Pi Loop - Raspberry Pi Headless External Speakers

This is a guide to getting a python script on boot to play audio on 3.5mm speakers on a Raspberry Pi 3 B+ when a monitor isn't connected. Audio on linux is never fun.

Getting Started

Flash the raspberry pi lite operating system to an SD card, and plug it in. Connect the raspberry pi to an HDMI monitor, a keyboard, and a power source and let it boot.

First, login to the raspberry pi using the default username and password.

raspberrypi login: pi
Password: raspberry

Set up WiFi by adding the following to this file:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

network={
   ssid="Wifi Network Name"
   psk="YourPassword"
}

Then run the following. The raspberry pi will restart, and you will need to login again afterwards.

rfkill unblock wifi
sudo ifconfing wlan0 up
sudo reboot

Wait a few moments for your pi to connect to your network. Once you can see an IP address by running the following command, you should be set.

ifconfig wlan0
> inet 10.0.0.1

Install SSH (Optional)

Installing SSH will allow you to run most commands remotely from your laptop.

sudo apt-get update && sudo apt-get -y install openssh-server
sudo systemctl enable ssh
sudo service ssh start

Find the IP of your raspberry pi.

ifconfig wlan0
> inet 10.0.0.1

Configure Dependencies and Code

Install dependencies, and then install the example code.

sudo apt-get update && sudo apt-get -y install mpg321 git
cd /home/pi && git clone https://github.com/rydercalmdown/pi_loop.git

Add the following line to /etc/rc.local just before the last line that contains exit 0;. This will cause the script to run on boot.

sudo nano /etc/rc.local

python /home/pi/pi_loop/app/app.py > /dev/null &

Configure Audio

Set 3.5mm as your default output.

sudo raspi-config

Advanced Options > Audio > Headphones 1

Also set up auto-login.

Boot Options > Desktop / CLI > Console Autologin

You will need to then reboot.

Once rebooted, the pi should automatically log itself in. Next, set volume to be louder:

amixer cset numid=1 900

Then, unplug the HDMI cable and restart the raspberry pi.

sudo reboot

The audio should be playing over your 3.5mm speakers, without a monitor connected, when the raspberry pi boots. If it's not, sorry, I can't help you more than this. Linux audio makes me want to throw myself in a volcano.