ROS & Arduino - Control Stepper motors

Requirements

• Arduino IDE with rosserial_arduino installed (and Teensy plugin if you use the Teensy board)
• Arduino board (I used a Teensy 3.5)
• 3 stepper motors (I used NEMA 17)
• 3 motor drivers (I used A4988 but you can also use DRV8825 by making the appropriate changes in code)
• 3 electrolytic capacitors (at least 47μF)
• Some LED's (I used one RGB LED)
• Power Supply (I used a 12V 8.5A)

Instructions

1. Enter the ROS environment source /opt/ros/<distro>/setup.bash
2. Start ROS master roscore
3. Upload .ino file to arduino (Make sure you have installed rosserial_arduino) and run it.
4. In a new terminal run rosrun rosserial_python serial_node.py /dev/ttyACM0 . Make sure to specify the correct port (same port you used in the Arduino IDE to upload the code)
5. In a new terminal interact with your Arduino program through ROS topics.
   e.g. rostopic pub motor2/start std_msgs/Empty --once will execute once the following method

void startMotor2(const std_msgs::Empty& toggle_msg)

whereas rostopic pub motor1/start std_msgs/Int8 15 --once will execute once the following method

void startMotor1(const std_msgs::Int8& rpm)

by passing as an argument an rpm of 15

6. You can see all available topics by running in a terminal rostopic list