Mini ToF

ROS 2 package for interfacing with miniature ToF sensors without any hardware or firmware expertise required. This package includes support for capturing raw histogram data from the sensors, which has been studied in academic work for many applications like object detection [1], 3D reconstruction[2, 3, 4], and even seeing around corners[5, 6].

Currently supported sensors:

• AMS TMF882X (TMF8820, TMF8821, TMF8828)
• ST VL53L8CH

See the mini_tof_firmware repository for information about supported hardware (sensors and microcontollers).

Related Packages

mini_tof_interfaces is a ROS 2 package containing the ROS 2 interface definitions for this package.

mini_tof_firmware is a GitHub repository containing microcontroller firmware necessary for using this package.

Installation

Install ROS Package

Option 1: Install pre-built binary from command line

This option is coming soon. For now, you must build from source.

Option 2: Build from Source

1. Clone this repo and the interfaces package to the src directory of your ROS 2 workspace:

    cd ~/ros2_ws/src
    git clone git@github.com:uwgraphics/mini_tof.git
    git clone git@github.com:uwgraphics/mini_tof_interfaces.git
    

1. Install python dependencies using rosdep:

    cd ~/ros2_ws
    rosdep install --from-paths src --ignore-src -r -y
    

Note: If you encounter issues with rosdep, you can also install packages manually. Refer to the package.xml files in the mini_tof and mini_tof_interfaces packages for a list of dependencies.

1. Build the workspace

    cd ~/ros2_ws
    colcon build --symlink-install
    

Hardware, Microcontroller Setup, and Firmware

To use this package, a microcontroller must be connected to the ToF sensor and run firmware that communicates with the sensor and ROS 2. Follow the steps in the README for the mini_tof_firmware repository to set up the microcontroller and upload the firmware.

Usage

The mini_tof package is meant to be a simple, lightweight package which passes along information reported by miniature time-of-flight sensors to ROS 2 topics. There are only two nodes in the package:

1. tof_publisher: Publishes data reported by the sensor (e.g. distance, ambient light, histograms) to ROS 2 topics.
2. tof_visualizer: Visualizes the data reported by the sensor in real time using PyQtGraph.

Command line

Launch a publisher node for the TMF882X sensor with:

ros2 run mini_tof tof_publisher --ros-args -p mcu_port:=/dev/ttyACM0 -p sensor_model:=TMF882X

Or launch a publisher node for the VL53L8CH sensor with:

ros2 run mini_tof tof_publisher --ros-args -p mcu_port:=/dev/ttyUSB0 -p sensor_model:=VL53L8CH -p num_zones:=16

Check that messages are getting published to the mini_tof_data topic with:

ros2 topic echo /mini_tof_data

Visualize the reported data in real time with:

ros2 run mini_tof tof_visualizer

Launch files

Like any ROS node, the publisher and visualizer can also be launched via launch files. An example launch file for the VL53L8CH sensor looks like:

from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    return LaunchDescription([
        Node(
            package='mini_tof',
            name='tof_publisher',
            executable='tof_publisher',
            output='screen',
            parameters=[{
                'mcu_port': '/dev/ttyUSB0',
                'sensor_model': 'VL53L8CH',
                'num_zones': 16
            }]
        ),
        Node(
            package='mini_tof',
            name='tof_visualizer',
            executable='tof_visualizer',
            output='screen'
        ),
    ])

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