SunSPOTs

Overview

• Processor/Memory: 180MHz 32-bit ARM920T core processor with 512K RAM and 4M Flash 
• Networking: 2.4GHz radio with an integrated antenna on the board - IEEE 802.15.4 compliant - claim to reach distances of 80 meters
• Battery:  3.7V rechargeable, 750 mAh lithium-ion battery
• With both the CPU and the radio active the battery can support about 7 hours of operation. 
• Sensors
• a 3-axis accelerometer (with two range settings: 2G or 6G)
• a temperature sensor
• a light sensor
• 8 tri-color LEDs
• analog inputs, momentary switches, I/O pins
• OS: There is no operating system used. The Sun SPOT runs a Java VM on the bare metal. 
• Java ME compliant - CLDC 1.1 and MIDP 1.0

Mobile Information Device Profile (MIDP)/ Connected Limited Device Configuration (CLDC)

• CLDC - basic set of libraries present in J2ME
• MIDP - moble phone/PDA proile  for CLDC.  Together, MIDP/CLDC comprise the complete runtime environment.

MIDlets

• startApp 
• destroyApp
• pauseApp

package org.sunspotworld.demo;

import com.sun.spot.sensorboard.EDemoBoard;

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

import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class HelloWorld extends MIDlet {

    private ITriColorLED leds[] = EDemoBoard.getInstance().getLEDs();

    protected void startApp() throws MIDletStateChangeException {
        System.out.println("Hello, world!");
        for (int i = 0; i < leds.length; i++) {
            leds[i].setColor(LEDColor.BLUE);
            leds[i].setOn();
        }
    }

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

    /**
     * Called if the MIDlet is terminated by the system.
     * I.e. if startApp throws any exception other than MIDletStateChangeException,
     * if the isolate running the MIDlet is killed with Isolate.exit(), or
     * if VM.stopVM() is called.
     * 
     * It is not called if MIDlet.notifyDestroyed() was called.
     *
     * @param unconditional If true when this method is called, the MIDlet must
     *    cleanup and release all resources. If false the MIDlet may throw
     *    MIDletStateChangeException  to indicate it does not want to be destroyed
     *    at this time.
     */
    protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
    }

}

Running a Program

• To compile and deploy your program, one option is to use the NetBeans IDE.  (There may also be an eclipse plugin somewhere if you want to look for it.)  You can also build/deploy/run from the command line.
• If you run your program with the SPOT attached to the USB cable, standard output will be displayed on the console.  This can be very helpful for debugging.
• The name of the initial class to be run must be specified in resources/META-INF/MANIFEST.MF.  Make sure you change this value if you intend to change the initial class.
• Following are the commands you will find most useful:
• ant jar-app - compile the project and build a jar
• ant info - display information about the connected device
• ant jar-deploy - deploy the application to the connected SPOT
• ant run - run the application
• ant deploy - compile and deploy
• ant deploy run - compile, deploy, and run
• When in doubt, reset the spot.  During the deploy phase, you will typically see [waiting for reset].  Once an application has been deployed, you will need to disconnect the SPOT and reset it in order to start it.

Linux Setup

• You will need to use Linux if you plan to do development on the lab machines.  The sdk is not installed on the windows side.
• The SDK is installed at /usr/java/SunSPOT.  You can navigate there and open the demos.  In order to compile them you will need to make a local copy.
• In order to build/run, you will need a copy of the .sunspot.properties file in your home directory.  You can download it from here.  Make sure you save it in your home directory as .sunspot.properties.

Other SPOT Information

• By default, deep-sleep mode is enabled.  This means that whenever the SPOT can, it will enter a deep-sleep state during which it cannot receive/route messages or perform any other computation.  The SPOT will enter this state if no thread will be ready to run in the next 2-3 seconds.  This is useful for saving battery, but not useful if you want the SPOT to proccess or route data.  The ISleepManager class can be used to enable/disable deep-sleep mode.
• There are two types of network communication available: the radiostream protocol and the radiogram protocol.  "The radiostream protocol provides reliable, buffered, stream-based communication between two devices.  The radiogram protocol provides datagram-based communication between two devices."

Date: 2008-03-27