Java Sun SPOT Application Development using Java ME (J2ME)

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Let your Java app "feel the wind" on its face (BuiltInSensorsDemo.java)


/*
* Copyright (c) 2006 Sun Microsystems, Inc.
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to 
* deal in the Software without restriction, including without limitation the 
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
* sell copies of the Software, and to permit persons to whom the Software is 
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in 
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
* DEALINGS IN THE SOFTWARE.
 **/       
package org.sunspotworld.demo;

/*
 * BuiltInSensorsDemo.java
 *
 * Illustrates use of the on-board sensors.
 * Intended as a starting template for building your own app.
 * For radio, see the RadioStrength demo.
 *
 *    This app waits for you to hold down SW1. While down, LED1 will
 *    Show green if shaken left to right.
 *    Once the button is released, it will show the temperature
 *    on LED1 (either red or blue), and the light level on LED2 in green.
 *
 * author: Randy Smith  
 * date: August 2, 2006 
 */ 

import com.sun.spot.sensorboard.EDemoBoard;
import com.sun.spot.sensorboard.io.IScalarInput;
import com.sun.spot.sensorboard.io.ITemperatureInput;
import com.sun.spot.sensorboard.peripheral.ITriColorLED;
import com.sun.spot.sensorboard.peripheral.ISwitch;
import com.sun.spot.sensorboard.peripheral.ILightSensor; 
import com.sun.spot.sensorboard.peripheral.LEDColor;
import com.sun.spot.util.Utils;
import java.io.IOException;

import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
 
public class BuiltInSensorsDemo extends MIDlet {  
    private ISwitch sw1                  = EDemoBoard.getInstance().getSwitches()[0];  
    private ISwitch sw2                  = EDemoBoard.getInstance().getSwitches()[1];  
    private ITriColorLED leds[]          = EDemoBoard.getInstance().getLEDs();
    private ILightSensor lightSensor     = EDemoBoard.getInstance().getLightSensor();  
    private ITemperatureInput tempSensor = EDemoBoard.getInstance().getADCTemperature();
    private IScalarInput accelX          = EDemoBoard.getInstance().getAccelerometer().getXAxis();
    
    private double accelNullPoint = 465.5;  //Theoretically, should be the reading when at rest.

    /**
     * Main application loop.
     * IOException is thrown by reading the acclerometer, temperature, or light.
     */
    private void run()throws IOException {  
        for(int i = 0; i < leds.length; i++){
            leds[i].setOn();                    // Enable this LED
            leds[i].setRGB(0,0,0);              // Set it to black
        }
        leds[0].setColor(LEDColor.TURQUOISE);   // See LEDColor for more predefined colors.
        
        /*
         * Wait for user to hold down SW1. Indicate left-right shaking in green light 
         * on the first LED
         */
        if(sw1.isOpen()) sw1.waitForChange();   // If it is open, wait for SW1 to close...
        while(sw1.isClosed()){                  // ...and while closed register shaking.
            double lateralShake =  accelX.getValue() - accelNullPoint;
            leds[0].setRGB(0, (int) (lateralShake * lateralShake / 100.0), 0);
            Utils.sleep(100);                   //Like Thread.sleep(..) but catches and ignores an InterruptedExceptionn.
        }
        
        /*
         * Now that the user has released SW1, we indicate ADC chip temperature on LED[0],
         * and light level on LED[1]. 
         */
        while(true){
            // heatIndication is scaled so that reaching 20 degrees away from 72 gives the maximum LED brightness (255)
            int heatIndication = (int) ((tempSensor.getFahrenheit() - 72.0) * 255.0 / 20);
            if(heatIndication > 0){
                leds[0].setRGB(heatIndication, 0, 0);                  //above 72 degrees (room temp) in red
            } else {
                leds[0].setRGB(0, 0, - heatIndication);                //below 72 degrees (room temp) in blue
            }
            
            int lightIndication = lightSensor.getValue();              //ranges from 0 - 740
            leds[1].setRGB(0, lightIndication / 3, 0);                 //Set LED green, will range from 0 - 246
            Utils.sleep(200); 
        }
    }

   
    /**
     * The rest is boiler plate code, for Java ME compliance
     *
     * startApp() is the MIDlet call that starts the application.
     */
    protected void startApp() throws MIDletStateChangeException { 
        try {
            run();
        } catch (IOException ex) { //A problem in reading the sensors. 
            ex.printStackTrace();
        }
    }

    /**
     * This will never be called by the Squawk VM.
     */
    protected void pauseApp() { 
    }

    /**
     * Only called if startApp throws any exception other than MIDletStateChangeException.
     */
    protected void destroyApp(boolean arg0) throws MIDletStateChangeException { 
    }

}
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