Published June 24, 2024 © GPL3+

Arduino line follower controlled by ROS1

You will learn how to establish serial communication between ROS and Arduino by implementing a simple publisher and subscriber setup.

IntermediateFull instructions provided5 hours211

Arduino line follower controlled by ROS1

Things used in this project

Hardware components

Arduino Nano R3

6v N20 Motor 100rpm

44mm N20 wheel

N20 Mounting bracket

N20 castor

MX1508 motor driver

TCRT5000L IR Array

3.7v LIPO battery

Software apps and online services

Arduino IDE

ROS Robot Operating System

Hand tools and fabrication machines

Soldering iron (generic)

Digilent Mastech MS8217 Autorange Digital Multimeter

Story

OVERVIEW:

This project aims to grasp the fundamentals of ROS1, understanding the workings of publishers and subscribers. Although the line follower isn't exceptionally fast, it serves as a practical example of utilizing rosserial on an Arduino board. To do this project, a foundational understanding of ROS is necessary, including concepts such as creating workspaces, packages, and scripts.

WORKING:

The Arduino gathers data from the IR sensors (e.g., 0000, 10000, etc.) and publishes it to the ROS node. The ROS node subscribes to this data and executes a script. Based on the received IR sensor data, the script issues commands to the line follower (e.g., forward, right, stop). The Arduino subscribes to these commands and changes the line follower's movements accordingly.

STEPS:

1] Create a Workspace.

2] Create a package inside the src folder of your workspace

3] Create a script folder inside src folder of your package

4] Copy paste the script which I attached (in code section) and save it

5] Then catkin_make your workspace

after doing these steps, follow the "line_follower_steps.txt" file attached in downloads section.

and you are done!!

PHOTOS:

1 / 3

WORKING VIDEO:

Code

#!/usr/bin/env python

import rospy
from std_msgs.msg import String

def ir_state_callback(msg):
    if msg.data == "00100":
        led_pub.publish("forward")
    elif msg.data == "00010":
        led_pub.publish("right")
    elif msg.data == "01000":
        led_pub.publish("left")
    elif msg.data == "00001":
        led_pub.publish("cright")
    elif msg.data == "10000":
        led_pub.publish("ceft")
    elif msg.data == "00011":
        led_pub.publish("sright")
    elif msg.data == "11000":
        led_pub.publish("sleft")
    elif msg.data == "00110":
        led_pub.publish("mright")
    elif msg.data == "01100":
        led_pub.publish("mleft")
    elif msg.data == "00000":
        led_pub.publish("stop")

rospy.init_node('arduino_led_control')

rospy.Subscriber('/ir_state', String, ir_state_callback)
led_pub = rospy.Publisher('/mov_state', String, queue_size=10)

rospy.spin()

#include <ros.h>
#include <std_msgs/String.h>

ros::NodeHandle nh;

const int irPin1 = 2;
const int irPin2 = 3;
const int irPin3 = 4;
const int irPin4 = 5;
const int irPin5 = 6;

const int ledPin = 13;     // LED pin

std_msgs::String str_msg;
ros::Publisher ir_pub("/ir_state", &str_msg);

void movCallback(const std_msgs::String& cmd_msg) {
  String command = cmd_msg.data;

  if (command == "forward") {
    digitalWrite(7, 0);
    digitalWrite(8, 1);
    digitalWrite(9, 0);
    digitalWrite(10, 1);
  } else if (command == "right") {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 1);
  } else if (command == "left") {
    digitalWrite(7, 0);
    digitalWrite(8, 1);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
  } else if (command == "cright") {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 1);
  } else if (command == "cleft") {
    digitalWrite(7, 0);
    digitalWrite(8, 1);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
  } else if (command == "sright") {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 1);
  } else if (command == "sleft") {
    digitalWrite(7, 0);
    digitalWrite(8, 1);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
  } else if (command == "mright") {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 1);
  } else if (command == "mleft") {
    digitalWrite(7, 0);
    digitalWrite(8, 1);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
  } else if (command == "stop") {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
  } else {
    digitalWrite(7, 0);
    digitalWrite(8, 0);
    digitalWrite(9, 0);
    digitalWrite(10, 0);
    digitalWrite(11, 0);

  }
}

ros::Subscriber<std_msgs::String> sub("mov_state", &movCallback);

void setup() {
  pinMode(irPin1, INPUT);
  pinMode(irPin2, INPUT);
  pinMode(irPin3, INPUT);
  pinMode(irPin4, INPUT);
  pinMode(irPin5, INPUT);

  pinMode(ledPin, OUTPUT);

  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);

  nh.initNode();
  nh.advertise(ir_pub);
  nh.subscribe(sub);
}

void loop() {
  int irState1 = digitalRead(irPin1);
  int irState2 = digitalRead(irPin2);
  int irState3 = digitalRead(irPin3);
  int irState4 = digitalRead(irPin4);
  int irState5 = digitalRead(irPin5);

  if (irState1 && irState2 && !irState3 && irState4 && irState5 ) {
    str_msg.data = "00100";
  } else if (irState1 && irState2 && irState3 && !irState4 && irState5 ) {
    str_msg.data = "00010";
  } else if (irState1 && !irState2 && irState3 && irState4 && irState5 ) {
    str_msg.data = "01000";
  } else if (!irState1 && !irState2 && !irState3 && !irState4 && !irState5 ) {
    str_msg.data = "11111";
  } else if (!irState1 && irState2 && irState3 && irState4 && irState5 ) {
    str_msg.data = "10000";
  } else if (irState1 && irState2 && irState3 && irState4 && !irState5 ) {
    str_msg.data = "00001";
  } else if (!irState1 && !irState2 && irState3 && irState4 && irState5 ) {
    str_msg.data = "11000";
  } else if (irState1 && irState2 && irState3 && !irState4 && !irState5 ) {
    str_msg.data = "00011";
  } else if (irState1 && !irState2 && !irState3 && irState4 && irState5 ) {
    str_msg.data = "01100";
  } else if (irState1 && irState2 && !irState3 && !irState4 && irState5 ) {
    str_msg.data = "00110";
  } else {
    str_msg.data = "00000";
  }

  ir_pub.publish(&str_msg);
  nh.spinOnce();

  // Wait for incoming messages from ROS
  delay(100);
}

Credits

akash a s

4 projects • 5 followers

Electronics student who loves making projects

Arduino line follower controlled by ROS1

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

OVERVIEW:

WORKING:

STEPS:

PHOTOS:

WORKING VIDEO:

Schematics

circuit diagram

Code

Script file.txt

Arduino ino file.txt

Credits

akash a s

Comments

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Arduino line follower controlled by ROS1

Arduino line follower controlled by ROS1

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

OVERVIEW:

WORKING:

STEPS:

PHOTOS:

WORKING VIDEO:

Schematics

circuit diagram

Code

Script file.txt

Arduino ino file.txt

Credits

akash a s

Comments

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