Obstacle Avoidance Robot

JAIPUR ENGINEERING COLLEGE AND
RESEARCH CENTER, JAIPUR
PRESENTATION ON
Obstacle Avoidance Robot
SUBMITTED TO: SUBMITTED BY:
Mr. Rajesh Bhatija Yash Kumar Sati
Ms. S.K Singh
Submitted in partial fulfillment for the award of Degree of Bachelor of Technology of
Rajasthan Technical University, Kota

OVERVIEW
 What is Obstacle Avoidance Robot?
 What is a Sensor?
 Introduction to Ultrasonic Sensor?
 How does Ultrasonic Sensor works?
 Ultrasonic Sensor connections.
 Servo Motor.
 Servo Motor connections.
 Algorithm for Obstacle Avoidance Robot.
 Obstacle Avoidance Robot:
 Connections.
 Working.
 Applications.
1

WHAT IS OBSTACLE AVOIDANCE ROBOT?
 Obstacle avoidance is a means of a robot being able to move around in
an unknown environment without colliding with surrounding objects.
Fig. Pictorial demonstration of obstacle avoidance
robot working.
2

WHAT IS A SENSOR?
 A sensor is a device that detects and responds to some type of input from
the physical environment.
 The specific input could be light, heat, motion, moisture, pressure.
 The output is generally a signal that is converted to human-readable
form.
3

INTRODUCTION TO ULTRASONIC SENSOR
 What is ultrasonic?
ULTRA – BEYOND & SONIC – SOUND
 The sound beyond human hearing range (20,000 Hz) is known as
ultrasonic.
 Ultrasonic sensor?
 Ultrasonic sensors are the sensors that convert ultrasound waves to
electrical signals or vice-versa.
Fig. HC-SR04 Ultrasonic Sensor. 4

HOW DOES ULTRASONIC SENSOR WORKS?
 How does a bat sense distance?
 Bats sense distance using sound.
 They emit sound waves and receive back reflected waves.
 The time it takes to receive the waves back provides them with a very
good estimate of the distance.
This is exactly how ultrasonic sensors estimate distance.
Fig. Analogy explaining how does ultrasonic sensor works.
5

 An ultrasonic sensor has 2 parts:
TRANSMITTER & RECEIVER
 A transmitter that sends out a signal that humans cannot hear.
 A receiver that receives the signal after it has bounced off nearby objects.
 The sensor sends out its signal and determines how long the signal takes
to come back.
Fig. Ultrasonic sensor working.
6

 If the object is very close to the sensor, the signal comes back quickly.
 If the object is far away from the sensor, the signal takes longer to come
back.
 If the object is too far away from the sensor, the signal takes so long to
come back (or is weak when it comes back) that the receiver cannot
detect it.
Fig. Ultrasonic sensor working. 7

ULTRASONIC SENSOR CONNECTIONS
RED – POWER, YELLOW – SIGNAL & BLACK – GROUND
Fig. Ultrasonic sensor HC-SR04
with each color wires.
Fig. Ultrasonic sensor structure.
8

SERVO MOTOR
 What is a servo motor?
 A servo motor is a rotary actuator or linear actuator that allows for
precise control of angular or linear position, velocity and acceleration.
 It consist of a suitable motor coupled to a sensor for position feedback.
Fig. Servo motor.
9

SERVO MOTOR CONNECTIONS
 Servo motors have three wires:
RED, BLACK & YELLOW or ORANGE
 Red wire: Power wire (connected to the 5V pin on the Arduino board)
 Black wire: Ground (connected to a ground pin on the Arduino board)
 Yellow wire: Signal pin (connected to a digital pin on Arduino board)
Fig. Servo motor connections.
10

ALGORITHIM FOR OBSTACLE AVOIDANCE
ROBOT
11

CONNECTIONS
Fig. Obstacle avoidance robot using Arduino circuit.
12

WORKING
 Before going to working of the project, it is important to understand how
the ultrasonic sensor works. The basic principle behind the working of
ultrasonic sensor is as follows:
 Using an external trigger signal, the Trig pin on ultrasonic sensor is
made logic high for at least 10µs. A sonic burst from the transmitter
module is sent. This consists of 8 pulses of 40KHz.
 The signals return back after hitting a surface and the receiver detects
this signal. The Echo pin is high from the time of sending the signal and
receiving it. This time can be converted to distance using appropriate
calculations.
 The aim of this project is to implement an obstacle avoiding robot using
ultrasonic sensor and Arduino. All the connections are made as per the
circuit diagram. The working of the project is explained below:
 When the robot is powered on, both the motors of the robot will run
normally and the robot moves forward. During this time, the ultrasonic
sensor continuously calculate the distance between the robot and the
reflective surface. 13

 This information is processed by the Arduino. If the distance between
the robot and the obstacle is less than 15cm, the Robot stops and scans
in left and right directions for new distance using Servo Motor and
Ultrasonic Sensor. If the distance towards the left side is more than that
of the right side, the robot will prepare for a left turn. But first, it backs
up a little bit and then activates the Left Wheel Motor in reversed in
direction.
 Similarly, if the right distance is more than that of the left distance, the
Robot prepares right rotation. This process continues forever and the
robot keeps on moving without hitting any obstacle.
Formula for distance measurement:
Distance = (Time x Speed Of Sound) / 2
14

APPLICATIONS
 Self-Driving cars.
 In army applications like sonar system.
 In household application like cleaning robots etc.
 In children toys.
Fig. Demonstration of robot in household applications.
15

REFERENCES
 www.google.com (Google)
 www.images.google.com (Google Images)
 www.electronicshub.org (Electronics Hub)
 www.wikipedia.com (Wikipedia)
 www.flaticon.com (Flaticon)

Obstacle Avoidance Robot

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