Add support for Fine Offset WN34 temperature sensor (#2122)

README.md

@@ -303,6 +303,7 @@ See [CONTRIBUTING.md](./docs/CONTRIBUTING.md).
  [218] Microchip HCS200/HCS300 KeeLoq Hopping Encoder based remotes (FSK)
  [219] Fine Offset Electronics WH45 air quality sensor
  [220] Maverick XR-30 BBQ Sensor
+ [221] Fine Offset Electronics WN34 temperature sensor
 
 * Disabled by default, use -R n or a conf file to enable
 

conf/rtl_433.example.conf

@@ -442,6 +442,7 @@ stop_after_successful_events false
  protocol 218 # Microchip HCS200/HCS300 KeeLoq Hopping Encoder based remotes (FSK)
  protocol 219 # Fine Offset Electronics WH45 air quality sensor
  protocol 220 # Maverick XR-30 BBQ Sensor
+ protocol 221 # Fine Offset Electronics WN34 temperature sensor
 
 ## Flex devices (command line option "-X")
 

include/rtl_433_devices.h

@@ -228,6 +228,7 @@
  DECL(hcs200_fsk) \
  DECL(fineoffset_wh45) \
  DECL(maverick_xr30) \
+ DECL(fineoffset_wn34) \
 
  /* Add new decoders here. */
 

src/CMakeLists.txt

@@ -102,6 +102,7 @@ add_library(r_433 STATIC
  devices/fineoffset_wh1080.c
  devices/fineoffset_wh31l.c
  devices/fineoffset_wh45.c
+ devices/fineoffset_wn34.c
  devices/fineoffset_ws80.c
  devices/flex.c
  devices/fordremote.c

src/devices/fineoffset_wn34.c

@@ -0,0 +1,131 @@
+/** @file
+ Fine Offset Electronics WN34 Temperature 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 WN34 Temperature Sensor.
+
+- also Ecowitt WN34S (soil), WN34L (water)
+- also Froggit DP150 (soil), DP35 (water)
+
+Preamble is aaaa aaaa, sync word is 2dd4.
+
+Packet layout:
+
+ 0 1 2 3 4 5 6 7 8
+ YY II II II 0T TT BB XX AA
+ 34 00 29 65 02 85 44 66 f3
+
+- Y: 8 bit fixed sensor type 0x34
+- I: 24 bit device ID
+- T: 11 bit temperature, offset 40, scale 10
+- B: 7 bit battery level (unit of 20 mV)
+- X: 8 bit CRC
+- A: 8 bit checksum
+
+*/
+
+static int fineoffset_wn34_decode(r_device *decoder, bitbuffer_t *bitbuffer)
+{
+ data_t *data;
+ uint8_t const preamble[] = {0xAA, 0x2D, 0xD4};
+ uint8_t b[9];
+ unsigned bit_offset;
+
+ bit_offset = bitbuffer_search(bitbuffer, 0, 0, preamble, sizeof(preamble) * 8) + sizeof(preamble) * 8;
+ 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. Row length: %u. Header index: %u", bitbuffer->bits_per_row[0], bit_offset);
+ return DECODE_ABORT_LENGTH;
+ }
+
+ bitbuffer_extract_bytes(bitbuffer, 0, bit_offset, b, sizeof(b) * 8);
+
+ decoder_log_bitrow(decoder, 1, __func__, b, sizeof (b) * 8, "");
+
+ // Verify family code
+ if (b[0] != 0x34) {
+ decoder_logf(decoder, 2, __func__, "Msg family unknown: %2x", b[0]);
+ decoder_logf_bitbuffer(decoder, 2, __func__, bitbuffer, "Row length(bits_per_row[0]): %u", bitbuffer->bits_per_row[0]);
+ return DECODE_ABORT_EARLY;
+ }
+
+ // Verify checksum, same as other FO Stations: Reverse 1Wire CRC (poly 0x131)
+ uint8_t crc = crc8(b, 7, 0x31, 0x00);
+ uint8_t chk = add_bytes(b, 8);
+
+ if (crc != b[7] || chk != b[8]) {
+ decoder_logf(decoder, 2, __func__, "Checksum error: %02x %02x", crc, chk);
+ return DECODE_FAIL_MIC;
+ }
+
+ // Decode data
+ int id = (b[1] << 16) | (b[2] << 8) | (b[3]);
+ int temp_raw = (b[4] & 0x7) << 8 | b[5];
+ float temperature = (temp_raw - 400) * 0.1f; // range -40.0-60.0 C
+ int battery_mv = (b[6] & 0x7f) * 20; // mV
+
+ /*
+ * A 5 bar battery indicator is shown in the Ecowitt WS View app.
+ * Through observation of battery_mv values and the app indicator,
+ * it was determined that battery_mv maps non-linearly to the number
+ * of bars. Set battery_ok by mapping battery bars from 0 to 1 where
+ * 1 bar = 0 and 5 bars = 1.
+ */
+ int battery_bars;
+
+ if (battery_mv > 1440)
+ battery_bars = 5;
+ else if (battery_mv > 1380)
+ battery_bars = 4;
+ else if (battery_mv > 1300)
+ battery_bars = 3;
+ else if (battery_mv > 1200)
+ battery_bars = 2;
+ else
+ battery_bars = 1;
+
+ float battery_ok = (battery_bars - 1) * 0.25f;
+
+ /* clang-format off */
+ data = data_make(
+ "model", "", DATA_STRING, "Fineoffset-WN34",
+ "id", "ID", DATA_FORMAT, "%x", DATA_INT, id,
+ "battery_ok", "Battery", DATA_FORMAT, "%.1f", DATA_DOUBLE, battery_ok,
+ "battery_mV", "Battery Voltage", DATA_FORMAT, "%d mV", DATA_INT, battery_mv,
+ "temperature_C", "Temperature", DATA_FORMAT, "%.01f C", DATA_DOUBLE, temperature,
+ "mic", "Integrity", DATA_STRING, "CRC",
+ NULL);
+ /* clang-format on */
+
+ decoder_output_data(decoder, data);
+ return 1;
+}
+
+static char *output_fields[] = {
+ "model",
+ "id",
+ "battery_ok",
+ "battery_mV",
+ "temperature_C",
+ "mic",
+ NULL,
+};
+
+r_device fineoffset_wn34 = {
+ .name = "Fine Offset Electronics WN34 temperature sensor",
+ .modulation = FSK_PULSE_PCM,
+ .short_width = 58,
+ .long_width = 58,
+ .reset_limit = 2500,
+ .decode_fn = &fineoffset_wn34_decode,
+ .fields = output_fields,
+};