students.iitk.ac/roboclub

1. http://students.iitk.ac.in/roboclub

2. LINE FOLLOWING ROBOT • Main Components: • Sensors • Micro controller • Motor drivers • Chasis

3. SENSORS

4. How IR Led sensors work?? On the basis of variation in reflection property of Different Colours

5. MICRO CONTROLLERS Atmega

6. 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

7. ARDUINO – Open Source Platform

8. What is Arduino?? • Open-source physical computing platform. • Physical Input / Output board (I/O) with programmable Integrated Circuit (IC) • Contains Atmega series Micro controller

9. Why Arduino ?? • Easy to use • Provides a number of libraries to program the microcontroller easily • Hardware platform already has the power and reset circuitry setup • 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

10. Getting Started • Check out: http://arduino.cc/en/Guide/HomePage • Download & install the Arduino environment (IDE) • Connect the board to your computer via the USB cable • If needed, install the drivers. • Launch the Arduino IDE • Select your board • Select your serial port • Open the blink example • Upload the program

11. Arduino IDE See: http://arduino.cc/en/Guide/Environment for more information

12. Try It: Connect the USB Cable

13. Select Serial Port and Board

15. A Little Bit About Programming • Code is case sensitive • Statements are commands and must end with a semi-colon • Comments follow a // or begin with /* and end with */ • loop and setup

16. Our First Program

17. Terminology

18. Digital I/0 • pinMode(pin, mode) • Sets pin to either INPUT or OUTPUT • digitalRead(pin) • Reads HIGH or LOW from a pin • digitalWrite(pin, value) • Writes HIGH or LOW to a pin

19. MOTOR DRIVER

20. 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

21. H-Bridge • An electronic circuit that enables a voltage to be applied across a load in either direction.

22. What is PWM ??  Known as Pulse Width Modulation  Simple method of obtaining analog output of any value between 0 and 5V

23. Suppose we need 3V for our device at a • specified pin. •  We supply 5V on it for (3/5)* 100 % = 60% of the time period and 0V for the remaining • time period •  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.

26. Programming for Motor Driver in Arduino

27. ALGORITHM BLOCK DIAGRAM

28. 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.

30. PWM of Left motor=MEAN PWM –(kp*deviation) PWM of Right motor=MEAN PWM +(kp*deviation) Kp – Constant of Proportionality Derived experimentally