Filter likely BullTron BLE devices

README.md

@@ -144,6 +144,13 @@ The default write registers are the observed live MOS status registers
 `0x0035` and `0x0036`; keep them editable until those write registers are
 verified on your exact hardware/firmware.
 
+Scan results are sorted so likely BullTron devices appear first. The Android app
+accepts scanned devices whose BLE name contains `DL` or `B35`, or whose legacy
+advertising payload contains marker bytes for `DL`, `PU`, or `JHB`. The desktop
+app mirrors those name/advertising hints and also treats the confirmed BMS
+service UUID `fff0` as a strong match when the host Bluetooth stack exposes it
+during scanning.
+
 ## App Workflow
 
 The app's normal telemetry flow is:

bulltron_gui.py

@@ -55,6 +55,47 @@ WRITE_CHAR = "0000fff2-0000-1000-8000-00805f9b34fb"
 AT_CHAR = "0000fff3-0000-1000-8000-00805f9b34fb"
 SECRET_KEY_CHAR = "02f00000-0000-0000-0000-00000000ff05"
 VERSION_CHAR = "02f00000-0000-0000-0000-00000000ff04"
+BULLTRON_NAME_MARKERS = ("dl", "b35")
+BULLTRON_ADV_MARKERS = (b"DL", b"PU", b"JHB")
+
+
+def iter_advertisement_payloads(adv: Any) -> list[bytes]:
+    """Best-effort extraction of payload-like byte blobs from bleak metadata."""
+    payloads: list[bytes] = []
+    for data in getattr(adv, "manufacturer_data", {}).values():
+        if isinstance(data, bytes):
+            payloads.append(data)
+    for data in getattr(adv, "service_data", {}).values():
+        if isinstance(data, bytes):
+            payloads.append(data)
+    for item in getattr(adv, "platform_data", ()) or ():
+        if isinstance(item, bytes):
+            payloads.append(item)
+        elif isinstance(item, (tuple, list)):
+            payloads.extend(part for part in item if isinstance(part, bytes))
+    return payloads
+
+
+def bulltron_match_reason(name: str, service_uuids: list[str], payloads: list[bytes] | None = None) -> str | None:
+    lowered = name.lower()
+    if "bull" in lowered:
+        return "name:BullTron"
+    for marker in BULLTRON_NAME_MARKERS:
+        if marker in lowered:
+            return f"name:{marker.upper()}"
+    if MAIN_SERVICE in service_uuids:
+        return "service:fff0"
+    for payload in payloads or []:
+        # The Android app checks the legacy scanRecord at byte offsets 14..16
+        # for ASCII DL/PU/JHB markers, then requires byte 16 to be 0x00.
+        if len(payload) > 17 and payload[16] == 0x00:
+            for marker in BULLTRON_ADV_MARKERS:
+                if payload[14 : 14 + len(marker)].upper() == marker:
+                    return f"adv:{marker.decode('ascii')}"
+        for marker in BULLTRON_ADV_MARKERS:
+            if marker in payload.upper():
+                return f"adv:{marker.decode('ascii')}"
+    return None
 
 
 def crc16_modbus_swapped(data: bytes) -> int:
@@ -296,8 +337,8 @@ class BleWorker:
         for _, (dev, adv) in devices.items():
             name = dev.name or adv.local_name or "(unnamed)"
             service_uuids = [u.lower() for u in (adv.service_uuids or [])]
-            likely = "bull" in name.lower() or MAIN_SERVICE in service_uuids
+            reason = bulltron_match_reason(name, service_uuids, iter_advertisement_payloads(adv))
-            rows.append({"name": name, "address": dev.address, "rssi": adv.rssi, "likely": likely})
+            rows.append({"name": name, "address": dev.address, "rssi": adv.rssi, "likely": bool(reason), "reason": reason or ""})
         rows.sort(key=lambda row: (not row["likely"], -(row["rssi"] or -999)))
         self.ui_queue.put(("scan", rows))
         self.ui_queue.put(("status", f"Found {len(rows)} BLE devices"))
@@ -547,7 +588,8 @@ class BullTronGui(tk.Tk):
                 self.device_list.delete(0, tk.END)
                 for row in self.devices:
                     mark = "*" if row["likely"] else " "
-                    self.device_list.insert(tk.END, f"{mark} {row['name']}  {row['address']}  RSSI {row['rssi']}")
+                    reason = f" [{row['reason']}]" if row["reason"] else ""
+                    self.device_list.insert(tk.END, f"{mark} {row['name']}  {row['address']}  RSSI {row['rssi']}{reason}")
             elif kind == "connected":
                 self.status.set(f"Connected: {payload}")
             elif kind == "state":

tests/test_bulltron_gui.py

@@ -1,6 +1,6 @@
 import unittest
 
-from bulltron_gui import DeviceState, decode_response, read_frame, split_frames
+from bulltron_gui import DeviceState, bulltron_match_reason, decode_response, read_frame, split_frames
 
 
 class BullTronParserTest(unittest.TestCase):
@@ -41,6 +41,17 @@ class BullTronParserTest(unittest.TestCase):
         self.assertTrue(state.telemetry.discharge_mos)
         self.assertEqual(state.telemetry.cell_count, 4)
 
+    def test_bulltron_scan_filter_matches_apk_markers(self):
+        self.assertEqual(bulltron_match_reason("DL-1234", [], []), "name:DL")
+        self.assertEqual(bulltron_match_reason("B35-1234", [], []), "name:B35")
+        self.assertEqual(
+            bulltron_match_reason("unknown", ["0000fff0-0000-1000-8000-00805f9b34fb"], []),
+            "service:fff0",
+        )
+        payload = bytes.fromhex("00" * 14 + "4A4842" + "00")
+        self.assertEqual(bulltron_match_reason("unknown", [], [payload]), "adv:JHB")
+        self.assertIsNone(bulltron_match_reason("keyboard", [], [b"\x01\x02\x03"]))
+
 
 if __name__ == "__main__":
     unittest.main()