--- /dev/null
+/* Nexus sensor protocol with ID, temperature and optional humidity
+ * also FreeTec NC-7345 sensors for FreeTec Weatherstation NC-7344.
+ *
+ * the sensor sends 36 bits 12 times,
+ * the packets are ppm modulated (distance coding) with a pulse of ~500 us
+ * followed by a short gap of ~1000 us for a 0 bit or a long ~2000 us gap for a
+ * 1 bit, the sync gap is ~4000 us.
+ *
+ * the data is grouped in 9 nibbles
+ * [id0] [id1] [flags] [temp0] [temp1] [temp2] [const] [humi0] [humi1]
+ *
+ * The 8-bit id changes when the battery is changed in the sensor.
+ * flags are 4 bits B 0 C C, where B is the battery status: 1=OK, 0=LOW
+ * and CC is the channel: 0=CH1, 1=CH2, 2=CH3
+ * temp is 12 bit signed scaled by 10
+ * const is always 1111 (0x0F)
+ * humiditiy is 8 bits
+ *
+ * The sensor can be bought at Clas Ohlsen
+ */
+
+#include "rtl_433.h"
+#include "util.h"
+#include "data.h"
+
+extern int rubicson_crc_check(bitrow_t *bb);
+
+static int nexus_callback(bitbuffer_t *bitbuffer) {
+ bitrow_t *bb = bitbuffer->bb;
+ data_t *data;
+
+ char time_str[LOCAL_TIME_BUFLEN];
+
+ if (debug_output > 1) {
+ fprintf(stderr,"Possible Nexus: ");
+ bitbuffer_print(bitbuffer);
+ }
+
+ uint8_t id;
+ uint8_t battery;
+ uint8_t channel;
+ int16_t temp;
+ uint8_t humidity;
+ int r = bitbuffer_find_repeated_row(bitbuffer, 3, 36);
+
+ /** The nexus protocol will trigger on rubicson data, so calculate the rubicson crc and make sure
+ * it doesn't match. By guesstimate it should generate a correct crc 1/255% of the times.
+ * So less then 0.5% which should be acceptable.
+ */
+ if (r >= 0 &&
+ bitbuffer->bits_per_row[r] <= 37 && // we expect 36 bits but there might be a trailing 0 bit
+ bb[r][0] != 0 &&
+ bb[r][2] != 0 &&
+ bb[r][3] != 0 &&
+ !rubicson_crc_check(bb)) {
+
+ /* Get time now */
+ local_time_str(0, time_str);
+
+ /* Nibble 0,1 contains id */
+ id = bb[r][0];
+
+ /* Nibble 2 is battery and channel */
+ battery = bb[r][1]&0x80;
+ channel = ((bb[r][1]&0x30) >> 4) + 1;
+
+ /* Nible 3,4,5 contains 12 bits of temperature
+ * The temerature is signed and scaled by 10 */
+ temp = (int16_t)((uint16_t)(bb[r][1] << 12) | (bb[r][2] << 4));
+ temp = temp >> 4;
+
+ /* Nibble 6,7 is humidity */
+ humidity = (uint8_t)(((bb[r][3]&0x0F)<<4)|(bb[r][4]>>4));
+
+ // Thermo
+ if (bb[r][3] == 0xF0) {
+ data = data_make("time", "", DATA_STRING, time_str,
+ "model", "", DATA_STRING, "Nexus Temperature",
+ "id", "House Code", DATA_INT, id,
+ "battery", "Battery", DATA_STRING, battery ? "OK" : "LOW",
+ "channel", "Channel", DATA_INT, channel,
+ "temperature_C", "Temperature", DATA_FORMAT, "%.02f C", DATA_DOUBLE, temp/10.0,
+ NULL);
+ data_acquired_handler(data);
+ }
+ // Thermo/Hygro
+ else {
+ data = data_make("time", "", DATA_STRING, time_str,
+ "model", "", DATA_STRING, "Nexus Temperature/Humidity",
+ "id", "House Code", DATA_INT, id,
+ "battery", "Battery", DATA_STRING, battery ? "OK" : "LOW",
+ "channel", "Channel", DATA_INT, channel,
+ "temperature_C", "Temperature", DATA_FORMAT, "%.02f C", DATA_DOUBLE, temp/10.0,
+ "humidity", "Humidity", DATA_FORMAT, "%u %%", DATA_INT, humidity,
+ NULL);
+ data_acquired_handler(data);
+ }
+ return 1;
+ }
+ return 0;
+}
+
+static char *output_fields[] = {
+ "time",
+ "model",
+ "id",
+ "battery",
+ "channel",
+ "temperature_C",
+ "humidity",
+ NULL
+};
+
+r_device nexus = {
+ .name = "Nexus Temperature & Humidity Sensor",
+ .modulation = OOK_PULSE_PPM_RAW,
+ .short_limit = 1744,
+ .long_limit = 3500,
+ .reset_limit = 5000,
+ .json_callback = &nexus_callback,
+ .disabled = 0,
+ .demod_arg = 0,
+ .fields = output_fields
+};
projects / rtl-433.git / blobdiff