stefanschroeder / dietpi-radio

Raspberry-Pi Radio

This project builds a radio with a raspberry-pi type SBC and a rotary encoder to control the volume and channel.

Prior art

• https://blog.sharedove.com/adisjugo/index.php/2020/05/10/using-ky-040-rotary-encoder-on-raspberry-pi-to-control-volume/
• https://www.instructables.com/Raspberry-Pi-Radio/

Install Dietpi

Download:

wget https://dietpi.com/downloads/images/DietPi_RPi-ARMv6-Bullseye.7z

Extract

7z x DietPi_RPi-ARMv6-Bullseye.7z

Insert SD-card and find the drivename of your SD-card

lsblk

or dmesg

Install on SDcard.

dd if=DietPi_RPi-ARMv6-Bullseye.img of=/dev/mmcblk0 bs=4M status=progress

Mount the first partition of the SD-card

mount /dev/mmcblk0p1 /mnt

Set your keyboard

sed -i 's/AUTO_SETUP_KEYBOARD_LAYOUT=gb/AUTO_SETUP_KEYBOARD_LAYOUT=de/' /mnt/dietpi.txt

Enable WiFi

sed -i 's/AUTO_SETUP_NET_WIFI_ENABLED=0/AUTO_SETUP_NET_WIFI_ENABLED=1/' /mnt/dietpi.txt

Set WiFi-Country Code

sed -i 's/AUTO_SETUP_NET_WIFI_COUNTRY_CODE=GB/AUTO_SETUP_NET_WIFI_COUNTRY_CODE=DE/' /mnt/dietpi.txt

Set hostname

sed -i 's/AUTO_SETUP_NET_HOSTNAME=DietPi/AUTO_SETUP_NET_HOSTNAME=radio/' /mnt/dietpi.txt

Fix Timezone (optional)

sed -i 's/London/Berlin/' /mnt/dietpi.txt

Disable HDMI output

sed -i 's/AUTO_SETUP_HEADLESS=0/AUTO_SETUP_HEADLESS=1/' /mnt/dietpi.txt

Set Wifi-Credentials

sed -i 's/aWIFI_SSID\[0\]=\x27\x27/aWIFI_SSID[0]=\x27MyWifiName\x27/' /mnt/dietpi-wifi.txt
sed -i 's/aWIFI_KEY\[0\]=\x27\x27/aWIFI_KEY[0]=\x27MySuperSecretWifiPassword\x27/' /mnt/dietpi-wifi.txt

Note: The square brackets must be quoted. The single quotes must be written as \x27 to not interfere with the quoting.

Eject SD-card

umount /mnt

SD-card is ready to launch!

Plug into device. Power up.

There is more than one way to determine the IP address of the device after it successfully connected to the network.

• You can login to your router and determine the device.

• You can scan the network (from another computer to find the device as soon as it shows up) using a tool like 'nmap':

  sudo nmap -v -sn 192.168.0.0/24

This can be tiresome if there is a lot going on in your network. Therefore it is recommended to note down the MAC-address of your device the first time you have unambiguously identified your device.

Wait for this command to succeed. Retrieve the IP address.

Log into the machine using the default credentials.

ssh root@radio # with default password 'dietpi'

After the first login, there are some updates that may lead to a reboot because of an updated kernel. Your ssh-session will be interrupted and you have to re-login after the system has restarted:

ssh root@radio # with default password 'dietpi'

When you login, the system will ask you to do some maintenance.

You can now change the default passwords, update the package-database, decline the invitation to participate in a survey, etc.

Update the package database

apt update

Configure Audio (for Raspberry's with audio jack):

dietpi-config

Enable Audio -> Select Onboard 3.5 mm bcm2835

Cmdline:

/boot/dietpi/func/dietpi-set_hardware rpi-bcm2835-3.5mm

After configuring the audio. The device will be rebooted once more.

Note: Sound card = rpi-bcm2835-3.5mm

Install a few commands that we use

apt install -y mplayer git python3-rpi.gpio

The required package alsa-utils will have been installed already when configuring the audio. python3 will be installed as a dependency of python3-rpi.gpio.

Gateway (Audio)

At this point you should be able to play audio.

Test with

mplayer https://reckhorn.com/media/music/Test-1.wav

This will play some drums. If it doesn't, don't continue.

Debugging Audio

To debug audio, the following tools are helpful:

amixer will provide information about the soundcard.

alsamixer will allow you to control the volume. Set to 100% initially.

Installing the radion application

Clone the radio repo (we are in /root)

git clone https://github.com/StefanSchroeder/dietpi-radio.git

cp dietpi-radio/radio.service /etc/systemd/system

systemctl enable radio.service
systemctl start radio.service

Usage

After the next reboot the radio application will automatically start.

Use the rotary encoder to control the volume. Press the knob to switch to the next channel.

The URLs of radio channels are listed in the JSON file. The current variable indicates the initial channel (starting with 0). The volume variable indicates the initial volume. The amixer variable indicates the name of the audio device as indicated by the amixer command.

OPEN POINTS

• Hifiberry-support
• Preinstall application
• Autoupdate
• PiZero support