LEGO Mindstorms

Understanding Rotations

An overview of a new unit of measurement for distance

Connecting to the robot

Before we get started, let's run the code from the last lesson. Plug your bot into your computer via USB. When the robot is successfully plugged in, the bottom right of your screen will change.

What you see are all of your 8 connection ports. In Port D, we have connected our Large Motor. On the right of the connection ports are 3 buttons: Download, Run, and Run Selected. We reccomend downloading, then pressing play directly on the robot. Otherwise, the robot will run while being connected. 

Run the program

Press the Download Button and unplug when finished.Turn on your robot, and locate the file you made using the arrow keys on the robot. Then, press play. Watch as the motor connected to your selected port moves!

What are rotations?

A rotation is when a motor is able to rotate a full 360 degrees. Every one of these is considered a rotation. In the last lesson, we programmed a move tank that moved one rotation. They are essentially used to measure the movement a robot should do based on the number of rotations done by the robot’s motors. When dealing with turns, the rotations sets the maximum number of rotations either of the motors can do before stopping that motion (the work done by the the single move block).

How do I measure rotations?

Measuring a rotation is pretty easy. Get a ruler that has centimeters on it. Run the program, and measure from the center of the wheel axle until it ends. This value is your Distance per Rotation.