Once you have mastered the basic blinking leds, simple sensors and buzzing motors, it’s time to move on to bigger and better projects. That usually involves combining bits and pieces of simpler sketches and trying to make them work together. The first thing you will discover is that some of those sketches that ran perfectly by themselves, just don’t play well with others. There are ways to effectively juggle multiple tasks on an Arduino. This series of guides will show you how.
Arduino is a great starting point for electronics, and with a motor shield it can also be a nice tidy platform for robotics and mechatronics. Here is a design for a full-featured motor shield that will be able to power many simple to medium-complexity projects. Build the kit, and learn how to use it with these detailed instructions.