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/** @file
Prologue sensor protocol.
*/
/** @fn int prologue_callback(r_device *decoder, bitbuffer_t *bitbuffer)
Prologue sensor protocol,
also FreeTec NC-7104 sensor for FreeTec Weatherstation NC-7102,
and Pearl NC-7159-675.
The sensor can be bought at Clas Ohlson.
Note: this is a false positive for AlectoV1.
The sensor sends 36 bits 7 times, before the first packet there is a sync pulse.
The packets are ppm modulated (distance coding) with a pulse of ~500 us
followed by a short gap of ~2000 us for a 0 bit or a long ~4000 us gap for a
1 bit, the sync gap is ~9000 us.
The data is grouped in 9 nibbles
[type] [id0] [id1] [flags] [temp0] [temp1] [temp2] [humi0] [humi1]
- type: 4 bit fixed 1001 (9) or 0110 (5)
- id: 8 bit a random id that is generated when the sensor starts, could include battery status
the same batteries often generate the same id
- flags(3): is 0 when the battery is low, otherwise 1 (ok), first reading always says low
- flags(2): is 1 when the sensor sends a reading when pressing the button on the sensor
- flags(1,0): the channel number that can be set by the sensor (1, 2, 3, X)
- temp: 12 bit signed scaled by 10
- humi: 8 bit always 11001100 (0xCC) if no humidity sensor is available
*/
#include "decoder.h"
extern int alecto_checksum(uint8_t *b);
static int prologue_callback(r_device *decoder, bitbuffer_t *bitbuffer)
{
uint8_t *b;
data_t *data;
int type;
int id;
int battery;
int button;
int channel;
int temp_raw;
int humidity;
if (bitbuffer->bits_per_row[0] <= 8 && bitbuffer->bits_per_row[0] != 0)
return DECODE_ABORT_EARLY; // Alecto/Auriol-v2 has 8 sync bits, reduce false positive
int r = bitbuffer_find_repeated_row(bitbuffer, 4, 36); // only 3 repeats will give false positives for Alecto/Auriol-v2
if (r < 0)
return DECODE_ABORT_EARLY;
if (bitbuffer->bits_per_row[r] > 37) // we expect 36 bits but there might be a trailing 0 bit
return DECODE_ABORT_LENGTH;
b = bitbuffer->bb[r];
if ((b[0] & 0xF0) != 0x90 && (b[0] & 0xF0) != 0x50)
return DECODE_FAIL_SANITY;
// Check for Alecto collision, if the checksum is correct it's not Prologue/ThermoPro-TX2
if (alecto_checksum(b))
return DECODE_FAIL_SANITY;
// Prologue/ThermoPro-TX2 sensor
type = b[0] >> 4;
id = ((b[0] & 0x0F) << 4) | ((b[1] & 0xF0) >> 4);
battery = b[1] & 0x08;
button = (b[1] & 0x04) >> 2;
channel = (b[1] & 0x03) + 1;
temp_raw = (int16_t)((b[2] << 8) | (b[3] & 0xF0)); // uses sign-extend
temp_raw = temp_raw >> 4;
humidity = ((b[3] & 0x0F) << 4) | (b[4] >> 4);
/* clang-format off */
data = data_make(
"model", "", DATA_STRING, "Prologue-TH",
"subtype", "", DATA_INT, type,
"id", "", DATA_INT, id,
"channel", "Channel", DATA_INT, channel,
"battery_ok", "Battery", DATA_INT, !!battery,
"temperature_C", "Temperature", DATA_FORMAT, "%.02f C", DATA_DOUBLE, temp_raw * 0.1,
"humidity", "Humidity", DATA_COND, humidity != 0xcc, DATA_FORMAT, "%u %%", DATA_INT, humidity,
"button", "Button", DATA_INT, button,
NULL);
/* clang-format on */
decoder_output_data(decoder, data);
return 1;
}
static char *output_fields[] = {
"model",
"subtype",
"id",
"channel",
"battery_ok",
"temperature_C",
"humidity",
"button",
NULL,
};
r_device prologue = {
.name = "Prologue, FreeTec NC-7104, NC-7159-675 temperature sensor",
.modulation = OOK_PULSE_PPM,
.short_width = 2000,
.long_width = 4000,
.gap_limit = 7000,
.reset_limit = 10000,
.decode_fn = &prologue_callback,
.disabled = 0,
.fields = output_fields,
};