dotwee/alsa2mqtt

• Syncs ALSA volume (same volume slider as in alsamixer) with MQTT
• Publishes state of device to MQTT usually from /proc/asound/card0/pcm0p/sub0/status

Use this to react to changes in volume or to change the ALSA volume by external events.

Topics

dersimn/SoundPi/online → true

dersimn/SoundPi/status/device-in-use → {
      "val": true,
      "state": "RUNNING"
    }

dersimn/SoundPi/status/volume → 21

dersimn/SoundPi/set/volume ← 42

Install

apt install build-essential git libasound2-dev

git clone https://github.com/dotwee/docker-alsa2mqtt
cd docker-alsa2mqtt
npm i

Usage

See node index --help

alsa2mqtt 0.0.2
Control ALSA volume from MQTT

Usage: index [options]

Options:
      --prefix                                      [default: "dersimn/SoundPi"]
      --alsa-card                                           [default: "default"]
      --polling-interval  polling interval (in ms) for status updates
                                                                 [default: 3000]
      --version           Show version number                          [boolean]
  -h, --help              Show help                                    [boolean]
  -v, --verbosity         Possible values: "error", "warn", "info", "debug"
  -u, --mqtt-url          mqtt broker url. See
                          https://github.com/mqttjs/MQTT.js#connect-using-a-url
  -m, --alsa-mixer                                                    [required]
  -s, --alsa-status-file                                              [required]

Example:

node index -v debug -u mqtt://10.1.1.100 -m Line -s /proc/asound/card1/pcm0p/sub0/status

Install as systemd service

Copy alsa2mqtt.service to /etc/systemd/system/alsa2mqtt.service, and edit parameters in ExecStart, then:

systemctl daemon-reload
systemctl enable alsa2mqtt.service 
systemctl start alsa2mqtt.service

Docker

Get the container image

from docker hub

$ docker pull dotwee/alsa2mqtt:latest

from github packages

$ docker pull ghcr.io/dotwee/alsa2mqtt:latest

available tags

• linux/arm/v7
• linux/arm64
• linux/amd64

or build it locally from source

If you don't want to use the public container image from Docker Hub, build the image locally:

$ docker build --tag dotwee/aksa2mqtt:latest github.com/dotWee/docker-alsa2mqtt

Run the image

Simply run docker run --rm -v "$ALSA_STATUS_FILE:ALSA_STATUS_FILE" dotwee/aksa2mqtt:latest and append your arguments.

Replace make sure to mount the alsa status file! Replace $$ALSA_STATUS_FILE to whatever value --alsa-status-file gets set.

Example:

$ docker run --rm -v "/proc/asound/card1/pcm0p/sub0/status:/proc/asound/card1/pcm0p/sub0/status" dotwee/aksa2mqtt:latest -v debug -u mqtt://10.1.1.100 -m Line --alsa-status-file /proc/asound/card1/pcm0p/sub0/status

Running the image without providing arguments will run with --help by default:

$ docker run --rm dotwee/aksa2mqtt:latest                                                 
alsa2mqtt 0.0.2
Control ALSA volume from MQTT

Usage: index.js [options]

Options:
      --prefix                                      [default: "dersimn/SoundPi"]
      --alsa-card                                           [default: "default"]
      --polling-interval  polling interval (in ms) for status updates
                                                                 [default: 3000]
      --version           Show version number                          [boolean]
  -h, --help              Show help                                    [boolean]
  -v, --verbosity         Possible values: "error", "warn", "info", "debug"
  -u, --mqtt-url          mqtt broker url. See
                          https://github.com/mqttjs/MQTT.js#connect-using-a-url
  -m, --alsa-mixer                                                    [required]
  -s, --alsa-status-file                                              [required]

Credits

• alsa-monitor