How to make a Line Follower Robot Which Stops at an Obstacle

1#include <Ultrasonic.h> //This calls upon the libray for the Ultrasonic   sensor
2
3Ultrasonic ultrasonic (9, 10);/*Says that the Trig pin is pin 9 and   the Echo pin is pin 10. It also gives the sensor a name. In this case, the name   is ultrasonic.*/
4
5const int right_irsensor = 8;/*Says that the right IR sensor   is connected to pin 8. const is for saying that it will always be connected to pin   8. int is for integer. 8 is an integer, so we use int. After int, a variable or   a constant is declared. In this case, it is a constant. A variable can change values   while a constant cannot.*/
6const int left_irsensor = 7;
7const int motor_rightFront   = 3;//the wire of the right motor which controls its forward motion is connected   to pin 3
8const int motor_rightBack = 2;//the wire of the motor which controls   its backward motion is connected to pin 3
9const int motor_leftFront = 5;//The   varables can be named however you want. I decided to go along with simple names.
10const   int motor_leftBack = 4;
11int x;
12int y;/*x and y are two variables that I will   be using in order to declare inputs and outputs. This method is not necessary, but   it is easier than the conventional method*/
13
14void setup() {
15// put your   setup code here, to run once:
16Serial.begin(9600);
17for(x = 2; x<6; x++){//As   long as x starts at 2 and increases by 1 each time and remains less than 6. In other   words, pins 1 to 5.
18pinMode(x, OUTPUT);/*Declaring x as an output. The pinMode()   function is used to do this. In short, pins 2 to 5 are outputs. This makes sense   since motors are control devices, to which commands are given.*/
19}
20for(y=7;   y<9 ; y++){
21pinMode(y, INPUT);//The two IR sensors are declared as inputs. The   sensors give values, so this also makes sense.
22}
23}
24
25void loop() {
26//   put your main code here, to run repeatedly:
27int right_sensor = digitalRead(right_irsensor);/*declaring   a variable called right_sensor to take the reading from the right IR sensor. We   are using digitalRead() since it is only a white and black surface. It will read   LOW for black and HIGH for white.*/
28int left_sensor = digitalRead(left_irsensor);
29int   reading = ultrasonic.read();//Declaring a variable for the Ultrasonic sensor to   read. Here, the name you gave to the sensor has to be used for the command. So,   <your name>.read
30if(reading>29){ //If the reading is more than 29 cm, then the   robot can run.
31if(right_sensor == HIGH && left_sensor == LOW){/*The right sensor   detects white and the left sensor detects black.*/
32left();//turn left. 
33}
34if(right_sensor   == LOW && left_sensor == HIGH){
35right();
36}
37if(right_sensor == LOW && left_sensor   == LOW){
38yay();
39}
40if(right_sensor == HIGH && left_sensor == HIGH){
41forward();
42}
43}
44else{
45yay();//if   it is not more than 29 cm, then it will stop. yay() is defined as a function below.   
46}
47}
48
49void right(){//void is used to define functions. This function   will make the robot turn right.
50/*digitalWrite() is used to make things work   or stop based on digital signals given to it in the form of HIGH and LOW.HIGH is   to make something work while LOW is to stop it.*/ 
51digitalWrite(motor_rightFront,   LOW);//make the right motor stop moving forward
52digitalWrite(motor_rightBack,LOW   );//make the right motor stop moving backward
53digitalWrite(motor_leftFront, LOW);//make   the left motor stop moving forward
54digitalWrite(motor_leftBack, HIGH);//make   the left motor stop moving backward
55}
56
57void left(){
58digitalWrite(motor_rightFront,   LOW);
59digitalWrite(motor_rightBack, HIGH);
60digitalWrite(motor_leftFront, LOW);
61digitalWrite(motor_leftBack,   LOW);
62
63}
64
65void forward(){
66digitalWrite(motor_rightFront, LOW);
67digitalWrite(motor_rightBack,   HIGH);
68digitalWrite(motor_leftFront, LOW);
69digitalWrite(motor_leftBack, HIGH);
70
71}
72
73void   yay(){ //This is to make it stop. stop is a function on its own, so I could not   name this function stop.
74digitalWrite(motor_rightFront, LOW);
75digitalWrite(motor_rightBack,   LOW);
76digitalWrite(motor_leftFront, LOW);
77digitalWrite(motor_leftBack, LOW);
78}
79
80void   backward(){
81digitalWrite(motor_rightFront, HIGH);
82digitalWrite(motor_rightBack,   LOW);
83digitalWrite(motor_leftFront, HIGH);
84digitalWrite(motor_leftBack, LOW);
85}

1#include <Ultrasonic.h> //This calls upon the libray for the Ultrasonic  sensor
2
3Ultrasonic ultrasonic (9, 10);/*Says that the Trig pin is pin 9 and  the Echo pin is pin 10. It also gives the sensor a name. In this case, the name  is ultrasonic.*/
4
5const int right_irsensor = 8;/*Says that the right IR sensor  is connected to pin 8. const is for saying that it will always be connected to pin  8. int is for integer. 8 is an integer, so we use int. After int, a variable or  a constant is declared. In this case, it is a constant. A variable can change values  while a constant cannot.*/
6const int left_irsensor = 7;
7const int motor_rightFront  = 3;//the wire of the right motor which controls its forward motion is connected  to pin 3
8const int motor_rightBack = 2;//the wire of the motor which controls  its backward motion is connected to pin 3
9const int motor_leftFront = 5;//The  varables can be named however you want. I decided to go along with simple names.
10const  int motor_leftBack = 4;
11int x;
12int y;/*x and y are two variables that I will  be using in order to declare inputs and outputs. This method is not necessary, but  it is easier than the conventional method*/
13
14void setup() {
15// put your  setup code here, to run once:
16Serial.begin(9600);
17for(x = 2; x<6; x++){//As  long as x starts at 2 and increases by 1 each time and remains less than 6. In other  words, pins 1 to 5.
18pinMode(x, OUTPUT);/*Declaring x as an output. The pinMode()  function is used to do this. In short, pins 2 to 5 are outputs. This makes sense  since motors are control devices, to which commands are given.*/
19}
20for(y=7;  y<9 ; y++){
21pinMode(y, INPUT);//The two IR sensors are declared as inputs. The  sensors give values, so this also makes sense.
22}
23}
24
25void loop() {
26//  put your main code here, to run repeatedly:
27int right_sensor = digitalRead(right_irsensor);/*declaring  a variable called right_sensor to take the reading from the right IR sensor. We  are using digitalRead() since it is only a white and black surface. It will read  LOW for black and HIGH for white.*/
28int left_sensor = digitalRead(left_irsensor);
29int  reading = ultrasonic.read();//Declaring a variable for the Ultrasonic sensor to  read. Here, the name you gave to the sensor has to be used for the command. So,  <your name>.read
30if(reading>29){ //If the reading is more than 29 cm, then the  robot can run.
31if(right_sensor == HIGH && left_sensor == LOW){/*The right sensor  detects white and the left sensor detects black.*/
32left();//turn left. 
33}
34if(right_sensor  == LOW && left_sensor == HIGH){
35right();
36}
37if(right_sensor == LOW && left_sensor  == LOW){
38yay();
39}
40if(right_sensor == HIGH && left_sensor == HIGH){
41forward();
42}
43}
44else{
45yay();//if  it is not more than 29 cm, then it will stop. yay() is defined as a function below.  
46}
47}
48
49void right(){//void is used to define functions. This function  will make the robot turn right.
50/*digitalWrite() is used to make things work  or stop based on digital signals given to it in the form of HIGH and LOW.HIGH is  to make something work while LOW is to stop it.*/ 
51digitalWrite(motor_rightFront,  LOW);//make the right motor stop moving forward
52digitalWrite(motor_rightBack,LOW  );//make the right motor stop moving backward
53digitalWrite(motor_leftFront, LOW);//make  the left motor stop moving forward
54digitalWrite(motor_leftBack, HIGH);//make  the left motor stop moving backward
55}
56
57void left(){
58digitalWrite(motor_rightFront,  LOW);
59digitalWrite(motor_rightBack, HIGH);
60digitalWrite(motor_leftFront, LOW);
61digitalWrite(motor_leftBack,  LOW);
62
63}
64
65void forward(){
66digitalWrite(motor_rightFront, LOW);
67digitalWrite(motor_rightBack,  HIGH);
68digitalWrite(motor_leftFront, LOW);
69digitalWrite(motor_leftBack, HIGH);
70
71}
72
73void  yay(){ //This is to make it stop. stop is a function on its own, so I could not  name this function stop.
74digitalWrite(motor_rightFront, LOW);
75digitalWrite(motor_rightBack,  LOW);
76digitalWrite(motor_leftFront, LOW);
77digitalWrite(motor_leftBack, LOW);
78}
79
80void  backward(){
81digitalWrite(motor_rightFront, HIGH);
82digitalWrite(motor_rightBack,  LOW);
83digitalWrite(motor_leftFront, HIGH);
84digitalWrite(motor_leftBack, LOW);
85}