Capra SpaceMouse Package

This ROS 2 package provides a node that publishes SpaceMouse input as a Joy message. It continuously reads the state of the SpaceMouse and publishes the data, and can handle the SpaceMouse being disconnected.

Overview

The main node in this package is spacemouse_joy.py, which handles the connection to the SpaceMouse, reads its state, and publishes the data as a Joy message. If the SpaceMouse is disconnected, the node will attempt to reconnect and continue publishing zero values for all axes until the connection is restored.

The outputs represent the axes as follows:

• float - Translation X (left/right)
• float - Translation Y (forward/backward)
• float - Translation Z (up/down)
• float - Rotation Pitch (lateral axis - forward/backward)
• float - Rotation Roll (longitudinal axis - left right)
• float - Rotation Yaw (perpendicular axis - twist)
• int - Left button
• int - Right button

Files

• spacemouse_joy.py: This file contains the SpaceMouseJoy class, which is responsible for connecting to the SpaceMouse, reading its state, and publishing the data as a Joy message. It also handles reconnection attempts if the SpaceMouse is disconnected.

• joy_listener.py: This file contains the JoyListener class, which subscribes to the Joy messages published by the spacemouse_joy.py node. It prints the axes and button states to the console, providing a clean output to verify that the publisher is working correctly.

Setup

This setup is simplified for Ubuntu 22.04. See the original documentation for a complete setup.

Part 1: Installing PySpaceMouse

Source: PySpaceMouse GitHub

1. Install the package:

   pip install pyspacemouse

2. Install dependencies:

   1. The library uses hidapi as a low-level interface to the device and easyhid as a Python abstraction for easier use.

      sudo apt-get install libhidapi-dev

   2. Add rules for permissions:

      sudo echo 'KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="plugdev"' > /etc/udev/rules.d/99-hidraw-permissions.rules
      sudo usermod -aG plugdev $USER
      newgrp plugdev

   3. easyhid is a hidapi interface for Python - required on all platforms:

      pip install git+https://github.com/bglopez/python-easyhid.git

Part 2: Give Permission to Access HID Devices

Source (Chinese): CSDN Blog

By default, ordinary users may not have permission to access HID devices.

1. Run the following command to add the idVendor and idProduct of the 3D SpaceMouse in udev rules:

   sudo tee /etc/udev/rules.d/99-spacemouse.rules > /dev/null <<EOF
   SUBSYSTEM=="input", GROUP="input", MODE="0660"
   KERNEL=="hidraw*", ATTRS{idVendor}=="256f", ATTRS{idProduct}=="c635", MODE="0666"
   EOF

   These IDs are for CAPRA's SpaceMouse. See the original setup for other devices.

2. Reload udev rules:

   sudo udevadm control --reload-rules
   sudo udevadm trigger

3. Disconnect and reconnect the SpaceMouse.

4. Make sure the current user belongs to the input group (expect no output):

   sudo usermod -a -G input $USER

5. Log out and log back in to Ubuntu.