bleak.exc.BleakError: Multiple Characteristics with this UUID, refer to your desired characteristic by the handle attribute instead.

[Andrei-Iosifescu123]

• bleak version: 0.12.1
• Python version: Python 3.9.5
• Operating System: Windows 10 21H1
• BlueZ version (bluetoothctl -v) in case of Linux:

Description

I got the below error when trying to write 0x02 to a characteristic:

Traceback (most recent call last):
  File "C:\Users\User\Desktop\test.py", line 36, in <module>
    loop.run_until_complete(run(ADDRESS, True))
  File "C:\python\lib\asyncio\base_events.py", line 642, in run_until_complete
    return future.result()
  File "C:\Users\User\Desktop\test.py", line 30, in run
    await client.write_gatt_char(ALERT_CHARACTERISTIC, b"%s" % (t))
  File "C:\python\lib\site-packages\bleak\backends\winrt\client.py", line 631, in write_gatt_char
    characteristic = self.services.get_characteristic(char_specifier)
  File "C:\python\lib\site-packages\bleak\backends\service.py", line 179, in get_characteristic
    raise BleakError(
bleak.exc.BleakError: Multiple Characteristics with this UUID, refer to your desired characteristic by the `handle` attribute instead.

What I Did

C:\Users\User\Desktop>python test.py
Connected: True
Alerting...
Traceback (most recent call last):
  File "C:\Users\User\Desktop\test.py", line 36, in <module>
    loop.run_until_complete(run(ADDRESS, True))
  File "C:\python\lib\asyncio\base_events.py", line 642, in run_until_complete
    return future.result()
  File "C:\Users\User\Desktop\test.py", line 30, in run
    await client.write_gatt_char(ALERT_CHARACTERISTIC, b"%s" % (t))
  File "C:\python\lib\site-packages\bleak\backends\winrt\client.py", line 631, in write_gatt_char
    characteristic = self.services.get_characteristic(char_specifier)
  File "C:\python\lib\site-packages\bleak\backends\service.py", line 179, in get_characteristic
    raise BleakError(
bleak.exc.BleakError: Multiple Characteristics with this UUID, refer to your desired characteristic by the `handle` attribute instead.

[dlech]

Did you try what the error message suggests?

bleak.exc.BleakError: Multiple Characteristics with this UUID, refer to your desired characteristic by the handle attribute instead.

[Andrei-Iosifescu123]

Did you try what the error message suggests?

bleak.exc.BleakError: Multiple Characteristics with this UUID, refer to your desired characteristic by the handle attribute instead.

How do I get the handle attribute?

[dlech]

First, get the BleakGATTService object for the service you want, then from the service, get the characteristic. The BleakGATTCharacteristic object has the handle attribute in question.

[Andrei-Iosifescu123]

First, get the BleakGATTService object for the service you want, then from the service, get the characteristic. The BleakGATTCharacteristic object has the handle attribute in question.

How do I do that?

[dlech]

Maybe something like this?

async with BleakClient(device) as client:
    my_service, = (s for s in client.get_services() if s.uuid == MY_SERVICE_UUID)
    my_char = my service.get_characteristic(MY_CHAR_UUID)
    client.write_gatt_char(my_char, MY_VALUE)
    ...