Thank you Guys,
Actually my initial intention was to start out with line-following project, not because it is cool or anything, but I remember having been assigned this project in an electrical engineering class when i was still college 10 years ago. my class was devided into 4 teams being handed with the a programmable kits and asked to make the robot that can following the line…well at the end the semester we were asked to cary out the demo, and guess what… non of teams’ robots could stay on the line for more 30 seconds. The professor was nice enough to let everyone passed the class.
I am going to try redoing this again. Maze is another good idea, but it may be tough…