Raspiaudio Digital Radio for Raspberry Pi

Youtube video presentation :

Add this shield to a Raspberry Pi Zero, 4 or 5 to install a fully local FM, DAB, AM and HD Radio (United States) receiver in minutes, listen without internet, record audio, and control everything from a polished web UI on your local network.

The Raspiaudio Digital Radio Shield for Raspberry Pi is a compact all-in-one radio board that brings AM, FM, DAB, DAB+, and HD Radio support to Raspberry Pi boards with a 40-pin header. It combines a local Web UI, CLI control, analog audio output, I2S digital audio, a built-in 1 x 5 W amplifier, a switchable onboard speaker output, and an onboard 3-way navigation control with up, down, and push actions for standalone menu-based projects.

HD Radio is subject to licensing. Please verify that you are legally allowed to use it in your country and for your intended application.

The focus is simple:

• no internet required to listen to radio
• resilient local control
• browser-based Web UI for daily use
• CLI access for automation, scripting, and custom applications

The whole project is open source:

• GitHub: RASPIAUDIOadmin/Digital-Radio-for-Raspberry-Pi
• Product: Raspiaudio Digital Radio Shield for Raspberry Pi

Store

Software release v1.5.3

This release improves HD Radio subchannel discovery after field feedback from US testing.

FM / HD still scans analog FM carriers first and then probes the detected FM frequencies for HD Radio. During long scans the Web UI shows backend-driven progress such as FM 144/206 | 31 found and HD probe 20/45 | FM 45 found | HD 0, so the scan should not look stuck while HD probing continues.

New in v1.5.3: the scan no longer relies only on the SI4689 audio_program_available mask to discover subchannels. For every HD carrier that locks, the backend explicitly probes HD1, HD2, HD3, and HD4 with START_DIGITAL_SERVICE(0, program_id). This should expose extra entries such as HD2 and HD3 even when the first status reply only advertises HD1.

Selecting a subchannel also verifies that the SI4689 reports the requested program as playing before accepting the tune. This avoids showing an HD2 entry while the chip is still playing HD1.

When the broadcaster provides the data, the backend reads HD Radio station info and PSD metadata such as station name, title, artist, album, genre, and available programs. HD subchannels are exposed as selectable entries like HD1, HD2, and HD3, and the UI labels the active HD program instead of treating the whole frequency as a single station.

Media artwork support has also started: the backend now reuses the existing DAB artwork path when the SI4689 returns recognizable image payloads for HD Radio. This is best effort for now and depends on what each station broadcasts.

If SPI is not enabled, the Web UI can now propose to add dtparam=spi=on to /boot/firmware/config.txt after confirmation. Reboot the Raspberry Pi after using this helper so /dev/spidev0.* appears.

If HD Radio subchannels still do not appear in your area, run the server with logs and share the scan output so we can compare the SI4689 status during each HD program probe.

Quickstart

Because we understand that you might be busy with your job or family, here is how to have instant fun.

Clone the project:

git clone https://github.com/RASPIAUDIOadmin/Digital-Radio-for-Raspberry-Pi.git
cd Digital-Radio-for-Raspberry-Pi

Start the local radio server:

sudo python3 radio.py serve --port 8686

Then open:

http://piradio.local:8686/

If SPI is not active yet, the Web UI shows an Enable SPI prompt. Confirm it, reboot the Raspberry Pi when requested, then start the server again.

Use sudo so the backend can access Raspberry Pi hardware and, when needed, update the boot config for SPI or I2S setup.

If you are already on the Raspberry Pi, this is enough to get the Web UI and the CLI backend running.

Manual SPI setup

The Web UI can enable SPI automatically. Use this manual method only if you prefer to configure the Raspberry Pi yourself, or if the automatic helper cannot update the boot config.

sudo raspi-config

Then select:

Interface Options -> SPI -> Enable

Reboot and check that SPI devices exist:

sudo reboot
ls /dev/spidev*

You should see /dev/spidev0.0 and /dev/spidev0.1.

Main features

• DAB / DAB+
• FM
• HD Radio
• AM
• AM HD
• local Web UI to scan, browse, tune, change volume, manage favorites, and handle recordings
• selectable audio output from the Web UI: analog output on the shield or direct browser playback
• CLI to control the backend from the terminal or integrate the radio into your own software
• direct HTTP stream URLs for VLC, a browser, Music Assistant, or any compatible network player
• analog audio output on the shield
• I2S audio path for digital capture and recording
• built-in 1 x 5 W amplifier
• switchable onboard speaker output
• onboard 3-way navigation button: up, down, and push
• audio jack output
• screwless passive speaker output for an external speaker
  • 4 ohm recommended
  • 8 ohm supported
• SMA antenna connector for the included antenna or a different external antenna
• AM antenna balun for impedance matching
• AM loop antenna connection support
• amplifier enable on GPIO17
• local recordings list in the browser

Why this project

Unlike an internet radio product, this setup does not depend on network streaming to play stations.

That makes it useful when you want:

• a radio that still works without internet access
• direct access to terrestrial broadcast bands
• a local control API you can reuse in your own program
• a Raspberry Pi based platform that is easy to extend

Web UI first

The recommended workflow is the local Web UI.

It gives you:

• source mode selection
• audio output selection between Analog output and Browser output
• station scan
• station selection
• favorites
• amplifier on / off
• volume control
• recording controls
• recordings browser
• a simple radio workflow directly from a browser on the local network

Start the server on the Raspberry Pi:

sudo python3 radio.py serve --port 8686

Then open:

http://piradio.local:8686/

I2S recording on Raspberry Pi

If you want recording from the SI4689 I2S output, enable the Raspberry Pi capture overlay in /boot/firmware/config.txt:

dtparam=i2s=on
dtoverlay=adau7002-simple,card-name=si4689_i2s

Then reboot the Raspberry Pi.

After reboot, you should see the capture card with:

arecord -l

Expected result:

card 2: si4689i2s [si4689_i2s], device 0: ...

The server now auto-detects this ALSA capture device for recordings, so the normal command stays:

sudo python3 radio.py serve --port 8686

The default backend uses the Raspberry Pi as the I2S clock master and the SI4689 as I2S slave, which matches the Skyworks SDK example and the adau7002-simple capture overlay.

By default, the backend also trims the first 3 seconds of each WAV recording to remove the unstable I2S startup noise.

If needed, you can still force a device manually:

sudo python3 radio.py serve --port 8686 --record-device plughw:CARD=si4689i2s,DEV=0

If your hardware is wired for the opposite clock direction, you can override it:

sudo python3 radio.py serve --port 8686 --i2s-master

If you want to keep the full raw capture without trimming the first seconds:

sudo python3 radio.py serve --port 8686 --record-trim-seconds 0

Stream URLs and Music Assistant integration

The server can expose the shield as a live radio source for Music Assistant, VLC, a browser, or any player that can open an HTTP audio stream.

Browser Output mode

The Web UI has two listening modes at the top of the page:

• Analog output plays audio through the shield DAC, jack output, and onboard amplifier.
• Browser output plays the currently tuned station directly in the web browser on the local network.

Browser Output uses /audio/live.wav, a direct PCM WAV stream captured from the SI4689 I2S output through the Raspberry Pi ALSA capture device. It avoids MP3 compression, so it is the recommended mode for best quality on a local network.

The blue volume slider is shared by both outputs. It controls the SI4689 analog volume and the browser player volume, so there is only one volume control in the Web UI.

Browser Output requires the I2S capture overlay described in I2S recording on Raspberry Pi. If the Web UI does not detect the si4689_i2s capture device, it shows an installation prompt. After confirmation, the server can add the required lines to /boot/firmware/config.txt, enable the system service at boot, and ask you to reboot.

This helper requires the server to be started with sudo:

sudo python3 radio.py serve --port 8686

Stream URLs require the SI4689 I2S audio capture device to be installed on the Raspberry Pi. The Web UI browser output uses direct PCM WAV from si4689_i2s through ALSA, with no MP3 compression. MP3 endpoints remain available for external players that need compressed audio or ICY metadata. Install the I2S overlay described in I2S recording on Raspberry Pi before using /audio/live.wav, /audio/live.mp3, station stream URLs, or generated playlists.

The important endpoints are:

http://piradio.local:8686/audio/live.mp3
http://piradio.local:8686/audio/live.mp3?icy=1
http://piradio.local:8686/audio/live.wav
http://piradio.local:8686/audio/stations/<station_id>.mp3
http://piradio.local:8686/stream.wav?station_id=<station_id>
http://piradio.local:8686/api/station-streams?mode=dab
http://piradio.local:8686/playlists/dab.m3u
http://piradio.local:8686/playlists/dab.m3u?format=wav
http://piradio.local:8686/playlists/favorites.m3u
http://piradio.local:8686/api/live-metadata

How it works:

• /audio/live.mp3 streams the currently tuned station
• /audio/live.mp3?icy=1 streams the currently tuned station with forced ICY metadata for compatible players
• /audio/live.wav streams the currently tuned station as direct PCM WAV, recommended for browser output on a local network
• /audio/stations/<station_id>.mp3 retunes the hardware to the requested station and streams it
• /stream.wav?station_id=<station_id> retunes the hardware to the requested station and streams direct WAV from the I2S capture device
• /api/station-streams?mode=dab returns the available DAB stations with MP3 and WAV stream URLs
• /playlists/dab.m3u exports all DAB stations as an MP3 playlist with ICY metadata
• /playlists/dab.m3u?format=wav exports all DAB stations as a direct WAV playlist, recommended for Music Assistant when reliability matters more than ICY metadata
• /playlists/favorites.m3u exports only favorites
• /api/live-metadata returns the current DAB now-playing text and artwork URL as JSON

Use your usual player instead of the Web UI

You do not have to use the Raspiaudio Web UI if you prefer your usual player.

For a quick test, paste the live stream URL directly into a browser:

http://piradio.local:8686/audio/live.wav

For a station browser, open the generated DAB playlist in VLC with Media -> Open Network Stream:

http://piradio.local:8686/playlists/dab.m3u

If your network does not resolve piradio.local, use the Raspberry Pi IP address instead, for example:

http://192.168.1.154:8686/playlists/dab.m3u

VLC will display the stations from the playlist. Selecting another item retunes the Raspberry Pi service to that station, so you can switch between DAB stations from VLC without opening the Web UI. Generated playlists use metadata-enabled station URLs automatically.

Important limitation:

• the shield is a single hardware tuner
• starting a different station retunes the hardware for everyone

Add the live source to Music Assistant

The simplest approach is to add the generated WAV playlist to the Builtin provider in Music Assistant.

http://piradio.local:8686/playlists/dab.m3u?format=wav

The WAV playlist uses direct I2S capture and the server keeps only one active stream at a time, which avoids unstable concurrent probes from Music Assistant retuning the single SI4689 tuner while another capture process is still running.

If you prefer MP3 and ICY metadata, import the MP3 playlist instead:

http://piradio.local:8686/playlists/dab.m3u

You can also add a single station URL manually.

For example:

http://piradio.local:8686/audio/stations/dab%3A0000f21b%3A00000001%3A195936.mp3

Once imported, Music Assistant can redistribute that terrestrial radio source to all supported players on the network.

Live metadata in the MP3 stream

When a client requests ICY metadata, or when the URL includes ?icy=1, the live stream injects:

• station name in the ICY headers
• current DAB text as StreamTitle
• artist/title fields when they can be parsed from DAB DLS text
• current DAB artwork URL as StreamUrl and StreamArtwork when the multiplex provides MOT artwork

This works especially well with Music Assistant because it reads ICY StreamTitle from radio streams and can surface the current song in the UI and on compatible players.

Note:

• a plain browser MP3 request usually does not request ICY metadata, so it may play audio without showing title or artwork
• the generated M3U playlists include ?icy=1 station URLs for metadata-capable players
• Music Assistant reliably consumes StreamTitle
• artwork is exposed as a URL, not embedded as binary image data inside the MP3 stream
• artwork handling depends on the downstream client and current Music Assistant support for the source type

Example:

StreamTitle='THE WEEKND - In Your Eyes';
StreamUrl='http://piradio.local:8686/api/dab/artwork?ts=...';
StreamArtwork='http://piradio.local:8686/api/dab/artwork?ts=...';

CLI mode

The CLI uses the same backend as the Web UI.

That means you can control the radio manually from the terminal, or use the commands as a base for your own scripts and applications.

Simple interactive CLI workflow

Open a first terminal on the Raspberry Pi and start the local backend:

sudo python3 radio.py serve --port 8686

Then keep a second terminal open and send commands interactively, one by one:

python radio.py status
python radio.py stations --mode dab
python radio.py play 0
python radio.py volume 31
python radio.py volume +2
python radio.py amp on
python radio.py record start
python radio.py record stop
python radio.py recordings

Useful examples:

python radio.py boot --mode dab
python radio.py scan --mode fm
python radio.py stations --mode fm
python radio.py play AIRZEN RADIO
python radio.py play dab:0000f204:00000009:199360
python radio.py favorite 0

To see all available commands:

python radio.py --help

Repository layout

• radio.py entry point for the CLI
• raspiaudio_radio/ shared backend, HTTP server, and Web UI
• firmwares/ firmware and patch files used by the radio backend
• legacy/ older low-level scripts kept for reference

Current backend scope

The current radio backend is intentionally kept simple:

• SPI control
• local firmware host-load
• Web UI + CLI on the same backend
• station playback
• favorites
• local browser control
• I2S recording workflow

Flash boot notes

Boot from external flash is now validated on the Raspberry Pi with the SI4689.

In practice, flash boot is especially interesting when the host talks to the tuner over a slower control link such as I2C. With fast SPI host-load, the gain is smaller, because SPI host-load is already quite fast. With I2C, flash boot should save much more startup time.

Validated flash programming sequence:

• host-load rom00_patch.016.bin
• erase chip with 0x05 0xFF 0xDE 0xC0
• write flash using FLASH_WRITE_BLOCK 0x05 0xF0 0x0C 0xED ...

Validated flash boot sequence:

• host-load rom00_patch_mini.003.bin
• send LOAD_INIT
• FLASH_LOAD the full patch from 0x00004000
• send LOAD_INIT
• FLASH_LOAD the DAB firmware from 0x00092000
• send BOOT

Program the external flash from the normal CLI:

python radio.py flash dab

Start the web server by booting the firmware from flash:

sudo python3 radio.py serve --port 8686 --boot-source flash

You can also ask the server to try flash first and fall back to normal SPI host-load if flash boot fails:

sudo python3 radio.py serve --port 8686 --boot-source auto

Validation method:

• tune to DAB multiplex 199360 kHz
• wait for acq=true and valid=true
• confirm that the service list is readable after boot

Benchmark measured on the Raspberry Pi on DAB 199360 kHz, from reset to a valid DAB lock (acq=true, valid=true):

Control speed	Host-load over SPI	Flash boot mini	Flash boot full
30 MHz	2.37 s	1.14 s	2.40 s
1 MHz	7.10 s	1.07 s	1.00 s
500 kHz	12.57 s	1.16 s	0.99 s

So, with the default fast SPI setup, host-load is already usable. The flash path becomes much more compelling when the host side is intentionally slowed down for debug, or when using a slower control interface such as I2C.

Hardware notes

Current shield-oriented defaults:

• RSTB = BCM25
• AMP_EN = BCM17
• SPI bus/device = 0/0
• local firmware files loaded from firmwares/
• onboard navigation input with up / down / push
• onboard speaker output with dedicated on / off control
• SMA antenna connector
• AM impedance-matching balun
• passive speaker connector

Dependencies

On Raspberry Pi OS:

Raspberry Pi Zero / 3 / 4:

sudo apt install python3-spidev python3-rpi.gpio python3-smbus2 alsa-utils ffmpeg

Raspberry Pi 5:

sudo apt install python3-spidev python3-rpi-lgpio python3-smbus2 alsa-utils ffmpeg

python3-rpi-lgpio provides the same RPi.GPIO Python import used by the code, but supports the newer Raspberry Pi 5 GPIO controller.

Open source and reusable

This repository is not only a radio player.

It is also a base to:

• build your own radio application
• integrate the SI4689 shield into a custom Raspberry Pi project
• create your own UI on top of the CLI or HTTP backend
• experiment with local digital radio features without depending on cloud services

Inputs / Outputs

• Power input:
  • 5V on Raspberry Pi header pins 2 and 4
  • GND on pins 6, 9, 14, 20, 25, 30, 34, 39
• SPI radio interface:
  • MOSI on GPIO10 / pin 19
  • MISO on GPIO9 / pin 21
  • SPICLK on GPIO11 / pin 23
  • SSBSI on GPIO8 / pin 24
• Radio control:
  • INT on GPIO23 / pin 16
  • SI4689 RST on GPIO25 / pin 22
  • ENABLE_AMPLI on GPIO17 / pin 11
• I2S digital audio:
  • I2S BCK on GPIO18 / pin 12
  • I2S LRCK on GPIO19 / pin 35
  • I2S DOUT on GPIO20 / pin 38
• Navigation button:
  • Switch CW on GPIO5 / pin 29
  • Switch PUSH on GPIO6 / pin 31
  • Switch CCW on GPIO13 / pin 33
• RF and audio connections on the shield:
  • SMA antenna connector
  • AM loop antenna input
  • AM impedance-matching balun
  • audio jack output
  • onboard speaker output with on / off switch
  • passive external speaker output via screwless connector