Introduction

This Robot is an intelligent device which follows the line (black path). if there is any obstacle on the line so this robot automatically sense the obstacle in front of it. And avoid them by turning itself in another direction and automatically come to their original path.

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Infrared Sensor is used to detect the black line on the path and Ultrasonic Sensor is used to detect obstructions on the path. If any obstacle in front of it then then it stop and turning itself in another direction and again it reaches its original path(black line).

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Components Required

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1. Arduino NANO or Uno (any version)
2. HC-SR04 Ultrasonic Sensor
3. LM298N Motor Driver Module
4. TCRC 5000 IR sensor
5. Battery
6. Wheels

7. Chassis
8. Jumper Wires
9. 5V DC Motors

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Circuit Diagram:

As shown in figure 1

 

Coding of this model:
 

#include <NewPing.h>;

#define leftIr A0
#define rightIr A1
#define leftIrPower 8
#define rightIrPower 10

#define leftMotorSpeed 3

#define leftMotorP 4
#define leftMotorN 5

#define rightMotorN 6
#define rightMotorP 7
#define rightMotorSpeed 9

#define ultrasonicTrigger 11
#define ultrasonicEcho 12

 

// Max distance read by ultrasonic sensor
const int maxDistance = 400;

 

NewPing ultrasonic(ultrasonicTrigger, ultrasonicEcho, maxDistance);

 

const char GREEN_SIGN = &#39;d&#39;; // Drive
const char RED_SIGN = &#39;s&#39;; // Stop

const int MIN_DISTANCE_FROM_OBJECT = 5;

 

// Error of the distance read by the ultrasonic sensor
const float DISTANCE_OFFSET = -0.31;

 

// Motors speed (0 - 255)
const float FORWARD_SPEED = 112;
const float CURVE_SPEED = FORWARD_SPEED;

 

// Variable responsible for ignoring small variations in reflectance
const int SENSITIVITY_OFFSET = 30;

 

// Reflectance thresholds of the external parts to the central band
int leftThreshold;
int rightThreshold;

char vehicleAction;

 

void setup() {
Serial.begin(115200);

pinMode(leftIr, INPUT);
pinMode(rightIr, INPUT);
pinMode(leftIrPower, OUTPUT);
pinMode(rightIrPower, OUTPUT);
leftThreshold = analogRead(leftIr);
rightThreshold = analogRead(rightIr);

pinMode(leftMotorSpeed, OUTPUT);
pinMode(leftMotorP, OUTPUT);
pinMode(leftMotorN, OUTPUT);

pinMode(rightMotorSpeed, OUTPUT);
pinMode(rightMotorN, OUTPUT);

pinMode(rightMotorP, OUTPUT);

pinMode(ultrasonicTrigger, OUTPUT);
pinMode(ultrasonicEcho, INPUT);
}

 

void loop() {
if (Serial.available() &gt; 0) {
char serial = Serial.read();

if (serial == GREEN_SIGN || serial == RED_SIGN) {
vehicleAction = serial;
}
}

 

if (vehicleAction == GREEN_SIGN)
drive();
else if (vehicleAction == RED_SIGN)
stopCar();
}

 

void drive() {
if (hasObstacle()) stopCar();
while (hasObstacle()) delay(100);

 

// If a new vehicle action was received, must process it first
if (Serial.available() &gt; 0) return;

int leftIrValue = analogRead(leftIr) - SENSITIVITY_OFFSET;
int rightIrValue = analogRead(rightIr) - SENSITIVITY_OFFSET;

if (leftIrValue &lt;= leftThreshold &amp;&amp; rightIrValue &lt;= rightThreshold)

moveForward();
else if (leftIrValue &gt; leftThreshold &amp;&amp; rightIrValue &lt;= rightThreshold)
moveLeft();
else if (leftIrValue &lt;= leftThreshold &amp;&amp; rightIrValue &gt; rightThreshold)
moveRight();
else if (leftIrValue &gt; leftThreshold &amp;&amp; rightIrValue &gt; rightThreshold)
stopCar();

 

// Runs an action during just 125ms to make sure it doesn&#39;t cross the line

delay(125);
stopCar();
delay(75);
}

boolean hasObstacle() {
int distance = ultrasonic.ping_cm();

// Check if distance different of 0, because NewPing library returns 0 if

// the distance is greater than the specified
return distance &gt; 0 &amp;&amp; distance &lt;= MIN_DISTANCE_FROM_OBJECT;
}

void moveForward() {
// PWM
analogWrite(leftMotorSpeed, FORWARD_SPEED);
analogWrite(rightMotorSpeed, FORWARD_SPEED);

 

// Direction
digitalWrite(leftMotorP, HIGH);
digitalWrite(leftMotorN, LOW);
digitalWrite(rightMotorP, HIGH);
digitalWrite(rightMotorN, LOW);
}

void moveLeft() {
// PWM
analogWrite(leftMotorSpeed, 0);
analogWrite(rightMotorSpeed, CURVE_SPEED);

 

// Direction
digitalWrite(leftMotorP, LOW);
digitalWrite(leftMotorN, LOW);
digitalWrite(rightMotorP, HIGH);

digitalWrite(rightMotorN, LOW);
}

void moveRight() {
// PWM
analogWrite(leftMotorSpeed, CURVE_SPEED);
analogWrite(rightMotorSpeed, 0);

 

// Direction
digitalWrite(leftMotorP, HIGH);
digitalWrite(leftMotorN, LOW);
digitalWrite(rightMotorP, LOW);
digitalWrite(rightMotorN, LOW);
}

 

void stopCar() {
// PWM
analogWrite(leftMotorSpeed, 0);
analogWrite(rightMotorSpeed, 0);

 

// Direction
digitalWrite(leftMotorP, LOW);
digitalWrite(leftMotorN, LOW);
digitalWrite(rightMotorP, LOW);
digitalWrite(rightMotorN, LOW);

}

 

Advantages

• This type of robot is also used in Amazon company for transport the luggages.

• This robot works as peon, employees, in an industries or any educational institute.

• It is a one time investment it can works as a Employee.

• They can be used for household work like automatic vacuum cleaning.

 

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