ericbolo/rpi-bluletooth-receiver.md

## rpi-bluletooth-receiver.md

      
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              rpi-bluletooth-receiver.md
            
          
    Introduction

This walks you through setting up your Raspberry PI 3 (Raspbian Jessie) as a bluetooth audio receiver.
Credits
https://www.raspberrypi.org/forums/viewtopic.php?t=68779. Parts of this tutorial did not work for me, so I'm noting my fixes here.
Also, I added instructions for setting up a custom USB sound card for better quality.
Set up USB sound card on Raspberry PI

List audio devices

aplay -l

This will list the available audio devices. In my case:
**** List of PLAYBACK Hardware Devices ****
card 1: Set [C-Media USB Headphone Set], device 0: USB Audio [USB Audio]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 2: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 2: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Configure ALSA

We need to tell ALSA (Advanced Linux Sound Architecture) to use the USB sound card.
sudo nano /usr/share/alsa/alsa.conf

Change
defaults.ctl.card 0

to
default.ctl.card 1

and
defaults.pcm.card 0

to
defaults.pcm.card 1

Install dependencies

sudo apt-get update

sudo apt-get install bluez pulseaudio-module-bluetooth python-gobject python-gobject-2

Note: bluez is used to manage bluetooth and pulse-audio is used for sound-management.
Change audio default settings

Add "pi" user (or whichever is your user) to the lp group to allow it to manage bluetooth

sudo usermod -a -G lp pi

Change the default bluetooth audio settings

The original tutorial says to edit sudo nano /etc/bluetooth/audio.conf, but no such file in latest RPI. Instead, edit /etc/bluetooth/main.conf.
Add complete the following line in the [General] section:
Enable=Source,Sink,Media,Socket

Configure pulse-audio resampling algorithms

sudo nano /etc/pulse/daemon.conf

Add or edit the following line:
resample-method = trivial

Reboot:
sudo reboot

Pair with your bluetooth device

The RPI 3 comes with bluetooth.
I used the GUI and followed these steps:
1. Right click the bluetooth systeay icon at the top right and click "Make discoverable"
2. Right click the bluetooth systray icon at the top right. Add device , then select the appropriate device from the scanned list, and connect. This will ask to confirm a code on both the RPI and the bluetooth device. Confirm on both sides.
3. Connect via the Bluetooth manager: Menu > Preferences > Bluetooth Manager, right click on the device and click "Connect"

Note: I found the above process to work for me, but not sure I need to connect twice.
The device needs to be paired and trusted.
Connect bluetooth source with local sink with pulse-audio

Make sure pulseaudio daemon is running

pulseaudio -D

List pulse-audio controller sources

pactl list sources short

In the list you should see something like bluez_source.AA_AA_AA_AA_AA_AA where AA_AA_AA_AA_AA_AA  is the MAC address of your bluetooth device.
List pulse-audio controller sinks

pactl list sinks short

Couple sink and source

Note: you must change the name of the sink and source to the names of your own bluetooth device and sink:
pactl load-module module-loopback source=bluez_source.AA_AA_AA_AA_AA_AA sink=alsa_output.usb-0d8c_C-Media_USB_Headphone_Set-00-Set.analog-stereo
You can test by playing a youtube video, music file, etc. on your bluetooth-connected phone.
TODO: add instructions for automating connection and sink/source coupling. Haven't gotten to that part yet.