client-sdk-ros2-integration

Aria + ROS2 Integration

The Client SDK ships an example ROS2 publisher / subscriber pair that streams raw Aria sensor data through ROS2 topics. Sensor messages stay in FlatBuffer format end-to-end — a thin custom message type (AriaRaw) carries them on the wire, and the SDK's data converter decodes them in the subscriber.

Reference + full code walkthrough: https://facebookresearch.github.io/projectaria_tools/gen2/ark/client-sdk/python-sdk/ros2-example

Why a custom message type

Aria streams data in FlatBuffer format. Re-encoding into standard sensor_msgs/* types would:

1. Lose timing precision — nanosecond timestamps survive better in raw bytes.
2. Force one publisher per sensor type — Aria has many sensors, that's a lot of plumbing.
3. Break when new sensor types are added.

So the example uses one AriaRaw topic for all sensors, carrying:

int64 id        # SDK message type ID (indicates which sensor / message type)
uint8[] payload # raw FlatBuffer bytes

The subscriber uses aria.oss_data_converter.OssDataConverter to decode each payload into a typed Python object (NumPy image, IMU struct, eye-gaze object, etc.) based on the id.

Critical constraint: the custom-message package MUST be named aria_data_types

Both example files import:

from aria_data_types.msg import AriaRaw

Any other package name fails with ImportError. The aria_data_types package contains only the AriaRaw.msg definition.

Prerequisites

• Client SDK installed in a virtual environment (see the client-sdk skill).
• Device authenticated: aria_gen2 auth pair.
• ROS2 (Humble or later) installed, with a workspace (e.g. ~/ros2_ws).
• C++ compiler for building the custom message package.

Workflow

1. Extract SDK samples       python3 -m aria.extract_sdk_samples --out ~/Downloads
                              → yields AriaRaw.msg, ros2_publisher_example.py,
                                ros2_subscriber_example.py
2. Create C++ package        aria_data_types  (with AriaRaw.msg)
                              — follow the standard ROS2 custom-message tutorial
3. Create Python package     e.g. py_pubsub  (publisher + subscriber nodes)
4. Copy example code         ros2_publisher_example.py → publisher_member_function.py
                             ros2_subscriber_example.py → subscriber_member_function.py
5. Add to py_pubsub/package.xml:
                             <exec_depend>aria_data_types</exec_depend>
6. BUILD aria_data_types FIRST, then py_pubsub:
                             colcon build --packages-select py_pubsub
7. In BOTH terminals: export the same ROS_DOMAIN_ID
                             export ROS_DOMAIN_ID=0
8. Terminal A:  ros2 run py_pubsub talker    (publisher — connects to device)
   Terminal B:  ros2 run py_pubsub listener  (subscriber)