HFP on Raspberry Pi

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Update (Sep 7, 2017):
If you are using Raspbian Stretch, please refer here instead of steps below. This post below is for Raspbian Jessie.

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The purpose of this post is to enable Bluetooth Handsfree Profile (HFP) on Raspberry Pi so that Raspberry Pi can act like as a handsfree speaker phone or a handsfree car kit. There is one thing needs to be mentioned before start. The original plan was to use Raspberry Pi3’s on-board Bluetooth chip for this project. Unfortunately, it didn’t work. It seems that the problem is related with the chip. So, we have to use a Bluetooth dongle instead.

Here is the list of contents of this post.

Contents:
– Hardware Prerequisites
– Software Prerequisites
– Steps
1. Setting Up
2. oFono
3. PulseAudio
4. Connect your Phone
5. Make a Call!
– Conclusion
– Reference

Let’s get started.

 

Hardware Prerequisites
Since Raspberry Pi doesn’t have microphone input by default, it need to be added. In this post, I’ll use a USB sound card with a 3.5 mm jack microphone.

Also, as mentioned above, we’ll use a Bluetooth dongle instead of on-board Bluetooth chip.

– Raspberry Pi 3 B+
– Bluetooth dongle (Panda Bluetooth 4.0 USB Adapter)
– USB Sound Card (SYBA USB sound adapter / FG-UAUDV1-C119)
– Microphone with 3.5 mm audio jack
– Speakers with 3.5 mm audio jack (e.g. Rumfo Mini Speaker)

 

Software Prerequisites
Below are the required versions to enable Bluetooth HFP according to PulseAudio release note.

– Bluez 5.0 (or later)
– PulseAudio 6.0 (or later)
– oFono 1.13 (or later)

 

Steps
1. Setting Up
1-1. Connect Bluetooth dongle and USB sound card with Raspberry Pi.
1-2. Connect the microphone and speakers to 3.5 mm audio jacks on the USB sound card.
1-3. Boot up Raspberry Pi Board. If it’s not set up yet, please refer this post.
1-4. As described, we don’t use on-board Bluetooth chip. So it needs to be disabled. To do that, open “/etc/modprobe.d/raspi-blacklist.conf”.

sudo nano /etc/modprobe.d/raspi-blacklist.conf

1-5. Add lines below and save.

blacklist btbcm
blacklist hci_uart

1-6. Then reboot the board.

sudo reboot

1-7. After reboot, check dmesg and make sure there is no Bluetooth-related errors.

dmesg | grep -i bluetooth

1-8. Also, make sure hci0 is UP.

hciconfig

The result should be like this:

hci0:    Type: BR/EDR  Bus: USB
    BD Address: 00:1A:7D:DA:71:08  ACL MTU: 310:10  SCO MTU: 64:8
    UP RUNNING
    RX bytes:622 acl:0 sco:0 events:38 errors:0
    TX bytes:1437 acl:0 sco:0 commands:38 errors:0

If it’s DOWN for some reason, then turn it up.

sudo hciconfig hci0 up

2. oFono
2-1. oFono is not installed by default, so let’s install it.

sudo apt-get install ofono -y

2-2. Make sure the version is 1.13 or later.

pi@raspberrypi:~ $ ofonod --version
1.15

2-2. Then, start the service.

sudo systemctl start ofono

You can check the service running like below.

systemctl -a |grep ofono
  ofono.service     loaded    active   running   LSB: oFono Mobile Telephony Daemon

3. PulseAudio
Since the preinstalled PulseAudio is 5.0, it needs to be updated to at least 6.0.

pi@raspberrypi:~ $ pulseaudio --version
pulseaudio 5.0

3-1. Uninstall the current PulseAudio.

sudo apt-get purge pulseaudio -y

3-2. Open “/etc/apt/sources.list”.

sudo nano /etc/apt/sources.list

3-3. Add the line below:

deb http://ftp.debian.org/debian jessie-backports main

3-4. Execute commands below:

gpg --keyserver pgpkeys.mit.edu --recv-key 8B48AD6246925553
gpg --keyserver pgpkeys.mit.edu --recv-key 7638D0442B90D010
gpg -a --export 8B48AD6246925553 | sudo apt-key add --
gpg -a --export 7638D0442B90D010 | sudo apt-key add --

3-5. Update the package list.

sudo apt-get update

3-6. Install PulseAudio and its Bluetooth module:

sudo apt-get -t jessie-backports install pulseaudio pulseaudio-module-bluetooth -y

3-7. Check the version and make sure it’s 6.0 or later.

$ pulseaudio --version
pulseaudio 7.1

3-8. Open “/etc/pulse/default.pa”.

sudo nano /etc/pulse/default.pa

3-9. Add “headset=ofono” on the line of ‘module-bluetooth-discover’.

load-module module-bluetooth-discover headset=ofono

3-10. To enable echo canceling, add the lines below:

### Echo cancel and noise reduction
.ifexists module-echo-cancel.so
load-module module-echo-cancel aec_method=webrtc source_name=ec_out sink_name=ec_ref
set-default-source ec_out
set-default-sink ec_ref
.endif

3-11. Start PulseAudio.

pulseaudio --start

4. Connect your Phone
4-1. Launch bluetoothctl.

bluetoothctl

4-2. Then, input below commands.

power on
agent on
default-agent

4-3. Start searching your phone. Make sure your phone is discoverable.

scan on

4-4. After detecting your phone, turn scan off.

scan off

devices command shows a list of found devices.

[bluetooth]# devices
Device XX:XX:XX:XX:XX:XX Galaxy S7

4-5. Then, pair, trust and connect to your phone by specifying the Bluetooth device address (in this case it’s “XX:XX:XX:XX:XX:XX”, please replace it wity your device’s address).

pair XX:XX:XX:XX:XX:XX
trust XX:XX:XX:XX:XX:XX
connect XX:XX:XX:XX:XX:XX

If everything is ok, you should see “successful” at the end of the result for each command like below.

[bluetooth]# pair XX:XX:XX:XX:XX:XX
...
Pairing successful

[bluetooth]# trust XX:XX:XX:XX:XX:XX
...
trust succeeded

[bluetooth]# connect XX:XX:XX:XX:XX:XX
...
Connection successful

5. Make a Call!
To make a call, we’ll use oFono test scripts which is included in the source code.
5-1. First, download the source and extruct.

wget https://www.kernel.org/pub/linux/network/ofono/ofono-1.15.tar.gz
tar -xzvf ofono-1.15.tar.gz

5-2. Then, you can make a call by:

python ./test/dial-number 1234567890

If you want to end the call, then execute:

python ./test/hangup-active

 

Conclusion
Thanks for all the forums and articles I referred, now HFP is working on Raspberry Pi!
Next, I’m planning to apply echo canceling and ambient noise suppression, maybe equalizer.

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Update (June 22, 2017):
Added one step (step 3-10) to enable echo cancellation. It seems that ‘module-echo-cancel’ does not only echo cancellation but ambient noise suppression. I haven’t check the noise suppression yet but I think the echo cancellation is working well based on my brief testing.

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Update (May 2, 2018):
The steps to enable equalizer on HFP sending audio is newly posted.

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Reference
– Connect Bluetooth Headset To Raspberry Pi 3 (A2DP & HSP)
http://youness.net/raspberry-pi/bluetooth-headset-raspberry-pi-3-ad2p-hsp

– PulseAudio 6.0 Release Notes –freedesktop.org
https://www.freedesktop.org/wiki/Software/PulseAudio/Notes/6.0/

– PulseAudio Documentation –freedesktop.org
https://freedesktop.org/wiki/Software/PulseAudio/Documentation/

– module-echo-cancel –freedesktop.org
https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Modules/#index45h3

– Pulseaudio echo cancellation — Debian User Forums
http://forums.debian.net/viewtopic.php?f=16&t=128306