Keyboard Teleoperation

This document outlines essential commands for setting up a ROS2 environment, particularly focusing on micro-ROS integration with a Teensy microcontroller and keyboard teleoperation.

Prerequisites

Before starting keyboard teleoperation, ensure you have:

Discovery Server Running: See Discovery Server Setup for setup instructions
Robot Powered On: Ensure your both the Pi and Teensy are powered and connected
Network Connectivity: Verify connection between your computer and the robot

Power and Log on to Raspberry Pi

The Raspberry Pi will host the micro-ROS agent and other ROS2 nodes. Ensure it’s powered on and you’re logged in. Required ROS2 environment variables set in the .profile file for automated setup upon login.

You will need a separate terminal window 📟 for each process below:

Setup a terminal with miniterm to monitor Teensy debug output

Open a new terminal window 📟

Get your Teensy serial number

SERIAL_NUM=$(
basename "$(find /dev/serial/by-id/ -name 'usb-Teensyduino*if0[02]' | head -1)" \
| sed -E 's/.*_([0-9A-Za-z]+)-if0[02]/\1/'
)
echo "Teensy serial: $SERIAL_NUM"

Start Miniterm

python3 -m serial.tools.miniterm "/dev/serial/by-id/usb-Teensyduino_Dual_Serial_${SERIAL_NUM}-if02" 115200

This command starts a miniterm session to display debug messages from the Teensy. The path identifies your Teensy and the {SERIAL_NUM} command pulls your serial number, and 115200 sets the baud rate. You should expect to see “WAITING_AGENT” if the Teensy is awaiting a connection.

Start the micro-ROS Agent

Open a new terminal window 📟

The micro-ROS agent acts as a bridge between the micro-ROS client running on the Teensy and the ROS2 network.

Get your Teensy serial number (you have to do this again since its a new window)

SERIAL_NUM=$(
basename "$(find /dev/serial/by-id/ -name 'usb-Teensyduino*if0[02]' | head -1)" \
| sed -E 's/.*_([0-9A-Za-z]+)-if0[02]/\1/'
)
echo "Teensy serial: $SERIAL_NUM"

cd ~
sudo docker run -it --rm \
  -v /dev:/dev --privileged --net=host \
  --env-file ./env.list --name agent\
  microros/micro-ros-agent:kilted \
  serial --dev "/dev/serial/by-id/usb-Teensyduino_Dual_Serial_${SERIAL_NUM}-if00" -v4

This Docker command starts the micro-ROS agent:

sudo docker run: Executes a Docker container.
-it: Runs in interactive mode with a pseudo-TTY.
--rm: Automatically removes the container when it exits.
-v /dev:/dev: Mounts the host’s /dev directory into the container, allowing access to serial devices.
--privileged: Grants the container elevated privileges, necessary for direct hardware access.
--net=host: Uses the host’s network stack, simplifying network configuration.
--env-file ./env.list: Loads environment variables from the env.list file.
microros/micro-ros-agent:kilted: Specifies the Docker image to use.
serial --dev ...: Instructs the agent to connect via a serial port, specifying the Teensy’s serial device path.
-v4: Sets the verbosity level for the agent’s output.

Start the Keyboard Monitor Node

Open a new terminal window 📟

This node allows you to control your robot or application using keyboard inputs.

cd ~/repos/common_platform/common_platform_ws
source install/setup.bash
ros2 launch evdev_teleop evdev_teleop.launch.py

This command launches the evdev_teleop package, which sets up a ROS2 node to read keyboard input and publish corresponding control commands.

Keyboard Commands 🎮

⚠️ Important: Put your robot on the ground before starting teleoperation!

Command	Key	Action
⬆️	Forward Arrow	Move forward
⬇️	Backward Arrow	Move backward
⬅️	Left Arrow	Turn left
➡️	Right Arrow	Turn right
⏸️	Spacebar	Stop/Emergency brake