initial implementation for GT_WT_02 decoder

include/rtl_433_devices.h

@@ -27,7 +27,8 @@
 		DECL(calibeur_RF104) \
 		DECL(X10_RF) \
 		DECL(DSC) \
-		DECL(brennstuhl_rcs_2044)
+		DECL(brennstuhl_rcs_2044) \
+		DECL(gt_wt_02)
 
 
 typedef struct {

include/util.h

@@ -39,4 +39,11 @@ uint8_t crc8(uint8_t const message[], unsigned nBytes, uint8_t polynomial);
 /// @param buf: output buffer, long enough for YYYY-MM-DD HH:MM:SS
 void local_time_str(time_t time_secs, char *buf);
 
+/**
+ * convert unit from celsius to fahrenheit
+ * @param celsius input temperature in Celsius
+ * @return temperature value in Fahrenheit
+ */
+float celsius2fahrenheit(float celsius);
+
 #endif /* INCLUDE_UTIL_H_ */

src/CMakeLists.txt

@@ -44,6 +44,7 @@ add_executable(rtl_433
 	devices/x10_rf.c
 	devices/dsc.c
 	devices/brennstuhl_rcs_2044.c
+	devices/gt_wt_02.c
 )
 
 target_link_libraries(rtl_433

src/devices/gt_wt_02.c

@@ -0,0 +1,123 @@
+#include "rtl_433.h"
+#include "util.h"
+
+/*
+ * GT-WT-02 sensor on 433.92MHz
+ *
+ * Copyright (C) 2015 Paul Ortyl
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ */
+
+ /* NOTE: not everything is correct, more examples are necessary to
+  * complete the protocol description
+  *
+  * Example provided by https://github.com/ludwich66
+
+ 2 examples
+ [01] {37} 34 00 ed 47 60 : 00110100 00000000 11101101 01000111 01100000
+ code, BatOK,not-man-send, Channel1, +23,7°C, 35%
+
+ [01] {37} 34 8f 87 15 90 : 00110100 10001111 10000111 00010101 10010000
+ code, BatOK,not-man-send, Channel1,-12,1°C, 10%
+
+ SENSOR: GT-WT-02 (ALDI Globaltronics..)
+ TYP AAAAAAAA BCDDEFFF FFFFFFFF FGGGGGGG xxxxx
+ BIT 76543210 76543210 76543210 76543210 76543
+
+ TYPDescriptian
+ A = Rolling Device Code, Change after battery replacement
+ B = Battery 0=OK 1=LOW
+ C = Manual Send Button Pressed 0=not pressed 1=pressed
+ D = Channel 00=CH1, 01=CH2, 11=CH3
+ E = Temp 0=positive 1=negative
+ F = PositiveTemp =12 Bit bin2dez Temp,
+ F = negative Temp = 4095+1- F (12Bit bin2dez) , Factor Divid F / 10 (1Dezimal)
+ G = Humidity = 7 Bit bin2dez 00-99
+ x = unknown
+*/
+
+
+static int gt_wt_02_process_row(int row, const bitbuffer_t *bitbuffer);
+static int gt_wt_02_callback(bitbuffer_t *bitbuffer)
+{
+  int counter = 0;
+  for(int row=0; row<bitbuffer->num_rows; row++)
+    counter += gt_wt_02_process_row(row, bitbuffer);
+  return counter;
+}
+
+static int gt_wt_02_process_row(int row, const bitbuffer_t *bitbuffer)
+{
+  const uint8_t *b = bitbuffer->bb[row];
+  const int length = bitbuffer->bits_per_row[row];
+
+  if ( 37 != length)
+    return 0;
+
+  //fprintf(stderr, "GT-WT-02: %02x %02x %02x %02x %02x\n", b[0], b[1], b[2], b[3], b[4]);
+
+  const int sensor_id      =  b[0];                    /* 8 x A */
+  const int battery_low    = (b[1] >> 7 & 1);          /* 1 x B */
+  const int button_pressed = (b[1] >> 6 & 1);          /* 1 x C */
+  const int channel        = (b[1] >> 4 & 3);          /* 2 x D */
+  const int negative_sign  = (b[1] >> 3 & 1);          /* 1 x E */
+  const int temp           = (((b[1] & 15) << 8) | b[2]); /* E + 11 X G */
+  const int humidity = (b[3]>>1) & 0x7F;
+
+  float tempC = (negative_sign ? ( temp - (1<<12) ) : temp ) * 0.1F;
+  {
+    time_t time_now;
+    char time_str[LOCAL_TIME_BUFLEN];
+    time(&time_now);
+    local_time_str(time_now, time_str);
+
+    printf("%s GT-WT-02 Sensor %02x: battery %s, channel %d, button %d, temperature %3.1f C / %3.1f F, humidity %2d%%\n"
+        , time_str, sensor_id, battery_low ? "low" : "OK", channel, button_pressed
+        , tempC, celsius2fahrenheit(tempC), humidity
+        );
+  }
+  return 1;
+}
+
+r_device gt_wt_02 = {
+  .name          = "GT-WT-02 sensor",
+  .modulation    = OOK_PULSE_PPM_RAW,
+  .short_limit   = 1150,
+  .long_limit    = 2500,
+  .reset_limit   = 2500,
+  .json_callback = &gt_wt_02_callback,
+  .disabled      = 0,
+  .demod_arg     = 0,
+};
+
+// Test code
+// gcc -I src/ -I include/ -std=gnu99 -D _TEST_DECODER src/devices/gt_wt_02.c src/util.c
+#ifdef _TEST_DECODER
+int main()
+{
+  bitbuffer_t bb;
+  bb.num_rows = 3;
+  bb.bits_per_row[0] = 37;
+  bb.bits_per_row[1] = 37;
+  bb.bits_per_row[2] = 37;
+  const uint8_t b0[] = {0x34, 0x00, 0xed, 0x47, 0x60};
+  const uint8_t b1[] = {0x34, 0x8f, 0x87, 0x15, 0x90};
+  const uint8_t b2[] = {0x34, 0x00, 0xde, 0x77, 0x78};
+
+  memcpy(bb.bb[0], b0, 5);
+  memcpy(bb.bb[1], b1, 5);
+  memcpy(bb.bb[2], b2, 5);
+
+  gt_wt_02_callback(&bb);
+/*
+ * Result:
+2015-08-16 19:08:16 GT-WT-02 Sensor 34: battery OK, channel 0, button 0, temperature 23.7 C / 74.7 F, humidity 35%
+2015-08-16 19:08:16 GT-WT-02 Sensor 34: battery low, channel 0, button 0, temperature -12.1 C / 10.2 F, humidity 10%
+2015-08-16 19:08:16 GT-WT-02 Sensor 34: battery OK, channel 0, button 0, temperature 22.2 C / 72.0 F, humidity 59%
+*/
+
+}
+
+#endif

src/util.c

@@ -45,6 +45,10 @@ void local_time_str(time_t time_secs, char *buf) {
 	strftime(buf, LOCAL_TIME_BUFLEN, "%Y-%m-%d %H:%M:%S", tm_info);
 }
 
+float celsius2fahrenheit(float celsius)
+{
+  return celsius * 9 / 5 + 32;
+}
 
 
 // Test code