Line Follower Robot

What is line follower:

Line follower robot is an autonomous machine that can follow a path. The path can be seen like a white line on a black surface (or vice-versa) or it can be invisible as magnetic field.

Requirement of line follower robot:

Sensing a line and maneuvering the robot to stay on path, while constantly correcting wrong moves by using feedback mechanism forms a simple and effective closed loop system. As a programmer we get an opportunity to ?teach? the robot how to follow the line therefore it gives robot human like property of responding to stimuli.

Consider the practical application of line follower robot is:

Guidance system for industrial robots moving on shop floor
Automated cars running on road with embedded magnet.

Hardware Required:

12V, 1A DC Adapter-1 piece
Analog IR Sensor-3 piece
AVR Microcontroller Board-1 piece
DC Motor Driver-1 piece
AVR USB Programmer-1 piece
1 to 1 Connector-15 piece
10 to 10 FRC Female Connector-2 piece
Robot-1 piece

Software Required:

BASCOM-AVR Integrated Development Environment (IDE)
AVRDUDE-GUI
WinAVR-2010
USBasp Driver

Block Diagram:

Algorithm:

R=rightmost sensor which reads 0, L=leftmost sensor which reads 0. If no sensor on right (or Left) is 0 than L (or R) equals to 0.
If all sensor read 1 then go to step 3,

If L<R Move Right

If L>R Move Left

If L=R Move Forward

Move anticlockwise if line was last seen on Left, Move clockwise if line was last seen on Right. Repeat step 3 till line is found.

Circuit Diagram:

Consider the eagle software based schematic circuit of line follower robot is:-

Source Code:

$regfile = "m16def.dat".
$crystal = 1000000
Config Lcd = 16 * 2
Config Lcdpin = Pin , Rs = Portb.2 , E = Portb.3 , Db4 = Portb.4 , Db5 = Portb.5 , Db6 = Portb.6 , Db7 = Portb.7
Config Adc = Single , Prescaler = Auto , Reference = Avcc
Start Adc
Config Timer1 = Pwm , Pwm = 8 , Prescale = 1 , Compare A Pwm = Clear Down , Compare B Pwm = Clear Down
Start Timer1
Dim Lb As Integer , Lw As Integer , Lm As Integer , L As Integer
Dim Rb As Integer , Rw As Integer , Rm As Integer , R As Integer
Cls
Lcd "sense black"
Wait 5
Lb = Getadc(1)
Rb = Getadc(0)
Lowerline
Lcd Lb ; "_" ; Rb
Wait 1
Cls
Lcd "sense white"
Wait 5
Lw = Getadc(1)
Rw = Getadc(0)
Lowerline
Lcd Lw ; "_" ; Rw
Wait 1
Cls
Lm = Lw + Lb
Lm = Lm / 2
Rm = Rw + Rb
Rm = Rm / 2
Do
Cls
L = Getadc(1)
R = Getadc(0)
If L < Lm And R < Rm Then
Lcd "fwd"
Pwm1a = 100
Portd.6 = 0
Pwm1b = 100
Portd.3 = 0
Elseif L > Lm And R < Rm Then
Lcd "left"
Pwm1a = 100
Portd.6 = 0
Pwm1b = 0
Portd.3 = 0
Elseif L < Lm And R > Rm Then
Lcd "right"
Pwm1a = 0
Portd.6 = 0
Pwm1b = 100
Portd.3 = 0
Elseif L > Lm And R > Rm Then
Lcd "stop"
 Pwm1a = 0
 Portd.6 = 0
 Pwm1b = 0
 Portd.3 = 0
End If
  Loop

End

Consider the screenshot of source code used in Line Follower robot using BASCOM-AVR Integrated Development Environment (IDE) is:-