How IR Led sensors work??
On the basis of variation in reflection
property of Different Colours
Difficulties with Atmega
• Software is not User Friendly
• Many softwares required :
•CVAVR – Editor and Compiler
•AVR Studio – Transfer code to Atmega
• External Programmer required
So is there a better solution
ARDUINO – Open Source Platform
What is Arduino??
• Open-source physical
• Physical Input / Output
board (I/O) with
• Contains Atmega series
Why Arduino ??
• Easy to use
• Provides a number of libraries to program the
• Hardware platform already has the power and reset
• Hardware provides circuitry to program and
communicate with the microcontroller over USB
• Arduino has a great community of users that you can
get help from
1. Download & install the Arduino environment (IDE)
2. Connect the board to your computer via the USB
3. If needed, install the drivers.
4. Launch the Arduino IDE
5. Select your board
6. Select your serial port
7. Open the blink example
8. Upload the program
See: http://arduino.cc/en/Guide/Environment for more
• Code is case
• Statements are
must end with a
follow a // or
begin with /*
and end with */
• loop and setup
Sets pin to either INPUT or OUTPUT
Reads HIGH or LOW from a pin
Writes HIGH or LOW to a pin
Why MOTOR DRIVER ???
• Micro controllers (Atmega ,Arduino)
require 5-10 mA while motors
require 150 mA and above so Motor
Driver is used .
• For driving motor at different rpm
by using PWM
An electronic circuit that enables a voltage to be
applied across a load in either direction.
What is PWM ??
Known as Pulse Width Modulation
Simple method of obtaining
analog output of any value
between 0 and 5V
• Suppose we need 3V for our device at a
We supply 5V on it for (3/5)* 100 % = 60% of the
time period and 0V for the remaining
The average voltage at the pin for a time
period becomes 3V
If this step is repeated very fast (T is very
small), then the output behaves as a analog
signal of 3V.
Programming for Motor
Driver in Arduino
Line following using 2 sensors
Both the sensors detect the line then both
motors rotate at same pwm.
Hence the bot moves forward .
When the right sensor detects the line , left motor
is given more speed .
Hence the bot moves towars right.
When the left sensor detects the line , right
motor is given more speed.
Hence the bot moves towards left.
PWM of Left motor=MEAN PWM
PWM of Right motor=MEAN PWM
Kp – Constant of Proportionality