Arduino Programming Basics : Part 3 (HINDI): Switch, IR-Sensor, PWM

Interfacing a switch with Arduino
Definition of Pull-up and Pull-down resistance
Interfacing switch and 7-segment display with Arduino
Switch de-bouncing
RGB LED
Interfacing Infrared sensor,
Tips on developing a Line Follower robot
Basics of Pulse Width Modulation (PWM)
Getting different colour-shades from RGB LED using PWM