ROS_Teensy-4.1

Complete Tutorial on how to setup Teensy 4.1 with ROS on Nvidia Jetson.

This Tutorial is consist of two parts -

1. Setting Up Teensy 4.1 With Arduino IDE on Jetson Nano.
2. Testing of Teensy 4.1 With ROS Program On Jetson Nano.

Setting Up Teensy 4.1 With Arduino IDE on Jetson Nano.

HARDWARE REQUIRED Nvidia Jetson Nano Teensy 4.1 Datesheet-Teensy 4.1 Micro USB cable

SOFTWARE REQUIRED Linux (Ubuntu) , Arduino IDE , TeensyDuino , TeensyLoader

DESCRIPTION AND SPECIFICATION OF TEENSY 4.1

Teensy 4.1 Is the First Arduino-Compatible Board with 100 Mbit Ethernet . The new Teensy 4.1 from PJRC simplifies that decision because It combines the real-time nature of an Arduino-compatible microcontroller with the processing and I/O performance of an operating system-based SBC in a slim package. Teensy 4.1 from PJRC is an update of their already mighty Arduino-compatible board. As the minor revision number suggests, the new board is an extension that builds on the previously introduced 4.0.

To Know Go to this Youtube link - https://www.youtube.com/watch?v=I4MDh-lencY&feature=youtu.be

Specification of Teensy 4.1

Pin Diagram of Teensy 4.1

INSTRUCTIONS-

Step 1

Establishing the connection between the PC and the Teensy 4.1 using the Micro USB

Simply Connect the micro USb side to the Teensy 4.1 microcontroller and plug in USB to your system , you can also use your mobile charger to establish the connection.

Step 2

Download the Teensyduino in Linux and Setup in Arduino IDE and Linux Environment

Teensyduino is a software add-on for the Arduino software. So to download it you can go to this website - Teensyduino Download

Once You open this site , it’s look like this -

Now, You have to choose the corresponding Teensyduino file according to your system requirements , Here were setting up the teensy 4.1 on jetson nano so, we have opted the Linux Installer (X86 64 bit) option.

Once you download the Teensyduino Installer file on Linux system, keep it aside and follow this steps..

1. Download the Linux udev rules from this link Linux udev rules and copy the file to /etc/udev/rules.d.

2. To do this create the text file and paste the all the linux udev rules into this text file

   And rename the file name with “00-teensy.rules”

3. After that, open the folder where you keep this text file “00-teensy.rules” and open the terminal and execute this command line which move/paste this text to “/etc/udev/rules.d/00-teensy.rules” location

        sudo cp 00-teensy.rules /etc/udev/rules.d/
   

4. Now Install the arduino IDE in your system if not installed yet.

5. If the arduino IDE already installed in your system than you have to install the teensyduino in your system , for installing the teensyduino go back to the Teensydunino file folder and open terminal and run this lines on it to start installation process

      chmod 755 TeensyduinoInstall.linux64
      
      sudo ./TeensyduinoInstall.linux64
   

Just running this command lines on terminal a small window will be get open on the screen like this -

Teensyduino Graphical Installer

The Teensyduino installer adds the necessary support files to Arduino. Your copy of Arduino must be one of the supported versions listed on this first screen.

Select the location where you extracted the Arduino Software The Next button will only activate when a supported version of the Arduino Software is found.

Teensyduino can automatically install many libraries that are tested and verified to work with Teensy. Usually it's best to allow the installer to add them all.

The installer will copy all the necessary files into your Arduino Software, when you click the "Install" button.

When installation is finished, you will see this final screen. Just click Done to quit the installer.

Step 3

Programming of Teensy 4.1 using Arduino IDE and Teensyduino

Programming of Teensy 4.1 using Arduino IDE and Teensyduino

1. Start Arduino & Choose The Board , Now you are ready to run Arduino. The first step is to select the board you will be using, from the Tools->Boards menu. This menu will have entries for Teensy because you ran the Teensyduino installer.

2. The Arduino Software comes with many examples. Use the File->Examples->Digital->Blink menu to open the LED blink example.

3. Compile and Download To compile this code, click the "Verify" button.

A message will appear showing the compiled size. The Teensy Loader will update with the new file Just press the button on Teensy to program the code.

Completed

Teensy 4.1 Setup in Linux System Jetson Nano using TeensyDuino and Arduino IDE.

teensy4.1.mp4

Testing of Teensy 4.1 With ROS Program On Jetson Nano.

Create a ROS Program To Control A Servo Motor Using Teensy 4.1

In this test , We connect a Servo Motor to the Teensy 4.1 and try to control Servo Motion Using ROS Program.

So , Let’s Start and Follow the Given Instructions.

INSTRUCTIONS

1. Establishing the connection between the PC and the Teensy 4.1 using the Micro USB

   Simply Connect the micro USB side to the Teensy 4.1 microcontroller and plug in USB to your system , you can also use your mobile charger to establish the connection.

   

2. Circuit Connection of Servo Motor to Teensy 4.1

   Just Connect the Vcc Pin of the servo to the teensy 4.1 5V and GND to Ground of the Teensy 4.1 and Input pin of the servo to the D9 of the teensy 4.1..

3. Uploading of the ROS Serial Program in Teensy 4.1 to control the Servo Motors

   The code for this tutorial is made extremely simple through the use of the Arduino Servo library. The Servo Library handles all of the low level control to generate and maintain the servo pulses. All your code needs to do is specify the pin the servo is attached to and then write the angle to the servo object. Underneath, the Servo library uses the Arduino's built in timer interrupts to generate the correct pulses. In this example, we only control one servo, but the same library can be used to control up to 12 servos on most Arduino boards and 48 on the Arduino Mega.

Arduino Code

  #include <WProgram.h>
  #include <Servo.h> 
  #include <ros.h>
  #include <std_msgs/UInt16.h>

  ros::NodeHandle  nh;

  Servo servo;

  void servo_cb( const std_msgs::UInt16& cmd_msg){
    servo.write(cmd_msg.data); //set servo angle, should be from 0-180  
    digitalWrite(13, HIGH-digitalRead(13));  //toggle led  
  }


  ros::Subscriber<std_msgs::UInt16> sub("servo", servo_cb);

  void setup(){
     pinMode(13, OUTPUT);

     nh.initNode();
     nh.subscribe(sub);

     servo.attach(9); //attach it to pin 9
  }

  void loop(){
     nh.spinOnce();
     delay(1);
  }

4. Use the Rosserial Package and open the three terminals

   Terminal 1

    roscore
   

   Terminal 2

    rosrun rossserial_arduino serial.py _port="port_number_of_the_teensy_4.1"
   

   Terminal 3 (publish the message on this terminal)

    rostopic pub servo std_msgs/UInt16  <angle>
   

Completed

Video Link - ROS Servo Teensy 4.1