1. REU 2009- LEGO MINDSTORMS NXT SOCCER Kenneth Mendoza, Paul Balda, Abimilex Reverón & Mentor : Andres Buss Molina Department of Computer Science & Engineering INTRODUCTION Main goal of the project is to assemble and program 3 LEGO Mindstorms NXT robots autonomously to play soccer. With this in mind it has led many creative minds to create a robotic soccer competition at an international level. Many of the rules have been developed with the FIFA laws in mind to create a basic model with minor deviations. These deviations are necessary because of certain limitations of Artificial Intelligence. SOFTWARE ROBOTC for Mindstorms – This is the software we are using to program the speed and direction of the motors, scanning objects using Ultrasonic Sensors and detecting boundaries using the Light Sensor. This software also allowed for integration between the NXT and camera NXTCAM developed by Mindsensor for image processing. Control the camera using ROBOTC.Use the library that has been created for the camera. How the camera manages the colors that are stored in the NXT for reference? The camera will only recognize the colors that have been stored and when it recognizes a color it then assigns some coordinates. Red and Blue are the colors that the camera recognizes the best. This is why red and blue were used for the goal area. Robot positionThe robots locate the center of the field using the data being obtained from the camera. To recognize the ball.The robot uses the data it has obtained from the camera to locate the ball. Follow the ball and move the motors as fast as the ball. Move MotorB= -[(Δy -Δx)/Ball Area] Move MotorC= -[(Δy+Δx)/Ball Area] If Δy =+ and Δx=-, Δy =- and Δx=- the ball is moving to the left If Δy =- and Δx=+, Δy =+ and Δx=+ the ball is moving to the right Kick the ballOnce the ball is located the robot moves towards the ball. Before losing the ball from it’s “Blind Spot” the robot accelerates forward. The robot loses the ball.The Robot records the last coordinate position and responds accordingly. To score a goal.Once the Robot has the ball and knows which goal to score it then proceeds towards it at various angles to kick the ball. Basic operation of the ‘Goal keeper’ and logic. 1. How to detect opponent using sonar? To detect the opponent the robot uses three sonars and relies on the values received. These values represent the distance of the object being detected. 2. How to prevent opponent form scoring? To prevent the opponent from scoring, the motor movement configuration is placed under the tree configuration of the sonar. While receiving a value from the sonars, the motors are on standby until the set value in an if-else statement has been met. Once the condition has met the specified range represented by a value the motors engage in the direction for the detected object. 3.How to stay within the boundaries of the Goal box? To stay within boundaries the Robot ‘Goal keeper’ is equipped with an Infrared light( I.R.). The I.R. detects various colors and shades; in fact, bright colors have a high I.R. value and the dark colors have a low I.R. value. Therefore, the Goal keeper’s boundaries are marked with white and the field a dark forest green. 4.How to return to center of the defending goal box? The motors have a build in sensor in the gears that keep track of the rotations. Based on how many rotations in the positive or negative direction towards the detected object that will be the number of rotations the robot will rotate back to the original position. Tasks and solutions - Forwards