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CHAPTER-1

INTRODUCTION

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1.1 Introduction to Robotics

Robotics is the branch of mechanical engineering, electrical engineering and computer

science that deals with the design, construction, operation, and application of robots, as

well as computer systems for their control, sensory feedback, and information processing.

It may be human controlled or automatic.

1.2 Problem Statement

Nowadays, robotic technologies have become more important since a lot of industry is

trying to improve their machinery weapons. This technology has developed year by year

to make sure an excellent result. Recently, by time goes by, a lot of mechanical robots

have been invented to help peoples running their daily life.

Obstacles Avoidance Mobile Robot is actually a simple collision avoidance machines.

Besides that, its future development is very big to explore. By using this simple collision

avoidance system, a lot of new and variety mobile robot with multiple functions can be

invented. Real-time obstacle avoidance is one of the key issues to successful applications

of mobile robot systems. All mobile robots feature some kind of collision avoidance,

ranging from primitive algorithms that detect an obstacle and steer the robot short of it in

order to avoid a collision, through sophisticated algorithms, that enable the robot to

detour obstacles. The latter algorithms are much more complex, since they involve not

only the detection of an obstacle, but also 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.

1.3 Objective of this Project

The main objectives of this project are:

i. To design a mobile robot with an ability to avoid obstacle.

ii. To develop a mobile robot using microcontroller and control it with Smartphone via

Bluetooth technology.

1.4 Report Outline

We will discuss the design of the robot in Chapter 2. The implementation and some

required components are presented in Chapter 3. The design is presented in Chapter 4.

The results are discussed in Chapter 5. Finally, the report concludes in Chapter 6.

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CHAPTER-2

DESIGN OF THE ROBOT

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2.1 Introduction

Robotics is becoming a very important part of our lives. The design process is changing

rapidly as the demand increases. So in this chapter we will describe the robotics design,

block diagram, Algorithm and its component‟s description.

2.2 Block Diagram of the Project

Figure 2.1: Block Diagram of the project

2.3 Required Components

SL/N

Name of components

01 ATmega8 microcontroller

02 L293D (Motor Driver IC)

03 Voltage regulator 7805 IC

04 Heat sink

05 Battery

06 HC-05 Bluetooth module

07 LED

Android phone

with app Bluetooth

Power supply

Voltage

regulator

Atmega8

micro

controller

Motor

L293D IC

Motor

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08 Resistor

09 Switch

10 Capacitor

11 2 DC Motor

12 2 wheel

13 PCB board

14 Connecting Wire

15 Crystal

2.4 7805 Voltage Regulator IC

A voltage regulator is designed to automatically maintain a constant voltage level.

A voltage regulator may be a simple "feed-forward" design or may include negative

feedback control loops. It may use an electromechanical mechanism, or electronic

components

Figure 2.2: Typical Voltage Regulator IC

Referring to the figure 2.2, voltage regulator is used to provide regulated 5V to power the

PIC16F877A microcontroller. This is very essential since the microcontroller will blow if

the voltage supplied to it is exceeding its voltage rating.

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Figure 2.3: Circuitry of Voltage Regulator IC

Voltage regulators comprise a class of widely used ICs. Regulator IC units

contain the circuitry for reference source, comparator amplifier, control device and

overload protection all in a single IC. Although the internal construction of the IC is

somewhat different from that described for discrete voltage regulator circuits, the external

operation is much the same. IC unit provide regulation of a fixed positive voltage, a fixed

negative voltage or an adjustably set voltage. A power supply can be built using a

transformer connected to the ac supply line to step the ac voltage to desired amplitude,

then rectifying that ac voltage, filtering with a capacitor and RC filter, if desired, and

finally regulating the dc voltage using an IC regulator. The regulators can be selected for

operation with load currents from hundreds of mill-amperes to tens of amperes,

corresponding to power

2.5 HC-05 Bluetooth

Figure 2.4: HC-05 Bluetooth

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2.5.1 Overview

HC‐05 module is an easy to use Bluetooth SPP (Serial Port Protocol) module,

designed for transparent wireless serial connection setup. Serial port Bluetooth module is

fully qualified Bluetooth V2.0+ EDR (Enhanced Data Rate) 3Mbps Modulation with

complete 2.4GHz radio transceiver and baseband. It uses CSR Blue core 04 External

single chip Bluetooth systems with CMOS technology and with AFH (Adaptive

Frequency Hopping Feature). It has the footprint as small as 12.7mmx27mm. Hope it will

simplify your overall design/development cycle.

2.5.2 Specifications:

2.5.2.1 Hardware features

Typical ‐80dBm sensitivity.

Up to +4dBm RF transmits power.

Low Power 1.8V Operation, 3.3 to 5 V I/O.

PIO control.

UART interface with programmable baud rate.

With integrated antenna.

With edge connector.

2.5.2.2 Software features

Slave default Baud rate: 9600, Data bits: 8, Stop bit: 1, Parity: No parity.

PIO9 and PIO8 can be connected to red and blue led separately. When

Master and slave are paired, red and blue led blinks 1time/2s in interval, while

disconnected only blue led blinks 2times/s.

Auto‐connect to the last device on power as default.

Permit pairing device to connect as default.

Auto‐pairing PINCODE:”1234” as default.

Auto‐reconnect in 30 min when disconnected as a result of beyond the range of

connection.

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2.5.3 Pin out configuration of Bluetooth and microcontroller

Figure 2.5: Pin out configuration microcontroller and Bluetooth

2.5.4 Bluetooth Wireless Navigation

HC-06 / HC-05 Bluetooth module is used to receive data from android based

device.

After pairing (connecting) the Bluetooth module with android phone or tablet,

open the application and connect to the paired device HC-06 or HC-05.

Android application will send letters „F‟, „B‟, „R‟ and „L‟ to move robot

forward, backward, right and left respectively.

These are received by the Bluetooth receiver; those letters are available in TX

pin of HC-06.

TX pin of Bluetooth module is connected to RX pin (26) of PIC

microcontroller, which receives information from the Bluetooth module.

That information is used as an interrupt to switch between user defined

functions that we have specified.

We have written different functions to perform assigned tasks viz Move

forward, backward, turn left and right. These functions will change the values

of pins RC0, RC1, RC2 and RC3. Wheel rotations are controlled by these

pins.

Here we are using IC L293D to drive wheel motor, which is capable of

driving 2 motors at a time.

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2.6 L293D Motor Driver IC

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).

It works on the concept of H-bridge. H-bridge is a circuit which allows the voltage to be

flown in either direction. As we 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 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 we 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.

2.6.1 Pin Diagram of L293D motor driver IC

Figure 2.6: 16 Pin Diagram of L293D

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2.6.2 Working of L293D

Here 4 input pins for this 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 we

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

2.6.3 L293D Logic Table

Let‟s 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]

In a very similar way the motor can also operated across input pin 15, 10 for motor on the

right hand side.

2.6.4 Circuit Diagram of L293D motor driver IC controller

Figure: 2.7: Circuit Diagram of L293D

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2.6.5 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.

VCC pin 16 is the voltage for its own internal Operation. The maximum voltage ranges

from 5v and up to 36v.

2.7 Capacitor

A capacitor is a passive two-terminal electrical component used to store energy

electro statically in an electric field. The forms of practical capacitors vary widely, but all

contain at least two electrical conductors separated by a dielectric (insulator). Capacitors

are widely used as parts of electrical circuits in many common electrical devices.

Figure 2.8: Physical View of Capacitor

When there is a potential difference across the conductors, an electric field

develops across the dielectric, causing positive charge to collect on one plate and

negative charge on the other plate. Energy is stored in the electrostatic field. An ideal

capacitor is characterized by a single constant value, capacitance. This is the ratio of the

electric charge on each conductor to the potential difference between them. The SI unit of

capacitance is the farad, which is equal to one coulomb per volt.

The capacitance is greatest when there is a narrow separation between large areas

of conductor; hence capacitor conductors are often called plates, referring to an early

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means of construction. In practice, the dielectric between the plates passes a small

amount of leakage current and also has an electric field strength limit, the breakdown

voltage. The conductors and leads introduce an undesired inductance and resistance.

A capacitor consists of two conductors separated by a non-conductive region. The

non-conductive region is called the dielectric. In simpler terms, the dielectric is just an

electrical insulator. Examples of dielectric media are glass, air, paper, vacuum, and even

a semiconductor depletion region chemically identical to the conductors. A capacitor is

assumed to be self-contained and isolated, with no net electric charge and no influence

from any external electric field. The conductors thus hold equal and opposite charges on

their facing surfaces, and the dielectric develops an electric field. In SI units, a

capacitance of one farad means that one coulomb of charge on each conductor causes a

voltage of one volt across the device.

An ideal capacitor is wholly characterized by a constant capacitance C, defined as the

ratio of charge ±Q on each conductor to the voltage V between them. C = Q/V, where C

is the capacitance in farad (F), Q is the electric charge in coulombs (C) and V is the

voltage between the capacitor‟s plates in volts (V).

2.7.1 Types of Capacitor

Types Feature

Variable capacitor Variable capacitor has changeable capacitor

Electrolyte capacitor Electrolytic capacitor are used when high

capacitance is needed .most of the electrolytic

capacitor are polarized.

Ceramic capacitor Ceramic capacitor has ceramic dielectric material

.has high voltage functionality.

Tantalum capacitor Tantalum oxide dielectric material. Has high

capacitance.

Spherical capacitor Spherical capacitor has a sphere shape.

Power capacitor Power capacitors are used in high voltage power

system.

Mica capacitor High accuracy capacitors.

Paper capacitor Paper dielectric material

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2.7.2 Capacitor Voltage Reference

Type J – Dipped Tantalum Capacitors.

Type K – Mica Capacitors.

Type L – Polyester/Polystyrene Capacitors

Type M – Electrolytic 4 Band Capacitors

Type N – Electrolytic 3 Band Capacitors.

2.7.3 104j Capacitor

In this project we have used type j (Dipped Tantalum Capacitors) capacitor

Figure 2.9: 104j Capacitor

2.7.4 Specification of 104j Capacitor

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2.8 Crystal oscillator

A crystal oscillator is an electronic oscillator circuit that uses the mechanical

resonance of a vibrating crystal of piezoelectric material to create an electrical signal with

a very precise frequency. This frequency is commonly used to keep track of time (as in

quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to

stabilize frequencies for radio transmitters and receivers. The most common type of

piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them

became known as crystal oscillators, but other piezoelectric materials including

polycrystalline ceramics are used in similar circuits.

Quartz crystals are manufactured for frequencies from a few tens of kilohertz to hundreds

of megahertz. More than two billion crystals are manufactured annually. Most are used

for consumer devices such as wristwatches, clocks, radios, computers, and cell phones.

Quartz crystals are also found inside test and measurement equipment, such as counters,

signal generators, and oscilloscopes.

Here we used a crystal of 12 MHz as clock oscillator for Microcontroller.

Figure 2.10: Crystal oscillator

2.9 Heat sink

In electronic systems, a heat sink is a passive heat exchanger that cools a device

by dissipating heat into the surrounding medium. In computers, heat sinks are used to

cool central processing units or graphics processors.

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Figure 2.11: Heat sink

2.10 Resistor

A resistor is a passive two-terminal electrical component that implements electrical

resistance as a circuit element.

The current through a resistor is in direct proportion to the voltage across the

resistor's terminals. This relationship is represented by Ohm's law: I = V/ R.

Where I is the current through the conductor in units of amperes, V is the

potential difference measured across the conductor in units of volts, and R is the

resistance of the conductor in units of ohms (symbol: Ω).

The ratio of the voltage applied across a resistor's terminals to the intensity of

current in the circuit is called its resistance, and this can be assumed to be a constant

(independent of the voltage) for ordinary resistors working within their ratings.

Figure 2.12: Physical view of Resistor

2.11 Mini DC Gear Motor and wheel

Mini DC Gear Motor is a cost-effective, high usability and quality motor by

Robot base, it can be used for program-controlled tracing robot car and wheel robot, also

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can do PWM control ,speed measurement combining Adriano-compatible controller and

DC Motor driver. In this project we used 2 DC motor.

Figure 2.13: Mini Dc motor and wheel, stearing wheel.

2.11.1 Specifications of DC motor

1. Gear ratios: 48:1

2. No-load speed (3V): 120RPM

3. No-load speed (6V): 240RPM

4. No-load current (3V): 40mA

5. No-load current (6V): 70mA

6. Block running current (3V): 390mA

7. Block running current (3V): 680mA

8. Torque size (3V): 3200mg * cm

9. Torque size (6V): 5500mg * cm

10. Size: 70.50 mm x 27.00 mm x 23.00 mm

11. Weight: about 40g

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2.12 LED

A light-emitting diode (LED) is a semiconductor device that emits visible light when an

electric current passes through it. The light is not particularly bright, but in most LEDs it

is monochromatic, occurring at a single wavelength. The output from an LED can range

from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400

nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a

device is known as an infrared-emitting diode (IRED).

An LED or IRED consists of two elements of processed material called P-type

semiconductors and N-type semiconductors. These two elements are placed in direct

contact, forming a region called the P-N junction. In this respect, the LED or IRED

resembles most other diode types, but there are important differences. The LED or IRED

has a transparent package, allowing visible or IR energy to pass through. Also, the LED

or IRED has a large PN-junction area whose shape is tailored to the application.

Benefits of LEDs and IREDs, compared with incandescent and fluorescent illuminating

devices, include:

Low power requirement: Most types can be operated with battery power supplies.

High efficiency: Most of the power supplied to an LED or IRED is converted into

radiation in the desired form, with minimal heat production.

Long life: When properly installed, an LED or IRED can function for decades.

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Figure 2.14: LED

2.13 Diode

A diode is a simple electrical device that allows the flow of current only in one direction.

So it can be said to act somewhat like a switch. A specific arrangement of diodes can

convert AC to pulsating DC; hence it is sometimes also called as a rectifier. It is derived

from "di-ode” which means a device having two electrodes. The symbol of a p-n junction

diode is shown below, the arrowhead points in the direction of conventional current flow.

Figure 2.15: Diode

2.13.1 Characteristic of Diode

The p-n junction is a basic building block in any semiconductor device. It is formed by

joining a p type (intrinsic semiconductor doped with a trivalent impurity) and n type

semiconductor (intrinsic semiconductor doped with a pentavalent impurity) together with

a special fabrication technique such that a p-n junction is formed. Hence it is a device

with two elements, the p-type forms anode and the n-type forms the cathode. These

terminals are brought out to make the external connections. Here we have used a

SCHOTTKY Diode (35V 9A DO204AR).

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Figure 2.16: Characteristics of Diode

2.14 Battery

A rechargeable battery is an energy storage device that can be charged again after being

discharged by applying DC current to its terminals

Figure 2.17: Battery.

Rechargeable batteries allow for multiple usages from a cell, reducing waste and

generally providing a better long-term investment in terms of dollars spent for usable

device time. This is true even factoring in the higher purchase price of rechargeable and

the requirement for a charger.

A rechargeable battery is generally a more sensible and sustainable replacement to one-

time use batteries, which generate current through a chemical reaction in which a reactive

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anode is consumed. The anode in a rechargeable battery gets consumed as well but at a

slower rate, allowing for many charges and discharges.

In use, rechargeable batteries are the same as conventional ones. However, after

discharge the batteries are placed in a charger or, in the case of built-in batteries, an

AC/DC adapter is connected.

While rechargeable batteries offer better long term cost and reduce waste, they do have a

few cons. Many types of rechargeable cells created for consumer devices, including AA

and AAA, C and D batteries, produce a lower voltage of 1.2v in contrast to the 1.5v of

alkaline batteries. Though this lower voltage doesn't prevent correct operation in

properly-designed electronics, it can mean a single charge does not last as long or offer

the same power in a session. This is not the case, however, with lithium polymer and

lithium ion batteries.

Some types of batteries such as nickel cadmium and nickel-metal hydride can develop a

battery memory effect when only partially discharged, reducing performance of

subsequent charges and thus battery life in a given device.

Rechargeable batteries are used in many applications such as cars, all manner of

consumer electronics and even off-grid and supplemental facility power storage.

2.14.1 Applications

Suitable to cordless phone, solar lighting, electrical drill, shaver, emergency lighting,

back-up power, cordless tool, power tool, flashlight, torch, Robot etc

2.15 Summary

In this chapter we have described design of the project and various components

description which has been used in the project.

In the next chapter we will describe implementation of the project.

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CHAPTER-3

IMPLEMENTATION

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3.1 Introduction

In this chapter we will describe about Microcontroller IC, circuit diagram, circuit

construction and its working procedure, PCB layout and microcontroller programming.

3.2 Microcontroller

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a

single integrated circuit containing a processor core, memory, and programmable

input/output peripherals.

3.2.1 The pin diagram of Atmega8 microcontroller

Figure 3.1: Pin diagram of ATmega8

3.2.2 ATmega8 Microcontroller IC

This is the main controller of the robot. When the robot is turned on, the main controller

is ready to receive an instruction from Android phone via Bluetooth. It is 28 pin of

microcontroller.

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3.2.3 Features

3.2.3.1 Advanced RISC Architecture

– 130 Powerful Instructions – Most Single-clock Cycle Execution

– 32 × 8 General Purpose Working Registers

– Fully Static Operation

– Up to 16MIPS Throughput at 16MHz

– On-chip 2-cycle Multiplier

3.2.3.2 High Endurance Non-volatile Memory segments

– 8Kbytes of In-System Self-programmable Flash program memory

– 512Bytes EEPROM, 1Kbyte Internal SRAM

– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM

– Data retention: 20 years at 85°C/100 years at 25°C (1)

– Optional Boot Code Section with Independent Lock Bits In-System Programming by

on-chip Boot Program True Read-While-Write Operation

– Programming Lock for Software Security

3.2.3.3 Peripheral Features

– Two 8-bit Timer/Counters with Separate Prescaler, one Compare Mode

– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode

– Real Time Counter with Separate Oscillator

– Three PWM Channels

– 8-channel ADC in TQFP and QFN/MLF package Eight Channels 10 -bit Accuracy

– 6-channel ADC in PDIP package

- Six Channels 10 -bit Accuracy

– Byte-oriented Two-wire Serial Interface

– Programmable Serial USART

– Master/Slave SPI Serial Interface

– Programmable Watchdog Timer with Separate On-chip Oscillator

– On-chip Analog Comparator

3.2.3.4 Special Microcontroller Features

– Power-on Reset and Programmable Brown-out Detection

– Internal Calibrated RC Oscillator

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– External and Internal Interrupt Sources

– Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, and

Standby

3.2.3.5 I/O and Packages

– 23 Programmable I/O Lines

– 28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLF

3.2.3.6 Operating Voltages

– 2.7V - 5.5V (ATmega8L)

– 4.5V - 5.5V (ATmega8)

3.2.3.7 Speed Grades

– 0 - 8MHz (ATmega8L)

– 0 - 16MHz (ATmega8)

3.2.3.8 Power Consumption

--at 4 MHz, 3V, 25C

– Active: 3.6mA

– Idle Mode: 1.0mA

– Power-down Mode: 0.5μA

3.3 Microcontroller Program

//program for microcontroller ……………………

/*******************************************************

This program was created by the

CodeWizardAVR V3.12 Advanced

Automatic Program Generator

©Copyright 1998-2014 Pavel Haiduc, HP InfoTech s.r.l.

http://www.hpinfotech.com

Chip type : ATmega8

Program type : Application

AVR Core Clock frequency: 12.000000 MHz

Memory model : Small

Data Stack size : 256

/*******************************************************/

#include <mega8.h>

#include <stdio.h>

#include <delay.h>

#define Motor_A_PORT1 PORTB.0

#define Motor_A_PORT2 PORTB.3

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#define Motor_B_PORT1 PORTB.4

#define Motor_B_PORT2 PORTB.5

#define Motor_Enable1 PORTB.1

#define Motor_Enable2 PORTB.2

// Declare your global variables here

#define DATA_REGISTER_EMPTY (1<<UDRE)

#define RX_COMPLETE (1<<RXC)

#define FRAMING_ERROR (1<<FE)

#define PARITY_ERROR (1<<UPE)

#define DATA_OVERRUN (1<<DOR)

// USART Receiver buffer

#define RX_BUFFER_SIZE 8

char rx_buffer [RX_BUFFER_SIZE];

#if RX_BUFFER_SIZE <= 256

unsigned char rx_wr_index=0, rx_rd_index=0;

#else

unsigned int rx_wr_index=0, rx_rd_index=0;

#endif

#if RX_BUFFER_SIZE < 256

unsigned char rx_counter = 0;

#else

unsigned int rx_counter=0;

#endif

// This flag is set on USART Receiver buffer overflow

bit rx_buffer_overflow;

// USART Receiver interrupt service routine

interrupt [USART_RXC] void usart_rx_isr (void)

{

char status,data;

status=UCSRA;

data=UDR;

if ((status & (FRAMING_ERROR | PARITY_ERROR | DATA_OVERRUN))==0)

{

rx_buffer[rx_wr_index++]=data;

#if RX_BUFFER_SIZE == 256

// special case for receiver buffer size=256

if (++rx_counter == 0) rx_buffer_overflow=1;

#else

if (rx_wr_index == RX_BUFFER_SIZE) rx_wr_index=0;

if (++rx_counter == RX_BUFFER_SIZE)

{

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rx_counter=0;

rx_buffer_overflow=1;

}

#endif

}

}

#ifndef _DEBUG_TERMINAL_IO_

// Get a character from the USART Receiver buffer

#define _ALTERNATE_GETCHAR_

#pragma used+

///

char getchar (void)

{

char data;

while (rx_counter==0);

data=rx_buffer[rx_rd_index++];

#if RX_BUFFER_SIZE != 256

if (rx_rd_index == RX_BUFFER_SIZE) rx_rd_index=0;

#endif

#asm("cli")

--rx_counter;

#asm("sei")

return data;

}

#pragma used-

#endif

// USART Transmitter buffer

#define TX_BUFFER_SIZE 8

char tx_buffer[TX_BUFFER_SIZE];

#if TX_BUFFER_SIZE <= 256

unsigned char tx_wr_index=0,tx_rd_index=0;

#else

unsigned int tx_wr_index=0,tx_rd_index=0;

#endif

#if TX_BUFFER_SIZE < 256

unsigned char tx_counter=0;

#else

unsigned int tx_counter=0;

#endif

// USART Transmitter interrupt service routine

interrupt [USART_TXC] void usart_tx_isr(void)

{

if (tx_counter)

{

--tx_counter;

UDR=tx_buffer[tx_rd_index++];

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#if TX_BUFFER_SIZE != 256

if (tx_rd_index == TX_BUFFER_SIZE) tx_rd_index=0;

#endif

}

}

#ifndef _DEBUG_TERMINAL_IO_

// Write a character to the USART Transmitter buffer

#define _ALTERNATE_PUTCHAR_

#pragma used+

void putchar(char c)

{

while (tx_counter == TX_BUFFER_SIZE);

#asm("cli")

if (tx_counter || ((UCSRA & DATA_REGISTER_EMPTY)==0))

{

tx_buffer[tx_wr_index++]=c;

#if TX_BUFFER_SIZE != 256

if (tx_wr_index == TX_BUFFER_SIZE) tx_wr_index=0;

#endif

++tx_counter;

}

else

UDR=c;

#asm("sei")

}

#pragma used-

#endif

// Standard Input/Output functions

#include <stdio.h>

#include <delay.h>

void main(void)

{

char command; // Declare your local variables here

// Input/Output Ports initialization

// Port B initialization

// Function: Bit7=Out Bit6=Out Bit5=Out Bit4=Out Bit3=Out Bit2=Out Bit1=Out

Bit0=Out

DDRB=(1<<DDB7) | (1<<DDB6) | (1<<DDB5) | (1<<DDB4) | (1<<DDB3) |

(1<<DDB2) | (1<<DDB1) | (1<<DDB0);

// State: Bit7=0 Bit6=0 Bit5=0 Bit4=0 Bit3=0 Bit2=0 Bit1=0 Bit0=0

PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) |

(0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization

// Function: Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In

DDRC=(0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) |

(0<<DDC1) | (0<<DDC0);

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// State: Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T

PORTC=(0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) |

(0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization

// Function: Bit7=In Bit6=In Bit5=In Bit4=out Bit3=In Bit2=In Bit1=In Bit0=In

DDRD=(0<<DDD7) | (0<<DDD6) | (0<<DDD5) | (1<<DDD4) | (0<<DDD3) |

(0<<DDD2) | (0<<DDD1) | (0<<DDD0);

// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T

PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) |

(0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// Timer(s)/Counter(s) Interrupt(s) initialization

TIMSK=(0<<OCIE2) | (0<<TOIE2) | (0<<TICIE1) | (0<<OCIE1A) | (0<<OCIE1B) |

(0<<TOIE1) | (0<<TOIE0);

// External Interrupt(s) initialization

// INT0: Off

// INT1: Off

MCUCR=(0<<ISC11) | (0<<ISC10) | (0<<ISC01) | (0<<ISC00);

// USART initialization

// Communication Parameters: 8 Data, 1 Stop, No Parity

// USART Receiver: On

// USART Transmitter: On

// USART Mode: Asynchronous

// USART Baud Rate: 9600

UCSRA=(0<<RXC) | (0<<TXC) | (0<<UDRE) | (0<<FE) | (0<<DOR) | (0<<UPE) |

(0<<U2X) | (0<<MPCM);

UCSRB=(1<<RXCIE) | (1<<TXCIE) | (0<<UDRIE) | (1<<RXEN) | (1<<TXEN) |

(0<<UCSZ2) | (0<<RXB8) | (0<<TXB8);

UCSRC=(1<<URSEL) | (0<<UMSEL) | (0<<UPM1) | (0<<UPM0) | (0<<USBS) |

(1<<UCSZ1) | (1<<UCSZ0) | (0<<UCPOL);

UBRRH=0x00;

UBRRL=0x4D;

// Global enable interrupts

#asm("sei")

while (1)

{ Motor_Enable1=1;

Motor_Enable2=1;

delay_ms(200);

Motor_Enable1=0;

Motor_Enable2=0;

delay_ms(200);

Motor_Enable1=1;

Motor_Enable2=1;

PORTD.4=1;

command=getchar();

//putchar(command);

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if(command=='S')

{Motor_A_PORT1=0;

Motor_A_PORT2=0;

Motor_B_PORT1=0;

Motor_B_PORT2=0;

delay_ms(100);

}

if(command=='F')

{

Motor_A_PORT1=1;

Motor_A_PORT2=0; //

Motor_B_PORT1=1;

Motor_B_PORT2=0;

delay_ms(100);

}

if(command=='B')

{Motor_A_PORT1=0;

Motor_A_PORT2=1; //

Motor_B_PORT1=0;

Motor_B_PORT2=1;

delay_ms(100);

}

if(command=='L')

{Motor_A_PORT1=0;

Motor_A_PORT2=1; //

Motor_B_PORT1=1;

Motor_B_PORT2=0;

delay_ms(100);

}

if(command=='R')

{ Motor_A_PORT1=1; //

Motor_A_PORT2=0;

Motor_B_PORT1=0;

Motor_B_PORT2=1;

delay ms(100);}

}

}

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3.4 PCB Layout

Figure 3.2: PCB Diagram of This Project

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3.5 Circuit module

Figure 3.3: Circuit module

3.6 Circuit Construction

Power source is from battery.

We designed the project with12V. But we supplied only 9.6 V. However, it

works properly.

It is a combination of 8 batteries. Each battery is 1.2 V.

It has two terminals. Positive and negative terminals which are connected to

positive and negative terminal of PCB.

Then we see a capacitor. It is the filter capacitor. It eliminates the ripple. Ripple

is very harmful for system. Although battery is pure DC.

Other capacitors are also used to eliminate the ripple.

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Microcontroller is needed a minimum of 5 volt. Otherwise it does not work

properly.

For this case we used a 7805 voltage regulator IC which holds 5v.

Pin 8 of L293D IC is connected with the source.

For motor rotation it requires a minimum of 7.5 volt, otherwise motor will not

rotate.

Pin 16 is connected to the output of 7805 IC for biasing.

We used a Bluetooth. For Bluetooth 5v is needed. It is connected with 5v positive

and ground.

TX, RX pins of microcontroller and Bluetooth are connected. It is used to

communicate with the microcontroller.

3.7 Android application Development

Android is an open source operating system based on the Linux kernel, and designed

primarily for touch screen mobile devices such as smart phones and tablets.

For this application, we used MIT App Inventor site, where can be developed Android

apps.

3.7.1 What is MIT App inventor?

App Inventor is a cloud-based tool, which means that you can build apps right in your

web browser. This website offers all of the support that you‟ll need as you learns how to

build your own apps. The App Inventor software or "service" is at

ai2.appinventor.mit.edu. You can get there by clicking the orange "Create" button from

any page on this website.

3.7.2 Android application view

Figure 3.4: Android application view

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3.7.3 Screenshot of the Development of Android application

Figure 3.5: Screenshot of the Development of Android application

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Figure 3.6: Screenshot of the Development of Android application

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3.8 Working procedure

At First we on the power switch and circuit gets power which is indicated by LED.

Then we have to connect Bluetooth module with the Android phone.

At Smartphone app, Bluetooth device is searched. If found with name "HC-05"

device, the connection is made with a pass code “1234”. It must be paired.

According to program:

When we press forward button it goes ahead.

If we press stop it stops.

If we press Backward it goes to backward.

If we press left it goes to left. It means it moves to left, and vice versa.

By this we can avoid the obstacle using command by application.

3.9 Softwares Used

3.9.1 Proteus 8

Proteus 8 is best simulation software for various designs with microcontroller. It

is mainly popular because of availability of almost all microcontrollers in it. So it is a

handy tool to test programs and embedded designs for electronics hobbyist. We can

simulate our programming of microcontroller in Proteus 8 Simulation Software.

After simulating circuit in Proteus 8 Software we can directly make PCB design with it.

3.9.2 Code vision AVR

Integrated Development Environment for the 8-bit Atmel AVR and XMEGA

Microcontrollers.

Application that runs under Windows® XP, Vista, Windows 7 and Windows 8,

32-bit and 64-bit

Easy to use Integrated Development Environment and ANSI C compatible

Compiler

Editor with auto indentation, syntax highlighting for both C and AVR assembler,

function parameters and structure/union members auto complete

Supported data types: bit, bool, char, int, short, long, 64-bit long.

Fast floating point library with hardware multiplier and enhanced core

instructions support for all the new ATmega chips

AVR specific extensions for:

Transparent, easy accessing of the EEPROM & FLASH memory areas, without

the need of special functions like in other AVR compilers

Bit level access to I/O registers

Interrupt support

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Support for placing bit variables in the General Purpose I/O Registers (GPIOR)

available in the new chips (ATtiny2313, ATmega48/88/168,

ATmega165/169/325/3250/329/3290/645/6450/649/6490,

ATmega1280/1281/2560/2561/640, ATmega406 and others)

Compiler optimizations:

Peephole optimizer

Advanced variables to register allocator, allows very efficient use of the AVR

architecture

Common Block Subroutine packing (what our competition calls “Code

Compressor”), replaces repetitive code sequences with calls to subroutines. This

optimizer is available as Standard in CodeVisionAVR, at no additional costs, not

like in our competitor‟s products.

Common sub-expression elimination

Loop optimization

Branch optimization

Subroutine call optimization

Cross-jumping optimization

Constant folding

Constant literal strings merging

Store-copy optimization

Dead code removing optimization

4 memory models: tiny (8 bit data pointers for chips with up to 256 bytes of

RAM), small (16 bit data pointers for chips with more than 256 bytes of ram),

medium (for chips with 128k of flash) and large (for chips with 256k or more

flash).

3.10 Summary

In this chapter we have described about microcontroller IC, circuit diagram,

circuit construction, working procedure, PCB layout, microcontroller programming and

designing software.

In the next chapter we will describe the application and limitation of the project.

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CHAPTER 4

PROJECT OUTLOOK, APPLICATION

AND LIMITATIONS

Page 38

4.1 Introduction

In Previous chapter we have described design and implementation of the project. In this

chapter we will describe outer look of the project, its application and limitation.

4.2 Project Outlook

Figure 4.1: Outer look of the robot

4.3 Application of this project

The robot can be used for reconnaissance or surveillance. Like, if there is any

hidden bomb under anything.

It can be ensured and notified through the robot.

The robot is small in size so can be used for spying.

This Project uses Bluetooth technology and in the future switched to wife.

After using camera it can be used as a photographer.

This types of robot used as toy‟s kids.

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4.4 Limitation

It is use for short distance only.

Rapidly power reduced.

Bluetooth too low-bandwidth.

4.5 Summary

In this chapter we have described application and limitation of the project.

In the next chapter we will describe about price and discussion of the project.

Page 40

CHAPTER 5

DISCUSSION

Page 41

5.1 Introduction

In this chapter we will discuss about this project.

5.2 Price

The components are used in this project is very chip. Such as ATmgega8

microcontroller IC, 7805 Voltage regulator IC, L293D Motor Driver IC, HC-05

Bluetooth, Crystal, Hit sink, Battery, Steering wheel, wheel, DC motor. LED, Switch

Capacitor, Resistor, PCB, and connecting wires. All of these are available in our local

market.

5.3 Discussion

We tried to control the robot by the smart phone, and avoid the obstacle. That is why we

designed an android app which communicates with microcontroller via Bluetooth

module.

In this project, we have gained the concept of embedded C, designing app, Java

environment which are important for future development.

We kept some additional parts such as buzzer, resistor, LED, and rail connector/ bus bars

in PCB. They are designed for the future use.

5.4 Advantages

Portable and Easy To Use.

Easy to control.

Simple in Construction.

Easy To Maintain And Repair.

Efficient and Low Cost Design.

Low Power Consumption.

The programming of the microcontroller is easy.

5.5 Disadvantages

It is time consuming project.

It is use for short distance only.

Rapidly power reduced.

Bluetooth too low-bandwidth.

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5.6 Summary

In this chapter we have discussed price comparison, discussion, advantages and

disadvantages of the project.

In the next chapter the report will be formally concluded.

Page 43

CHAPTER 6

FUTURE EXTENSIONS AND

CONCLUSION

Page 44

6.1 Future Extensions

Obstacle avoidance

Install Ultrasonic sensor.

Vision

Use camera to transmit frames back to android application for display to

user.

Bluetooth too low-bandwidth, switch to Wi-Fi.

6.2 Conclusion

Our objective was to design a mobile controlled robot, which can avoid the obstacle. For

designing and development of the project, we have used various components like

microcontroller, Smartphone, Bluetooth, DC motor and others components. We have also

used MIT app inventor site for developing software and designing software for PCB

layout.

In this case we faced in some challenges like software developing, microcontroller

programming and layout designing, components assembling etc. Actually it was very

difficult for us. After all we overcome these challenges by hard work and eventually we

have been succeeded by the grace of Almighty Allah. This is a milestone for the future

development, the latter of which will be made us better.

Page 45

References

1. Robot making. [http://roboticsbd.com/index.php/robot-making-bangla]

2. Datasheet atmega8. [http://www.atmel.com/images/atmel-2486-8-bit-avr-

microcontroller-atmega8_l_datasheet.pdf]

3. Resistor. Wikipedia. [http://en.wikipedia.org/wiki/Resistor]

4. Color Code. Wikipedia. [http://en.wikipedia.org/wiki/Electonic_color_code]

5. Resistor. Capacitor. Diode. LED.

[http://www.embeddedadventures.com/Tutorials/tutorials_detail/121]

6. Switch. Wikipedia. [http://en.wikipedia.org/wiki/Switch]

7. app invention. [http://ai2.appinventor.mit.edu/]

8. Voltage-Regulator. Wikipedia. [http://en.wikipedia.org/wiki/78xx]

9. L293D H Driver IC. [http://www.ti.com/product/l293D]

10. L293D H Driver IC. [http://www.engineersgarage.com/electronic-

components/l293d-motor-driver-ic]

11. Atmega8. [https://www.futurlec.com/Atmel/ATMEGA8L.shtml]

12. HC-05 Bluetooth. [https://developer.mbed.org/users/edodm85/notebook/HC-05-

bluetooth/]

13. All IC's Data Sheet. [http://www.alldatasheet.com/]

14. Power management. [https://www.fairchildsemi.com/]

15. Obstacle avoiding robot. [https://www.youtube.com/….]

16. Rechargeable Battery. [https://en.wikipedia.org/wiki/Rechargeable_battery]

17. Heat sink. Wikipedia. [https://en.wikipedia.org/wiki/Heat_sink]