Audio

This section documents basic audio payload examples for Lichee-Jack.

Lichee-Jack provides audio control through the AUDIOCTL utility, allowing payloads to:

Control onboard microphone (ADC)
Control onboard speaker (DAC)
Adjust mute state and volume
Combine with standard ALSA tools (arecord, aplay) for capture and playback

These examples are intentionally simple and script-friendly, suitable for payload chaining.

Examples

Echo (Live Mic → Speaker)

This example creates a real-time audio loopback, piping microphone input directly to the speaker.


# Unmute onboard microphone and set ADC volume (0–24)
AUDIOCTL MICUNMUTE
AUDIOCTL MICVOL 5
 
# Unmute speaker and set DAC volume (0–32)
AUDIOCTL SPKUNMUTE
AUDIOCTL SPKVOL 5
 
# Record audio in S16_LE, 48 kHz WAV and pipe to speaker
arecord -D hw:0,0 -r 48000 -f S16_LE -t wav | aplay -D hw:1 &
 
# Forked process
# Run `pkill arecord` to stop this example payload

Record to WAV

This example records microphone audio to a WAV file inside the loot directory.


readonly LOOT_DIR=/root/loot.d/record2wav
 
mkdir -p $LOOT_DIR
 
# Auto-increment filename
COUNT=$(($(ls -1 $LOOT_DIR/*.wav 2>/dev/null | wc -l) + 1))
 
# Enable microphone at maximum sensitivity
AUDIOCTL MICUNMUTE
AUDIOCTL MICVOL 24
 
# Indicate recording state (dim white blink)
LED -c151515 -l -b -s 1000000
 
# Record audio
arecord -D hw:0,0 -r 48000 -f S16_LE -t wav \
  $LOOT_DIR/record2wav_$COUNT.wav
 
# Recording finished
LED -c FF0000

Notes

Volume ranges depend on codec configuration:
- MIC (ADC): 0–24
- Speaker (DAC): 0–32
arecord blocks until terminated; use & or signals for background operation
Combine with LED or shmled to provide visible recording indicators
Audio payloads may expose privacy-sensitive data — use responsibly