Add support for JCHENG SECURITY Contact and PIR sensors

include/rtl_433_devices.h

@@ -299,6 +299,8 @@
     DECL(ec3k) \
     DECL(orion_endpoint_2020) \
     DECL(geevon_tx19) \
+    DECL(jc_contact) \
+    DECL(jc_pir) \
 
     /* Add new decoders here. */
 

src/CMakeLists.txt

@@ -164,6 +164,7 @@ add_library(r_433 STATIC
     devices/interlogix.c
     devices/intertechno.c
     devices/jasco.c
+    devices/jc_sensor.c
     devices/kedsum.c
     devices/kerui.c
     devices/klimalogg.c

src/devices/jc_sensor.c

@@ -0,0 +1,185 @@
+/** @file
+    JCHENG SECURITY Contact and PIR sensors.
+
+    Copyright (C) 2025 Giorgi Kotchlamazashvili
+
+    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 "decoder.h"
+
+/**
+JCHENG SECURITY Contact Sensor - door/window contact sensor.
+
+The sensor uses OOK PWM modulation:
+- Short pulse: 400 us
+- Long pulse: 1200 us
+- Reset limit: 1260 us
+
+Data layout (25 bits):
+
+    PPPP IIII IIII IIII IIII OBSX XX
+
+- P: 4 bit preamble (fixed 0xF)
+- I: 16 bit sensor ID
+- O: 1 bit is_on flag
+- B: 1 bit battery_ok (1 = battery good)
+- S: 1 bit state (1 = closed, 0 = open)
+- X: 3 bit unknown/unused
+
+Raw data is sent MSB first.
+*/
+static int jc_contact_decode(r_device *decoder, bitbuffer_t *bitbuffer)
+{
+    // Look for repeated rows with 25 bits
+    int row = bitbuffer_find_repeated_row(bitbuffer, 2, 25);
+    if (row < 0) {
+        return DECODE_ABORT_LENGTH;
+    }
+
+    if (bitbuffer->bits_per_row[row] != 25) {
+        return DECODE_ABORT_LENGTH;
+    }
+
+    uint8_t *b = bitbuffer->bb[row];
+
+    // Check preamble: first 4 bits must be 0xF (1111)
+    if ((b[0] >> 4) != 0x0F) {
+        return DECODE_ABORT_EARLY;
+    }
+
+    // Extract 16-bit ID from bits 4-19
+    // b[0] has preamble in high nibble, first nibble of ID in low nibble
+    // b[1] has middle byte of ID
+    // b[2] has last nibble of ID in high nibble
+    int id = ((b[0] & 0x0F) << 12) | (b[1] << 4) | (b[2] >> 4);
+
+    // Extract flags from bits 20-22 (in b[2] low nibble and b[3] high bits)
+    // Bit 20 = is_on, Bit 21 = battery_ok, Bit 22 = state
+    int is_on      = (b[2] >> 3) & 0x01;  // bit 20
+    int battery_ok = (b[2] >> 2) & 0x01;  // bit 21
+    int state      = (b[2] >> 1) & 0x01;  // bit 22 (1=closed, 0=open)
+
+    /* clang-format off */
+    data_t *data = data_make(
+            "model",      "",           DATA_STRING, "Jcheng-Contact",
+            "id",         "ID",         DATA_FORMAT, "%04x", DATA_INT, id,
+            "closed",     "Closed",     DATA_INT,    state,
+            "battery_ok", "Battery OK", DATA_INT,    battery_ok,
+            "event",      "Event",      DATA_INT,    is_on,
+            NULL);
+    /* clang-format on */
+
+    decoder_output_data(decoder, data);
+    return 1;
+}
+
+static char const *const jc_contact_output_fields[] = {
+        "model",
+        "id",
+        "closed",
+        "battery_ok",
+        "event",
+        NULL,
+};
+
+r_device const jc_contact = {
+        .name        = "JCHENG SECURITY Contact Sensor",
+        .modulation  = OOK_PULSE_PWM,
+        .short_width = 400,
+        .long_width  = 1200,
+        .gap_limit   = 1400,
+        .reset_limit = 1260,
+        .tolerance   = 341,
+        .decode_fn   = &jc_contact_decode,
+        .disabled    = 1, // disabled by default (no checksum)
+        .fields      = jc_contact_output_fields,
+};
+
+/**
+JCHENG SECURITY PassiveIR Sensor - PIR motion sensor.
+
+The sensor uses OOK PWM modulation:
+- Short pulse: 400 us
+- Long pulse: 1200 us
+- Reset limit: 12000 us
+
+Data layout (25 bits):
+
+    PPPP PPPP IIII IIII IIII TMBX XX
+
+- P: 8 bit preamble (fixed 0xAA)
+- I: 12 bit sensor ID
+- T: 1 bit tamper flag
+- M: 1 bit motion detected
+- B: 1 bit battery_low (1 = low battery)
+- X: 3 bit unknown/unused
+
+Raw data is sent MSB first.
+*/
+static int jc_pir_decode(r_device *decoder, bitbuffer_t *bitbuffer)
+{
+    // Look for repeated rows with 25 bits
+    int row = bitbuffer_find_repeated_row(bitbuffer, 2, 25);
+    if (row < 0) {
+        return DECODE_ABORT_LENGTH;
+    }
+
+    if (bitbuffer->bits_per_row[row] != 25) {
+        return DECODE_ABORT_LENGTH;
+    }
+
+    uint8_t *b = bitbuffer->bb[row];
+
+    // Check preamble: first byte must be 0xAA
+    if (b[0] != 0xAA) {
+        return DECODE_ABORT_EARLY;
+    }
+
+    // Extract 12-bit ID from bits 8-19
+    int id = ((b[1] << 4) | (b[2] >> 4)) & 0x0FFF;
+
+    // Extract flags from bits 20-22 (in b[2] low nibble)
+    // Bit 20 = tamper, Bit 21 = motion, Bit 22 = battery_low
+    int tamper      = (b[2] >> 3) & 0x01;  // bit 20
+    int motion      = (b[2] >> 2) & 0x01;  // bit 21
+    int battery_low = (b[2] >> 1) & 0x01;  // bit 22
+
+    /* clang-format off */
+    data_t *data = data_make(
+            "model",       "",            DATA_STRING, "Jcheng-PIR",
+            "id",          "ID",          DATA_FORMAT, "%03x", DATA_INT, id,
+            "motion",      "Motion",      DATA_INT,    motion,
+            "tamper",      "Tamper",      DATA_INT,    tamper,
+            "battery_ok",  "Battery OK",  DATA_INT,    !battery_low,
+            NULL);
+    /* clang-format on */
+
+    decoder_output_data(decoder, data);
+    return 1;
+}
+
+static char const *const jc_pir_output_fields[] = {
+        "model",
+        "id",
+        "motion",
+        "tamper",
+        "battery_ok",
+        NULL,
+};
+
+r_device const jc_pir = {
+        .name        = "JCHENG SECURITY PassiveIR Sensor",
+        .modulation  = OOK_PULSE_PWM,
+        .short_width = 400,
+        .long_width  = 1200,
+        .gap_limit   = 1400,
+        .reset_limit = 12000,
+        .tolerance   = 341,
+        .decode_fn   = &jc_pir_decode,
+        .disabled    = 1, // disabled by default (no checksum)
+        .fields      = jc_pir_output_fields,
+};