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DocumentationPayloadsMiscMusic Player

Music Player

The Music Player payload turns Lichee-Jack into a simple standalone audio player.

It continuously plays music files from storage and allows the user to skip tracks using the USER button (exposed as a Linux input event device).

This payload is mainly intended as:

  • A demonstration of audio playback on Lichee-Jack
  • An example of input-event driven control inside payloads
  • A reference for combining Audio + LED + GPIO / input devices

Features

  • Plays .opus audio files in a directory (sorted order)
  • Uses SoX → ALSA for decoding and playback
  • USER button (/dev/input/event0) skips to the next track
  • LED feedback during initialization and playback
  • Loops playlist indefinitely

Requirements

  • Audio files stored locally (recommended format: .opus)
  • sox installed with ALSA support
  • Working ALSA output device (hw:1,0 by default)
  • USER button exposed as an input device (gpio-keys)

Directory Layout Example

/root/data/music/
└── demo/
    ├── track01.opus
    ├── track02.opus
    └── track03.opus

Payload Script

#!/bin/bash
#
# Title:      Lichee-Jack Music Player with Skip Button
# Author:     KaliAssistant <work.kaliassistant.github@gmail.com>
# Version:    1.0
#
# Controls:
#   USER button (gpio-keys → /dev/input/event0): Skip track
#
# Audio pipeline:
#   SoX → ALSA hw:1,0
 
MUSIC_DIR="/root/data/music/MUSIC_DIR_TO_PLAY"
INPUT_EVENT="/dev/input/event0"
ALSA_DEV="hw:1,0"
 
# -----------------------------
# Hardware / Audio Init
# -----------------------------
 
# LED: yellow blink during init
LED -c FFFF00 -l -b -s 100000
 
# Wait for ALSA PCM device
until [ -e /dev/snd/pcmC1D0p ]; do
    sleep 0.2
done
 
# Wake codec once
aplay -D hw:1,0 /dev/zero -f S16_LE &>/dev/null &
sleep 0.5
pkill aplay &>/dev/null
 
# LED: rainbow when ready
LED -l -r -s 23000
 
# -----------------------------
 
# Set speaker volume
AUDIOCTL SPKVOL 5
sleep 1
 
# Load playlist
mapfile -t SONGS < <(find "$MUSIC_DIR" -type f -iname "*.opus" | sort)
if [[ ${#SONGS[@]} -eq 0 ]]; then
    echo "No music files found in $MUSIC_DIR"
    exit 1
fi
 
INDEX=0
PLAY_PID=0
 
# Play current song
play_song() {
    local song="${SONGS[$INDEX]}"
    echo -e "\nNow playing: $(basename "$song")"
 
    sox "$song" -t alsa "$ALSA_DEV" &
    PLAY_PID=$!
}
 
# Detect button press (EV_KEY, value = 1)
button_pressed() {
    timeout 3 dd if="$INPUT_EVENT" bs=24 count=1 2>/dev/null \
        | hexdump -v -e '8/1 "%02x "' \
        | grep -q "01 01 00"
}
 
# -----------------------------
# Main Loop
# -----------------------------
 
while true; do
    play_song
 
    while kill -0 "$PLAY_PID" 2>/dev/null; do
        if button_pressed; then
            echo -e "\nSkip button pressed!"
            kill "$PLAY_PID" 2>/dev/null
            sleep 1
            break
        fi
        sleep 1
    done
 
    INDEX=$(( (INDEX + 1) % ${#SONGS[@]} ))
done

Notes

  • .opus is recommended for small size and good quality, but SoX supports many formats
  • Input handling is intentionally simple and blocking-safe
  • LED usage is optional but strongly recommended for user feedback
  • This payload runs indefinitely until terminated

Ideas for Extension

  • Add long-press detection (pause / stop)
  • Support playlists or random shuffle
  • Synchronize LED color with track index or BPM
  • Add USB Mass Storage mode to drop music dynamically
Last updated on
MiscRecon