在 Raspberry Pi Pico W 上取消与 aioble 的蓝牙 LE 连接

Question

设置与问题

我正在使用 MicroPython (v1.22.2) 开发低功耗蓝牙应用程序，其中包含用于外围设备 (Raspberry Pi Pico W) 的 aioble 库和用于在 Raspberry Pi 3 B+ 上运行的中央设备的 Python bluepy 库。我面临的问题是 BLE 连接在几秒钟（10-20 秒）后反复取消。外围设备发送有关传感器状态（打开/关闭）的通知，中央设备接收这些通知。

这是所发生情况的简化版本：

• 中央设备连接到外围设备。
• 外围设备发送一些通知。
• 突然，连接被取消。

外围端代码片段：

# Bluetooth GATT setup
_DOOR_SERVICE_UUID = bluetooth.UUID('12345678-1234-5678-1234-56789abcdef0')
_DOOR_STATE_UUID = bluetooth.UUID('12345678-1234-5678-1234-56789abcdef1')
_ADV_APPEARANCE_GENERIC_DOOR_SENSOR = const(768)
_ADV_INTERVAL_MS = 250_000

door_service = aioble.Service(_DOOR_SERVICE_UUID)
door_state_characteristic = aioble.Characteristic(door_service, _DOOR_STATE_UUID, read=True, notify=True)
aioble.register_services(door_service)
...
...
# Bluetooth advertising task
async def peripheral_task():
    global current_connection
    while True:
        if not current_connection:
            print("No Connection, attempting to advertise")
            try:
                async with await aioble.advertise(
                    _ADV_INTERVAL_MS,
                    name="DoorSensor",
                    services=[_DOOR_SERVICE_UUID],
                    appearance=_ADV_APPEARANCE_GENERIC_DOOR_SENSOR,
                ) as connection:
                    current_connection = connection
                    print("Connection from", connection.device)
                    await connection.disconnected()
            except asyncio.CancelledError as e:
                print(f"Cancelled: {str(e)}")
                current_connection = None
            except Exception as e:
                print(f"Unhandled exception: {str(e)}")
            finally:
                current_connection = None
        else:
            if not current_connection.is_connected():
                print("lost connection")
            print("connected")
            await asyncio.sleep(1)
...
# loop which checks door state and notifies central
...
    if current_connection:
        door_state_characteristic.notify(current_connection, _encode_door_state(1))
    await asyncio.sleep(1)

中央侧代码：

from bluepy.btle import Peripheral, DefaultDelegate

class MyDelegate(DefaultDelegate):
    def __init__(self):
        DefaultDelegate.__init__(self)

    def handleNotification(self, cHandle, data):
        print("Notification from Handle: {}".format(cHandle))
        state = int.from_bytes(data, byteorder='little')
        print("Door State Changed:", "Open" if state else "Closed")

def connect_to_sensor():
    peri = Peripheral("D8:3A:DD:9E:82:B1", "public")
    peri.setDelegate(MyDelegate())

    print("Connected to device")

    # Get service and characteristic
    svc = peri.getServiceByUUID("12345678-1234-5678-1234-56789abcdef0")
    ch = svc.getCharacteristics("12345678-1234-5678-1234-56789abcdef1")[0]

    print("Service and characteristic found")

    # Correct CCCD UUID for enabling notifications
    cccd_uuid = "00002902-0000-1000-8000-00805f9b34fb"
    cccd = ch.getDescriptors(forUUID=cccd_uuid)[0]
    cccd.write(b"\x01\x00", True)  # Enable notifications

    print("Subscribed to notifications")

    return peri

p = None

while True:
    if p:
        try:
            if p.waitForNotifications(1.0):
                continue
            print("Waiting for notifications...")
        except Exception as e:
            print(f"got some weird error\n{e}")
            p = None
    elif not p:
        p = connect_to_sensor()
        
p.disconnect()

到目前为止我尝试过的：

• 我在外围设备的脚本中实现了重新连接策略，在取消发生后立即重新启动广告。
• 我在外围脚本和中央脚本中添加了异常处理，以捕获并记录连接或通知处理过程中发生的任何错误。

期望：

• 我期望通过在断开连接后立即重新启动广告，系统将保持中央设备重新连接近乎连续的可用性。
• 我希望详细的错误记录能够揭示取消或断开连接的具体原因，帮助我查明并解决根本问题。

持续存在的问题：

• 虽然重连策略确实允许系统从断开连接中快速恢复，但它会导致重复取消和重连的循环，而且似乎没有任何明确的模式或错误消息，从而难以诊断根本原因。
• 错误日志没有显示任何可以解释取消发生原因的特定异常或错误。唯一的输出通常是“已取消”，没有更多详细信息。

外设输出

No Connection, attempting to advertise
Connection from Device(ADDR_PUBLIC, e4:aa:ea:fb:e0:32, CONNECTED)
It's open # notification
It's open # notification
Cancelled: 
No Connection, attempting to advertise
Connection from Device(ADDR_PUBLIC, e4:aa:ea:fb:e0:32, CONNECTED)
It's open # notification
Cancelled: 
No Connection, attempting to advertise
Connection from Device(ADDR_PUBLIC, e4:aa:ea:fb:e0:32, CONNECTED)
It's open # notification
It's open # notification

使用bluetoothctl测试

使用 bluetoothctl 测试我的机器（Ubuntu 22.04）的连接似乎表明外围设备断开连接，而不是中央设备。

Answer 1

意外断开可能是由于

的默认timeout_ms造成的

await connection.disconnected()

在您的外围代码中。

我会用：

await connection.disconnected(timeout_ms=None)