Merge pull request #94 from vestom/fineoffset

Added support for Fine Offset Electronics Temp/Humidity sensor

.gitignore

@@ -45,3 +45,4 @@ build/
 .project
 
 *.orig
+*~

include/rtl_433.h

@@ -35,9 +35,10 @@
 #define BITBUF_ROWS             50
 
 /* Supported modulation types */
-#define     OOK_PWM_D		1   /* Pulses are of the same length, the distance varies */
+#define     OOK_PWM_D		1   /* Pulses are of the same length, the distance varies (PPM) */
 #define     OOK_PWM_P		2   /* The length of the pulses varies */
 #define     OOK_MANCHESTER	3	/* Manchester code */
+#define     OOK_PWM_RAW	    4   /* Pulse Width Modulation. No startbit removal. Short pulses = 1, Long = 0 */
 
 typedef struct {
     unsigned int    id;

include/rtl_433_devices.h

@@ -17,5 +17,6 @@ extern r_device mebus433;
 extern r_device intertechno;
 extern r_device newkaku;
 extern r_device alectov1;
+extern r_device fineoffset_WH2;
 
 #endif /* INCLUDE_RTL_433_DEVICES_H_ */

src/CMakeLists.txt

@@ -30,7 +30,8 @@ add_executable(rtl_433
 	devices/mebus.c
 	devices/intertechno.c
 	devices/alecto.c
-	devices/newkaku.c)
+	devices/newkaku.c
+	devices/fineoffset.c)
 
 target_link_libraries(rtl_433
 	${LIBRTLSDR_LIBRARIES}

src/devices/fineoffset.c

@@ -0,0 +1,110 @@
+/* Fine Offset Electronics sensor protocol
+ *
+ * The protocol is for the wireless Temperature/Humidity sensor 
+ * Fine Offset Electronics WH2
+ * aka Agimex Rosenborg 66796 (sold in Denmark)
+ * aka ClimeMET CM9088 (Sold in UK)
+ * aka ...
+ *
+ * The sensor sends two identical packages of 48 bits each ~50s. The bits are PWM modulated with On Off Keying
+ *
+ * The data is grouped in 6 bytes / 12 nibbles
+ * [pre] [pre] [type] [id] [id] [temp] [temp] [temp] [humi] [humi] [crc] [crc]
+ *
+ * pre is always 0xFF
+ * type is always 0x4 (may be different for different sensor type?)
+ * id is a random id that is generated when the sensor starts
+ * temp is 12 bit signed magnitude scaled by 10 celcius
+ * humi is 8 bit relative humidity percentage
+ * 
+ * Based on reverse engineering with gnu-radio and the nice article here:
+ *  http://lucsmall.com/2012/04/29/weather-station-hacking-part-2/
+ *
+ * Copyright (C) 2015 Tommy Vestermark
+ * 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 "rtl_433.h"
+
+
+// Generic CRC-8
+// (Should probably be moved to somewhere common)
+// polynomial byte is from x^7 to x^0 (x^8 is implicitly one)
+uint8_t crc8(uint8_t const message[], unsigned nBytes, uint8_t polynomial) {
+    uint8_t remainder = 0;	
+    unsigned byte, bit;
+
+    for (byte = 0; byte < nBytes; ++byte) {
+        remainder ^= message[byte];
+        for (bit = 0; bit < 8; ++bit) {
+            if (remainder & 0x80) {
+                remainder = (remainder << 1) ^ polynomial;
+            }
+            else {
+                remainder = (remainder << 1);
+            }
+        }
+    }
+    return remainder;
+}
+
+
+static int fineoffset_WH2_callback(uint8_t bb[BITBUF_ROWS][BITBUF_COLS], int16_t bits_per_row[BITBUF_ROWS]) {
+    uint8_t ID;
+    float temperature;
+    float humidity;
+
+    const uint8_t polynomial = 0x31;    // x8 + x5 + x4 + 1 (x8 is implicit)
+
+    // Validate package
+    if (bits_per_row[0] >= 48 &&        // Dont waste time on a short package
+        bb[0][0] == 0xFF &&             // Preamble
+	    bb[0][5] == crc8(&bb[0][1], 4, polynomial)	// CRC (excluding preamble)
+	) 
+    {
+	    // Nibble 3,4 contains ID
+        ID = ((bb[0][1]&0x0F) << 4) | ((bb[0][2]&0xF0) >> 4);
+
+        // Nible 5,6,7 contains 12 bits of temperature
+        // The temperature is signed magnitude and scaled by 10
+        int16_t temp;
+        temp = bb[0][3];
+        temp |= (int16_t)(bb[0][2] & 0x0F) << 8;
+        if(temp & 0x800) {
+            temp &= 0x7FF;	// remove sign bit
+            temp = -temp;	// reverse magnitude
+        }
+        temperature = (float)temp / 10;
+
+        // Nibble 8,9 contains humidity
+        humidity = bb[0][4];
+
+        fprintf(stderr, "Fine Offset Electronics, WH2:\n");
+        fprintf(stderr, "ID          = 0x%2X\n", ID);
+        fprintf(stderr, "temperature = %.1f C\n", temperature);
+        fprintf(stderr, "humidity    = %2.0f %%\n", humidity);
+        // fprintf(stderr, "raw         = %02x %02x %02x %02x %02x %02x\n",bb[0][0],bb[0][1],bb[0][2],bb[0][3],bb[0][4],bb[0][5]);
+
+        if (debug_output)
+            debug_callback(bb, bits_per_row);
+
+        return 1;
+    }
+    return 0;
+}
+
+
+r_device fineoffset_WH2 = {
+    /* .id             = */ 12,
+    /* .name           = */ "Fine Offset Electronics, WH-2 Sensor",
+    /* .modulation     = */ OOK_PWM_RAW,
+    /* .short_limit    = */ 200,	// Short pulse 136, long pulse 381, fixed gap 259
+    /* .long_limit     = */ 700,	// Maximum pulse period (long pulse + fixed gap)
+    /* .reset_limit    = */ 700,	// We just want 1 package
+    /* .json_callback  = */ &fineoffset_WH2_callback,
+};
+
+
+

src/rtl_433.c

@@ -796,6 +796,55 @@ static void manchester_decode(struct dm_state *demod, struct protocol_state* p,
     }
 }
 
+
+/* Pulse Width Modulation. No startbit removal */
+static void pwm_raw_decode(struct dm_state *demod, struct protocol_state* p, int16_t *buf, uint32_t len) {
+    unsigned int i;
+    for (i = 0; i < len; i++) {
+        if (p->start_c) p->sample_counter++;
+
+        // Detect Pulse Start (leading edge)
+        if (!p->pulse_start && (buf[i] > demod->level_limit)) {
+            p->pulse_start    = 1;
+            p->sample_counter = 0;
+            // Check for first bit in sequence
+            if(!p->start_c) {
+                p->start_c = 1;
+            }
+        }
+
+        // Detect Pulse End (trailing edge)
+        if (p->pulse_start && (buf[i] < demod->level_limit)) {
+            p->pulse_start      = 0;
+            if (p->sample_counter <= p->short_limit) {
+                demod_add_bit(p, 1);
+            } else {
+                demod_add_bit(p, 0);
+            }
+        }
+
+        // Detect Pulse period overrun
+        if (p->sample_counter == p->long_limit) {
+                demod_next_bits_packet(p);
+        }
+
+        // Detect Pulse exceeding reset limit
+        if (p->sample_counter > p->reset_limit) {
+            p->sample_counter   = 0;
+            p->start_c          = 0;
+            p->pulse_start      = 0;
+
+            if (p->callback)
+                events+=p->callback(p->bits_buffer, p->bits_per_row);
+            else
+                demod_print_bits_packet(p);
+
+            demod_reset_bits_packet(p);
+        }
+    }
+}
+
+
 /** Something that might look like a IIR lowpass filter
  *
  *  [b,a] = butter(1, 0.01) ->  quantizes nicely thus suitable for fixed point
@@ -874,6 +923,9 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) {
                     case OOK_MANCHESTER:
                         manchester_decode(demod, demod->r_devs[i], demod->f_buf, len/2);
                         break;
+                    case OOK_PWM_RAW:
+                        pwm_raw_decode(demod, demod->r_devs[i], demod->f_buf, len / 2);
+                        break;
                     default:
                         fprintf(stderr, "Unknown modulation %d in protocol!\n", demod->r_devs[i]->modulation);
                 }
@@ -1013,6 +1065,7 @@ int main(int argc, char **argv) {
     register_protocol(demod, &alectov1);
     register_protocol(demod, &intertechno);
     register_protocol(demod, &mebus433);
+    register_protocol(demod, &fineoffset_WH2);
 
     if (argc <= optind - 1) {
         usage();