radioROS

radioROS is a simple Python-based ROS2 package that allows robots to utilize an RC receiver in their projects. This package should theoretically work for any receiver since there is an ESP32 that carefully reads the PWM data and publishes it via serial. Other packages use SBUS, which is not standardized, and most receivers don't have this feature, and those that do are expensive.

Getting Started

Hardware Setup

1. First, get an ESP32 and upload the esp32_code.ino that's within the firmware directory.

2. Connect the ESP32 to the receiver as follows:

   

   It's very simple with only 8 connections in total. Be sure to pair the receiver beforehand.

Software Setup

1. Clone this repo into your ROS2 workspace:

   cd ros2_ws/src
   git clone https://github.com/TheHassanShahzad/radioROS.git
   cd ..
   colcon build --packages-select radioROS
   source install/setup.bash

Nodes

The package contains two nodes:

1. pwm_publisher

   • Responsible for reading the incoming serial data from the ESP32 and publishing the data to the /receiver_data topic of type Int16MultiArray.
   • Takes serial_port as a parameter (default is /dev/ttyUSB0).

2. pwm_to_twist

   • Subscribes to the /receiver_data topic and publishes Twist messages to the /cmd_vel topic.
   • Takes the following parameters:
     • max_linear_speed (default is 1.0)
     • max_angular_speed (default is 1.0)
     • topic (default is cmd_vel)

Important Notes

• pwm_to_twist can only work if pwm_publisher is running.
• pwm_publisher only works if the transmitter is powered on, so the ESP32 is publishing PWM data.

Firmware for ESP32

The ESP32 code required to make this ROS2 package work can be found in the firmware directory. Follow these steps to upload the code to your ESP32:

1. Open the esp32_code.ino file located in the firmware directory using the Arduino IDE or any other compatible IDE.
2. Connect your ESP32 to your computer.
3. Select the correct board and port in the IDE.
4. Upload the code to the ESP32.