ImNotAVirus

Bluetooth PAN serving a Phoenix app

For my first Nerves project, I would like to create a Phoenix application that would be available only via Bluetooth Personal Area Network (PAN).

I’ve never done this before, but from what I could understand it would be feasible.

During my researches, I came across this stackoverflow post explaining in detail how to setup a Bluetooth PAN on Raspbian.

So I tried to reproduce the steps for Nerves :

First, I created a new system based on nerves_system_rpi3
On this system I installed bluez-tools and bluez-utils packages
I’ve also activated the Bluetooth subsystem support in make linux-menuconfig → Networking Support

Once the firmware burn on my SD card and the Raspberry started, I executed the following commands :

# Run D-Bus & Bluetoothd daemons
mkdir -p /var/run/dbus
/usr/bin/dbus-daemon --system
/usr/libexec/bluetooth/bluetoothd &

# Create PAN interface
ip link add pan0 type bridge

# Configure interface
ifconfig pan0 192.168.50.1 netmask 255.255.255.0 up

Until then, no problem.
But when I tried to execute bt-agent -c NoInputNoOutput or bt-network -s nap pan0, I got the following error:

bt-agent: bluez service is not found
Did you forget to run bluetoothd?

However, when I display the list of processes, I can see bluetoothd running.

I would like to know if anyone has ever had this problem or if anyone has ever succeeded in setting up a Bluetooth PAN.

Thanks in advance.

8 comments

/nerves #nerves-system #raspberrypi #bluetooth

0 1621 8

2020-08-19 13:32:28 UTC

Most Liked

outlog

think you need to comment out dtoverlay=pi3-miniuart-bt in config.txt

can’t really grasp it all - but believe that overlay moves BT to tttyS0 aka the mini-uart, so it’s not on ttyAMA0 - see https://github.com/raspberrypi/documentation/blob/master/configuration/uart.md

Post #4

fhunleth

Co-author of Nerves

You’re following the steps that I’d take if I were doing this. As a sanity check, does this work on Raspbian? And I wonder if dmesg shows any errors?

Also, not that this is a bad thing, but this is an ambitious first project. I think that you’ll be the first person to get Bluetooth PANs working with Nerves, so I’m very curious to hear your progress.

Post #1

ImNotAVirus

First of all, thank you for your answer.

I just tried this afternoon on Raspbian and I was able to setup a working PAN.
For dmesg, there is no error.

I like to have ambitious projects when I try out a technology. It allows me to really try to understand how it works, especially when I’m trying to do something and there is little documentation on the topic ^^

I will try again and I will update this post if I manage to get the NAP working on Nerves.

Post #2

Last Post!

ImNotAVirus

Small progress: I added a symbolic link from /var/lib/bluetooth to /tmp/bluetooth (via rootfs_overlay) but I still have the same error.

(bt-agent:363): GLib-CRITICAL **: 13:30:51.254: PCRE library is compiled without UTF8          
(bt-agent:363): GLib-CRITICAL **: 13:30:51.255: PCRE library is compiled without UTF8 properties support
bt-agent: bluez service is not found
Did you forget to run bluetoothd?

Now I don’t understand what the problem is since I don’t have any error anymore (neither from dmesg nor from bluetoothd).

Post #8