How to make obstacle avoiding robot using Arduino & Ultrasonic sensor ?

So you wanna build a robot which never hits anything; you’ve come to the right place ! It barely takes 15 minutes to do this ! So without wasting our time let’s learn how to make an obstacle avoiding robot !

Requirements :-

Chassis OR any toy car.
Arduino UNO/Mega.
Ultrasonic sensor HC SR-04.
2 DC motors.
9V/12V 1A battery.
Motor driver module L298.
Jumpers.
Single stranded wires.
A pizza slice & a can of beer to celebrate 😉

Procedure :-

So yes, I’m going to divide the whole making into 4 parts –

Connections of Ultrasonic sensor → Connections of L298N → Code → Testing

If you haven’t used or experimented before with the ultrasonic sensor, I would suggest you to get familiar with it first ! I have a detail tutorial on ultrasonic sensor HC SR-04 which will guide you throughout !

Here is detailed Tutorial on Ultrasonic Sensor HC-SR04

Connections :-

Connections of Ultrasonic sensor –

VCC – VCC terminal of Arduino.
GND – GND terminal of Arduino.
Trigpin – digital pin 9 on Arduino.
Echo pin – digital pin 10 on Arduino.

Connections of L298N –

+12V – Positive terminal of the battery.
GND – a)GND of Arduino b)Negative terminal of battery.
Input terminal 1 – Pin 4
Input terminal 2 – Pin 5
Input terminal 3 – Pin 6
Input terminal 4 – Pin 7
Output terminal 1 – Positive of first motor.
Output terminal 2 – Negative of first motor.
Output terminal 3 – Positive of second motor.
Output terminal 4 – Negative of second motor.

Coding :-

int trigPin = 9;
int echoPin = 10;
int revright = 4;      //REVerse motion of Right motor
int fwdleft = 7;      
int revleft= 6;       
int fwdright= 5;       //ForWarD motion of Right motor
int c = 0;

void setup() {
  //Serial.begin(9600); 
   pinMode(5, OUTPUT);
   pinMode(6, OUTPUT);
   pinMode(4, OUTPUT);
   pinMode(7, OUTPUT);
   pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  // put your setup code here, to run once:

}

void loop() {
  long duration, distance;
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration=pulseIn(echoPin, HIGH);
  distance =(duration/2)/29.1;
  //Serial.print(distance);
  //Serial.println("CM");
  delay(10);
 
  
  if((distance>20))
 {
  digitalWrite(5,HIGH);                               //       If you dont get proper movements of your robot,
   digitalWrite(4,LOW);                               //        then alter the pin numbers
   digitalWrite(6,LOW);                               //
   digitalWrite(7,HIGH);                              //
 }
 
  else if(distance<20)  
 {
   digitalWrite(5,HIGH);
   digitalWrite(4,LOW);
   digitalWrite(6,HIGH);                                  //HIGH
   digitalWrite(7,LOW);
                                            
 }
 
}

int trigPin = 9;

int echoPin = 10;

int revright = 4; //REVerse motion of Right motor

int fwdleft = 7;

int revleft= 6;

int fwdright= 5; //ForWarD motion of Right motor

int c = 0;

void setup() {

//Serial.begin(9600);

pinMode(5, OUTPUT);

pinMode(6, OUTPUT);

pinMode(4, OUTPUT);

pinMode(7, OUTPUT);

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

// put your setup code here, to run once:

}

void loop() {

long duration, distance;

digitalWrite(trigPin,HIGH);

delayMicroseconds(1000);

digitalWrite(trigPin, LOW);

duration=pulseIn(echoPin, HIGH);

distance =(duration/2)/29.1;

//Serial.print(distance);

//Serial.println("CM");

delay(10);

if((distance>20))

{

digitalWrite(5,HIGH); // If you dont get proper movements of your robot,

digitalWrite(4,LOW); // then alter the pin numbers

digitalWrite(6,LOW); //

digitalWrite(7,HIGH); //

}

else if(distance<20)

{

digitalWrite(5,HIGH);

digitalWrite(4,LOW);

digitalWrite(6,HIGH); //HIGH

digitalWrite(7,LOW);

}

Testing :-

If the distance detected by the ultrasonic sensor is less than 25cm, then the bot will take a turn else, it will keep moving straight ! Simple… right ?

Well, here is a video tutorial which will make your job more easy !

Do I need to say this, NO… but anyway I will,

If you have any problem regarding connections or coding or during interfacing, all you have to do is comment down below OR contact me 🙂 I’ll very happy to help you

MechStuff