Workshop on Microcontroller - · PDF file2 Workshop on "Line Follower Robocar", By-Mohammaed...

Workshop on Line Follower Robo-car

Organized By: Telecom Club

Presented By

Mohammed Abdul Kader

Assistant Professor, Dept. of EEE, IIUC

Email:[email protected] Website: kader05cuet.wordpress.com

Workshop on "Line Follower Robocar", By-Mohammaed Abdul Kader,Assistant Prof, EEE, IIUC 2

Line Follower Robo-Car

Line follower robo-car is a simple example of automated system with feedback.

Line follower robot is a robo car that can follow a path. The path can be visible like a black

line on the white surface (or vice-verse). It is an integrated design from the

knowledge of Mechanical, Electrical and Computer engineering.

Required Components

DC Motor

IR Sensor

Chassis Microcontroller

Motor Driver


Timer/ Counter

I/O Port

What is Microcontroller?

Micro-computer in a single chip.


Name of Some Microcontroller Manufacturer

ATMEL (AVR microcontroller)

Microchip (PIC microcontroller)

Texas Instruments (TI)

Freescale

Philips

Motorola ARDUINO


Crystal Oscillator Program Loader Microcontroller Linear Voltage Regulator

Advantages of Arduino: Reduces hardware complexity


Advantages of Arduino: Programming Easy

• Programming in C

• Lot of functions in the library.

• No need to learn internal

architecture of microcontroller.


Arduino UNO Digital I/O Pins

Vcc and GND Pins


Digital I/O Pins

Most of the important pins of microcontroller are digital input-output pins.

These pins are used to connect INPUT Device (i.e. Push Button, keypad, digital sensors

etc) and OUTPUT Device (i.e. LED, Display, Relay, Motor etc.) with microcontroller.

These pins can act as INPUT or

OUTPUT.

Digital Output pin means microcontroller

can make this pin HIGH or LOW state

(Write Operation).

Digital Input pin means microcontroller

can read HIGH or LOW state from other

devices (Read Operation).


Configuring Digital I/O Pins

digitalWrite(pin number, HIGH/LOW)

digitalWrite(13,HIGH)

digitalWrite(13,LOW)

pinMode(pin Number, OUTPUT)

An LED is connected with pin 13.

The pin should be an OUTPUT pin.

We can configure a pin as OUTPUT by

“pinMode” function.

pinMode(13, OUTPUT)

Configuring as OUTPUT

Making a Pin HIGH or LOW

Microcontroller can make a digital pin HIGH or LOW by

digitalWrite function.


Program Structure in ARDUINO

Verify Program

Load Program

Processor run the instructions

written here only once after

loading program or reset .

Serial monitor

Processor run the instructions written here

repeatedly after loading program or reset .

i.e. void loop() function creates an infinite

loop.


void setup()

{

pinMode(13,OUTPUT);

}

void loop()

{

digitalWrite(13,HIGH);

delay(300);

digitalWrite(13,LOW);

delay(300);

}

LED Blinking

Note: To insert a time delay in the program use following function-

delay(time_in_ms);



When IR falls in IR

photo diode

When IR doesn’t fall in

IR photo diode

How IR sensor works


Sensing Line (Distinguishing Between Black and White Colors)

OUTPUT is LOW

when sensor gets

white surface

OUTPUT is HIGH

when sensor gets

Black surface


Sensor Module


Reading IR Sensor

Boolean a;

void setup()

{

pinMode(7,INPUT);

}

void loop()

{

a=digitalRead(7);

}

Moving a Robocar

Workshop on "Line Follower Robocar", By-Mohammaed Abdul

Kader,Assistant Prof, EEE, IIUC

17

Direction control of DC Motor

+

-

+

-

HIGH

LOW

2.7 to 5V

0 to 0.5V

40 mA

P=VI = 5 X 40 mA = 200 mW= 0.2 W

Not enough power to drive a DC motor.

The DC motor used in our project

needs voltage of 6 to 12 V and 300-

1000 mA current. Minimum of

(6X300) =1800 mW or, 1.8 W power

So, OUTPUT pins of microcontroller can not

drive the DC motor required in our project.

How can we control the direction of DC motor

by microcontroller? Workshop on "Line Follower Robocar", By-Mohammaed Abdul Kader,Assistant Prof, EEE, IIUC

18

H-Bridge Motor driver

HIGH

LOW

Workshop on "Line Follower Robocar", By-Mohammaed Abdul Kader,Assistant Prof, EEE,

IIUC 19

HIGH

LOW

Workshop on "Line Follower Robocar", By-Mohammaed Abdul Kader,Assistant Prof,

EEE, IIUC 20


LOW

HIGH

ON

ON

OFF

OFF



HIGH

LOW



Motor Driver IC (L298N)



Speed Control of DC Motor

In ARDUINO,

duty cycle of PWM is set by the function

analogWrite(pin_no, duty_cycle)

Where, duty_cycle = 0 to 255 (0 to 100%)

L298 Motor Driver Module



Tracking Algorithm (Principle of line tracking):


Start

Left_Sensor==HIGH and

right_sensor==HIGH

Read left_sensor

and right_sensor

Rotate both

motor in

forward

YES

A

Left_Sensor==LOW and

right_sensor==HIGH

Stop left motor

and rotate right

motor in forward

A

YES

NO

Left_Sensor==HIGH and

right_sensor==LOW

Stop right motor

and rotate left

motor in forward

A

YES

NO

Stop both motors

NO

A

END

Flow-Chart


Circuit Diagram


Program

int rightsensor=6;

int leftsensor=7;

int rightmotorP=12;

int rightmotorN=11;

int leftmotorP=10;

int leftmotorN=9;

void setup() {

pinMode(rightsensor,INPUT);

pinMode(leftsensor,INPUT);

pinMode(rightmotorP,OUTPUT);

pinMode(rightmotorN,OUTPUT);

pinMode(leftmotorP,OUTPUT);

pinMode(leftmotorN,OUTPUT);

analogWrite(5, 100);

analogWrite(3,100);

}

void loop() {

boolean rs=digitalRead(rightsensor);

boolean ls=digitalRead(leftsensor);

if(rs==HIGH && ls==HIGH)

{

digitalWrite(rightmotorP,HIGH);

digitalWrite(rightmotorN,LOW);

digitalWrite(leftmotorP, HIGH);

digitalWrite(leftmotorN, LOW);

}

else if(rs==HIGH && ls==LOW)

{

digitalWrite(rightmotorP,LOW);


digitalWrite(leftmotorP, HIGH);


}

else if(rs==LOW && ls==HIGH)

{

digitalWrite(rightmotorP,HIGH);


digitalWrite(leftmotorP, LOW);


}


else

{





delay(50);


digitalWrite(rightmotorN,HIGH);

digitalWrite(leftmotorN, HIGH);


delay(50);

}

}

Workshop on Microcontroller - · PDF file2 Workshop on "Line Follower Robocar", By-Mohammaed...

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