Robonix ALSA Audio Primitive

This package exposes a Linux host’s ALSA microphone and speaker through the standard Robonix audio contracts. It is a reusable hardware primitive and does not depend on Webots.

Requirements

• Linux with arecord and aplay from alsa-utils
• Robonix installed and initialized with rbnx setup
• uv available on PATH
• at least one ALSA capture or playback device

On Debian or Ubuntu:

sudo apt-get update
sudo apt-get install -y alsa-utils

Deployment

Reference the package from a robot deployment manifest:

primitive:
  - name: audio_driver
    url: https://github.com/syswonder/primitive-audio-driver-rbnx
    branch: main
    config:
      mic_device: null
      speaker_device: null

When a device is null, the primitive scans ALSA and selects a suitable device. Use arecord -l and aplay -l to find explicit device identifiers such as hw:1,0. The complete configuration surface and defaults are in config.spec.

Build and start it through the robot deployment:

rbnx build
rbnx boot

rbnx build first creates an isolated package-owned Python environment, installs the pinned protobuf/gRPC compiler and runtime into it, and then generates the contract bindings with that same interpreter. The build imports every generated *_pb2.py and *_pb2_grpc.py module before accepting the package. At runtime, the primitive reuses this environment. During Driver(CMD_INIT), it scans ALSA and initializes the selected capture and playback devices.

Capabilities

Contract	Purpose
robonix/primitive/audio/mic	Streams raw microphone PCM to a caller.
robonix/primitive/audio/speaker	Plays caller-provided raw PCM.
robonix/primitive/audio/list_devices	Lists ALSA devices and the current route.
robonix/primitive/audio/select_device	Changes the input or output device.
robonix/primitive/audio/driver	Provides the standard lifecycle interface.

The microphone path defaults to mono, 16-bit PCM and probes a supported sample rate, preferring 16 kHz. The speaker path defaults to mono, 16-bit PCM at 24 kHz. Consumers must send PCM matching the configured format.

Development checks

python3 -m unittest -v test_speaker_driver.py
python3 -m unittest discover -s tests -v
rbnx build

The package uses arecord and aplay only at runtime; the unit test does not access an audio device.