Project report on PC Controlled Robot

Under the guidance of

Er. Priyanshu Tripathi Er. Uma Shanker

(Project Guide) (Project Incharge)

Uvsofts Technologies Pvt. Ltd.

Submitted for fulfillment of the requirements for the

award of the certificate of Summer Internship Program-

2014

By :-

Nikhil Sharma (as Asst. Research Engineer Trainee),

Department of Geophysics,

Banaras Hindu University, Varanasi-22100

Acknowledgement

It is high privilege for me to express my deep sense of gratitude

to all those members of Uvsofts Technologies Pvt. Ltd, who

helped me in the completion of the project, especially my guide

Er. Priyanshu tripathi, who was always there at the hour of

need for completion of my project work.A special thanks to all

co-interns at Uvsofts Technologies Pvt. Ltd whose

competitiveness brought best out of me.I would also like to

take this opportunity to thank my dear parents and family

whose support gave me a lot of strength and will power to

make this project possible.

Special and sincere thanks to all Professors of Department of

Geophysics, Banaras Hindu University, Varanasi who allowed

and inspired me to take part in this Internship.

Nikhil Sharma,

M.Sc. (Tech.)

Geophysics (1st year)

Certificate of completion

This is to certify that the project and the project report entitled PC

controlled robot is done my Mr. Nikhil Sharma under my guidance. He

has fulfilled the entire requirement for this project. I really appreciate

his hard work and efforts.

Er. Priyanshu Tripathi Er. Uma Shanker

(Project Guide) (Project Incharge)

Uvsofts Technologies Pvt. Ltd,

New Delhi

Table of contents:

1. Abstract

2. Introduction

3. Hardware implementation

3.1 dc motor

3.2 working of motor

3.3 L293D motor driver IC

3.4 Working of L293D

4. Microcontroller

4.1 AVR-ATmega Microcontroller

4.2 Features and Memory segments

4.3 Pin diagram

4.4 PIN description

5. Creation of Program Using AVR studio

5.1 Introduction

5.2 Steps for creating AVR program

5.3 Program code for Microcontroller

5.4 Output of AVR Studio Code.

6. USART

6.1 Introduction

6.2 Serial communication

6.3 Bit and Baud Rate

6.4 RS 232 Communication

6.5 Uses in AVR Microcontroller

6.6 USART Baud Rate Register

6.7 Code for USART Program

7. Other Projects

8. Conclusion

9. Bibliography

Abstract

This project is about designing and building an autonomous robot

controlled by a PC. Project requires the use of an AVR Microcontroller,

dc motors , wheels, as basic hardware. The code is written in C

programming language. The project requires to be written in AVR

studio in C programming language ( also USARTs code for transmission

and reception). USART is used in the Project for serial communication.

The basic objective of the project is to move a robot controlled by a PC.

This can be used for unmanned missions for geoexploration where

manned missions are not possible or risky. Use of robot for data

acquisition also brings forth advantages like accuracy, repetitive nature

of robot, long duration working without fatigue as well as the direct

data transmission by plotting a transmitter on it.

HARDWARE IMPLEMENTATION

DC MOTOR and its working :

DC MOTOR

A DC motor is a mechanically commutated electric motor powered from direct current

These are the motors which convert DC signals into rotational motion. In robotics applications they are preferred over AC motors as the motor and the

complete circuit require same kind of supply i.e. DC supply.

L293D DRIVING IC

L293D is a dual bridge IC and is used for driving two

motors. Each motor is connected to one H-Bridge.

The L298 Motor Driver has 4 inputs to control the motion

of the motors and two enable inputs which are used for

switching the motors on and off.

A double H-Bridge, since motion of two motors can be

simultaneously controlled on each half.

PINS OF L293D IC

DC MOTOR WITH L293D IC

AVR ATMEGA 8 MICRO-CONTROLLER

INTRODUCTION :

ATmega8 is a 8-bit microcontroller based on the AVR

RISC architecture.

By executing powerful instructions in a single clock

cycle, the ATmega8 achieves throughput

approaching 1 MIPS per MHz.

In order to maximize performance and parallelism,

the AVR uses a Harvard architecture- which

separates memories and buses for program and

data.

Instruction in program memory are executed with

single level pipelining.

This concept enables instructions to be executed in

every clock cycle.

Single clock cycle, the ATmega8 achieves throughput

approaching 1 MIPS per MHz.

FEATURES High-performance 8 bit Microcontroller Up to 16 MIPS Throughput at 16 MHz 32 x 8 General Purpose Working Registers Six ADC channels in PDIP package

Internal Calibrated Oscillator

TYPES OF PACKAGES

28-pin PDIP (Plastic Dual In-line Package) 32-pin TQFP (Thin Quad film Package)

MEMORY SEGMENTS

8K Bytes of Flash program memory 512 Bytes EEPROM (Electrically Erasable Programmable Read Only

Memory)

1K Byte Internal RAM (Random Access Memory)

PIN OUT

PIN DESCRIPTION:

VCC:- Digital supply voltage

GND :- Ground

Port B is an 8-bit bi-directional I/O port with internal pull-

up resistors.

Port C is an 8-bit bi-directional I/O port with internal pull-

up resistors. In additional ADC.

Port D is an 8-bit bi-directional I/O port with internal pull-

up resistors

AVCC:- The supply voltage pin for the A/D Converter

RESET:- A low level on this pin for longer than the

minimum pulse length will generate a reset, even if the

clock is not running

AREF:- The analog reference pin for the A/D Converter.

Three ports i.e PortB, PortC, PortD

Three registers associated with every port

DDRx Data Direction Register

PINx Port input

PORTx- Port output

*Note x is subscript and could be either of B, C, D

CREATION OF PROGRAM USING AVR

STUDIO

STEP 1 : Open AVR studio 4 IDE. You should see the

program banner below.

STEP 2 : When the IDE opens, youll see the

programming and simulator environment as well as a

dialog box requesting information : Are you starting a

new project or opening a saved project ?

STEP 3 : Click on the New Project button.

STEP 4 : In the next dialogue box, choose the AVR GCC

STEP 5 : Type in the project name and the initial file

name.

STEP 6 : Click on the next button.

STEP 7 : Choose AVR SIMULATOR for the Debug

Platform and then scroll down the right window to

choose ATmega8 & AVR processor.

STEP 8 : Click on the finish button. You should then see

the IDE.

STEP 9 : Type in the program as shown.

STEP 10 : When you have completed the program save it.

Its also a good practice to periodically save your

program as you type.

STEP 11 : Assemble you program. You may do this by

selecting Build from the Build Menu or by striking the

[F7] key.

STEP 12 : Continue assembling and correcting errors until

the program assembles without error.

MICROCONTROLLER PROGRAM CODE :

#include

#include

void usartinit(int baudrate)

{

UBRRL=baudrate;

UBRRH=(baudrate>>8);

UCSRC|=(1

while(!(UCSRA & (1

while(str[i]!='\0')

{

usartwrite(str[i]);

i++;

}}

void main()

{

char ch;

usartinit(77);

DDRB=0xff;

while(1)

{

ch=read();

if(ch=='a')

{

PORTB=0b00010010;

usart_string(" moves FORWARD");

}

if(ch=='b')

{

PORTB=0b00001100;

usart_string(" moves BACKWARDS");

}

if(ch=='c')

{

PORTB=0b00000010;

usart_string(" moves LEFT");

}

if(ch=='d')

{

PORTB=0b00010000;

usart_string(" moves RIGHT");

}

if(ch=='e')

{

PORTB=0b00000000;

usart_string("STOP");

}

}

}

USART

SERIAL V/S PARALLEL COMMUNICATION

2

SERIAL COMMUNICATION :

AVR microcontrollers have a dedicated hardware for serial

communication; this part is called Universal Synchronous

Asynchronous Receiver and Transmitter (USRT).

You just have to supply the data to transmit and it will do

the rest.

The data to be transmitted is written to one of the register

of USRT and USRT transmits it.

Also USART automatically senses the transmission of RX

line and then inputs the whole Byte and when it has the

byte it informs the CPU to read the data from one of its

registers.

BAUD RATE AND BIT RATE

Baud rate is the number of bits transmitted in one second.

Bit Rate is the number of data bits transmitted in one second.

Both of them has the same unit bits/second. Baud rate is determined by the number of bits in

one frame while bit rate is determined by the number of data its in that frame.

Atmega16 support five different data sizes 5,6,7,8 and 9 bits.

RS232 COMMUNICATION

RS232 is a asynchronous serial communication protocol widely used in computers and digital systems.

It is called asynchronous because there is no separate synchronizing clock signal as there are in other serial protocols like SPI and I2C.

The Protocol is such that it automatically synchronize itself.

We can use RS232 to easily create a data link between our MCU based project and standard PC.

Excellent example is a commercial serial PC mouse.

RS232

In Rs 232 there are two data lines RX and TX. TX is the wire in which the data is sent out to other device. RX is the line in which other device put the data it need to sent

to the device. We know that a HIGH = +5V and LOW= 0V in TTL/MCU circuits

nut in RS232 a HIGH= -12V and a LOW =+12V.This increases the range and reliability of data transfer.

Thus to interface a RS232 with the MCU we need to use an IC MAX232.As there is clock line so for synchronization accurate timing is required so transmissions are carried out with certain standard speeds.

The speeds are measured in bits per second. Number of bits transmitted is also known as baud rate. Some standard baud rates are1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200..etc

UART OF AVR MICROCONTROLLERS

The UART of AVR is versatile and can be setup for various different mode as required by your application.

The Universal Synchronous and Asynchronous serial Receiver and Transmitter

(UART) is a highly flexible serial communication device.

The UART of the AVR is Connected to the CPU by the following Six Registers

It is a 16 bit register. The higher byte of the bud rate is stored in

UBRRH while the lower value of the baud rate is stored in UBRRL.

This register is used by the USART to generate the data

transmission at specified speed.

The UBRR value is calculated according to following formula

Where fosc is your CPU frequency

UBRR can hold only integer value. So it is better to use the baud

rates that give UBRR value that is purely integer or very close to

integer. So if UBRR value comes to be 7.68 and you decide to use

UBRR=8 then it has high error percentage, and communication is

unreliable.

USART BAUD RATE REGISTER

USART Initializing :

void usart_init()

{

UBRRL=25;

UCSRB|=(1

Transmission using USART :

void usart_transmit(unsigned int data)

{

while(!( UCSRA & (1

Reception using USART :

unsigned int usart_receive(void)

{

while((UCSRA & (1

Conclusion

We have successfully completed the project on PC Controlled Robot.

This project was about about handling a robot which could be used for

Geoexploration purposes where human reach is still restricted or

inhibited. While doing so apt knowledge of computer hardware and

software was gained by the help of research guides through a

continuous process of learning by practical analysic side by side. Use of

robot for data acquisition also brings forth advantages like accuracy,

repetitive nature of robot, long duration working without fatigue as

well as the direct data transmission by plotting a transmitter on it.

OTHER PROJECTS :

Working with LEDS

7 SEGMENT Display

Traffic light control

Line follower robot

Edge avoider robot

Obstacle avoider robot

LED matrix

LCD display

Relay

Bibliography

The books which were a real help are:

The AVR microcontroller and embedded systems using assembly

and C by Muhammad ali mazidi,sarmad naimi,sepehr naimi.

Robotics with embedded C by Toshendra K sharma.

Robotics-fundamentals and concepts by Ashitava Ghosal.

Embedded Microprocessor Systems Real World Applications by

Stuart R. Ball.

Mechatronics: An Introduction by the Robert H Bishop.

The useful sites were:

www.wikipedia.com

www.thetech.org/exhibitsevents/online/robot

www.mathworks.com

www.robomart.com

http://www.robotcafe.com