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 attention 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 {
    }
}

/*
 
Copyright 2008 The SPOTBot Team

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

 */