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

/*
 * Title: TrafficLightSender
 * Author: Kevin McIntosh
 * Description:
 * SunSpot's LEDs will periodically switch between green, yellow, and red in order to simulate a traffic light.   
 * Also trasmits radio signals at different strengths using the dynamicSend() method
 * from the Beacon class.  
 * 
 * Pay close attention in keeping settings (port, channel, etc.) in synch with 
 * TrafficLightFinder SPOTBot.  Currently the Beacon class sets the default 
 * setting for this class. 
 */
package org.sunspotworld;

import com.sun.spot.sensorboard.EDemoBoard;
import com.sun.spot.sensorboard.peripheral.ITriColorLED;

import com.sun.spot.sensorboard.peripheral.LEDColor;
import com.sun.spot.util.Utils;
import java.io.*;
import java.util.Random;
import javax.microedition.io.Datagram;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

/**
 * A class intended to simulate a traffic light while simultaneously tranmiting 
 * radio strength signals.
 *   
 * @author Kevin McIntosh
 */
public class TrafficLightSender extends MIDlet {

    private static final int PACKETS_PER_SECOND = 5;
    private static final int PACKET_INTERVAL = 1000 / PACKETS_PER_SECOND;
    private static final int TOTAL_NUMBER_OF_STATES = 2;//Red light and green light.  Yellow light acts as a stall and is not a true state in this sense 
    private static final int THROW_OFF = 3000;
    private static int randomDigit = 1;
    private static Datagram data = null;
    private static ITriColorLED[] leds = EDemoBoard.getInstance().getLEDs();
    private static final int PORT = 41;
    private static final int DELAY = 1000;
    private static final int NUM_CYCLES = 20;
    private static Beacon sender = null;

    /**
     * Displays red in the LEDs
     */
    public static void redLight() {
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
            leds[i].setColor(LEDColor.RED);
            leds[i].setOn();
        }
    }

    /**
     * Displays green in the LEDs
     */
    public static void yellowLight() {
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
            leds[i].setColor(LEDColor.YELLOW);
            leds[i].setOn();
        }
    }

    /**
     * Displays green in the LEDs
     */
    public static void greenLight() {
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
            leds[i].setColor(LEDColor.GREEN);
            leds[i].setOn();
        }
    }

    /**
     * A method purely for show-off purposes.  Uses the LEDs to count-down from 
     * 3 to 0.
     */
    public static void countdown() {

        // 3
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
            leds[i].setColor(LEDColor.WHITE);
            leds[i].setOn();
        }
        System.out.println("Three");
        Utils.sleep(1000);

        // 2
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
        }

        for (int i = 0; i < 6; i++) {
            leds[i].setOn();
        }
        System.out.println("Two");
        Utils.sleep(1000);

        // 1
        for (int i = 0; i < 8; i++) {
            leds[i].setOff();
        }

        for (int i = 0; i < 4; i++) {
            leds[i].setOn();
        }
        System.out.println("One");
        Utils.sleep(1000);

    }

    
    private static void beaconSender() {

        try {
            sender = new Beacon(NUM_CYCLES, DELAY);

        } catch (IOException ex) {
            System.out.println("Error in creating setting for the Beacon");
        }

        try {
            sender.setCycles(1);
            sender.dynamicSend();
            System.out.println("So far it is working");
        } catch (IOException ex) {
            System.out.println("Error in sending");
        }
    }

    /**
     * Input a range of numbers.  The "range" will start from one and end with your number.
     * 
     * @param rangeOfDigits
     * @return A random digit within the givin range
     */
    public static int randomInt(int rangeOfDigits) {

        Random r = new Random();
        int randomNumber = r.nextInt(rangeOfDigits);
        randomNumber++;
        return randomNumber;

    }

    /**
     * Input a minimum and a maximum of a range of numbers.  
     * Returns a random digit within that range
     * 
     * @param lowerRange
     * @param upperRange
     * @return randomDigit
     */
    public static int randomInt(int lowerRange, int upperRange) {

        Random r = new Random();
        int randomDigit = r.nextInt(upperRange - lowerRange + 1);
        randomDigit = randomDigit + lowerRange;
        return randomDigit;

    }

    protected void startApp() throws MIDletStateChangeException {

        countdown();

        while (true) { //begin the search!!

            if (randomDigit == 1) {

                for (int i = 0; i < 1; i++) {

                    System.out.println("GO");
                    greenLight();
                    Utils.sleep(50);
                    beaconSender();
              
                    System.out.println("greenLight pass");

                    //Utils.sleep(randomInt(200, 500));

                }
                randomDigit = randomInt(TOTAL_NUMBER_OF_STATES);

            } else {

                System.out.println("Slow");
                yellowLight();

                //sendNewInt(SLOW);
                Utils.sleep(THROW_OFF); //the intention of yellowLight() is to throw off the searching algorythm.  Bassically, makes the signal harder to find

                System.out.println("Stop");
                //sendNewChar(STOP);
                redLight();
                Utils.sleep(4000);

                randomDigit = 1;
            }

            long nextTime = System.currentTimeMillis() + PACKET_INTERVAL;
            long delay = (nextTime - System.currentTimeMillis()) - 2;

            if (delay > 0) {
                Utils.sleep(delay);
            } else {
                Utils.sleep(PACKET_INTERVAL);
            }
        }



    }

    protected void pauseApp() {
        // This is not currently called by the Squawk VM
    }

    
    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.

 */