The below notes are kept for reference.
Raspberry Pi 3 on-board Bluetooth example
This project enables bluetooth and demonstrates some simple commands to interact with a bluetooth device.
To get this project up and running, you will need to signup for a balena account here and set up a Raspberry Pi 3, have a look at our Getting Started Tutorial if you haven't already. Once you are set up with balena, you will need to clone this repo locally:
$ git clone https://github.com/balena-projects/rpi3-bluetooth.git
Then add your balena application's remote repository to your local repository:
$ git remote add balena username@git.balena-cloud.com:username/myapp.git
and push the code to the newly added remote:
$ git push balena master
It should take a few minutes for the code to push. Once the code has pushed the scan.sh script will enable the on-board Bluetooth, you should see this in your logs:
To test everything works you will need to run some simple commands to scan for devices, connect to a device, discover characteristics and write to a characteristic.
Scan for devices:
$ hcitool lescan
LE Scan ...
18:B4:30:51:4C:E5 (unknown)
66:53:B2:89:24:D3 (unknown)
66:53:B2:89:24:D3 (unknown)
EE:50:F0:F8:3C:FF balena
EE:50:F0:F8:3C:FF (unknown)
18:B4:30:51:4C:E5 Nest Cam
the output shows 6 devices found, we are going to connect to the EE:50:F0:F8:3C:FF balena device:
$ gatttool -b EE:50:F0:F8:3C:FF -t random -I
[EE:50:F0:F8:3C:FF][LE]>
at the prompt enter connect to connect to the device:
[EE:50:F0:F8:3C:FF][LE]>connect
Attempting to connect to EE:50:F0:F8:3C:FF
Connection successful
[EE:50:F0:F8:3C:FF][LE]>
at the prompt enter char-desc to discover characteristics advertised by the device:
[EE:50:F0:F8:3C:FF][LE]> char-desc
handle: 0x0001, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0002, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0003, uuid: 00002a00-0000-1000-8000-00805f9b34fb
handle: 0x0004, uuid: 00002803-0000-1000-8000-00805f9b34fb
the output shows 4 characteristics found, we are going to write to the characteristic at handle: 0x0004, uuid: 00002803-0000-1000-8000-00805f9b34fb. At the prompt enter char-write-req 04 01 to write a 1 to the characteristic:
[EE:50:F0:F8:3C:FF][LE]> char-write-req 04 01
Characteristic value was written successfully
finally we need to close the connection, enter disconnect at the prompt:
[EE:50:F0:F8:3C:FF][LE]> disconnect
[EE:50:F0:F8:3C:FF][LE]>
followed by Ctrl + D to exit gatttool.