Efficient Wall Following Robot with Ultrasonic Sensor that Works in both Indoor and Outdoor Environments

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//Program to 

#include 
 
#define SONAR_NUM     2             //define Number of ultrasonic sensor used
#define MAX_DISTANCE 800            //Max distance between the object and robot
#define PING_INTERVAL 33           
 
#define trigPin1                 6                  // define pin connections for sensor and motor
#define echoPin1            5
#define trigPin2                11
#define echoPin2            10
#define LM1      2      
#define LM2      3     
#define RM1      7 
#define RM2      8    
 
int rangeFront = 0;
int rangeWall  = 0;
 
NewPing sonar[SONAR_NUM] = {                                // Define a Newping array to measure the distance
  NewPing(trigPin1, echoPin1, MAX_DISTANCE),
  NewPing(trigPin2, echoPin2, MAX_DISTANCE)
};
void setup()               // setup function to make pin configuration to define whether it is input or output
{
  Serial.begin(9600);
  int i;
  pinMode(LM1, OUTPUT);
  pinMode(LM2, OUTPUT);
  pinMode(RM1, OUTPUT);
  pinMode(RM2, OUTPUT);
  pinMode(en1, OUTPUT);
  pinMode(en2, OUTPUT);
 
  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);
  digitalWrite(trigPin1, LOW);
 
  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);
  digitalWrite(trigPin2, LOW);
}
 
int toCloseWall = 1800;           //Initialze and define the values for distance between wall and robot
int toFarWall = 2500;
int toCloseFront = 1000;
 
void loop()
{
Main:
  rangeFront = readRangeFront();  // Read the sensor value by the function call
  Serial.print(rangeFront);          
  Serial.print(" Front");
  Serial.println();
  rangeWall = readRangeWall();
  Serial.print(rangeWall);
  Serial.print(" Wall");
  Serial.println(); 
 
  if (rangeFront <= 400)         //As the sensor value reads the small values we are manipulating to high values
  {
    rangeFront = 3000;
  }
  if(rangeWall <= 400)
  {
    rangeWall = 3000;
  }
 
 if (rangeFront < toCloseFront)  //Condition to check whether front sensor is close to robot
 {
    delay(500);
    drive_backward();
    delay(500);
    Serial.print(" Drive Back");
    //turn_right();
    Serial.print(" Right Turn");
    Serial.println();
    delay(800);
    drive_forward();
    turn_left();
    delay(1700);
    goto Main;   
  } 
 
  if(rangeWall > toCloseWall && rangeWall < toFarWall) //condition to check distance measured by front and side sensor is maintained correctly
  {
    drive_forward();
    Serial.print(" Drive Forward");
    Serial.println();
    goto Main;
  } 
 
  if (rangeWall < toCloseWall)                       //condition to check side wall is close to robot
  {
    delay(100);
    //turn_left();
    turn_right();
    delay(500);
    Serial.print(" Turn Left");
    drive_forward();
    Serial.print(" Drive Forward");
    Serial.println();
    goto Main;
  }
  if (rangeWall > toFarWall)                         //condition to check robot is far from side wall
  {
    delay(100);
    //turn_right();
    turn_left();
    Serial.print(" Turn Right");
    delay(500);
    drive_forward();
    Serial.print(" Drive Forward");
    Serial.println();
    goto Main;
  } 
}
 
void motor_stop()                                  // function to stop the robot
{   
    digitalWrite(LM1, LOW);
    digitalWrite(LM2, LOW);
    digitalWrite(RM1, LOW);
    digitalWrite(RM2, LOW);
}
 
void drive_forward()                               // function to drive the robot forward
{   
    digitalWrite(LM1, HIGH);
    digitalWrite(LM2, LOW);
    digitalWrite(RM1, HIGH);
    digitalWrite(RM2, LOW);
}
 
void drive_backward()                             // function to drive the robot backward
{   
    digitalWrite(LM1, LOW);
    digitalWrite(LM2, HIGH);
    digitalWrite(RM1, LOW);
    digitalWrite(RM2, HIGH);
}
 
void turn_left()                                  // function to turn the robot left
{  
    digitalWrite(LM1, HIGH);
    digitalWrite(LM2, LOW);
    digitalWrite(RM1, LOW);
    digitalWrite(RM2, LOW);
}
 
void turn_right()                                     //function to turn the robot right
{
    digitalWrite(LM1, LOW);
    digitalWrite(LM2, LOW);
    digitalWrite(RM1, HIGH);
    digitalWrite(RM2, LOW);
}
 
int readRangeFront()                                 //function to read the front sensor value
{
  delay(50);
  unsigned rangeFront = sonar[0].ping();
  sonar[0].timer_stop();
  return rangeFront;
}
int readRangeWall()                                 // function to read the left sensor value
{
  delay(50);
  unsigned rangeWall = sonar[1].ping();
  sonar[1].timer_stop();
  return rangeWall;
}


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