Automatically connect your raspberry pi to a bluetooth device when the device is near and play entrance music based on the device's mac address. This library was used from an example library given in forums. Links to that are further below. Note that some of this is exaclty copy and pasted as in the forum, and to refer to the exact author you'll need to refer to the links. I was simply trying to reuse their work and don't claim credit.
The basic architecture/design of this program is you will have a system executable auto-agent which you can use as a background job if you would like. That executable will try to connect to a given mac address. Based on it's success/failure it will output different messages to stdout.
The main file of this library is EntranceMusic.py which creates a child process to call auto-agent for a list of mac addresses. If we are able to successfully connect to a mac address, then play a music file that is associated with that mac address. Otherwise, go down the list again and try to connect with bluetooth. The assumption is when the person's phone is close enough to connect to the pi, entrance music will start playing for that device.
It may seem a bit odd to have a file that can act as a job (auto-agent) instead of creating an object/class to encapsulate that logic, but I chose to keep it this way since this will give you an idea of what else you can do with bluetooth commands in python. We are only using a targeted part of this functionality, but if you are interested in building more complex applications, then this will give you and idea of what else you can do.
Resource: https://www.raspberrypi.org/forums/viewtopic.php?p=947185#p947185
You first need to enable your phone to connect to the pi. I was not able to do this by default, so you'll need to add the SP profile to the Pi. Edit this file:
sudo nano /etc/systemd/system/dbus-org.bluez.service
Add the compatibility flag, ' -C', at the end of the 'ExecStart=' line. Add a new line after that to add the SP profile. The two lines should look like this:
ExecStart=/usr/lib/bluetooth/bluetoothd -C
ExecStartPost=/usr/bin/sdptool add SP
Save the file and reboot.
After you enable your phone to pair (I have an iPhone 10), you need to initiate the pair in the UI and connect the Pi to the phone. Command line does not work for some reason. So you need to have already paired in the UI with the device before. To do this make the pi discoverable in the menu bar in the pi desktop UI, on the phone tap to connect, then accept the connection in the raspberry pi. Once this happens you can disconnect and running the auto connect script will work.
First download the repo with:
git clone https://github.com/tmckay1/pi_bluetooth_auto_connect.git
Next make bluezutils accessible from the system packages (you'll need to do this since we use auto-agent to call bluezutils and auto-agent is later copied to a system directory)
sudo cp bluezutils.py /usr/local/lib/python3.7/dist-packages/
Copy over the agent to the system bin and change the perms to make it executable
sudo cp auto-agent.py /usr/local/bin/auto-agent
sudo chmod 744 /usr/local/bin/auto-agent
This is only so you can run the auto-agent in the background in a job if you wanted. You can abstract out the implementation into a regular python class if you would like.
Depending on how you have your setup, you might need to do work to get the raspberry pi to output sound. We used pygame to play audio from the pi, but we also had to additional work to play sound. For one, we used a sound card and had the pi plugged into hdmi at the same time. We then set the default output for sound to be the sound card (instead of the headphones or hdmi) by editing /usr/share/alsa/alsa.conf and modifying
defaults.ctl.card 0
defaults.pcm.card 0
to be
defaults.ctl.card 2
defaults.pcm.card 2
Note that the number to the right above (0/2) represents the index of the sound device to use. Since I had my pi connected to hdmi and a sound card the indeces were 0 - headphones, 1 - hdmi, 2 - sound card, which is why we used 2. Depending on your seteup you might need a different index.
Now that you ran the above commands you should be able to run the test file. First you'll need to edit testAutoPair.py file which contains a dict of mac addresses pointing to music files to play for each device when connected to that device. Make sure to use the mac addresses of your devices. To find them you can open the command line in the raspberry pi and run bluetoothctl. Then run scan on when you enter the bluetoothctl shell. Wait for you device to show up (make sure it's discoverable) and you'll see the mac address. After editing the file, run
sudo python3 ./testAutoPair.py
within the directory of the git folder.
https://www.raspberrypi.org/forums/viewtopic.php?t=170353
2021-04-06 23:53:00,343 - bt_auto_loader - INFO - Starting to monitor Bluetooth connections
2021-04-06 23:53:31,992 - bt_auto_loader - INFO - Getting dbus interface for device: /org/bluez/hci0/dev_C4_98_80_E0_8F_01 interface: org.freedesktop.DBus.Properties property_name: org.bluez.MediaControl1
2021-04-06 23:53:31,993 - bt_auto_loader - INFO - Device: C4_98_80_E0_8F_01 has disconnected
2021-04-06 23:53:42,650 - bt_auto_loader - INFO - Getting dbus interface for device: /org/bluez/hci0/dev_C4_98_80_E0_8F_01 interface: org.freedesktop.DBus.Properties property_name: org.bluez.MediaControl1
2021-04-06 23:53:42,651 - bt_auto_loader - INFO - Device: C4_98_80_E0_8F_01 has disconnected
2021-04-06 23:59:29,715 - bt_auto_loader - INFO - Shutting down
2021-04-07 00:00:54,612 - bt_auto_loader - INFO - Starting to monitor Bluetooth connections
2021-04-07 00:01:51,449 - bt_auto_loader - INFO - Getting dbus interface for device: /org/bluez/hci0/dev_C4_98_80_E0_8F_01 interface: org.freedesktop.DBus.Properties property_name: org.bluez.MediaControl1
2021-04-07 00:01:51,450 - bt_auto_loader - INFO - Device: C4_98_80_E0_8F_01 has disconnected
2021-04-07 00:02:03,476 - bt_auto_loader - INFO - Getting dbus interface for device: /org/bluez/hci0/dev_C4_98_80_E0_8F_01 interface: org.freedesktop.DBus.Properties property_name: org.bluez.MediaControl1
2021-04-07 00:02:03,477 - bt_auto_loader - INFO - Running cmd: pactl load-module module-loopback source=bluez_source.C4_98_80_E0_8F_01