Missing manual? - GAP Central connecting to multiple peripherals.

Missing manual? - GAP Central connecting to multiple peripherals.

[John Whitmore]

BLE at the wrong end of a learning curve and trying to piece things together.

Perhaps I could just give a rough outline of the project. I want a Linux
device to listen for advertisements from a particular BLE sensor and connect
to those sensors, as and when they appear. Once connected, the Linux device
can send commands to the sensor, to turn on/off an LED or request sensor data
from each of the connected sensors.

The Linux kernel is 4.15 is an Ubuntu 16.04 based system.

I was looking at the latest bluez-5.50 doc directory but didn't see a file for
gap.txt, but adapter-api.txt looks like the API I'm looking for.

I'm trying to do this from Python, so currently thinking of using DBus
interface, another learning curve to address.

So after all that a specific bluex questions. I'm missing things, and possibly
incorrectly assuming that I need a certain kernel specified for bluez5.50, but
can't see any mention of versions of bluez relating to versions of kernel.

Secondly bluez-5.50 appears to be building an applicaiton, so I assume that
application has to be running to interface to Linux Kernel bluetooth stack and
handle the DBus API. So bluez should be a system service just started on
powerup?

Thanks for any help, I get the impression that this list is predominately for
guts of the Linux Kernel's bluetooth stack, but user side list is hard to
find.

Thanks again

John

Re: Missing manual? - GAP Central connecting to multiple peripherals.

[Barry Byford]

Hello John,

There are various Python examples available in the tree under the test
directory:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test

There are a number of Python libraries that have been implemented to
help with what you are looking to do.
There is a list of some of them at:
https://github.com/ukBaz/python-bluezero/wiki

I hope that helps.

Regards,
Barry

On Thu, 4 Jul 2019 at 22:32, John Whitmore <arigead@gmail.com> wrote:
>
> BLE at the wrong end of a learning curve and trying to piece things together.
>
> Perhaps I could just give a rough outline of the project. I want a Linux
> device to listen for advertisements from a particular BLE sensor and connect
> to those sensors, as and when they appear. Once connected, the Linux device
> can send commands to the sensor, to turn on/off an LED or request sensor data
> from each of the connected sensors.
>
> The Linux kernel is 4.15 is an Ubuntu 16.04 based system.
>
> I was looking at the latest bluez-5.50 doc directory but didn't see a file for
> gap.txt, but adapter-api.txt looks like the API I'm looking for.
>
> I'm trying to do this from Python, so currently thinking of using DBus
> interface, another learning curve to address.
>
> So after all that a specific bluex questions. I'm missing things, and possibly
> incorrectly assuming that I need a certain kernel specified for bluez5.50, but
> can't see any mention of versions of bluez relating to versions of kernel.
>
> Secondly bluez-5.50 appears to be building an applicaiton, so I assume that
> application has to be running to interface to Linux Kernel bluetooth stack and
> handle the DBus API. So bluez should be a system service just started on
> powerup?
>
> Thanks for any help, I get the impression that this list is predominately for
> guts of the Linux Kernel's bluetooth stack, but user side list is hard to
> find.
>
> Thanks again
>
> John

Re: Missing manual? - GAP Central connecting to multiple peripherals.

[John Whitmore]

On Fri, Jul 05, 2019 at 08:29:16AM +0100, Barry Byford wrote:
> Hello John,
> 
> There are various Python examples available in the tree under the test
> directory:
> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test
> 
> There are a number of Python libraries that have been implemented to
> help with what you are looking to do.
> There is a list of some of them at:
> https://github.com/ukBaz/python-bluezero/wiki
> 
> I hope that helps.
> 
> Regards,
> Barry
>

Thanks a million Barry, yes a great help.

I have used bluepy library to interface to the BTLE Devices but that has
proved unreliable at best. I'm not sure where the problems lie but basically
sometimes to connect I have to disconnect the USB BT Dongle and re-insert it
to get BlurTooth to work. I can scan and find the devices I'm looking for but
as soon as a connection is attempted I just get a null return from the
connection function. At present that means that bluetooth is not ready for
production on the linux device we're using. I'll try get the device into that
state and try connect with command line tools, just in case it gives some
indicaiton of what the problem actually is. At present there's no indication.

I'm sort of hoping that this is an issue with bluepy and I'll move to another
interface and see if that makes this any more reliable. It's for an LE sensor
for IoT in a production line, so unreliable is worst then useless.

Thanks again for your help

John