root/Projects/TrafficLightFinder/src/org/sunspotworld/TrafficLightFinder.java

/*
 * Title: TrafficLightFinder (Abstract)
 * Author: Kevin McIntosh
 * Description:
 * SPOTBot will search for the SunSpot running TrafficLightFinder.  
 * The "Traffic Light" will broadcast a radio signal, which a SPOT running this 
 * class will look for.  If the traffic light is green, the SPOT will resume the search
 * for the traffic light until the LED state changes to yellow.  This is where the
 * SunSPOT will be thrown off its search, and will attempt to "slow down" by heading 
 * forward for a number of seconds.  Finnaly, when the traffic light state changes to
 * red, the SunSPOT will stop. 
 * 
 * Pay close attemtion in keeping settings (port, channel, etc.) in synch with 
 * TrafficLightSender sunSPOT.  Currently, the settings are the default setting of
 * the BeaconListener class  
 */
package org.sunspotworld;

import com.sun.spot.util.*;
import java.io.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

/**
 * A class used to find the location of a SunSPOT running TrafficLightSender
 * 
 * @author Kevin McIntosh
 */
public class TrafficLightFinder extends MIDlet {

    private static TekBotMotorControl mcu = new TekBotMotorControl();
    private static BeaconListener listen = new BeaconListener ();
    private static int nowPower = 0;
    private static int newPower = 0;
    private static boolean ready = false;
    private static boolean green = true;

    /**
     * This is the area where you will write your searching algorythm.
     * @throws java.io.IOException - Thrown if the TrafficLightSender 
     * stops transmitting
     */
    public static void search() throws IOException {
        int count = 0;
        System.out.println("nowPower is currently set at: " + nowPower);
        mcu.forward();
        System.out.println("forward");
        newPower = listen.getBeacon(1000);
        System.out.println("The newPower is at: " + newPower);
        if (newPower < nowPower) {
            System.out.println("Insufficent power: Backing up");
            mcu.backward(1000);
            mcu.turnLeftDegrees(60);
            count++;
        } else {
            System.out.println("Sufficent Power: moving forward");
            mcu.forward();
            nowPower = newPower;
        }
        if (count == 4){
            count = 0;
            nowPower = -32;
        }
        System.out.println("The power being read is: " + nowPower);

    }

    protected void startApp() throws MIDletStateChangeException {

        while (ready == false) { //this while loop is before the SunSPOT begins the search
            
            try {
 
                nowPower = listen.getBeacon();
                System.out.println(nowPower);
                ready = true;
                
            } catch (IOException e) {
                mcu.stop();
                System.out.println("Waiting..");
            }
        }

        while (true) { //main while loop for the rest of the application

            try {
                while (true) { //need to be worked on

                    search();
                    System.out.println("Green Light; begin moving");

                }
            } catch (IOException e) {
                System.out.println("Yellowlight, begin to yield");
            }
           
                mcu.forward(1500);
                mcu.stop();
                System.out.println("At a red light");
                Utils.sleep(4000);
                            
        }
    }

    protected void pauseApp() {
    }

    protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
    }
}