Add support for Philips outdoor temperature sensor

This sensor is used with various Philips clock radios.

README.md

@@ -178,6 +178,7 @@ Supported device protocols:
     [91]  Infactory
     [92]  Ft004b	
     [93]  Ford car remote
+    [94]  Philips outdoor temperature sensor
 
 * Disabled by default, use -R n or -G
 

include/rtl_433.h

@@ -42,7 +42,7 @@
 
 #define MINIMAL_BUF_LENGTH      512
 #define MAXIMAL_BUF_LENGTH      (256 * 16384)
-#define MAX_PROTOCOLS           93
+#define MAX_PROTOCOLS           94
 #define SIGNAL_GRABBER_BUFFER   (12 * DEFAULT_BUF_LENGTH)
 
 /* Supported modulation types */

include/rtl_433_devices.h

@@ -96,7 +96,8 @@
 		DECL(tpms_renault) \
 		DECL(infactory) \
 		DECL(ft004b) \
-		DECL(fordremote)
+		DECL(fordremote) \
+		DECL(philips)
 
 
 typedef struct {

src/CMakeLists.txt

@@ -105,6 +105,7 @@ add_executable(rtl_433
 	devices/tpms_renault.c
 	devices/infactory.c
 	devices/fordremote.c
+	devices/philips.c
 
 )
 

src/Makefile.am

@@ -90,6 +90,7 @@ rtl_433_SOURCES      = baseband.c \
                        devices/tpms_ford.c \
                        devices/tpms_renault.c \
                        devices/infactory.c \
-		       devices/fordremote.c
+                       devices/fordremote.c \
+                       devices/philips.c
 
 rtl_433_LDADD        = $(LIBRTLSDR) $(LIBM)

src/devices/philips.c

@@ -0,0 +1,231 @@
+/* 
+ * Philips outdoor temperature sensor -- used with various Philips clock 
+ * radios (tested on AJ3650)
+ *
+ * Not tested, but these should also work: AJ7010, AJ260 ... maybe others?
+ *
+ * A complete message is 112 bits:
+ *      4-bit initial preamble, always 0
+ *      4-bit packet separator, always 0, followed by 32-bit data packet. 
+ *      Packets are repeated 3 times for 108 bits total.
+ *
+ * 32-bit data packet format:
+ *
+ * 0001cccc tttttttt tt000000 0b0?ssss
+ *
+ * c - channel: 0=channel 2, 2=channel 1, 4=channel 3 (4 bits)
+ * t - temperature in Celsius: subtract 500 and divide by 10 (10 bits)
+ * b - battery status: 0 = OK, 1 = LOW (1 bit)
+ * ? - unknown: always 1 in every packet I've seen (1 bit)
+ * s - CRC: non-standard CRC-4, reverse-engineered using RevEng (4 bits)
+ *     http://reveng.sourceforge.net
+ *     width=4  poly=0x9  init=0x1  refin=false  refout=false  xorout=0x0  check=0x5  residue=0x0  name=(none)
+ *  
+ * Pulse width:
+ *      Short: 2000 us = 0
+ *      Long: 6000 us = 1
+ * Gap width:
+ *      Short: 6000 us
+ *      Long: 2000 us
+ * Gap width between packets: 29000 us
+ * 
+ * Presumably the 4-bit preamble is meant to be a sync of some sort, 
+ * but it has the exact same pulse/gap width as a short pulse, and
+ * gets processed as data.
+ *
+ * Copyright (C) 2017 Chris Coffey (kpuc@sdf.org)
+ *
+ * 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"
+#include "util.h"
+
+#define PHILIPS_BITLEN       112
+#define PHILIPS_PACKETLEN    4
+#define PHILIPS_STARTNIBBLE  0x0
+
+/* Map channel values to their real-world counterparts */
+static const uint8_t channel_map[] = { 2, 0, 1, 0, 3 };
+
+
+/* philips_crc4_bit():
+ * Compute CRC-4 for a byte sequence, one bit at a time.
+ *
+ * Note that Philips uses a custom CRC implementation for this device; see above
+ * for details.
+ * 
+ * This function was generated using crcany (https://github.com/madler/crcany)
+ * License information: "This code is under the zlib license, permitting free
+ * commercial use."
+ */
+static unsigned philips_crc4_bit(unsigned crc, void const *mem, size_t len) 
+{
+    unsigned char const *data = mem;
+    if (data == NULL)
+        return 0x1;
+    crc <<= 4;
+    while (len--) {
+        crc ^= *data++;
+        for (unsigned k = 0; k < 8; k++)
+            crc = crc & 0x80 ? (crc << 1) ^ 0x90 : crc << 1;
+    }
+    crc >>= 4;
+    crc &= 0xf;
+    return crc;
+}
+
+
+/* philips_crc4_rem():
+ * Compute CRC-4 of the remaining high bits in the low byte of val.
+ *
+ * Note that Philips uses a custom CRC implementation for this device; see above
+ * for details.
+ * 
+ * This function was generated using crcany (https://github.com/madler/crcany)
+ * License information: "This code is under the zlib license, permitting free
+ * commercial use."
+ */
+static unsigned philips_crc4_rem(unsigned crc, unsigned val, unsigned bits) 
+{
+    crc <<= 4;
+    val &= ((1U << bits) - 1) << (8 - bits);
+    crc ^= val;
+    while (bits--)
+        crc = crc & 0x80 ? (crc << 1) ^ 0x90 : crc << 1;
+    crc >>= 4;
+    crc &= 0xf;
+    return crc;
+}
+
+
+static int philips_callback(bitbuffer_t *bitbuffer) 
+{
+    char time_str[LOCAL_TIME_BUFLEN];
+    uint8_t *bb;
+    unsigned int i;
+    uint8_t a, b, c;
+    uint8_t packet[PHILIPS_PACKETLEN];
+    uint8_t r_crc, c_crc;
+    uint8_t channel, battery_status;
+    int tmp;
+    float temperature;
+    data_t *data;
+
+    /* Get the time */
+    local_time_str(0, time_str);
+
+    /* Correct number of rows? */
+    if (bitbuffer->num_rows != 1) {
+        if (debug_output) {
+            fprintf(stderr, "%s %s: wrong number of rows (%d)\n", 
+                    time_str, __func__, bitbuffer->num_rows);
+        }
+        return 0;
+    }
+
+    /* Correct bit length? */
+    if (bitbuffer->bits_per_row[0] != PHILIPS_BITLEN) {
+        if (debug_output) {
+            fprintf(stderr, "%s %s: wrong number of bits (%d)\n", 
+                    time_str, __func__, bitbuffer->bits_per_row[0]);
+        }
+        return 0;
+    }
+
+    bb = bitbuffer->bb[0];
+
+    /* Correct start sequence? */
+    if ((bb[0] >> 4) != PHILIPS_STARTNIBBLE) {
+        if (debug_output) {
+            fprintf(stderr, "%s %s: wrong start nibble\n", time_str, __func__);
+        }
+        return 0;
+    }
+
+    /* Compare and combine the 3 repeated packets, with majority wins */
+    for (i = 0; i < PHILIPS_PACKETLEN; i++) {
+        a = bb[i+1]; /* First packet - on byte boundary */
+        b = (bb[i+5] << 4) | (bb[i+6] >> 4 & 0xf); /* Second packet - not on byte boundary */
+        c = bb[i+10]; /* Third packet - on byte boundary */
+
+        packet[i] = (a & b) | (b & c) | (a & c);
+    }
+
+    /* If debug enabled, print the combined majority-wins packet */
+    if (debug_output) {
+        fprintf(stderr, "%s %s: combined packet = ", time_str, __func__);
+        for (i = 0; i < PHILIPS_PACKETLEN; i++) {
+            fprintf(stderr, "%02x ",packet[i]);
+        }
+        fprintf(stderr, "\n");
+    }
+
+    /* Correct CRC? */
+    r_crc = packet[PHILIPS_PACKETLEN - 1] & 0x0f; /* Last nibble in the packet */
+    c_crc = philips_crc4_bit(1, packet, PHILIPS_PACKETLEN - 1); /* First three bytes */
+    c_crc = philips_crc4_rem(c_crc, packet[PHILIPS_PACKETLEN - 1], 4); /* Remaining high nibble */
+
+    if (r_crc != c_crc) {
+        if (debug_output) {
+            fprintf(stderr, "%s %s: CRC failed, calculated %x, received %x\n",
+                    time_str, __func__, c_crc, r_crc);
+        }
+        return 0;
+    }
+
+    /* Message validated, now parse the data */
+
+    /* Channel */
+    channel = packet[0] & 0x0f;
+    if (channel > (sizeof(channel_map) / sizeof(channel_map[0])))
+        channel = 0;
+    else
+        channel = channel_map[channel];
+
+    /* Temperature */
+    tmp = packet[1];
+    tmp <<= 2;
+    tmp |= ((packet[2] & 0xc0) >> 6);
+    tmp -= 500;
+    temperature = tmp / 10.0f;
+
+    /* Battery status */
+    battery_status = packet[PHILIPS_PACKETLEN - 1] & 0x40;
+
+    data = data_make("time",          "",            DATA_STRING, time_str,
+                     "model",         "",            DATA_STRING, "Philips outdoor temperature sensor",
+                     "channel",       "Channel",     DATA_INT,    channel,
+                     "temperature_C", "Temperature", DATA_FORMAT, "%.1f C", DATA_DOUBLE, temperature,
+                     "battery",       "Battery",     DATA_STRING, battery_status ? "LOW" : "OK",
+                     NULL);
+
+    data_acquired_handler(data);
+
+    return 1;
+}
+
+static char *philips_output_fields[] = {
+    "time",
+    "model",
+    "channel",
+    "temperature_C",
+    "battery",
+    NULL
+};
+
+r_device philips = {
+    .name          = "Philips outdoor temperature sensor",
+    .modulation    = OOK_PULSE_PWM_TERNARY,
+    .short_limit   = 500,
+    .long_limit    = 4000,
+    .reset_limit   = 30000,
+    .json_callback = &philips_callback,
+    .disabled      = 0,
+    .demod_arg     = 0,
+    .fields        = philips_output_fields,
+};
+