Error "dbus.exceptions.DBusException: org.bluez.Error.NotAvailable: Operation currently not available" on central about python-bluezero HOT 8 CLOSED

To help debug this can you try the following:

• Are you able to connect to the device using bluetoothctl?
• Does service bluetooth status show errors?

When running heartrate_monitor_peripheral.py have separate terminals open with the following running to get more debug information:

• bluetoothctl
• journalctl -f -u bluetooth
• sudo busctl monitor org.bluez
• sudo btmon

from python-bluezero.

Device 1

bluetoothctl:

Agent registered
[CHG] Controller E4:5F:01:A8:21:50 Pairable: yes

service bluetooth status:

● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2023-03-30 14:39:48 CEST; 1h 24min ago
       Docs: man:bluetoothd(8)
   Main PID: 708 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 4471)
        CPU: 59ms
     CGroup: /system.slice/bluetooth.service
             └─708 /usr/libexec/bluetooth/bluetoothd

Mar 30 14:39:48 raspberrypi systemd[1]: Starting Bluetooth service...
Mar 30 14:39:48 raspberrypi bluetoothd[708]: Bluetooth daemon 5.55
Mar 30 14:39:48 raspberrypi systemd[1]: Started Bluetooth service.
Mar 30 14:39:48 raspberrypi bluetoothd[708]: Starting SDP server
Mar 30 14:39:48 raspberrypi bluetoothd[708]: Bluetooth management interface 1.22 initialized
Mar 30 14:39:48 raspberrypi bluetoothd[708]: profiles/sap/server.c:sap_server_register() Sap driver initialization failed.
Mar 30 14:39:48 raspberrypi bluetoothd[708]: sap-server: Operation not permitted (1)
Mar 30 14:39:48 raspberrypi bluetoothd[708]: Failed to set privacy: Rejected (0x0

Device 2

bluetoothctl:

Agent registered
[CHG] Controller E4:5F:01:A8:21:8A Pairable: yes

service bluetooth status:

● bluetooth.service - Bluetooth service
     Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2023-03-30 14:39:47 CEST; 1h 25min ago
       Docs: man:bluetoothd(8)
   Main PID: 636 (bluetoothd)
     Status: "Running"
      Tasks: 1 (limit: 3933)
        CPU: 57ms
     CGroup: /system.slice/bluetooth.service
             └─636 /usr/libexec/bluetooth/bluetoothd

Mar 30 14:39:47 raspberrypi4 systemd[1]: Starting Bluetooth service...
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: Bluetooth daemon 5.55
Mar 30 14:39:47 raspberrypi4 systemd[1]: Started Bluetooth service.
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: Starting SDP server
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: Bluetooth management interface 1.22 initialized
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: profiles/sap/server.c:sap_server_register() Sap driver initialization failed.
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: sap-server: Operation not permitted (1)
Mar 30 14:39:47 raspberrypi4 bluetoothd[636]: Failed to set privacy: Rejected (0x0b)

Running your suggestion on Device 2 and then connect with heartrate_monitor_peripheral.py for device 1 I get the following output on the 4 different terminals:

I am not sure what to look for, there is a lot of stuff printed in the sudo busctl monitor org.bluez and the ```sudo btmon```` terminals.

What is interesting that heartrate_monitor_peripheral.py sometimes runs without an error. But then nothing is printed nor seen on those terminals so I guess the connections is not established then.

from python-bluezero.

Rather than referring to device1 and device2, it would be clearer if we could use peripheral and central for clarity.

It looks like the image that has the four terminals shown is of the peripheral RPi. The btmon log suggests that the central disconnected from the peripheral.

Remote User Terminated Connection (0x13) error message often means that the client can't find what it is looking for or there is an issue with the pairing

Let's try and break this down in to smaller steps to check what is working and what is not.

Firstly, only start the peripheral. Then use a generic Bluetooth Low Energy scanning and exploration tool like nRF Connect. Connect to the peripheral and check all the services are there. You should be able to select the services and read/get-notifications from them.

If that works fine, then move on to the RPi where the central will be run. Don't run the script, use the bluetoothctl tool to connect to the peripheral device and introspect the GATT characteristics.

If that all works then we should have established that the peripheral is working and the central Raspberry Pi is working. We can then focus in on the Python for the central

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I have to admit that I am new to BLE and when reading about it I think that I need a central device and one peripheral device both in connected mode. Because I need data to be exchanged between both devices.

I actually don't care about the energy consumption since the central device will be connected to the grid and the peripheral device to the a big battery. So it might be that I took the wrong example to play around with because I cannot use a predefined Generic Attribute Profile (GATT). Unless I can use one or more generic one (like fixed string 64, generic level and Boolean) or define my own if there is an easy way to so.

I need some proprietary communication between both devices so originally I was just thinking about sending bytes over BLE which are a combination of an identifier and the data and both sides know how to encode and decode this data based on the identifier (like ISO 11898 Controller area network (CAN)).

But again I am just trying to read myself into BLE so not sure what the best approach would be for my use case.

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If it it is just the two RPi's that you are communicating between and you want to send arbitrary data between the two then it might be a more gentle learning curve to use Bluetooth Classic.

That can be done with standard Python socket library:
https://blog.kevindoran.co/bluetooth-programming-with-python-3/

Or the Bluedot library has packaged up client server examples very well:
https://www.stuffaboutcode.com/2017/07/python-bluetooth-rfcomm-client-server.html

If you want BLE then this might be a better example to start from for the peripheral:
https://github.com/ukBaz/python-bluezero/blob/main/examples/ble_uart.py
And that should work with
https://www.nordicsemi.com/Products/Development-tools/nRF-Connect-for-mobile
or
https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&hl=en_GB&gl=US
So you can test one end before moving on to the central.

I think you should be able to leverage the microbit module in Bluezero as the central:
https://github.com/ukBaz/python-bluezero/blob/main/examples/microbit_uart.py

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Thanks for the links, myself I couldn't find that much regarding this topic. I have PyBluez up and running with a client and server on both sides but not in BLE mode.

Found through your links the BlueDot Bluetooth Comm API seems also really simple and something I want. I will take a look at this too.

From your repositories I found BLE GATT which seems interesting for the client on the central. But I am not sure if this can also be used for a client on the peripheral. And what can be used as a server.

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BLE_GATT and PyBluez do not support creating a BLE Peripheral. BlueDoT seems like it might be a good fit for your project.

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Closing because of inactivity

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