Add support for ThermoPro-TP211B temperature sensor

Author: arahimi

include/rtl_433_devices.h

@@ -299,6 +299,7 @@
     DECL(ec3k) \
     DECL(orion_endpoint_2020) \
     DECL(geevon_tx19) \
+    DECL(thermopro_tp211b) \
 
     /* Add new decoders here. */
 

src/CMakeLists.txt

@@ -253,6 +253,7 @@ add_library(r_433 STATIC
     devices/tfa_twin_plus_30.3049.c
     devices/thermopro_tp11.c
     devices/thermopro_tp12.c
+    devices/thermopro_tp211b.c
     devices/thermopro_tp28b.c
     devices/thermopro_tp82xb.c
     devices/thermopro_tx2.c

src/devices/thermopro_tp211b.c

@@ -0,0 +1,111 @@
+/** @file
+    ThermoPro TP211B Thermometer.
+
+    Copyright (C) 2026, Ali Rahimi.
+
+    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"
+
+/**
+ThermoPro TP211B 915 MHz FSK temperature sensor.
+
+Based on [this issue](https://github.com/merbanan/rtl_433/issues/3435), and thanks to the
+analysis conducted there.
+
+Flex decoder:
+
+    rtl_433 -f 915M -X "n=tp211b,m=FSK_PCM,s=105,l=105,r=1500,preamble=552dd4"
+
+Data layout after preamble:
+
+    Byte Position   0  1  2  3  4  5  6  7
+    Sample          01 1e d6 03 6c aa 14 ff
+    Sample          01 1e d6 02 fa aa c4 1e
+                    II II II fT TT aa CC CC
+
+- III: {24} Sensor ID
+- f:   {4}  Flags or unused, always 0
+- TTT: {12} Temperature, raw value, °C = (raw - 500) / 10
+- aa:  {8}  Fixed value 0xAA
+- CC:  {16} Unknown trailing bytes, possibly checksum
+- Followed by trailing d2 d2 d2 d2 d2 00 00 (not used).
+*/
+
+static int thermopro_tp211b_decode(r_device *decoder, bitbuffer_t *bitbuffer)
+{
+    uint8_t const preamble_pattern[] = {0x55, 0x2d, 0xd4};
+
+    uint8_t b[8];
+
+    if (bitbuffer->num_rows > 1) {
+        decoder_logf(decoder, 1, __func__, "Too many rows: %d", bitbuffer->num_rows);
+        return DECODE_FAIL_SANITY;
+    }
+    const int msg_len = bitbuffer->bits_per_row[0];
+
+    int offset = bitbuffer_search(bitbuffer, 0, 0, preamble_pattern, sizeof(preamble_pattern) * 8);
+
+    if (offset >= msg_len) {
+        decoder_log(decoder, 1, __func__, "Sync word not found");
+        return DECODE_ABORT_EARLY;
+    }
+
+    if ((msg_len - offset) < 64) {
+        decoder_logf(decoder, 1, __func__, "Packet too short: %d bits", msg_len);
+        return DECODE_ABORT_LENGTH;
+    }
+
+    offset += sizeof(preamble_pattern) * 8;
+    bitbuffer_extract_bytes(bitbuffer, 0, offset, b, 8 * 8);
+
+    // Sanity check: byte 5 should be fixed 0xAA
+    if (b[5] != 0xaa) {
+        decoder_log(decoder, 1, __func__, "Fixed byte mismatch (expected 0xAA at byte 5)");
+        return DECODE_FAIL_SANITY;
+    }
+
+    if ((!b[0] && !b[1] && !b[2] && !b[3] && !b[4])
+            || (b[0] == 0xff && b[1] == 0xff && b[2] == 0xff && b[3] == 0xff && b[4] == 0xff)) {
+        decoder_log(decoder, 2, __func__, "DECODE_FAIL_SANITY data all 0x00 or 0xFF");
+        return DECODE_FAIL_SANITY;
+    }
+
+    decoder_log_bitrow(decoder, 2, __func__, b, 64, "MSG");
+
+    int id       = (b[0] << 16) | (b[1] << 8) | b[2];
+    int temp_raw = ((b[3] & 0x0f) << 8) | b[4];
+    float temp_c = (temp_raw - 500) * 0.1f;
+
+    /* clang-format off */
+    data_t *data = data_make(
+            "model",         "",            DATA_STRING, "ThermoPro-TP211B",
+            "id",            "Id",          DATA_FORMAT, "%06x",   DATA_INT,    id,
+            "temperature_C", "Temperature", DATA_FORMAT, "%.1f C", DATA_DOUBLE, (double)temp_c,
+            NULL);
+    /* clang-format on */
+
+    decoder_output_data(decoder, data);
+    return 1;
+}
+
+static char const *const output_fields[] = {
+        "model",
+        "id",
+        "temperature_C",
+        NULL,
+};
+
+r_device const thermopro_tp211b = {
+        .name        = "ThermoPro TP211B Thermometer",
+        .modulation  = FSK_PULSE_PCM,
+        .short_width = 105,
+        .long_width  = 105,
+        .reset_limit = 1500,
+        .decode_fn   = &thermopro_tp211b_decode,
+        .fields      = output_fields,
+};