The first thing you should try when you buy the Mindstorm is to try the 4 samples they give.The first and easiest one is shooterbot I'll show you this first.
Shooterbot level difficulties:
When you open the box,you'll see the Quick Start kit.Yes,it can be build in 30 minutes same as it's written there but afterthat I took almost 2 hours to figure out how to program it just to move it forward and backward.But,whew,when it moves at last,it feels like the 3 yrs old boy get its first toy.Yea,although just a lame move.
Then,from this so called boring starter kit,we can upgrade to make a shooterbot. You should watch this cool animation first from Mindstorm website before you watch mine.Kewl,isn't?
The next step is to make a shooterbot that can shoot around it.Secure the parameters boy's!!
Then,we make it smarter by adding ultrasonic sensor so it can detect movement,and shoot.When it's detecting someone entering it's territory,it'll give warning first.Then,it'll shoot until you move outside.
Stuck at the middle???Maybe I can help you.Feel free to ask,ok :D
Until next time!!