ABSTRACT

The project is design to build an obstacle avoidance robotic vehicle using

ultrasonic sensors powered by solar power for its movement. A microcontroller
(ATmega328) is used to achieve the desired operation. A robot is a machine that
can perform task automatically or with guidance. The project proposes robotic
vehicle that has an intelligence built in it such that it directs itself whenever an
obstacle comes in its path. This robotic vehicle is built, using a micro-controller of
AT mega 328 family. An ultrasonic sensor is used to detect any obstacle ahead of
it and sends a command to the micro-controller. Depending on the input signal
received, the micro-controller redirects the robot to move in an alternate
direction by actuating the motors which are interfaced to it through a motor
driver. Some of the project is built with the IR sensors has its own application so
in our project those application is not compactable so we are using ultrasonic
sensor.

Key words – Arduino UNO, motor shield L293d, ultrasonic sensor HC-SR04, DC
Motor,Solar panel,Battery.
 INTRODUCTION
Obstacle avoidance Robot is designed in order to navigate the robot in unknown
environment by avoiding collisions. Obstacle avoiding robot senses obstacles in the path,
avoid it and resumes its running. There are some very popular methods for robot navigation
like wall-following, edge detection, line following and many more. A more general and
commonly employed method for obstacle avoidance is based on edge detection. A
disadvantage with obstacle avoidance based on edge detecting is the need of the robot to
stop in front of an obstacle in order to provide a more accurate measurement. All mobile
robots feature some kind of collision avoidance, ranging from primitive algorithms that
detect an obstacle and stop the robot in order to avoid a collision, using some sophisticated
algorithms that enable the robot to detour obstacles. The latter algorithms are more
complex, since they involve detection of an obstacle as well as some kind of quantitative
measurements concerning the obstacle's dimensions. Once these have been determined, the
obstacle avoidance algorithm needs to steer the robot around the obstacle and resume
motion toward the original target. The steering algorithm ensures that the robot does not
have to stop in front of an obstacle during its navigation. An ultrasonic sensor is used to
detect any obstacle ahead of it and sends a command to the micro-controller. Hence the
robots may overcome some of the problems during navigation, which are discussed above
and it can navigate smoothly during its operation avoiding the collisions. if we were use the
IR sensor Infrared sensors detect the object's distance with infrared radiation. When the
beam detects an object, the light beam returns to the receiver with an angle after reflection
there is a limitations in sensor those limitations are Performance of IR sensors has been
limited by their poor tolerance to light reflections such as ambient light or bright object
colors. No object recognition at the dead zone area, for example Sharp GP2D12 IR distance
sensor dead zone between 0 to 4 cm. IR sensors also give inaccurate detection result with
transparent or bright color materials. Detection results also depend on the weather
conditions and the sensing reliability of IR sensors decreases with moisture and humidity.
Furthermore, IR sensors can sense IR radiation from the sunlight, which can cause
correctable or non-correctable errors at output. Besides that, if analogue IR sensor is used,
signal losses will occur at the amplifier circuit. Meanwhile, PIR motion sensor needs a long
calibration time and is sensitive to thermal radiation. Besides that, PIR sensor is insensitive to
very slow motions or to objects in standing mode .

EXISTING SYSTEM

The obstacle avoiding robots are introduced by using IR sensor with limited speed and
powered with only motor batteries.

DRAWBACKS OF EXISTING SYSTEM

 Infrared sensors can’t work in dark environments while Ultrasonic Sensors can.
 Brighter surfaces are easier to detect for Infrared than dark surfaces, as the sensor
doesn’t detect darker surfaces. Infrared sensor values normally fluctuate in variant
light conditions.
 There are a lot of limitations in infrared sensors, like the inability to use them in
sunlight due to interference. It can make outdoor applications or dark indoor
applications very difficult.

 Use of renewable energy like solar power is not promoted when using motor batteries
to power the robot.
 LITERATURE SURVEY
Literature survey is the survey of existing work done by different groups or teams which can
be taken as a base for the proposed model or system.

Obstacle avoidance solar robot using ultrasonic sensor and Arduino is designed to to create
an autonomous robot which intelligently detects the obstacle in its path and navigates
according to the actions that user set for it. So this system provides an alternate way to the
existing system by replacing skilled labor with robotic machinery, which in turn can handle
more patients in less time with better accuracy and a lower per capita cost. industrial
implementation. Students can use it to learn the microcontroller programming using C++,
Arduino Uno compiler, ultra sonic sensors characteristics, motor driving circuit and signal
condition circuit design. Research on obstacle avoidance robot at the polytechnic level can
help students to develop communication, technical skills and teamwork. The design of such
robot is very flexible and various methods can be adapted for another implementation. It
shows that PIR sensors are more sensitive compared to IR sensors while detecting human
being.

 The robot is equipped with low-resolution optical sensors and electronic compass and
is driven by stepper motor. Thus, there are three guidance modes: target tracking
using optical sensors, directional guidance using compass, and dead reckoning. There
are another optical sensors equipped on board to detect obstacles. The vehicle is
controlled based on the information from these sensors. In the proposed technique,
the control algorithm is switched to wall following mode when facing an obstacle. This
technique is very simple but efficient. Several simulation and experiments
demonstrate good performance even though using low-resolution sensors.
 A navigation technique for a sonar- equipped mobile robot with real-time local map-
building in unknown environments. A navigation algorithm is constructed with the
proposed local map-building and reactive obstacle avoidance behaviours. The
 obtained local map could be used to build and/or update a global map of the
environment. It is used to plan a desirable path for the next run. In navigation
experiments using a commercial mobile robot named Pioneer-I, the built local map
was effective for navigation in several environments compared to a reactive navigation
technique without map-building, especially in complicated environments.
 Autonomous airborne systems have generated a lot of interest in civilian and military
applications. The operation of such systems involves routing and navigation toward
targets and obstacle avoidance. In this paper, these problems were tackled and
solutions were applied to land-based robots as well as a quad-rotor aerial system. The
quad-rotor flight path navigation and routing was programmed based on GPS and
onboard measurement data. Obstacle avoidance was implemented based on an
algorithm that relies on the idea of Virtual Potential field. Kalman filters were
implemented to improve the accuracy of the measured data. While 3D visualization
was used to visually identify obstacles. In the case of in-building reconnaissance,
where GPS signals are very weak and largely useless, we rely on laser sensors and data
aggregation from proximity feeds to identify obstacles and the shape of the
surrounding environment.
 The Mobile robot software system integrated with a prediction algorithm based on
potential field algorithms were used to improve the robot’s navigation. The developed
software system was tested, and the result was compared with and without the
prediction software system. The final results showed improvement of the navigation
compared to the different sensors such a sonar sensor.
 Ultrasonic sensors are adopted to implement a real-time obstacle avoidance system
for wheeled robots, so that the robot can continually detect surroundings, avoid
obstacles, and move toward the target area. Secondly, six ultrasound sensors installed
on the wheeled robot were utilized to detect large obstacles and to obtain distance
information between the robot and the obstacle. The PD controller was used in the
 wall-following method to achieve the optimized path design. Experimental results
verified that ultrasonic sensors of the obstacle avoidance system on the wheeled
robot, with ATMega162 embedded microcontroller as the core of the system, can
indeed help avoid obstacles and reach the established target area.
 Utilizing advanced sensors such laser, sonar, and camera integrated with intelligent
software system will make the mobile robot more intelligent and increase the degree
of freedom to perform very sophisticated robotics tasks. In this paper, using the Mat
lab platform to build a mobile robot in a virtual reality equipped with laser sensor as
the only source of perception to navigate in a dynamic environment was developed.
 Mobile robots have the capability to navigate in the environment. We need some
approaches for their collision-free and stable navigation. Authors have given their own
algorithm and have implemented in C- language to move a robot from initial to final
position. They have also shown the comparison in path length required by robot with
the model proposed by Sir Parhi et al. in 2009.
 METHODLOGY

The basic block diagram for the implementation of the project is as shown in figure1.

Fig. 1. Block Diagram of the system

The sonar system is used in HC-SR04 ultrasonic sensor to determine distance to an object like
bats do. It offers excellent non-contact range detection from about 2 cm to 400 cm or 1feet
to 13 feet. Its operation is not affected by sunlight or black material. The ultrasonic sensor
emits the short and high frequency signal. If they detect any object, then they reflect back
echo signal which is taken as input to the sensor through Echo pin .Firstly user initialize
Trigger and Echo pin as low and push the robot in forward direction. When obstacle is
detected Echo pin will give input as high to microcontroller. Pulse In function is used for
calculating the time of distance from the obstacle. Every time the function waits for pin to go
high and starts timing, then timing will be stopped when pin go to low. It returns the pulse
length in microseconds or when complete pulse was not received within the timeout it
returns. The timing has been determined means it gives length of the pulse and will show
errors in shorter pulses. Pulses from 10microseconds to 3 minutes in length are taken into
consideration. After determining the time, it converts into a distance. If the distance of
object is moderate then speed of robot get reduced and will take left turn, If obstacle is
present in left side then it will take right turn. If the distance of object is short then speed of
robot get reduced and will turn in backward direction and then can go in left or right
direction. This robot was built with an Arduino development board on which microcontroller
is placed. Arduino board is connected with DC Motor through Motor driver board (pin10,
pin11, pin12, pin13) which provides power to the actuators. Actuators are used to move
robot in Forward, Backward, Left and Right directions. The brief description of inputs pins for
movement of robot is given in below in table. The movement of robot will be stop whenever
there is an obstacle is present on its path which can be detected by ultrasonic sensors.
Ultrasonic sensors give time in length to the microcontroller as an input for further actions.

APPLICATIONS
 Used in mobile robot navigation systems
 Used for household work like automatic vacuum cleaning
 Used in dangerous environments, where human penetration could be fatal.
 Automatic change over’s of traffic signals
 Intruder alarm system
 Counting instruments access switches parking meters
 Back sonar of automobiles
 FLOW CHART
Figure 3. shows the Flow Chart of the working of the obstacle avoidance robot. Initially it
checks obstacle within 70cm.If there is an obstacle it stops moving and turns towards left
and checks if there is an object closer than 370cm . The check has two possible outcomes,
yes or no. Yes, meaning that there is indeed some object closer than 70 cm. No, meaning
that there is no objects detected within 30cm. If there is nothing within 70 cm the robot can
simply move forward as the path is clear. If there is something closer than 70 cm the robot
must perform obstacle avoidance .The first stage of obstacle avoidance is to stop the robot!
If you don't stop the robot immediately it will crash! After the robot has stopped it needs to
see what way it should go. It does this by looking both directions, much like you should when
you cross the road. First the robot turns left, takes a reading, turns right, and takes a reading.
Another check occurs to see what direction is the best way to go. If left is the way to go it has
to turn back to the left and then go forward. If right is the way to go the robot simply moves
forward as it is already facing in the right direction.
 SYSTEM ARCHITECTURE
Component Description:-
Arduino Uno:-

Arduino Uno is an AT mega 328p Microcontroller based prototyping board. It is an open

source electronic prototyping platform that can be used with various sensors and actuators.
Arduino Uno has 14 digital I/O pins out of which 6 pins are used in this project.
ATmega328p PIN OUT
HC – SR04(ULTRASONIC SENSOR):-

The sonar system is used in HC-SR04 ultrasonic sensor to determine distance to an object like
bats do. It offers excellent non-contact range detection from about 2 cm to 400 cm or 1feet
to 13 feet. Its operation is not affected by sunlight or black material. The ultrasonic sensor
emits the short and high frequency signal. If they detect any object, then they reflect back
echo signal which is taken as input to the sensor through Echo pin .Firstly user initialize
Trigger and Echo pin as low and push the robot in forward direction. When obstacle is
detected Echo pin will give input as high to The ultrasonic sensor consists of a multi vibrator,
which fixed at its base. The multi vibrator is combination of a resonator and vibrator the
ultrasonic waves generated by the vibration are delivers to the resonator. Ultrasonic sensor
actually consists of two parts: the emitter which produces a 40 kHz sound wave and detector
which detects 40 kHz sound wave and sends electrical signal back to the microcontroller. HC-
SR04 ultrasonic sensors are used which consist of 4 pins VCC, Trigger, Echo and GND.

Features of Ultrasonic Sensor:-

Compact and light weight

 High sensitivity and high pressure

 High reliability

 Power consumption of 20Ma

 Pulse in/out communication

 Narrow acceptance angle

 Provides exact, non-contact separation

 estimations within 2cm to 3m The explosion point LED shows estimations in

 advancement 3-pin header makes it simple to connect utilizing

 a servo development link

Solar panel
L293D(Mototr Driver):-

L293D is a typical Motor driver or Motor Driver IC which allows DC motor to drive on either
direction. L293D is a 16-pin IC which can control a set of two DC motors simultaneously in
any direction. It means that you can control two DC motor with a single L293D IC. Dual H-
bridge Motor Driver integrated circuit (IC).

MotorDriver
CONCEPT:-

It works on the concept of H-bridge. H-bridge is a circuit which allows the voltage to be flown
in either direction. As you know voltage need to change its direction for being able to rotate
the motor in clockwise or anticlockwise direction, Hence H-bridge IC are ideal for driving a DC
motor.

In a single L293D chip there are two h-Bridge circuit inside the IC which can rotate two dc
motor independently. Due its size it is very much used in robotic application for controlling
DC motors. Given below is the pin diagram of a L293D motor controller.

There are two Enable pins on l293d. Pin 1 and pin 9, for being able to drive the motor, the
pin 1 and 9 need to be high. For driving the motor with left H-bridge you need to enable pin
1 to high. And for right H-Bridge you need to make the pin 9 to high. If anyone of the either
pin1 or pin9 goes low then the motor in the corresponding section will suspend working. It’s
like a switch.

Working of L293D:-

There are 4 input pins for l293d, pin 2,7 on the left and pin 15 ,10 on the right as shown on
the pin diagram. Left input pins will regulate the rotation of motor connected across left side
and right input for motor on the right hand side. The motors are rotated on the basis of the
inputs provided across the input pins as LOGIC 0 or LOGIC 1.

In simple you need to provide Logic 0 or 1 across the input pins for rotating the motor.

L293D Logic Table:-

Lets consider a Motor connected on left side output pins (pin 3,6). For rotating the motor in
clockwise direction the input pins has to be provided with Logic 1 and Logic 0.

• Pin 2 = Logic 1 and Pin 7 = Logic 0 | Clockwise Direction

• Pin 2 = Logic 0 and Pin 7 = Logic 1 | Anticlockwise Direction
• Pin 2 = Logic 0 and Pin 7 = Logic 0 | Idle [No rotation] [Hi-Impedance state]
• Pin 2 = Logic 1 and Pin 7 = Logic 1 | Idle [No rotation]
Voltage Specification:-

VCC is the voltage that it needs for its own internal operation 5v; L293D will not use this
voltage for driving the motor. For driving the motors it has a separate provision to provide
motor supply VSS (V supply). L293d will use this to drive the motor. It means if you want to
operate a motor at 9V then you need to provide a Supply of 9V across VSS Motor supply.

The maximum voltage for VSS motor supply is 36V. It can supply a max current of 600mA per
channel.Since it can drive motors Up to 36v hence you can drive pretty big motors with this
l293d.