AWS DeepRacer I2C package

Overview

The AWS DeepRacer I2C ROS package creates the battery_node, which is part of the core AWS DeepRacer application and launches from the deepracer_launcher. For more information about the application and the components, see the aws-deepracer-launcher repository

This node is responsible for providing the vehicle battery level information. It provides functions to read the battery level values from the I2C bus and return the corresponding level information.

License

The source code is released under Apache 2.0 (https://aws.amazon.com/apache-2-0/).

Installation

Follow these steps to install the AWS DeepRacer I2C package.

Prerequisites

The AWS DeepRacer device comes with all the prerequisite packages and libraries installed to run the i2c_pkg. For more information about the preinstalled set of packages and libraries on the AWS DeepRacer and about installing the required build systems, see Getting started with AWS DeepRacer OpenSource.

The i2c_pkg specifically depends on the following ROS 2 packages as build and run dependencies:

• deepracer_interfaces_pkg: This package contains the custom message and service-type definitions used across the AWS DeepRacer core application.

Downloading and building

Open a terminal on the AWS DeepRacer device and run the following commands as the root user.

1. Switch to the root user before you source the ROS 2 installation:

    sudo su
   

2. Source the ROS 2 Foxy setup bash script:

    source /opt/ros/foxy/setup.bash 
   

3. Create a workspace directory for the package:

    mkdir -p ~/deepracer_ws
    cd ~/deepracer_ws
   

4. Clone the i2c_pkg on the DeepRacer device:

    git clone https://github.com/aws-deepracer/aws-deepracer-i2c-pkg.git
   

5. Fetch unreleased dependencies:

    cd ~/deepracer_ws/aws-deepracer-i2c-pkg
    rosws update
   

6. Resolve the i2c_pkg dependencies:

    cd ~/deepracer_ws/aws-deepracer-i2c-pkg && rosdep install -i --from-path . --rosdistro foxy -y
   

7. Build the i2c_pkg and deepracer_interfaces_pkg:

    cd ~/deepracer_ws/aws-deepracer-i2c-pkg && colcon build --packages-select i2c_pkg deepracer_interfaces_pkg
   

Usage

Although the battery_node is built to work with the AWS DeepRacer application, you can run it independently for development, testing, and debugging purposes.

Run the node

To launch the built battery_node as the root user on the AWS DeepRacer device, open another terminal on the AWS DeepRacer device and run the following commands as the root user:

1. Switch to the root user before you source the ROS 2 installation:

    sudo su
   

2. Source the ROS 2 Foxy setup bash script:

    source /opt/ros/foxy/setup.bash 
   

3. Source the setup script for the installed packages:

    source ~/deepracer_ws/aws-deepracer-i2c-pkg/install/setup.bash
   

4. Launch the battery_node using the launch script:

    ros2 launch i2c_pkg i2c_pkg_launch.py
   

Launch files

The i2c_pkg_launch.py included in this package provides an example demonstrating how to launch the deepracer_navigation_node.

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    return LaunchDescription([
        Node(
            package='i2c_pkg',
            namespace='i2c_pkg',
            executable='battery_node',
            name='battery_node'
        )
    ])

Node details

battery_node

Services

Service name	Service type	Description
battery_level	BatteryLevelSrv	A service that is called to get the current vehicle battery level information in the range of [0 to 11].

Resources

• Getting started with AWS DeepRacer OpenSource