BROKEN SIGNAL

Audio player and web radio for the M5Stack Cardputer ADV. Plays MP3 and M4A files with folder navigation, and streams internet radio stations (MP3) over WiFi.

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Features

• Help overlay — press H at any time, context-aware for current mode
• MP3 and M4A (AAC-LC) playback — native iTunes M4A support via a custom MP4 demuxer, no conversion needed
• Web radio streaming — press W to switch to radio mode and stream internet stations (MP3) over WiFi
• Folder navigation — full subfolder tree under /Music/, with lazy scanning so startup is instant
• Large folder support — folders with 200+ tracks paginated in pages of 25
• Five themes — switch live with keys 1–5, applied consistently across both player and radio UI
• Repeat modes — off / one / all
• Shuffle
• Recent tracks — virtual folder showing the last 10 played
• Persistent settings — theme, volume, repeat, and shuffle saved to /Music/settings.cfg between reboots
• Screen off — option to turn off display power while audio continues

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Themes

Key	Name	Palette
1	Neon Noir	Magenta + cyan on dark background
2	Glitch Terminal	Phosphor green CRT, amber accents
3	Corpo Chrome	Gold + chrome on dark slate
4	Miami Vice	Hot pink + turquoise on dark navy
5	Ash	Monochrome white-on-black

There are a few screenshots the bottom of this readme.

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Controls

Music player

Key	Action
; / .	Cursor up / down
ENTER	Open folder · Play track · Press again to stop
DEL	Back to parent folder
SPACE	Pause / Resume
,	Prev track (playing) · Prev page / parent folder (browsing)
/	Next track (playing) · Next page (browsing)
+ / =	Volume up
-	Volume down
R	Cycle repeat mode (off → one → all)
S	Toggle shuffle
W	Switch to web radio mode
O	Screen on / off
H	Help overlay
1–5	Switch theme

Web radio

Key	Action
; / .	Cursor up / down the station list
ENTER / SPACE	Play selected station · Press again to stop
A	Add station — prompts for URL then name
X	Remove selected station (with confirmation)
+ / =	Volume up
-	Volume down
W / DEL	Return to music player
O	Screen on / off
H	Help overlay
1–5	Switch theme

WiFi overlay

When no saved credentials are found, a network list appears automatically.

Key	Action
; / .	Scroll network list
ENTER	Select network · prompts for password
DEL	Cancel / dismiss

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Hardware

• M5Stack Cardputer ADV
• MicroSD card

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SD Card Layout

SD/
└── Music/
    ├── track.mp3
    ├── track.m4a
    ├── settings.cfg           ← theme, volume, repeat, shuffle (auto-created)
    ├── _radio/
    │   ├── webradio.cfg       ← saved station list (auto-created)
    │   └── wifi.cfg           ← WiFi credentials (auto-created on first connect)
    └── Album Folder/
        ├── 01 - Track.mp3
        └── 02 - Track.m4a

Subfolders nest to any depth. The _radio/ folder is automatically skipped by the music scanner. All config files are created automatically by the app; you do not need to create them manually.

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Installation from .bin

M5Launcher

Download the .bin from releases, copy to your sd card and install it via M5 Launcher Or browse the OTA repository and search for "Broken Signal"

M5Burner

Available on M5Burner

Build and upload via Arduino IDE

Dependencies

Install both libraries via the Arduino Library Manager or the links below:

Library	Source
M5Cardputer	https://github.com/m5stack/M5Cardputer
ESP8266Audio	https://github.com/earlephilhower/ESP8266Audio

Board setup

1. In Arduino IDE, add the ESP32 board package from Espressif
2. Select M5Stack Cardputer as the target board
3. Set Partition Scheme to one with enough app space (e.g. Huge APP)

Flash

1. Clone or download this repo
2. Open BrokenSignal.ino in Arduino IDE
3. Connect the Cardputer via USB-C
4. Upload

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Screenshots

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Technical notes

M4A playback — The player includes a bespoke MP4 container demuxer (AudioFileSourceM4A) that parses the moov atom tree, extracts the AAC sample table, and streams frames with ADTS headers prepended for AudioGeneratorAAC. Duration reading uses an end-of-file first strategy to avoid walking the FAT chain past large mdat blocks.

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License

AI models were heavily used to create this code. You may want to hire a team of lawyers to determine what kind of licence it ends up falling under. If you do, let me know — I genuinely have no clue.

As for my personal preference: simply mention the name of this repository and link back to it if you reuse or redistribute this code.

Thanks to earlephilhower for the audio library that made this possible.