Programming with My Blocks

Winston G. - OwlBot Programmer - 8^th Grade

Subroutines are a collection of programming commands that are used over and over again within the same program or set of programs. In the Lego Mindstorm software subroutines are called My Blocks. My Blocks not only save a lot of time when programming, they can simplify software design by automatically performing the mathematical calculations that are necessary to convert distances on the field of play into rotations on the robots motors. Here is an example of a MyBlock that allows the robot to follow a line that is printed on the field of play:

This block uses two light sensors straddling the line. It subtracts one brightness value from the other, divides it to make less violent changes, and passes it to the steering control of the move block.

The My Blocks are in blue. They each represent a frequently used combination of regular programming blocks.  Each blue block is really just a shortcut for ten or more regular blocks.  This program uses a My Block to follow a line until the robot detects a green object near the line.  The program then tells the robot to turn, pickup the green object, and follow the line back to base.

The idea for using My Blocks and our dual light sensor line following program came from the book Winning Design! Lego Mindstorms NXT Design Patterns for Fun and Competition, by James J. Trobaugh. This book is a must read for serious FLL teams.