineoffset_wh45.c Normal file
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@ -0,0 +1,153 @@
/** @file
Fine Offset Electronics WH45 air quality sensor.
Copyright (C) 2022 @anthyz
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.
*/
#include "decoder.h"
/**
Fine Offset Electronics WH45 air quality sensor,
- also Ecowitt WH45, Ecowitt WH0295
- also Froggit DP250
- also Ambient Weather AQIN
Preamble is aaaa aaaa, sync word is 2dd4.
Packet layout:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
YY II II II 0T TT HH Bp pp BP PP CC CC XX AA
45 00 36 60 02 7e 36 40 23 00 29 02 29 07 4f
- Y: 8 bit fixed sensor type 0x45
- I: 24 bit device ID
- T: 11 bit temperature, offset 40, scale 10
- H: 8 bit humidity
- B: 1 bit MSB of battery bars out of 5 (a value of 6 indicates external power via USB)
- p: 14 bit PM2.5 reading in ug/m3 * 10
- B: 2 bits LSBs of battery bars out of 5
- P: 14 bit PM10 reading in ug/m3 * 10
- C: 16 bit CO2 reading in ppm
- X: 8 bit CRC
- A: 8 bit checksum
Older air quality sensors (WH0290/WH41/WH43) from Fine Offset use a
particulate sensor from Honeywell that crudely estimates PM10 values
from PM2.5 measurements. Though Ecowitt and other displays only show
PM2.5, the rtl_433 WH0290 decoder includes the estimated PM10 value.
See the WH0290 decoder for more details.
The WH45 uses a Sensirion SPS30 sensor for PM2.5/PM10 and a
Sensirion SCD30 for CO2.
Technical documents for the SPS30 are here:
https://sensirion.com/products/catalog/SPS30
The sensor specification statement states that PM10 values are estimated
from distribution profiles of PM0.5, PM1.0, and PM2.5 measurements, but
the datasheet does a specify a degree of accuracy for the values unlike
the Honeywell sensor.
Technical documents for the SCD30 are here:
https://sensirion.com/products/catalog/SCD30/
*/
static int fineoffset_wh45_decode(r_device *decoder, bitbuffer_t *bitbuffer)
{
uint8_t const preamble[] = {0xaa, 0x2d, 0xd4}; // 24 bit, part of preamble and sync word
uint8_t b[15];
// bit counts have been observed between 187 and 222
if (bitbuffer->bits_per_row[0] < 170 || bitbuffer->bits_per_row[0] > 240) {
return DECODE_ABORT_LENGTH;
}
// Find a data package and extract data buffer
unsigned bit_offset = bitbuffer_search(bitbuffer, 0, 0, preamble, 24) + 24;
if (bit_offset + sizeof(b) * 8 > bitbuffer->bits_per_row[0]) { // Did not find a big enough package
decoder_logf_bitbuffer(decoder, 2, __func__, bitbuffer, "short package at %u", bit_offset);
return DECODE_ABORT_LENGTH;
}
// Extract package data
bitbuffer_extract_bytes(bitbuffer, 0, bit_offset, b, sizeof(b) * 8);
if (b[0] != 0x45) // Check for family code 0x45
return DECODE_ABORT_EARLY;
decoder_log_bitrow(decoder, 1, __func__, b, sizeof (b) * 8, "");
// Verify checksum and CRC
uint8_t crc = crc8(b, 13, 0x31, 0x00);
uint8_t chk = add_bytes(b, 14);
if (crc != b[13] || chk != b[14]) {
decoder_logf(decoder, 1, __func__, "Checksum error: %02x %02x", crc, chk);
return DECODE_FAIL_MIC;
}
int id = (b[1] << 16) | (b[2] << 8) | (b[3]);
int temp_raw = (b[4] & 0x7) << 8 | b[5];
float temp_c = (temp_raw - 400) * 0.1f; // range -40.0-60.0 C
int humidity = b[6];
int battery_bars = (b[7] & 0x40) >> 4 | (b[9] & 0xC0) >> 6;
// A battery bars value of 6 means the sensor is powered via USB (the Ecowitt WS View app shows 'DC')
int ext_power = battery_bars == 6 ? 1 : 0;
// Battery level is indicated with 5 bars. Convert to 0 (0 bars) to 1 (5 or 6 bars)
float battery_ok = MIN(battery_bars * 0.2f, 1.0f);
int pm2_5_raw = (b[7] & 0x3f) << 8 | b[8];
float pm2_5 = pm2_5_raw * 0.1f;
int pm10_raw = (b[9] & 0x3f) << 8 | b[10];
float pm10 = pm10_raw * 0.1f;
int co2 = (b[11] << 8) | b[12];
/* clang-format off */
data_t *data = data_make(
"model", "", DATA_STRING, "Fineoffset-WH45",
"id", "ID", DATA_FORMAT, "%06x", DATA_INT, id,
"battery_ok", "Battery Level", DATA_FORMAT, "%.1f", DATA_DOUBLE, battery_ok,
"temperature_C", "Temperature", DATA_FORMAT, "%.01f C", DATA_DOUBLE, temp_c,
"humidity", "Humidity", DATA_FORMAT, "%u %%", DATA_INT, humidity,
"pm2_5_ug_m3", "2.5um Fine Particulate Matter", DATA_FORMAT, "%.1f ug/m3", DATA_DOUBLE, pm2_5,
"pm10_ug_m3", "10um Coarse Particulate Matter", DATA_FORMAT, "%.1f ug/m3", DATA_DOUBLE, pm10,
"co2_ppm", "Carbon Dioxide", DATA_FORMAT, "%i ppm", DATA_INT, co2,
"ext_power", "External Power", DATA_INT, ext_power,
"mic", "Integrity", DATA_STRING, "CRC",
NULL);
/* clang-format on */
decoder_output_data(decoder, data);
return 1;
}
static char *output_fields[] = {
"model",
"id",
"battery_ok",
"temperature_C",
"humidity",
"pm2_5_ug_m3",
"pm10_0_ug_m3",
"co2_ppm",
"ext_power",
"mic",
NULL,
};
r_device fineoffset_wh45 = {
.name = "Fine Offset Electronics WH45 air quality sensor",
.modulation = FSK_PULSE_PCM,
.short_width = 58,
.long_width = 58,
.reset_limit = 2500,
.decode_fn = &fineoffset_wh45_decode,
.fields = output_fields,
};