src/devices/xc0348.c

   1 /*
   2  * Digitech XC0348 weather station
   3  * Reports 1 row, 88 pulses
   4  * Format: ff ID ?X XX YY ZZ ?? ?? ?? UU CC
   5  * - ID: device id
   6  * - ?X XX: temperature, likely in 0.1C steps (.1 e7 == 8.7C, .1 ef == 9.5C)
   7  * - YY: percent in a single byte (for example 54 == 84%)
   8  * - ZZ: wind speed (00 == 0, 01 == 1.1km/s, ...)
   9  * - UU: wind direction: 00 is N, 02 is NE, 04 is E, etc. up to 0F is seems
  10  * - CC: checksum
  11  *
  12  * still unknown - rain, pressure
  13  */
  14
  15 #include "data.h"
  16 #include "rtl_433.h"
  17 #include "util.h"
  18
  19 #define CRC_POLY 0x31
  20 #define CRC_INIT 0xff
  21
  22 static const char* wind_directions[] = {
  23     "N", "NNE", "NE",
  24     "ENE", "E", "ESE",
  25     "SE", "SSE", "S", "SSW", "SW",
  26     "WSW", "W", "WNW",
  27     "NW", "NNW",
  28 };
  29
  30 static float get_temperature(const uint8_t* br) {
  31     const int temp_raw = (br[2] << 8) + br[3];
  32     return ((temp_raw & 0x0fff) - 0x190) / 10.0;
  33 }
  34
  35 static int get_humidity(const uint8_t* br) {
  36     return br[4];
  37 }
  38
  39 static const char* get_wind_direction(const uint8_t* br) {
  40     return wind_directions[br[9] & 0x0f];
  41 }
  42
  43 static float get_wind_speed(const uint8_t* br) {
  44     return br[5] * 1.1f;
  45 }
  46
  47 static int digitech_ws_callback(bitbuffer_t *bitbuffer) {
  48     data_t *data;
  49     char time_str[LOCAL_TIME_BUFLEN];
  50     local_time_str(0, time_str);
  51
  52     if (bitbuffer->num_rows != 1) {
  53         return 0;
  54     }
  55     if (bitbuffer->bits_per_row[0] != 88) {
  56         return 0;
  57     }
  58
  59         const uint8_t *br = bitbuffer->bb[0];
  60
  61     if (br[0] != 0xff) {
  62         // preamble missing
  63         return 0;
  64     }
  65
  66     if (br[10] != crc8(br, 10, CRC_POLY, CRC_INIT)) {
  67         // crc mismatch
  68         return 0;
  69     }
  70
  71     const float temperature = get_temperature(br);
  72     const int humidity = get_humidity(br);
  73     const char* direction = get_wind_direction(br);
  74     const float speed = get_wind_speed(br);
  75     const char device_id = br[1];
  76
  77     data = data_make("time",          "",               DATA_STRING, time_str,
  78                      "model",         "",               DATA_STRING, "Digitech XC0348 weather station",
  79                      "id",            "",               DATA_INT,    device_id,
  80                      "temperature_C", "Temperature",    DATA_DOUBLE, temperature,
  81                      "humidity",      "Humidity",       DATA_INT,    humidity,
  82                      "direction",     "Wind direction", DATA_STRING, direction,
  83                      "speed",         "Wind speed",     DATA_DOUBLE, speed,
  84                      NULL);
  85     data_acquired_handler(data);
  86     return 1;
  87 }
  88
  89 static char *output_fields[] = {
  90         "time",
  91         "model",
  92         "id",
  93         "temperature_C",
  94         "humidity",
  95         "direction",
  96         "speed",
  97         NULL
  98 };
  99
 100 r_device digitech_ws = {
 101     .name           = "Digitech XC0348 Weather Station",
 102     .modulation     = OOK_PULSE_PWM_RAW,
 103     .short_limit    = 976,
 104     .long_limit     = 2400,
 105     .reset_limit    = 10520,
 106     .json_callback  = &digitech_ws_callback,
 107     .disabled       = 0,
 108     .demod_arg      = 0,
 109     .fields         = output_fields,
 110 };