balena bluetooth block

balenaOS optimized bluetooth agent. Easiest way to add bluetooth pairing to your projects!

Features

The bluetooth block is a Docker image that runs a pre-configured bluetooth pairing agent, some of it's features are:

• Handle bluetooth pairing and connection with other devices
• Support for any bluetooth interface (built-in or USB)
• Uses DBus to communicate with balenaOS bluetooth daemon
• Reconnect on boot to known and trusted devices

Note that this block does not deal with the bluetooth "data layer". Your application will need to handle the data stream corresponding to the desired bluetooth profile. For example, the audio block takes an already paired and connected bluetooth device and sets it up as an A2DP audio source.

Usage

Prebuilt images

We maintain images for this block on balenaHub Container Registry. The images can be accessed using:

bh.cr/balenalabs/bluetooth-<arch> or bhcr.io/balenalabs/bluetooth-<arch> where <arch> is one of: rpi, armv7hf, aarch64 or amd64.

For details on how to select a specific version or commit version of the image see our documentation.

docker-compose file

To use this image, create a container in your docker-compose.yml file as shown below:

version: '2'

services:

  bluetooth:
    image: bh.cr/balenalabs/bluetooth-<arch>  # where <arch> is one of rpi, armv7hf, aarch64 or amd64
    network_mode: host
    cap_add:
      - NET_ADMIN
    restart: on-failure
    labels:
      io.balena.features.dbus: 1

  my-bluetooth-app:
    build: ./my-bluetooth-app

Customization

Extend image configuration

You can extend the bluetooth block to include custom configuration as you would with any other Dockerfile. Just make sure you don't override the ENTRYPOINT as it contains important system configuration.

Here are some of the most common extension cases:

• Start the bluetooth daemon from your own bash script:

FROM bh.cr/balenalabs/bluetooth-aarch64

# Be sure to run exec /usr/src/bluetooth-agent in your script
COPY start.sh /usr/src/start.sh
CMD [ "/bin/bash", "/usr/src/start.sh" ]

Environment variables

The following environment variables allow some degree of configuration:

Environment variable	Description	Default	Options
BLUETOOTH_DEVICE_NAME	The bluetooth device name that will be advertised.	balenaSound <SHORT_UUID>	-
BLUETOOTH_HCI_INTERFACE	The bluetooth interface to be used.	hci0	-
BLUETOOTH_PAIRING_MODE	The bluetooth paring mode: - Secure Simple Pairing (SSP): Secure pinless pairing method - Legacy Pairing: PIN code based authentication. Less secure but older devices might only support this mode. Note that this mode is no longer allowed on iOS devices.	SSP	SSP, LEGACY
BLUETOOTH_PIN_CODE	PIN code used for Legacy Pairing. Must be numeric and up to six digits (1 - 999999).	0000	-

Supported devices

The bluetooth block has been tested to work on the following devices:

Device Type	Status
Raspberry Pi 1 / Zero
Raspberry Pi Zero W	✔
Raspberry Pi 2	✔ *
Raspberry Pi 3	✔
Raspberry Pi 4	✔
balenaFin	✔
Jetson Nano	✔ *
BeagleBone Black	✔ *
Intel NUC	✔ *

*: Requires external USB bluetooth dongle