Soundboard

A Soundboard for Raspberry Pi.

Contents

• What is the purpose of this tool?
• How does it work?
• Build
• Prerequisites
• Build and run soundboard container
• Recommendations
• Configuration
• Testing
• Troubleshoot
• Todo

What is the purpose of this tool?

This tool enables your Raspberry Pi to play a specific sound-file by pressing a
button connected via GPIO.

How does it work?

Depending on the number of buttons to use, the soundboard creates listeners
for the GPIO pins. If a button is pushed the associated sound-file will be played.
During playback no inputs from push buttons will be accepted.

Build

Linux (Raspbian)

Install needed Debian packages:

sudo apt-get install build-essential libasound2-dev alsa-utils

Get dependencies:

go get -u github.com/hajimehoshi/oto
go get -u github.com/faiface/beep
go get -u github.com/micha37-martins/gpio

Prerequisites

Hardware

• Raspberry PI 3 (other versions should also work but I did not test them)
• SD Card
• Power supply
• Wiring
• Pushbuttons
• A suitable case for a soundboard
• An output device like a speaker

Recommendations

It is expected to have a Pull-Up-Resistor
for every push button connected. The resistor should have between 10 and 100 kΩ.

Software

• I tested with Raspbian but other operating systems should also work
• golang 1.14+
• make

Older software versions may also work, but I did not test that.

Soundfiles

• .mp3 files have to be stored in ./soundfiles folder
• the .gitignore file in this folder have to be removed

Build and run soundboard container

Install Docker

To install Docker on a raspberry pi you basically need:

curl -sSL https://get.docker.com | sh

And after the command finished you most likely want to run:

sudo usermod -aG docker pi

Source: Docker install guide

Use Docker

Find your sound device by using

aplay -l

Use environment variable to set your desired sound device

examples:

ALSA_CARD=PCH
ALSA_CARD=HDMI
ALSA_CARD=0

Build container

docker build -t soundboard .

Run container

docker run -it --rm --device /dev/snd -e "ALSA_CARD=SET_YOUR_SOUND_DEVICE" -v /sys:/sys soundboard:0.0.1 /bin/sh

Play test sound:

speaker-test

Example:

docker run -it --rm --device /dev/snd -e "ALSA_CARD=0" -v /sys:/sys soundboard:0.0.1 /bin/sh

Use Docker-Compose

You can also use docker-compose to run the soundboard container. The sound_device you discovered using aplay -l can be configured in the .env file. The default is "PCH".

docker-compose up --build

The --build flag is needed at first start only.

Configuration

Configuration is done in /internal/config/config.go

Here the mapping between file and pin is set. The FileMapper
function assigns a filename to the corresponding button. The button
number has to be a two digit string: For example: "01" for your first button

The pin number for Raspberry Pi 2/3/4 can be found at
raspberrypi.org

Example: Map pin 5 to file 01

ButtonMap[5] = "01"

The number of entries in ButtonMap have to equal the number of soundfiles.

Testing

A usual go test is configured in the Makefile but it will not do an integration test. If you want to check if the soundboard plays a file use:

go test -tags=integration

Troubleshoot

• "No files in folder: ./soundfiles/"
  • Remove the hidden .gitignore file from the ./soundfiles folder
• "failed to open gpio 13 direction file for writing"
  • use sudo to run soundboard
  • e.g. sudo /usr/local/go/bin/go run cmd/main.go
• Cannot play sound when using a Docker container
  • mount the /sys directory to have acess to gpio file
  • select the correct sound_card

Todo

• write a soundboard.service example to document how to start soundboard using Systemd