Here are some links to the tutorials you can always consult.

Microcontroller (Atmega 16): http://www.sourabh.sankule.com/tutorial/avr.html

Other Electronics: http://www.sourabh.sankule.com/tutorial/electronics.html

Image Processing: http://home.iitk.ac.in/~ankuragr/Elementary%20Introduction%20to%20Image%20Processing%20Based%20Robots.pdf

Robot chassis design: http://home.iitk.ac.in/~ankuragr/Chasis.pdf

Motor Drivers: http://home.iitk.ac.in/~ankuragr/MotorDriver.pdf

Sensors: http://home.iitk.ac.in/~ankuragr/Sensors.pdf