refactor: implement packet parsing heuristics and introduce device-level state caching to throttle database writes and vitals updates

2026-07-11 14:24:14 +05:30
parent a4972b3251
commit 84b8acc904
32 changed files with 3499 additions and 180 deletions
@@ -0,0 +1,114 @@
+"""
+Verify the new parser offsets on the raw captured stream.
+New mappings:
+- HR: 989-byte packet, offset 904 (u16 LE)
+- SpO2: 286-byte packet, offset 264 (u16 LE)
+- Temperature: 56-byte packet, offset 8 (float32)
+- NIBP: 45-byte packet, offset 15, 17, 19 (u16 LE)
+"""
+import struct
+
+def read_u16_le(data, offset):
+    if offset + 2 > len(data):
+        return None
+    return struct.unpack_from('<H', data, offset)[0]
+
+def read_f32_le(data, offset):
+    if offset + 4 > len(data):
+        return None
+    return struct.unpack_from('<f', data, offset)[0]
+
+with open("/home/prathiyuman/Prathiyuman/ContecMonitor/fiveparaminte-main/scratch/raw_contec_stream.bin", "rb") as f:
+    stream = f.read()
+
+# Parse packets
+i = 0
+pkts = []
+while i < len(stream) - 8:
+    if (stream[i + 2] == 0x04 or stream[i + 2] == 0x01) and stream[i + 3] == 0x46:
+        pkt_len = struct.unpack_from('<H', stream, i)[0]
+        if 30 < pkt_len < 1050 and i + pkt_len <= len(stream):
+            pkts.append((pkt_len, stream[i:i + pkt_len]))
+        i += max(pkt_len, 4)
+    else:
+        i += 1
+
+vitals_cache = {
+    "heart_rate": None,
+    "spo2": None,
+    "temperature": None,
+    "systolic_bp": None,
+    "diastolic_bp": None,
+    "map_bp": None,
+}
+
+last_printed = {}
+
+for idx, (pkt_len, pkt) in enumerate(pkts):
+    changed = False
+    if pkt_len == 989:
+        hr = read_u16_le(pkt, 904)
+        # 65535 or 9999 means disconnected
+        if hr is not None and hr != 65535 and hr != 9999 and 20 <= hr <= 300:
+            if vitals_cache["heart_rate"] != float(hr):
+                vitals_cache["heart_rate"] = float(hr)
+                changed = True
+        elif hr == 65535 or hr == 9999:
+            if vitals_cache["heart_rate"] is not None:
+                vitals_cache["heart_rate"] = None
+                changed = True
+    elif pkt_len == 286:
+        spo2 = read_u16_le(pkt, 264)
+        if spo2 is not None and spo2 != 65535 and spo2 != 255 and 50 <= spo2 <= 100:
+            if vitals_cache["spo2"] != float(spo2):
+                vitals_cache["spo2"] = float(spo2)
+                changed = True
+        elif spo2 == 65535 or spo2 == 255:
+            if vitals_cache["spo2"] is not None:
+                vitals_cache["spo2"] = None
+                changed = True
+    elif pkt_len == 56:
+        temp = read_f32_le(pkt, 8)
+        if temp is not None and abs(temp - 9999.0) > 1.0 and 30.0 < temp < 45.0:
+            if vitals_cache["temperature"] != round(temp, 1):
+                vitals_cache["temperature"] = round(temp, 1)
+                changed = True
+        elif temp is not None and abs(temp - 9999.0) <= 1.0:
+            if vitals_cache["temperature"] is not None:
+                vitals_cache["temperature"] = None
+                changed = True
+    elif pkt_len == 45:
+        sys_bp = read_u16_le(pkt, 15)
+        dia_bp = read_u16_le(pkt, 17)
+        map_bp = read_u16_le(pkt, 19)
+        
+        # 9999 means no NIBP measurement active
+        if sys_bp is not None and sys_bp != 9999 and sys_bp > 0:
+            vitals_cache["systolic_bp"] = float(sys_bp)
+            changed = True
+        elif sys_bp == 9999 or sys_bp == 0:
+            if vitals_cache["systolic_bp"] is not None:
+                vitals_cache["systolic_bp"] = None
+                changed = True
+                
+        if dia_bp is not None and dia_bp != 9999 and dia_bp > 0:
+            vitals_cache["diastolic_bp"] = float(dia_bp)
+            changed = True
+        elif dia_bp == 9999 or dia_bp == 0:
+            if vitals_cache["diastolic_bp"] is not None:
+                vitals_cache["diastolic_bp"] = None
+                changed = True
+                
+        if map_bp is not None and map_bp != 9999 and map_bp > 0:
+            vitals_cache["map_bp"] = float(map_bp)
+            changed = True
+        elif map_bp == 9999 or map_bp == 0:
+            if vitals_cache["map_bp"] is not None:
+                vitals_cache["map_bp"] = None
+                changed = True
+
+    if changed:
+        current_vitals = {k: v for k, v in vitals_cache.items()}
+        if current_vitals != last_printed:
+            print(f"Pkt #{idx} (len={pkt_len}) -> Vitals: {current_vitals}")
+            last_printed = current_vitals