How to connect a bluetooth speaker to your Raspberry Pi 3 without GUI

First, you need to download all necesary applications:

sudo apt-get update && sudo apt-get install bluez pulseaudio-module-bluetooth python-gobject python-gobject-2 bluez-tools udev

Now, add our user (pi) to the Pulse audio group so we the user can play audio through it.

sudo usermod –a –G lp pi

Now, we need enable A2DP in our bluetooth configuration file /etc/bluetooth/audio.conf the following sentences:

[General]:
Enable=Source,Sink,Media,Socket

The next step is modify the Pulse daemon resampling method in /etc/pulse/daemon.conf
adding a new line after ;resample-method with the following info:

resample-method = trivial

To automate the bluetooth source to audio sink, we need to add a new configuration to udev init.d editing file /etc/udev/rules.d/99-input.rules and add this to the file:

SUBSYSTEM="input", GROUP="input", MODE="0660"

KERNEL=="input[0-9]*", RUN+="/usr/lib/udev/bluetooth"

Now, create a new folder where we going to run a script:


sudo mkdir /usr/lib/udev
cd /usr/lib/udev
touch bluetooth

Add this to /usr/lib/udev/bluetooth file:

#!/bin/bash
# This script is called by udev when you link a bluetooth device with your computer
# It's called to add or remove the device from pulseaudio
#
#

# Output to this file
LOGFILE="/var/log/bluetooth_dev"

# Name of the local sink in this computer
# You can get it by calling : pactl list short sinks
# AUDIOSINK="alsa_output.platform-bcm2835_AUD0.0.analog-stereo"
AUDIOSINK="alsa_output.0.analog-stereo.monitor"
# User used to execute pulseaudio, an active session must be open to avoid errors
USER="pi"

# Audio Output for raspberry-pi
# 0=auto, 1=headphones, 2=hdmi. 
AUDIO_OUTPUT=1

# If on, this computer is not discovearable when an audio device is connected
# 0=off, 1=on
ENABLE_BT_DISCOVER=1

echo "For output see $LOGFILE"

## This function add the pulseaudio loopback interface from source to sink
## The source is set by the bluetooth mac address using XX_XX_XX_XX_XX_XX format.
## param: XX_XX_XX_XX_XX_XX
## return 0 on success
add_from_mac(){
  if [ -z "$1" ] # zero params
    then
        echo "Mac not found" >> $LOGFILE
    else
        mac=$1 # Mac is parameter-1

        # Setting source name
        bluez_dev=bluez_source.$mac
        echo "bluez source: $mac"  >> $LOGFILE

        # This script is called early, we just wait to be sure that pulseaudio discovered the device
        sleep 1
        # Very that the source is present
        CONFIRM=`sudo -u pi pactl list short | grep $bluez_dev`
        if [ ! -z "$CONFIRM" ]
        then
            echo "Adding the loopback interface:  $bluez_dev"  >> $LOGFILE
            echo "sudo -u $USER pactl load-module module-loopback source=$bluez_dev sink=$AUDIOSINK rate=44100 adjust_time=0"  >> $LOGFILE

            # This command route audio from bluetooth source to the local sink..
            # it's the main goal of this script
            sudo -u $USER pactl load-module module-loopback source=$bluez_dev sink=$AUDIOSINK rate=44100 adjust_time=0  >> $LOGFILE
            return $?
        else
            echo "Unable to find a bluetooth device compatible with pulsaudio using the following device: $bluez_dev" >> $LOGFILE
            return -1
        fi
    fi
}

## This function set volume to maximum and choose the right output
## return 0 on success
volume_max(){
    # Set the audio OUTPUT on raspberry pi
    # amixer cset numid=3 <n> 
    # where n is 0=auto, 1=headphones, 2=hdmi. 
    amixer cset numid=3 $AUDIO_OUTPUT  >> $LOGFILE

    # Set volume level to 100 percent
    amixer set Master 100%   >> $LOGFILE
    pacmd set-sink-volume 0 65537   >> $LOGFILE
    return $?
}

## This function will detect the bluetooth mac address from input device and configure it.
## Lots of devices are seen as input devices. But Mac OS X is not detected as input
## return 0 on success
detect_mac_from_input(){
    ERRORCODE=-1

    echo "Detecting mac from input devices" >> $LOGFILE
    for dev in $(find /sys/devices/virtual/input/ -name input*)
    do
        if [ -f "$dev/name" ]
        then
            mac=$(cat "$dev/name" | sed 's/:/_/g')
            add_from_mac $mac

            # Endfor if the command is successfull
            ERRORCODE=$?
            if [ $ERRORCODE -eq 0]; then
                return 0
            fi
        fi
    done
    # Error
    return $ERRORCODE
}
## This function will detect the bt mac address from dev-path and configure it.
## Devpath is set by udev on device link
## return 0 on success
detect_mac_from_devpath(){
    ERRORCODE=-1
    if [ ! -z "$DEVPATH" ]; then
        echo "Detecting mac from DEVPATH"  >> $LOGFILE
        for dev in $(find /sys$DEVPATH -name address)
        do
            mac=$(cat "$dev" | sed 's/:/_/g')
            add_from_mac $mac

            # Endfor if the command is successfull
            ERRORCODE=$?
            if [ $ERRORCODE -eq 0]; then
                return 0
            fi

        done
        return $ERRORCODE;
    else
        echo "DEVPATH not set, wrong bluetooth device? " >> $LOGFILE
        return -2
    fi
    return $ERRORCODE
}


## Detecting if an action is set
if [ -z "$ACTION" ]; then
    echo "The script must be called from udev." >> $LOGFILE
    exit -1;
fi
## Getting the action
ACTION=$(expr "$ACTION" : "\([a-zA-Z]\+\).*")

# Switch case
case "$ACTION" in
"add")

    # Turn off bluetooth discovery before connecting existing BT device to audio
    if [ $ENABLE_BT_DISCOVER -eq 1]; then
        echo "Stet computer as hidden" >> $LOGFILE
        hciconfig hci0 noscan
    fi

    # Turn volume to max
    volume_max

    # Detect BT Mac Address from input devices
    detect_mac_from_input
    OK=$?

    # Detect BT Mac address from device path on a bluetooth event
    if [ $OK != 0 ]; then
        if [ "$SUBSYSTEM" == "bluetooth" ]; then
            detect_mac_from_devpath
            OK=$?
        fi
    fi

    # Check if the add was successfull, otherwise display all available sources
    if [ $OK != 0 ]; then
        echo "Your bluetooth device is not detected !" >> $LOGFILE
        echo "Available sources are:" >> $LOGFILE
        sudo -u $USER pactl list short sources >> $LOGFILE
    else
        echo "Device successfully added " >> $LOGFILE
    fi
    ;;

"remove")
    # Turn on bluetooth discovery if device disconnects
    if [ $ENABLE_BT_DISCOVER -eq 1]; then
        echo "Set computer as visible" >> $LOGFILE
        sudo hciconfig hci0 piscan
    fi
    echo "Removed" >> $LOGFILE
    ;;

#   
*)
    echo "Unsuported action $action" >> $LOGFILE
    ;;
esac

echo "--" >> $LOGFILE

Modify the file permissions and reboot your raspberry:

chmod 777 bluetooth 
reboot

To connect your bluetooth speaker, maybe you may find the commands bluez-*, but it's deprecated. You need to use bluetoothctl as follow:

bluetoothctl
power on
agent on
scan on
connect MAC_ADDRESS
Attempting to connect to 12:00:00:00:0B:4D
[CHG] Device 12:00:00:00:0B:4D Connected: yes
[CHG] Device 12:00:00:00:0B:4D UUIDs:
        00001108-0000-1000-8000-00805f9b34fb
        0000110b-0000-1000-8000-00805f9b34fb
        0000110c-0000-1000-8000-00805f9b34fb
        0000110e-0000-1000-8000-00805f9b34fb
        0000111e-0000-1000-8000-00805f9b34fb

Failed to connect: org.bluez.Error.Failed

If you see this error, you need to restart pulseaudio as follow and try again:

pulseaudio -k
pulseaudio --start

To run an audio you can use aplay.

aplay music.mp3

If you run aplay and only listen noise, use other player like mplayer.

mplayer music.mp3

Remeber that you can change the volume with alsamixer.
Enjoy it!

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