fix lỗi giải mã byte encoding
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@@ -16,21 +16,44 @@
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// ---------------------------------------------------------------
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// LD2450 / LD2453 SERIAL FRAMING — PER-USER-DIRECTED POLICY.
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//
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// (0) CRITICAL DIFFERENCE LD2450 vs LD2453 (ROOT CAUSE of "hand wave
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// still invalid" reported by the user):
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// * LD2450 coordinate encoding per slot = standard 2's complement
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// signed int16 little-endian.
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// * LD2453 coordinate encoding per slot = 16-bit SIGN-MAGNITUDE,
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// little-endian byte order.
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// bit 15 (MSB) = sign flag.
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// 1 ⇒ POSITIVE.
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// 0 ⇒ NEGATIVE.
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// bits 14..0 = 15-bit unsigned magnitude (absolute value).
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//
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// Evidence from the user's 2026-09-13 hand-wave capture:
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// Raw slot-1 bytes = [3B 80 BF 80 00 00 4A 01]
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// Previous (LD2450-style) 2's-complement cast → X=-32709 Y=-32577
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// → false "implausible WARN" even on a real target.
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// New LD2453 sign-magnitude decode:
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// X = 0x803B → sign=+ magnitude=0x003B = 59 mm
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// Y = 0x80BF → sign=+ magnitude=0x00BF = 191 mm
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// → distance ≈ 200 mm ≈ hand 20 cm in front of the antenna,
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// perfectly plausible → VALID ✔
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//
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// Speed (bytes 4-5 of each slot) is still interpreted as standard
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// signed int16 LE (cm/s); distance-resolution (bytes 6-7) stays as
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// standard uint16 LE (mm). Speed and resolution encodings are
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// IDENTICAL between LD2450 and LD2453.
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//
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// The user explicitly asked for the following behaviour — we follow it
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// exactly below and do NOT invent anything else:
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// (a) NEVER reject a syntactically-valid 30-byte 0x0003 frame as a
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// whole. Every [AA FF 03 00 .. .. 55 CC] gets counted in
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// framesParsed and promoted to _lastFrame.
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// (b) Per-slot sanity is the ONLY filtering point. If a slot's decoded
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// coordinates are physically implausible (Y < 0, Y > 6m,
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// |X| > 6m, …):
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// (b) Per-slot sanity is the ONLY filtering point. If a slot's
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// SIGN-MAGNITUDE decoded coords are physically implausible
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// (Y <= 0, Y > ~6.5m, |X| > ~6.5m, …):
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// * we print a WARN line to Serial Monitor,
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// * mark the slot valid=false IN the promoted RadarFrame,
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// * increment badSlotWarnings stat,
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// * do NOT send it up to the WebSocket / OLED / UI.
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//
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// This "trust the wire unless proven-impossible per-slot" policy maximises
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// recall — zero whole-frame dropped data loss.
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// * do NOT expose it to WebSocket / OLED / UI.
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//
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// (1) WIRE LAYOUT (byte-level, both chips):
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// Sync 2 bytes : 0xAA, 0xFF
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@@ -40,16 +63,16 @@
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//
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// (2) ACCEPTED FRAME TYPES FOR PARSING:
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// * 0x0003 — LD2450/LD2453 3-slot tracking report (30 bytes
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// total / 24 payload / 3 × 8 B/slot). This is the only
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// format we know how to interpret today. Frames with any
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// other frame-type words are skipped byte-by-byte until a
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// fresh AA FF sync is found.
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// total / 24 payload / 3 × 8 B/slot). Only difference
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// vs LD2450 = X/Y sign-magnitude encoding (see §0).
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//
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// (3) 8-BYTE SLOT LAYOUT (0x0003 frame payload slots):
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// [0..1] int16 X_mm signed; <0 left, >0 right
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// [2..3] int16 Y_mm signed; ALWAYS >0 for a real person
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// [4..5] int16 Speed_cm_s signed; +ve = closer
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// [6..7] uint16 DistanceRes_mm unsigned; NOT a "valid flag"
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// [0..1] X_mm LD2453 = sign-magnitude uint16 LE
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// LD2450 = 2's-compl signed int16 LE
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// Use decodeCoordSM16() below (LD2453 rule).
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// [2..3] Y_mm SAME ENCODING AS X. Y >= 1 for real target.
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// [4..5] Speed_cm_s standard signed int16 LE, cm/s.
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// [6..7] DistRes_mm standard uint16 LE, mm.
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// ---------------------------------------------------------------
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static const uint8_t FRAME_SYNC[] = { 0xAA, 0xFF };
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static const uint8_t FRAME_TAIL[] = { 0x55, 0xCC };
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@@ -71,10 +94,23 @@ static const uint16_t accepted_target_types[] = {
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static const size_t accepted_target_types_count =
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sizeof(accepted_target_types) / sizeof(accepted_target_types[0]);
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// Per-slot physical plausibility bounds (used for the WARN step (b) above).
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/* LD2453 SIGN-MAGNITUDE coordinate decoder (§0 above).
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* Takes the 2 little-endian slot bytes as [lo, hi] and returns a
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* signed mm coordinate. */
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static inline int32_t decodeCoordSM16(uint8_t lo, uint8_t hi) {
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const uint16_t raw = (uint16_t)lo | ((uint16_t)hi << 8);
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const bool positive = (raw & 0x8000u) != 0u; /* bit15 = sign flag */
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const uint32_t magnitude = (uint32_t)(raw & 0x7FFFu); /* bits 0..14 */
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const int32_t sign = positive ? 1 : -1;
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return sign * (int32_t)magnitude;
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}
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// Per-slot physical plausibility bounds. LD2453 nominal range = 0.5–6m,
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// use 6.5 m as an upper-bound ceiling so values just inside max range
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// (like the earlier ACK-like 6033 mm case) do not get false-WARNed.
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static const int32_t Y_MIN_MM = 1;
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static const int32_t Y_MAX_MM = 6000;
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static const int32_t X_ABS_MAX_MM = 6000;
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static const int32_t Y_MAX_MM = 6500;
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static const int32_t X_ABS_MAX_MM = 6500;
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// Returns true iff decoded (x,y) sit inside the radar's measurable
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// operational envelope (in front of the antenna and inside rated
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@@ -272,8 +308,8 @@ bool LD2453Parser::tryParseFrame() {
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}
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}
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int16_t x = (int16_t)(targetData[0] | (targetData[1] << 8));
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int16_t y = (int16_t)(targetData[2] | (targetData[3] << 8));
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int32_t x = decodeCoordSM16(targetData[0], targetData[1]);
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int32_t y = decodeCoordSM16(targetData[2], targetData[3]);
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int16_t speed = (int16_t)(targetData[4] | (targetData[5] << 8));
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uint16_t resolution = (uint16_t)(targetData[6] | (targetData[7] << 8));
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(void)resolution;
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Binary file not shown.
@@ -135,15 +135,13 @@ class RadarState:
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self.target_count = frame.get("target_count", 0)
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now = time.time()
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# Belt-and-suspenders physical-limits filter. The ESP32 side
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# should already have gated these, but in case old firmware is
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# still running or an ACK frame leaks through, we re-apply the
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# same sanity rules on the Orange Pi side:
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# Y in front of radar (y >= 1 mm), <= 6000 mm rated range
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# |X| <= 6000 mm (±60° cone + safety margin)
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# Belt-and-suspenders physical-limits filter, kept in sync with
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# the LD2453 ESP32 parser (sign-magnitude 15-bit magnitude +
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# nominal range extended to 6.5 m ceiling to avoid false drops
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# on real near-max-range targets, see LD2453Parser.cpp §0 and §2).
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PHYS_Y_MIN = 1
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PHYS_Y_MAX = 6000
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PHYS_X_ABS = 6000
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PHYS_Y_MAX = 6500
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PHYS_X_ABS = 6500
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valid_targets_this_frame = 0
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targets_data = frame.get("targets", [])
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