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Frequently Asked Questions

Here we list common questions that our users have. This list is updated periodically, so if you cannot find what you are looking for, please contact support@canedudev.com.

General Questions

What is the CanEduDev Rover?

The Rover is a sophisticated 1:5 scale model car designed for educational, research, and prototyping applications. It's a distributed embedded system platform featuring multiple STM32F302 microcontrollers communicating via CAN bus, with real-time operation using FreeRTOS and ROS2 integration for high-level control.

What can I do with the Rover?

The Rover is designed for:

  • Education and development in CAN-based communication systems
  • Real-time control systems research
  • Robotics and autonomous vehicle prototyping
  • Learning about distributed embedded systems
  • Integrating with ROS2 for advanced robotics applications
Is the Rover software open source?

Yes! The Rover's software is open source and hosted on GitHub. You can review, modify, and contribute to the codebase. The project includes firmware, ROS2 gateway, Python tools, and comprehensive documentation. Everything is licensed under the MIT license.

What operating systems are supported for development?

The Rover project is primarily developed and tested on Ubuntu 24.04 LTS. Windows users can utilize Ubuntu 24.04 WSL (Windows Subsystem for Linux). The bootstrap script handles automatic installation of all required dependencies.

Getting Started

What battery does the Rover use?

The Rover supports 2S-4S LiPo batteries with an XT60 connector, though 4S is recommended for best performance. You need to provide your own battery as it's not included with the Rover.

How do I install the battery?
  1. Remove the top cover of the Rover (mounted with dome nuts)
  2. Place your LiPo battery in the battery slot
  3. Connect both battery connectors to the power module (main power and cell balance connector)
  4. For first-time setup, place the Rover on a box with wheels suspended before turning it on

See the Getting Started guide for detailed instructions with images.

How do I turn the Rover on and off?

Press the main power switch to turn the system on or off. When powered on, you should see various green LED lights illuminate. Some Rover models have an ESC with a separate power switch that also needs to be pressed after the main power is on.

Why should I disconnect the battery when not in use?

If the Rover will be inactive for more than a couple of hours, disconnect the LiPo battery to avoid over-discharging, which can cause irreparable damage. LiPo batteries should never be discharged below 3.0 volts per cell.

Calibration and Maintenance

The Rover isn't driving straight. What should I do?

The Rover comes pre-calibrated from the factory, so in most cases you shouldn't need to adjust it. However, keep in mind:

  • The steering mechanism has some natural play in it
  • The Rover does not have auto-correction for steering (it won't automatically straighten out)
  • Small deviations are normal and expected

If you believe the calibration is significantly off or you've accidentally reset it, see the Calibration Guide for detailed instructions on how to recalibrate your Rover.

When should I recalibrate my Rover?

You should recalibrate your Rover if:

  • You've accidentally reset the calibration by holding SW2 for more than 5 seconds
  • The steering or throttle endpoints are not reaching their full range
  • You've switched to a different radio transmitter
  • The neutral position is significantly off

See the Calibration Guide for step-by-step instructions.

How do I calibrate my Rover?

Follow the detailed step-by-step instructions in the Calibration Guide.

Battery and Power

What is the low-voltage cutoff feature?

The Rover's power module includes a low-voltage cutoff feature that's enabled by default. When battery voltage is deemed too low, the power module will turn off most systems to protect your battery from over-discharge damage.

How should I store LiPo batteries?

Store LiPo batteries at a safe voltage level, typically around 3.7 to 3.8 volts per cell. For extended storage, use your charger's storage mode to set the battery to the appropriate voltage. Never store batteries fully charged or fully discharged.

What voltage should I never go below with LiPo batteries?

LiPo batteries should never be discharged below 3.0 volts per cell. Over-discharging can cause significant capacity loss, performance degradation, and in some cases render the battery completely unusable.

ROS2 Gateway

What is the ROS2 Gateway?

The ROS2 Gateway is a bridge between the Rover's CAN bus and ROS2. It allows you to control the rover using standard ROS2 topics, monitor system status, and integrate with the ROS2 ecosystem for autonomous behaviors. See the ROS2 documentation for details.

How do I start the ROS2 Gateway?

Use the provided script to run the gateway in a Docker container:

# Run interactively
./scripts/run-ros-gateway.sh

# Run as background daemon
./scripts/run-ros-gateway.sh --daemon

The script automatically configures the CAN interface and starts all ROS2 nodes. See the ROS2 Gateway documentation for manual setup instructions.

How do I control the Rover with ROS2?

Use the /rover/cmd_vel topic with geometry_msgs/Twist messages:

# Move forward at 50% throttle
ros2 topic pub /rover/cmd_vel geometry_msgs/msg/Twist \
    "{linear: {x: 0.5}, angular: {z: 0.0}}"

# Turn right while moving forward (positive angular.z = right)
ros2 topic pub /rover/cmd_vel geometry_msgs/msg/Twist \
    "{linear: {x: 0.5}, angular: {z: 0.349}}"

# Turn left while moving forward (negative angular.z = left)
ros2 topic pub /rover/cmd_vel geometry_msgs/msg/Twist \
    "{linear: {x: 0.5}, angular: {z: -0.349}}"

# Stop
ros2 topic pub /rover/cmd_vel geometry_msgs/msg/Twist \
    "{linear: {x: 0.0}, angular: {z: 0.0}}"

Note: angular.z is in radians. Positive values turn right, negative values turn left.

What ROS2 topics are available?

Control topics:

  • /rover/cmd_vel - Control commands for throttle and steering

Monitoring topics (read-only):

  • /rover/radio/cmd_vel - Physical radio commands (when radio active)
  • /rover/battery_monitor_*/cell_voltages - Individual cell voltages
  • /rover/battery_monitor_*/output - Battery output voltage and current
  • /rover/battery_monitor_*/regulated - Regulated output voltage and current
  • /rover/wheel_*/wheel_status - Wheel speeds and RPM
  • /rover/obstacle_detector_*/obstacle_distance - Distance readings
  • /rover/mayor/can_status - CAN bus status

Configuration topics:

  • /rover/wheel_*/report_frequency_hz - Configure wheel reporting frequency

See the Messages and Topics documentation for complete details.

What ROS2 nodes run in the gateway?

The gateway launches multiple nodes:

  • mayor_node - CAN Kingdom protocol coordinator
  • controller_node - Vehicle control with safety override
  • battery_node (2 instances) - Battery monitoring for control and AD systems
  • wheel_node (4 instances) - Wheel speed monitoring
  • obstacle_detector_node (2 instances) - Front and rear distance sensing

See the Nodes documentation for details on each node.

What ROS2 versions are supported?

The gateway supports both ROS2 Humble (Ubuntu 22.04) and ROS2 Jazzy (Ubuntu 24.04). The Docker images are tagged accordingly (e.g., ros-gateway-humble or ros-gateway-jazzy).

How does the safety override work?

When the physical radio transmitter's override button is active, it always takes precedence over ROS2 control commands. The controller node detects radio activity on the CAN bus and stops sending autonomous commands. You can monitor radio commands on the /rover/radio/cmd_vel topic. See the Safety documentation for more details.

Hardware and Architecture

What microcontroller does the Rover use?

All Rover modules use the STM32F302 microcontroller on a CPU board. This provides essential peripherals like UART, CAN, and SWD interfaces, plus SPI flash memory for storing application data.

What is the modular board architecture?

The Rover uses a modular design where a CPU board (STM32F302) combines with different carrier boards to create development boards. Each development board + application combination creates a module (Power, Servo, Motor, RC, etc.). See the Rover System documentation for architecture details.

What communication protocol does the Rover use?

The Rover uses a custom CAN Kingdom protocol at 125 kbps bitrate. The protocol coordinates communication between all components, with concepts like King, Mayor, Postmaster, Cities, and Envelopes organizing the system.

What hardware do I need for development?
  • Rover board(s) with STM32F302
  • ST-Link V2 or V3 programmer/debugger
  • USB cable
  • Kvaser Leaf or other SocketCAN-compatible interface
  • CAN cables and terminators (120Ω resistors)
  • 4S LiPo battery with XT60 connector
What modules come with the Rover?

Base modules (included with all setups):

  • Power Module - Power distribution and monitoring
  • Servo Module - Steering servo control
  • Motor Module - ESC/motor control
  • RC Module - Radio control interface

Optional modules:

  • Wheel Speed Module - Wheel speed data
  • FlexiRange - Ultrasonic distance sensing
  • Light Array - CAN-controllable LED lights
What CAN messages does the Rover use?

The Rover uses a variety of CAN messages for control and monitoring. See the CAN Messages documentation for complete details on all message types.

Where can I find the CAN message definitions?

CAN message definitions are documented in the CAN Messages Index.

The raw definitions are also available in the rover.dbc file in the repository.

Firmware and Updates

How do I upgrade the Rover's firmware?

See the Firmware Upgrade Guide for detailed instructions.

How do I know what firmware version I have?

Currently, there is no programmatic way to check the firmware version from the Rover itself. This feature is on our roadmap for future releases.

For now, the best way to track your firmware version is to:

  • Keep note of which release you flashed from Rover Releases
  • Check the date you last performed an upgrade
  • When in doubt, flash the latest version. We always try to maintain backwards compatibility.
What should I do if a firmware upgrade fails?

If flashing over CAN fails:

  1. Verify CAN interface is properly configured and connected
  2. Check that the Rover is powered on and communicating
  3. Try power cycling the Rover
  4. Use the SWD method as a fallback

If flashing over SWD fails:

  1. Verify ST-Link connection and drivers
  2. Check that you're using the correct binary file
  3. Ensure the start address is set to 0x08000000
  4. Try a different USB port or cable

Troubleshooting

The Rover doesn't turn on. What should I check?
  1. Check battery is fully charged and connected to both connectors (main power + cell balance)
  2. Ensure main power switch is pressed
  3. Check for any loose connections
  4. Verify battery voltage is above minimum threshold (3.0V per cell)
  5. If using an ESC with separate power switch, ensure it's also pressed
My CAN interface isn't working. How do I fix it?
  1. Check the interface is properly connected
  2. Set up the CAN interface with correct parameters: 
    sudo ip link set can0 type can bitrate 125000 restart-ms 100
sudo ip link set can0 up
  3. Verify with ip link show can0
  4. Check termination resistors (120Ω at each end of CAN bus)
  5. Ensure you have the correct permissions (user in dialout and netdev groups)
How do I monitor CAN bus traffic? 
# Monitor raw CAN messages
candump can0

# Or use the Python tools
python rover_py/candump.py
python rover_py/can-log-decoder.py
I can't connect to the ROS2 gateway. What's wrong?

Check the following:

  1. CAN interface is properly configured and up
  2. Gateway version matches your firmware version
  3. Rover is powered on and connected
  4. Docker container is running: docker ps --filter name=rover-ros-gateway
  5. Check logs: docker logs rover-ros-gateway
  6. Verify network settings (host, ipc, pid modes)
The ROS2 gateway nodes aren't publishing data. What's wrong?
  1. Verify the Rover is powered on and all modules are functioning
  2. Check CAN bus activity: candump can0
  3. Ensure firmware is flashed and configured correctly
  4. Check individual node logs in the gateway container
  5. Verify CAN bitrate matches (125000 bps)
  6. Check that CAN bus has proper termination

Safety

Is the Rover safe to use?

The Rover is not a toy and requires careful handling. Important safety considerations:

  • Battery safety: LiPo batteries can be dangerous if mishandled
  • Electrical hazards: Faulty wiring can cause injuries or fire
  • Moving parts: Keep hands clear of wheels and drivetrain when powered
  • Always test safely: Use the included carrying case for transport and suspend wheels when first testing

CanEduDev assumes no responsibility for damages due to incorrect handling.

What safety features does the Rover have?
  • Low-voltage cutoff: Protects battery from over-discharge
  • Overcurrent protection: Customizable limits to prevent damage
  • Reverse polarity protection: Prevents damage from incorrect battery connection
  • 100A fuse: Hardware protection against excessive current
  • Radio override: Physical radio can override autonomous control for safety

See the Safety documentation for details on the ROS2 safety architecture.

Still Have Questions?

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