A "plug and forget" Audio Player for ROCKNIX devices.

Currently this only supports the RG35XX Plus.

Jackwatcher is a “plug-and-forget” audio player daemon for ROCKNIX devices (currently RG35XX Plus only).

It waits for a 3.5 mm headphone jack insertion event, then runs a configurable player (musicctl) to play audio from a specified directory. While running, a companion btn-watcher process listens for controller input: LB/RB skip tracks, D-Pad seeks forward/backward.

Event reads are blocking, so idle CPU is effectively 0%.

Jackwatcher currently runs as root, as it assumes access to /dev/input/event. As such it is NOT suitable for use on a device with sensitive information.

• A ROCKNIX build on an RG35XX Plus (root SSH access).
• On your dev machine: Rust toolchain + optionally cross.
• On the device: at least one of mpv, mplayer, mpg123, or ffplay available in $PATH. (MPV is built into the current version of ROCKNIX)
• Audio files under /storage/audio (default) or whatever you pass to deploy.sh --music-dir.

There is a deploy.sh file that ChatGPT kindly prepared for me. As long as you have your device running over wifi, and can SSH into it, you should be able to use the script as laid out below.

# From your dev linux machine

$ ./deploy.sh --host root@10.0.0.159

The wrapper /storage/bin/jack-watcher-run pins JW_CMD=/storage/bin/musicctl and runs --watch --exec, so you don’t need to pass paths.

This installs to /storage/bin by default:

• /storage/bin/jack-watcher (the daemon)
• /storage/bin/musicctl (the player controller)
• /storage/bin/jack-watcher-run (wrapper that pins config and runs --watch --exec)

Run it (no systemd required):

ssh root@DEVICE_IP /storage/bin/jack-watcher-run
# plug/unplug 3.5mm; it should start/stop playback

Optional service (if your image supports it):

./deploy.sh --host root@DEVICE_IP --service

If you want to install manually, you can copy the files over to the memory card, but I'm too lazy to figure that out, sorry.

Optional flags

--music-dir: change source dir --prefix /storage: change install prefix --dry-run: show what would happen --skip-build: reuse existing local build

List devices and current state:

/storage/bin/jack-watcher --list
# expect something like:
# /dev/input/event1 H616 Audio Codec Headphone Jack   hp_switch=true initial=0

Foreground watch with logs:

/storage/bin/jack-watcher --watch --exec
# or just use the wrapper:
/storage/bin/jack-watcher-run

./deploy.sh --host root@DEVICE_IP --uninstall

This also removes the wrapper and systemd unit (if present). To stop a service without uninstalling:

ssh root@DEVICE_IP 'systemctl stop jack-watcher && systemctl disable jack-watcher'

• Enable power saving. We don't need the screen on while playing music, unless the user hits a button.
• Add hotkeys for pause. (You can use RB, LB to move between files, and the D-Pad to seek within a file)
• Resume position/artwork not implemented.
• Find an alternative to running as root. (This is the norm on Rocknix but still feels wrong)

• “Playlist has 0 items” / no sound: confirm the music directory has files:

  find /storage/audio -maxdepth 1 -type f | head

• No player found: install or ensure at least one of mpv/mplayer/mpg123/ffplay exists, or edit musicctl to point at a known binary on your image.

• No events when plugging 3.5mm: check device list:

  /storage/bin/jack-watcher --list

  If nothing shows hp_switch=true, your build may not expose SW_HEADPHONE_INSERT.

• It runs but keeps BGM playing: either disable EmulationStation background music, or keep KILL_THESE including emulationstation so musicctl takes over.

Licensed under GPL3. May consider dual licensing if it helps package the software if anyone ever wants to do so.

Yes: add /storage/bin/jack-watcher-run to your firmware’s autostart (or just background it with nohup … &).

Use --prefix /somewhere; the wrapper makes the binary path-agnostic.

Whatever your chosen player supports; musicctl scans mp3/m4a/ogg/opus/flac by default (adjust the find line if needed).

I find it annoying to have to pull out my phone, select an app, select a playlist, fight with the internet, and play music or a podcast before I start my workout.

I want an appliance that I can plug into my speaker and not deal with - Bluetooth - Wifi

I just want to plug and play with a device I already have. The RG35XX Plus has a 3.5 mm plug, and when using evdev, we can detect if something is plugged into the device, be it a speaker system or a headset.

GMU is included with Rocknix for the RG35XX Plus, but the controls don't work on the RG35XX Plus. Moreover, I can't seem to get it to load any playlist I set, and I can't quit the app once it starts. Seems like a bad idea until that has been resolved.

I assume users will want to have a different directory for auto-played audio. Maybe you have an audio book you want to play, or a podcast queue that you do not want as BGM. You can link the directories if you want to keep them the same.

You can use LB/RB to switch songs. However, this application purposely exposes no GUI. If you need one, please consider something else. This is meant to be a "plug and forget" style system.

Maybe someday, but I doubt it. The idea is to minimize annoyance, not deal with wifi and bluetooth issues.