X-Git-Url: https://git.rvb.name/rtl-433.git/blobdiff_plain/ca13278b24eb61443559bcb61e64627fba3d8823..6d15c6f967221af825cf84e3ed12b96c763b127b:/src/devices/bresser_3ch.c

diff --git a/src/devices/bresser_3ch.c b/src/devices/bresser_3ch.c
new file mode 100644
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--- /dev/null
+++ b/src/devices/bresser_3ch.c
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+/* Bresser sensor protocol
+ *
+ * The protocol is for the wireless Temperature/Humidity sensor
+ * Bresser Thermo-/Hygro-Sensor 3CH
+ *
+ * The sensor sends 15 identical packages of 40 bits each ~60s.
+ * The bits are PWM modulated with On Off Keying.
+ *
+ * A short pulse of 250 us followed by a 500 us gap is a 0 bit,
+ * a long pulse of 500 us followed by a 250 us gap is a 1 bit,
+ * there is a sync preamble of pulse, gap, 750 us each, repeated 4 times.
+ * Actual received and demodulated timings might be 2% shorter.
+ *
+ * The data is grouped in 5 bytes / 10 nibbles
+ * [id] [id] [flags] [temp] [temp] [temp] [humi] [humi] [chk] [chk]
+ *
+ * id is an 8 bit random id that is generated when the sensor starts
+ * flags are 4 bits battery low indicator, test button press and channel
+ * temp is 12 bit unsigned fahrenheit offset by 90 and scaled by 10
+ * humi is 8 bit relative humidity percentage
+ *
+ * Copyright (C) 2015 Christian W. Zuckschwerdt <zany@triq.net>
+ */
+#include "rtl_433.h"
+#include "pulse_demod.h"
+#include "util.h"
+#include "data.h"
+
+static int bresser_3ch_callback(bitbuffer_t *bitbuffer) {
+    bitrow_t *bb = bitbuffer->bb;
+    data_t *data;
+    char time_str[LOCAL_TIME_BUFLEN];
+
+    int id, status, battery_low, test, channel, temp_raw, humidity;
+    float temp_f;
+
+    /* note:
+       4 double wide sync pulses each go to an own row, the rows length will be
+       1 1 1 1 41 1 1 1 1 41 1 1 1 1 41 1 1 1 1 41 1 1 1 1 491
+     */
+    int r = bitbuffer_find_repeated_row(bitbuffer, 3, 40);
+    if (r < 0 || bitbuffer->bits_per_row[r] > 41) {
+        return 0;
+    }
+
+    uint8_t *b = bb[r];
+    b[0] = ~b[0];
+    b[1] = ~b[1];
+    b[2] = ~b[2];
+    b[3] = ~b[3];
+    b[4] = ~b[4];
+
+    if (((b[0] + b[1] + b[2] + b[3] - b[4]) & 0xFF) != 0) {
+        if (debug_output) {
+            fprintf(stderr, "Bresser 3CH checksum error\n");
+        }
+        return 0;
+    }
+
+    id = b[0];
+    status = b[1];
+    battery_low = (b[1] & 0x80) >> 7;
+    test = (b[1] & 0x40) >> 6;
+    channel = (b[1] & 0x30) >> 4;
+
+    temp_raw = ((b[1] & 0x0F) << 8) + b[2];
+    // 12 bits allows for values -90.0 F - 319.6 F (-67 C - 159 C)
+    temp_f = (temp_raw - 900) / 10.0;
+
+    humidity = b[3];
+
+    if ((channel == 0) || (humidity > 100) || (temp_f < -20.0) || (temp_f > 160.0)) {
+        if (debug_output) {
+            fprintf(stderr, "Bresser 3CH data error\n");
+        }
+        return 0;
+    }
+
+    local_time_str(0, time_str);
+    data = data_make("time",          "",            DATA_STRING, time_str,
+                     "model",         "",            DATA_STRING, "Bresser 3CH sensor",
+                     "id",            "",            DATA_INT, id,
+                     "channel",       "Channel",     DATA_INT, channel,
+                     "battery",       "Battery",     DATA_STRING, battery_low ? "LOW": "OK",
+                     "temperature_F", "Temperature", DATA_FORMAT, "%.2f F", DATA_DOUBLE, temp_f,
+                     "humidity",      "Humidity",    DATA_FORMAT, "%u %%", DATA_INT, humidity,
+                     NULL);
+    data_acquired_handler(data);
+
+    return 1;
+}
+
+static char *output_fields[] = {
+    "time",
+    "model",
+    "id",
+    "channel",
+    "battery",
+    "temperature_F",
+    "humidity",
+    NULL
+};
+
+r_device bresser_3ch = {
+    .name           = "Bresser Thermo-/Hygro-Sensor 3CH",
+    .modulation     = OOK_PULSE_PWM_RAW,
+    .short_limit    = 375,   // short pulse is ~250 us, long pulse is ~500 us
+    .long_limit     = 625,   // long gap (with short pulse) is ~500 us, sync gap is ~750 us
+    .reset_limit    = 1250,  // maximum gap is 1000 us (long gap + longer sync gap on last repeat)
+    .json_callback  = &bresser_3ch_callback,
+    .disabled       = 0,
+    .demod_arg      = 0,
+    .fields         = output_fields,
+};