http://www.wellho.net/regex/javare.html

Java Regular Expressions   java.util.regex

My first encounter with regex happens when I was using String.split() function. The split char is represented by special char used by regex. I thought the function is easy to use but is spending a lot of time figuring why the string cannot be split. I was splitting the IP address which is separated by the '.' dot or period. My colleague drop me some notes from the website, and now I finally know what really happen. Great article I must say.

Class typically use for wild card search in String.

The following are some char keyword in used by the regular expressions class. In order to use the char, use \ followed by the char or insert the printable string between \Q and \E

metacharacters->   ([{\^-$|]})?*+.

There are more about regex than I thought after searching the web.

http://en.wikipedia.org/wiki/Regular_expression

regex example

String str = "This is a sentence. This is a question, right? Yes! It is.";
String delims = "[ .,?!]+";
String[] tokens = str.split(delims);

String str[] = result.split("HWaddr | \\. |inet addr:| \\. |Bcast:| \\. |Mask:| \\. |UP", 6);
This splits the following chunck of text into

eth0 Link encap:Ethernet HWaddr b8:27:eb:87:9e:02
 inet addr:192.168.1.97 Bcast:192.168.1.255 Mask:255.255.255.0
 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
 RX packets:4670 errors:0 dropped:0 overruns:0 frame:0
 TX packets:2034 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:1000
 RX bytes:526428 (514.0 KiB) TX bytes:257010 (250.9 KiB)

str[0] -> eth0 Link encap:Ethernet
str[1] -> b8:27:eb:87:9e:02
str[2] -> 192.168.1.97
str[3] -> 192.168.1.255
str[4] -> 255.255.255.0
str[5] -> BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
 RX packets:4599 errors:0 dropped:0 overruns:0 frame:0
 TX packets:1960 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:1000
 RX bytes:522426 (510.1 KiB) TX bytes:249420 (243.5 KiB)
      

package sg.com.siongboon.mypackage; //Basic java class structure. Using a domain name as your package, ensures that it will likely to be a unique namespace.

public class ClassName
{
  private int myResult;

  static
  {
    //Similar to constructor which will be executed
    //before the object is created.
    //It can be use like a constructor for your static class object,
    //where a constructor is not allowed.
    //static initializer block, it is seldom used (see example on *.dll)
  } 

  public ClassName()
  { //class constructor
  }  

  public methodOne()
  { 
  }

  final public methodOne()
  { //method cannot be overriden by other class extending it
  }

  static public methodOne()
  { //method is the only instance. It will be common to all the class object
  }

  protected void finalize()
  { //method gets called when it is about to be delete by the garbage collector.
    //Should not be use as it is imposible to know when the object will get deletes.
  }

  public static void main(String args[])
  { //entry point for running this program
  }
}

//A simple illustration of Java access modifier, Private, Default, Protected, Public

Java access modifier:

public- Variables/methods using public modifier can be access easily by all objects.

protected- Protected members can be accessed by another package through inheritence. Class CC managed to access protected member C through inheritence. Class CC inherited Class AA, therefore member C becomes part of Class CC.

default- If there is no modifier specified, Java will treat it as the default modifier. Default members B gets a bit more difficult to access. Only classes within the same package can access to it. Member B using the default modifier can be access by Class BB. Class BB can creates an instance of Class AA or through static variable access to access to member B.

private- is the most restrictive modifier. The private member A can only be access within the class AA itselfs. Class AA being the creator, is able to access all it’s members A, B, C and D. It is recommended to start the data/method encapsulation using private modifier. Change the modifier when neccessary. There must be a good reason why private modifier is not use.

Future research the meaning on these defination:

What do these defination really means?

//defining a common interface for objects
public interface LiftButton
{
  //define all the methods/interface in the class
  public void openLiftDoor();
  public void closeLiftDoor();
  public void pressLiftFloor(int floorLevel);
  public void alarm();
}

Very often in our physical world, we share a common interface with many different type or brand of system.

Example is our elevator lift. The interface buttons are the same/similar in each brand of lift. The user need not require training in order to use the lift, because the operating procedure is the same as what the user has used before.

The same goes for our computer system. Each computer may be run by various brand/model of CPU/hardware/OS, but the keyboard/mouse interface remains the same.

Defining an interface helps us to define a common standard, such that when it comes a day where we need to swap an object (change CPU model), we can easily change it with minimal or without any effect on the system.

It is mentioned by Jim Waldo, in his book “Java The Good Parts”, that passing parameters through the method is evetually going to be of some sort of interface. You can pass parameters using object, but later down the road, there is a high chance that it will be later change to an interface as the coding grows comre sophisticated.

//Java do not have unsigned data type
//Representation of the unsigned for a signed data type.
byte temp;
int result;
result=(int)(temp[0]&0xFF);   //extract the unsigned value

long longNum = 289637082704667748;   //The literal 289637082704667748 of type int is out of range

long longNum = 289637082704667748L; //if the literal value is too big, L is required at the back

int result=(int)((1.26)+0.5);         //rounding off to the nearest integer




//'f' indicates that 1.5 is of data type float rather than a double.
//(any literal is intepreted as a double and not a float)
float x = 1.5f ;  
double x = 1.5;

//'l' indicates that 10000000000 is of data type long rather than a int .
//(any literal is intepreted as a int and not a long )
int x = 15 ;  
long x = 10000000000l;



//declare & allocate memory for byte & char array
byte remoteIP[] = new byte[4];
byte[] dataByte = new byte[]{(byte) 0xDB, (byte) 0xA1};
char[] dataBuf = new char[100];//declare & allocate memory for byte

//converting a byte array for string use
String dataStr = new String(dataByte,"ISO-8859-1");
//converting back to byte array after String manipulation
byte[] dataByte = dataStr.getBytes("ISO-8859-1"));

//Earlier method. (ineffective)
//Please note that byte data maybe lost after converting to string using this method.  
//The conversion uses a default charsetName; 
//if charset is not able to map the data to a char, it could convert it to the data 0x3F.
//In some case, a char 0xC2 may be inserted before a char which is > 0x7F.
String dataStr = new String(dataByte);
String dataStr = new String(dataByte,"US-ASCII");

//converting a string to byte[]
byte[] dataByte = dataStr.getBytes();
//converting a byte to char for string use (convert a byte to char)
char dataChar = (char) 0xDB;
//converting a byte to string for string use (convert a byte to String)
String str = String.valueOf((char)ch);
//more methods for dealing with bytes 
ByteBuffer byteBuffer = ByteBuffer.allocate(10);
byteBuffer.put(0x01);

for information about charset encoding.

http://www.anyang-window.com.cn/tag/java-encoding/page/3/

s = s.replaceAll("\\s","");      //remove invisible \r \n char
s = s.trim();                    //remove white space

//formatting a string like printf or sprintf
String str = String.format("Number=%2d, %f", 5, 1.56); //result>"Number= 5, 1.56"
String str = String.format("Leading Zero=%04d", 5); //result>"Leading Zero=0005"
String str = String.format("Hex value=0x%04x", 79 ); //result>"Hex value=0x004F"


DecimalFormat formatV = new DecimalFormat("###0.00");    //floating value to 2 decimal place
String str = String.format("%6s",formatV.format(value)); //right align
//value =  0.91, result -> "  0.91"
//value = 21.91, result -> " 21.91"
//value = 12   , result -> " 12.00"

//rounding off float double value to 2 decimal place
float unround = (float) 0.34456;
double roundOff = Math.round(unround*100)/100D;    //rounding off to 2 decimal place
logger.info((float)roundOff);                      //result = 0.34
    
float unround = (float) 0.34556;
double roundOff = Math.round(unround*100)/100D;    //rounding off to 2 decimal place
logger.info((float)roundOff);               


//convert a float or double to a more precision BigDecimal
BigDecimal precision = new BigDecimal(0.34556);    //try not to use a double or float converting to a BigDecimal. It will result in additional trailing numbers because floating number is never exact. Use String instead to be accurate.
BigDecimal precision2 = new BigDecimal("0.34556");

precision = precision.setScale(2, BigDecimal.ROUND_HALF_UP);  //setup BigDecimal to 2 decimal place, and round up.

precision = precision.setScale(2, BigDecimal.ROUND_HALF_EVEN);//Banker's Rounding (rounding to the even if number is in the middle 0.5 or 0.05, etc...)
//example: 0.1265 (3 decimal place) should be round to 0.126
//example: 0.12651 (3 decimal place) should be round to 0.127
//example: 0.1275 (3 decimal place) should be round to 0.128
//example: 0.1285 (3 decimal place) should be round to 0.128

Right align a 2 decimal place floating number.

If encounter floating point error while using a variable of float data type, try changing to the data type double or use int data type instead. If precision is absolutely necessary, use the object BigDecimal.

private enum BonjourService
{    
  //use enum if there is a fix defined number of constant
  //enum can help to restrict the number input choice for
  //the programmer to feed it into the method
        CAMERA, HTTP, PRINTER, IPP, PDL_DATASTREAM
}

private String getServiceProtocolName(BonjourService service)
{
  String servStr;
        if(service==BonjourService.CAMERA)
            servStr = "_camera._tcp";
        else if(service==BonjourService.HTTP)
            servStr = "_http._tcp";
        else if(service==BonjourService.PRINTER)
            servStr = "_printer._tcp";
        else if(service==BonjourService.IPP)
            servStr = "_ipp._tcp";
        else if(service==BonjourService.PDL_DATASTREAM)
            servStr = "_pdl-datastream";       
}

String str = "(" + BonjourService.CAMERA + ")";
String str = "(" + BonjourService.CAMERA.toString() + ")";
//str="(CAMERA)", enum variables can also be used as String object.


public enum BonjourService
{
  CAMERA("camera"),
  HTTP("http"),
  PRINTER("printer");

  //constructor cannot be public
  //constructor allows multiple parameters, so that
  //the enum can represent more than 1 parameter.
  private final String name;

  private BonjourService(String name)
  {
    this.name = name;
  }

  public String toString()
  {
    return name;
  }
}

Toolkit.getDefaultToolkit().beep(); //error beep tone (sound, bell)

Singleton structure will ensure that the class object can only be created once. Constructor has to be defined as private while the class variable & getInstance method is static so that they can be access with the object being created.

This is the first question that I ask myself when designing a new class object even since I learned about it; whether it can be created with multiple instance or only a single static instance of the object. In some application, especially when working with hardware devices, single instance is the only proper way to built your class. It can helps you to prevent mis-written codes, resulting in less bugs/crush program when the class is used by another programmer.

Instant timestamp = Instant.now();	//newer form of Timestamp method. (Java 8)
LocalDateTime timestamp2;               //
LocalDate date;	                        //immutable object. Cannot be changed once it is created (Java 8)
LocalTime time;	                        //immutable object. Cannot be changed once it is created (Java 8)

LocalDate date = LocalDate.now();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy MM dd");//formatter
String text = date.format(formatter);					//format date
LocalDate parsedDate = LocalDate.parse(text, formatter);		//parse date

//Timestamp string, output string "2010-03-08 14:59:30.252"
java.util.Date date= new java.util.Date();
logger.info(new Timestamp(date.getTime()));

//Calendar, Date, Time (data & formatting function)
Calendar cal;
cal = Calendar.getInstance();
int hourday = cal.get(Calendar.HOUR_OF_DAY);  //24 hour format
int hour = cal.get(Calendar.HOUR);            //12 hour format
int am_pm = cal.get(Calendar.AM_PM);          //
int minute = cal.get(Calendar.MINUTE);
int sec = cal.get(Calendar.SECOND);
int msec = cal.get(Calendar.MILLISECOND);

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MMM-dd (EEE)");
SimpleDateFormat sdf2 = new SimpleDateFormat("hh:mm:ss aaa");
String data = sdf.format(cal.getTime());               //Format string for date, time
String time = sdf2.format(cal.getTime());

DateFormat df = new SimpleDateFormat("yyyy-mm-dd");
Date dataObj = df.parse("2014-02-25");                 //Parse string for date, time


log4j
Example: FactoryLog for logging info, error, debug, etc messages.

Similar to System.out.println();

Save to project folder /lib /lib (factory logger).zip

Save to project folder /resource /resource (factory logger).zip

(Details of log file setup can be found in the file “log4j.properties”.

Includes a 2nd example to config Log4j for logging in Tomcat.)

Log4j references:
http://logging.apache.org/log4j/1.2/manual.html
http://juliusdavies.ca/logging.html
http://www.laliluna.de/articles/log4j-tutorial.html

//Using LogFactory for debugging & logging example.
//Remember to include the path to "lib" & "resources" in the classpath
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

protected static transient final Log logger = LogFactory.getLog(ClassName.class);

logger.error("");
if(logger.isDebugEnabled())
    logger.debug("Class name:<" + getClass().getSimpleName() + ">");
logger.info("Class name:<" + this.getClass().getName() + ">");  //print out the class name

//print out the method name
logger.info("Method name:<" + new Exception().getStackTrace()[0].getMethodName() + ">");
logger.info("Method name:<" + Thread.currentThread().getStackTrace()[1].getMethodName() + ">");

How to add *.jar library?Encountered the following errors?log4j:WARN No appenders could be found for logger (javax.swing.JApplet).
log4j:WARN Please initialize the log4j system properly.
Remember to add in the libraries in your project classpath. For Eclipse IDE the classpath is indicated in the .classpath in the project root directory.Alternative you can add the lib as follows in Eclipse:1) Right click on your project name (under “Package Explorer”) and click “Properties” 2) Select “Java Build Path”, and choose tab “Source”. Add the folders “lib” & “resource” under your project folder. 3) Choose tab “Libraries”. Click “Add JARS…” and add the “commons-logging-1.1.jar” & “log4j-1.2.14” library files. 4) Done.

//Two examples to print out error messages:
e.printStackTrace();
System.out.println("Got an IOException: " + e.getMessage());

logger.error("Got an IOException: ", e);

Example: File Write

Very often to specify a file path using a string, we need to use double slashes instead of only one in Java string.

C:\\Users\\Harald\\Folder1\\Version1\\Folder2.

This is because a slash ‘\’ is a escape char in a string. In order to indicate a ‘\’ intention, we need to put 2 slashes. This means that it will be quite odd to a typical computer user as we usually uses only one slash.

One method is to use back slash instead of forward slash. The file object classes will automatically treat ‘/’ back slash as the normal ‘\’ slash in Window OS.

Old was of specifiying the path,

processDirectory=”D:\\doc\\Expenses Invoice”

A solution of specifying the path,

processDirectory=”D:/doc/Expenses Invoice”

This solution, means that the user need not specify double slash, which can be quite confusing.

Writing an class object into a file, and reading the class obj back from the file. This acts as a means to permanently save the state or values store in the object that you have created.

There are also codes written to generate files, so that you can detect where your config files are stored in the user or project directory.

This class monitor new files added or removed from the directory. The class extends TimerTask which execute the run process every seconds.

Check out below (WatchService class) for newer methods of monitoring files and directory.

//Reading a data stream with non-blocking mode 
private OutputStream out = null;
private InputStream in = null;
out = new DataOutputStream(sp.getOutputStream());
in = new DataInputStream(sp.getInputStream());
byte byteRead = in.read(); // -1 if there is no data 


//reading the int data stream from a binary file
import java.io.*;
import java.util.*;

public class BinOutputFileApp
{
  public static void main(String arg[])
  {
    try
    {
      FileInputStream fis = new FileInputStream("binary.dat");
      DataInputStream in = new DataInputStream(new BufferedInputStream(fis));
      int a = in.readInt();
      int b = in.readInt();
      System.out.println(a); //print int "42"
      System.out.println(b); //print int "45"
    }
    catch (IOException e)
    {
      e.printStackTrace();
    }
  }

Project example: reading_int_datastream.zipExample of the data in the binary.dat file:0x00 0x00 0x00 0x2A 0x00 0x00 0x00 0x2DActual int content represented in the binary file above:42 45

Other very good reference:- http://www3.ntu.edu.sg/home/ehchua/programming/java/J5b_IO.html (very good NTU website on data stream by Chua Hock Chuan),

Java Input & Output Stream (by Chua Hock Chuan).pdf

Note: There is another better generic methods to read *.properties. Read more about “Apache Common configuration”. Commons Configuration provides a generic configuration interface which enables a Java application to read configuration data from a variety of sources. Commons Configuration provides typed access to single, and multi-valued configuration parameters.

Note:
Class loader resources are often read-only; i.e. held in read-only files / read-only directories.
ClassLoader cl = getClass().getClassLoader();
Unable to obtain classloader using a static class.

Use Java Preferences API instead for configurable preferences.

Properties prop = new Properties();

try
{
  //set the properties value
  prop.setProperty("database", "localhost");
  prop.setProperty("dbuser", "mkyong");
  prop.setProperty("dbpassword", "password");

  //save properties to project root folder
  prop.store(new FileOutputStream("resource/config.properties"), null);
}
catch (IOException ex)
{
  ex.printStackTrace();
} 

//Writing or printing to PDF file.


Using PDFBox.

Download library pdfbox-app-2.0.0.jar

//Example of using Java to read excel *.xls or calc *.ods file

import org.jopendocument.dom.spreadsheet.MutableCell;
import org.jopendocument.dom.spreadsheet.Sheet;
import org.jopendocument.dom.spreadsheet.SpreadSheet;

//Getting the 0th sheet for manipulation| pass sheet name as string
spreadSheet = SpreadSheet.createFromFile(file).getSheet(0);
          
//Get row count and column count
int nColCount = spreadSheet.getColumnCount();
int nRowCount = spreadSheet.getRowCount();

System.out.println("Rows :" + nRowCount);
System.out.println("Cols :" + nColCount);
//Iterating through each row of the selected sheet
MutableCell cell = null;
for(int nRowIndex = 0;nRowIndex < nRowCount;nRowIndex++)
{
    //Iterating through each column
    int nColIndex = 0;
    for(;nColIndex < nColCount;nColIndex++)
    {
      cell = spreadSheet.getCellAt(nColIndex, nRowIndex);
      System.out.print(cell.getValue() + " ");
    }
    System.out.println();
}

This example shows how you can use java to detect the processes running under the Windows Operating System. It can a mean to detect if another Windows application or service or task is currently running.

If can even list out all the currently running processes.

The string user.name is the string key required to retrieve the system variables string. The following list present the other possible system variable that you can retrieve from System.getProperty(keyString);

Add your own variables to the java environment system variables.

java YourProgram -D keyString=”mystring”.

example:
java myJavaProgram -D sg.myhomedir=”E:\myJaveProjects\”

//Threading example
public class myThreadClass extends Thread
{
  //flag to control process flow to be in syn with other critical function
  private static boolean fIsSynProcess=false;
  //object holding the reference to this thread
  private Thread thisThread = null;

  public myThreadClass()
  {
  }

  public void run()
  { //getting the thread process ID
    this.thisThread = Thread.currentThread();
    String threadName = getClass().getName() + ” : ” + this.thisThread.getName();
    logger.info(“…thread Started: ” + threadName);

    while((!isStopRequested()))
    {
        while((!isSynProcess())) 
        {
        }
    }
    logger.info(“…thread Stopped: ” + threadName);
  }

  private synchronized boolean isStopRequested()
  {
    if(thisThread==null)
      return(true);
    return(false);
  }
  
  public void requestStop()
  {
    Thread tempThread = thisThread;
    thisThread = null;
    //interrupt for used to exit from blocking function in the run() method's while loop
    if (tempThread != null)
      tempThread.interrupt();
  }

  private synchronized boolean isSynProcess()
  {
    return(fIsSynProcess);
  }

  private synchronized void holdThreadRun()    //prevent the run thread to terminate
  {
    fIsSynProcess=true;
  }

  private synchronized void releaseThreadRun()    //allow the run thread to terminate
  {
    fIsSynProcess=false;
  }
}

The thread example also illustrate the use of the keyword “synchronized“. The java run time will ensure that those methods which are labelled as synchronized will not be excuted in parallel. This is to prevent two or more processes to access the same variable/memory which will cause data corruption or process locked issue. A program base on threading algorithm is likely to face such problems that can be resolved by implementing “synchronized“.For more explaination on synchronized, please refer to the following,

http://download.oracle.com/javase/tutorial/essential/concurrency/syncmeth.html

//Another method of writing thread
Object obj = new Object();
new Thread(obj).start();
Object class must contain a method run();

//Object class must implements Runnable and that contains a method run();



this.setDaemon(true); explains: setting daemon to true, will ensure that this thread is spin off from the main’s method thread. When a program execute from main entry point, main itself is actually a thread. If daemon is set to true, the sub-thread spinoff will be under the main thread. When the main thread is terminated, all sub thread will be terminated, shutdownhook can also be activated. If daemon is set to false, the thread spin off as another separated thread by its own. When the main thread is terminated, the sub thread will still exists (with daemon set to false).

public class ThreadClassShutdownHook extends Thread
{
  protected static transient final Log logger = LogFactory.getLog(ThreadClassShutdownHook.class);

  private myThreadClass tc;
  
  public ThreadClassShutdownHook(myThreadClass tc)
  {
    this.tc = tc;
    logger.info(this.getClass().getName() + " created. ShutdownHook registered.");
    Runtime.getRuntime().addShutdownHook(this);
  }
  
  public void remove()
  {
    Runtime.getRuntime().removeShutdownHook(this);
  }
  
  public void run()
  {    if(tc != null)    {
      logger.info("ShutdownHook activated for " + this.getClass().getName()
      + ". Thread: " + Thread.currentThread().getName());
      tc.requestStop();    }
    else    {
      logger.info("ShutdownHook safely release for " + this.getClass().getName()
      + ". Thread: " + Thread.currentThread().getName());
    }

  }
}

public class Abc implements ShutdownHookClass
{
  protected static transient final Log logger = LogFactory.getLog(Abc.class);

  private myThreadClass tc;
  private Shutdownhook sdh;
  
  public Abc()
  {
    sdh.addShutdownHook(this);
  }

  @Override
  public void shutdownHookActivated()
  {
    close();
  }
  
  public void close()
  {
    if(sdh != null)
    {
      sdh.remove();
      sdh = null;
    }
  }
}

Implementing Shutdownhook using my utilities.jar file. Download the latest version from the section under “My Java Library“

//-----------------------------------------------------------------------------
//Using Desktop class to open file, so that the code will be OS platform independent
//The default application will launch automatically with the file.
//-----------------------------------------------------------------------------
String fileName = "resource/documentation/operating manual.pdf";
try
{
  Desktop.getDesktop().open(new File(fileName));
}
catch(IOException e)
{
  logger.info("Error opening file " + fileName + ". The default program to open this file may not been set. Please set the default program.");      
}

//opening a file on the project root directory
Desktop.getDesktop().open(new File("image.gif"));
//opening a file relative to the project directory
Desktop.getDesktop().open(new File("imageDir\\image.gif"));
Desktop.getDesktop().open(new File("imageDir/image.gif"));
//opening a file using absolute file name
Desktop.getDesktop().open(new File("d:\\myproject\\imageDir\\image.gif"));
//opening a pdf file
Desktop.getDesktop().open(new File("d:\\mypdf.pdf"));

//-----------------------------------------------------------------------------
//Non platform independent code. (for Window OS)
//-----------------------------------------------------------------------------
//Open gif image file
Process p1 = Runtime.getRuntime().exec("rundll32 SHELL32.DLL,ShellExec_RunDLL " + "d:\\myproject\\imageDir\\image.gif");
//Open pdf file
Process p2 = Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler d:\\mypdf.pdf");

//force close the opened file
p1.destroy();

//-----------------------------------------------------------------------------
//Opening a Openoffice calc template (*.ots) as a calc file (*.ods)
//Using Desktop.getDesktop().open() will open the *.ots template file instead of a *.ods calc file
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
//Using Desktop class to open directory/folder, so that the code will be OS platform independent
//-----------------------------------------------------------------------------
//opening a local directory/folder.
Desktop.getDesktop().open(new File("D:\\programs\\eclipse\\_workspace\\InvoiceDataExtractor"));
//opening a remote network drive using network name/path.
Desktop.getDesktop().open(new File("\\\\BOB-PC\\Bob share folder"));
//opening a remote network drive using IP address.
Desktop.getDesktop().open(new File("\\\\192.168.1.95\\Bob share folder"));


//-----------------------------------------------------------------------------
//Non platform independent code. (for Window OS)
//-----------------------------------------------------------------------------
//open "InvoiceDataExtractor" folder
Process p = new ProcessBuilder("explorer.exe", "D:\\programs\\eclipse\\_workspace\\InvoiceDataExtractor").start();
//open "_workspace" directory and select "InvoiceDataExtractor" folder
Process p = new ProcessBuilder("explorer.exe", "/select,D:\\programs\\eclipse\\_workspace\\InvoiceDataExtractor").start();



Reference:http://docstore.mik.ua/orelly/java-ent/dist/ch02_01.htm

//Opening TCP/IP server socket
ServerSocket s = null;
try
{
  try
  {
    thisThread = Thread.currentThread();
    String myName = thisThread.getName();
      s = new ServerSocket(getServerListeningPort());
      logger.info("HID RFID Server ...\"START\"...   , Thread: " + myName);
    while((isSynProcess()) || (!isStopRequested()))
    {
      try
      {
        HidRfidReader hid;
        Socket incoming = s.accept();
        hid = new HidRfidReader(incoming);
        hid.setDaemon(true); //set this as a user thread. If startService thread ended, these user thread will end as well.
        hid.start();
      }
      catch(UnAuthorisedDeviceException e)
      { //ip address is not reconigze/registered. Print debug message and return to main loop to accept incoming socket connection
        logger.warn("Warning!!! <Unauthorised Access Detected> " + e);
        //detects authorised device access
        //return to check for other incoming connection
      }
    }
  }
  catch(Exception e)
  {
    logger.error("Unhandled Error: " + e, e);
  }
  finally
  {
    s.close();
  }
}
catch(IOException e)
{
  e.printStackTrace();
}
logger.info("HID RFID Server   ...\"STOP\"...");

UDP is a connectionless communication protocol and does not handle the integrity of the data being send. This does not mean that it cannot be implemented for communication that requires 100% error free communication. It simply means that the lower level protocol will not help you ensure that all your data bytes are being send over, and that your application will need to handle those error checking if you need it.

There are various way to setup your UDP communicates. Two methods are breifly state for your awareness.

– socket define wihtin DatagramSocket

– socket define within DatagramPacket.

For UDP communication to and only to one IP addressed device, you should define your socket in the object DatagramSocket. For packet communication with multiple UDP devices or acting as a listener, you can define your socket within the DatagramPacket object; there will be no restriction to which devices you can communicate within the network. UDP protocol is very flexible to implement.

Compute Broadcast address from IP address and network MASK

Playing *.mp3 and *.wav audio/sound files

import java.io.File;
import javax.media.Format;
import javax.media.Manager;
import javax.media.MediaLocator;
import javax.media.Player;
import javax.media.PlugInManager;
import javax.media.format.AudioFormat;



    Format input1 = new AudioFormat(AudioFormat.MPEGLAYER3);
    Format input2 = new AudioFormat(AudioFormat.MPEG);
    Format output = new AudioFormat(AudioFormat.LINEAR);
    PlugInManager.addPlugIn("com.sun.media.codec.audio.mp3.JavaDecoder", new Format[] { input1, input2 }, new Format[] { output }, PlugInManager.CODEC);
    try
    {

      String file_location = "d:/mp3dog.mp3";
      System.out.print("start thread mp3 play: " + file_location + "\n");
      Player player = Manager.createPlayer(new MediaLocator(new File(file_location).toURI().toURL()));
      player.start();
      
      file_location = "d:/mp3siren.mp3";
      System.out.print("start thread mp3 play: " + file_location + "\n");
      Player player2 = Manager.createPlayer(new MediaLocator(new File(file_location).toURI().toURL()));
      player2.start();
      
      System.out.print("Two MP3 files playing together.\nNote that the media playing thread is still running.\n");
      
      //delay for 10sec before forcing thread to close
      try{Thread.sleep(10000);}catch(InterruptedException e){}
      
      System.out.print("Ending play thread.\n");
      player.close();
      player2.close();      
    }
    catch(Exception ex)
    {
      ex.printStackTrace();
    }

Download the following
– jmf.jar
– mp3plugin.jar
– mp3siren.mp3
– mp3dog.mp3

• Download http://java.sun.com/javase/technologies/desktop/media/jmf/2.1.1/download.html and extract the file jmf.jar (Java Media Framework, JMF). Put the jar file under your project/lib directory.
• JMF only support *.wav and *.aiff files. Download the MP3 plugin to play *.mp3 files. Download http://java.sun.com/javase/technologies/desktop/media/jmf/mp3/download.html, and extract the file “mp3plugin.jar”. Put the jar file under your project/lib directory.
• Make sure to add the jars to the compiler command or import the jar files to your project..
• add the codes (on the left) to your project to playback mp3 audio files.

Command Pattern: ExecutorService example: ExecutorService_Queue.java, ExecutorService_QueueJob.java Command Pattern: Observerexample1: Observer command pattern.pdfexample2: Observer pattern – Wikipedia, the free encyclopedia.pdfexample3: JavaWorld – October – How-to Java_ Observer and Observable.pdf

references:
http://www.go4expert.com/articles/design-pattern-simple-examples-t5127/

read log4j ndc (log the individual instance of client thread connected to the server)

Design pattern reference:

– java-design-patterns.pdf

GUI & Event Listener example
– Create window
– Window listener
– Mouse listener
– Keyboard listener
– Observer (command pattern)

GUI programming notes:
– GUI programming in java.pdf
– Writing gui applications in java.pdf

example to load image file to JPanel.
– example- LoadAndShow (example to load image)

Inserting applet into html file, where MyApplet.class is the java class to invoke, basecode “./” is the root directory the MyApplet.class is located.
<applet code=”MyApplet.class” codebase=”./” height=”600″ width=”600″></applet>

Without the *.class will also works
<applet code=”MyApplet” codebase=”./” height=”600″ width=”600″></applet>

If your MyApplet.class is located in the directory /appDir
html file location -> /index.html
apps file location -> /appDir/MyApplet.class
<applet code=”MyApplet.class” codebase=”./appDir” height=”600″ width=”600″></applet>

If the *.class to invoke is located inside a *.jar library archive file
<applet code=MyApplet.class archive=”JarFileName.jar” codebase=”./” width=width height=height> </applet>

How to signed a Java Applet for access to communication outside the server the applet reside on?

Applet

– Do not put the main Applet class in a package
– Do not do much coding in the Applet’s constructor, other than GUI initialisation. Codes should be place out of the constructor.

Problem:
– Applet hangs in the browser. Need to close the broswer and terminate the browser process to shutdown/restart the Java VM
Solution:
– Applet must use a thread to open new process, especially time consuming process. GUI programming has to be very much thread base.

Problem:
– The applet is able to send out UDP packet from Eclipse applet but not the same applet on the browser.
The browser is able to use the same UDP port to sent data out, but the applet using the same port cannot send the data out.
Solution:
– Remember the applet restrictions that unsigned applets may only access the host they were loaded from, for security purpose. To overcome this security restriction, you will need to signed the applet.

Browser test for Java Applet,
– http://www.javatester.org/enabled.html

Note for Java applet,
– Defining and Using Applet Parameters.pdf
– Call a Applet Java method from Javascript.pdf
– Call Javascript from a Java applet.pdf
– Signed Applet Tutorial.pdf

Note for Java Jar file,
– JAR files revealed.pdf

JNI Java Native Interface

Step 1) Write your normal java class implementing a native method as an abstract.

Myclass
{
  public Myclass()
  {
  }

  public void method1() //normal java method 
  {
  }

  private native void method2(); //native method 
}

Step 3) Use the command “javah” to generate a header file from your class file. Go to your generated class directory.

example:
javah Mypackage.Myclass

A header file Mypackage_Myclass.h will be generated.

Step 5) Build the C project to generate a *.so library file.

You may encounter an error message
“error: parameter name omitted”
You may have left out the function’s (or method’s) parameter names which will not be generated in the *.h.
Provide your parametters with a variable name.

Step 6) Use the *.so file for the *.java file that you have created initially. This is for the system class loader

Reference:
Java programming with JNI.pdf
Beginning JNI with NetBeans IDE and C_C++ Plugin on Linux.pdf

My Java Library

This utilities.zip contains my frequent/common used Java library, which contains the follow object- HexUtilities.java- ShutdownHook.java, ShutdownHookClass.java

– UtilitiesThread.java

utilities.zip

utilities (2011-03-25).jar

utilities (2013-08-11).jar

Introduction

The main concept in writing Java codes, is the understanding of object oriented programming (OOP). Java being a 100% OO programming language is quite fun to designed your software with. As simple as it seems to be, in fact took me years to learn what OO really means. It has been years, since 1997 since I first pick up the book on object oriented, and I am still learning as of today. I would think OO rather an art of designing software. There is no right or wrong, but a good OO designer is the one who can make a difficult software easy and fast to program. OO is really about memory management.

Download you need for your developments

Java IDE, Eclipse, http://www.eclipse.org/downloads/

1. Setup Eclipse & Java

2. Java Coding Example

3. Java Webservice & Flex 3

4. Java Servlet

5. Apache Ant

6. eXist (XML database)

– http://www3.ntu.edu.sg/home/ehchua/programming/java/JUnit_Ant.html (Very good NTU website on Java, by Chua Hock Chuan)

JUnit java code testing (by Chua Hock Chuan).pdf

– http://www3.ntu.edu.sg/home/ehchua/programming/android/Android_HowTo.html (Very good NTU website on Andriod, by Chua Hock Chuan)

How to Install Android SDK and Get Started (by Chua Hock Chuan).pdf

Useful Tools

Power Saver

When I first got to learn about this power saver product during an exhibition in Singapore, I was a little bit surprise about it. The meter measuring the current drop instantly when this power saver thing was turned on. The surprising part is not about its energy saving performance, but the fact that business people is really smart. How they are able to make use of a electrical physics to convince consumer into buying the product.

Myself, I am trained in Electrical & Electronics Engineer for my diploma and degree course. Although I have graduated from my university many years back, I had little experience in the field of the 230Vac single phase voltage system that we are using in our home. Nevertheless I am able to recognize what I was being presented in the exhibition. The power saver device is a scam. The purpose of dedicating this webpage is for me to present to those who have doubt in the device, to understand more about the power saver in a simple and experimental way. To let you see clearer how the scam works, and how you can see the fraud even at the exhibitor’s own setup.

Two things in common when power saver is presented to the consumer. You will always be presented with an instrument call ammeter (or current meter). The appliance used in the demonstration are of inductive property (eg. motor, fan, ballast lamp). These are the two main ingredients that will make the presentation looks convincing for a non-electrical trained consumer.

The ammeter was there to show the reading of the electrical current flowing through the power cable which is connected from the mains to the operating appliance. Higher current reading will means that more electrical current is being drawn from the electricity power grid. There are no tricks on this measurement, they are real. That was why everytime when the power saver is turned on, you were able to see the immediate drop in the electrical current. Most of the demonstration using a clamp ammeter. The meter is clamp to either the electrical live or neutral cable and is able to measure the magnetic field around the cable. The intensity of the magnetic field is proportional to the current flowing through the cable, that is why the current can be measured. The clamp meter is easy to setup and customer can easy be convince since the setup is clean not not hidden from the consumer’s sight.
A picture if the clamp-ammeter for measuring the current flowing through your electrical appliances. Clamp the live or neutral wire of your electrical cable to measure the current flowing.

The problem lies in the engineering knowledge which consumer is not aware about. Having the current reduced does not mean that the power consumption will be reduced. Most people will tends to link the idea of a reduce in current, to a reduce in energy consumption. This concept seems a bit illogical, but this is the real situation. Current and power are not directly related. Real energy consumption is determine by the wattage consumption, and not the current.

The actual technical terms are call real and imaginary power. They can be quite difficult to understand and I shall simplify it by not going too deep into the actual technical details.

There are 3 types of load/appliances that the electrical grid will deliver its power to. They are resistive, inductive and capacitive load. Inductive and capacitive are technically not efficient because extra current has to be drawn from the electrical grid in order to support the appliances. We call these load reactive load. Assuming a household appliance that consume 100W of power. No matter what type of load (resistive, inductive or capacitive) this appliance might be, the real power consumption of this appliance will be 100W. This means that the energy consumption should remains the same regardless of the load.

Most appliances that we have at home are of resistive and inductive nature.

Appliances at home that are Resistive in nature are,
– hot iron
– heater
– oven
– incandescent bulb

Appliances at home that are Inductive in nature are,
– fan
– fridge
– air-con compressor
– washing machine
– vacuum cleaner
– magnetic ballast fluorescent lighting

The only thing different between the type of load, is the current being drawn. For example this appliance is a 100W resistive load, drawing a current of 0.4A from the grid. This 0.4A will be the lowest current that a 100W load can go.

Example 1:

Power Supply —————————————–> 100W Resistive Appliances
Flowing Current 0.4A

If the 100W load is now inductive or capacitive in nature, we will expect a current reading more than 0.4A. This is because such a load requires more current to support the load. Inductive and capacitive load is a form of energy storage component for the electricity. The 100W inductive load though draw in more current from the power grid to fill its storage tank, it will not consume all the energy. The unused current will flow back to the grid. This extra in/out flow of the current is the reason for the rise in the current that we will measured.

Example 2:

Power Supply —————————————–> 100W Inductive Appliances
Flowing Current 0.6A

How much this extra current will be, will depend on the power factor. Power factor ranges from 0-1. It is an indication of the load type. A power factor of maximum 1.0 indicates a pure resistive load will have a minimum current. A power factor of 0.0 indicates a pure capacitive or inductive load will encounter the maximum current. Any power factor reading between 0.0 to 1.0 means that the load is a combination of both.

This power factor thing can be corrected like a see-saw as illustrated below..

Power factor 0.0————————–1.0 ————————–0.0
…………inductive————————resistive————————capacitive

Example 1 is a resistive load 100W 0.4A. The power factor will definitely be 1.0 .

Example 2 is an inductive load 100W 0.6A. The power factor could be let’s say 0.5.

The load being too much inductive with a power factor 0.5A can be corrected by installing a capacitive counter load in parallel. The correct capacitive load can pull up the power factor to 1.0. Too little capacitive counter load will not pull the load fully to the balanced power factor of 1.0. On the other hand, too much of the capacitive counter load will make the overall load capacitive in nature and hence power factor will also be lower than 1.0. The key to attain a power factor of 1.0 is by using the correct counter blance load. Attain a power factor of 1.0 will reduce the current to its minimum.

The power saver is actually a pure capacitance component inside with its value unknown. The demonstration appliance is typically a motor or magnetic ballast fluorescent lamp which is inductive in nature. When the inductive appliance is turned on, the current measured will consist of the extra current flow, therefore reading is higher. When the power saver is turned on at the same time, the load is though balanced with a power factor nearer to 1.0, therefore current is now lower. The closer the counter balance is matched, the low the current will be. The lowest current it can go will be based on its wattage as if it is a resistive load. But it is not easy to match it to exact power factor of 1.0 for a typical consumer.

As what I have understood, the power service provider do not charge consumer on the current that we have drawn, but on the real power that we have used up. It will not be fair if they charge us base on the current, because although we might draw higher current, we also returned the unused portion back to the grid.

For factory and industrial, the situation is slightly different. They will be charged on the extra current for the reactive load that they have introduce. Why is there such a different? This is because the industrial ususally draw very high current from the grid. If the current is high, the cable to support the high current has to be thicker. If the industrial user do not correct the factor of their manufacturing plant, it will be at the expense of the service provider to lay more cables for them. For industrial user, they will be charged base on the real power and the reactive power that they use. For home consumer, our usage is quite predictable and insignificant.

So unless your power meter measure and charges you on both the real and reactive power, you will not need to correct the power factor for your own house.

High current uses thicker cable. Cable not thick enough, heat will be generated. This is a form of cable loss. This is also how a safety fuse for electrical system works. The fuse will burn itself if the current is too high.

But wouldn’t that means that the cable out from the power station will be very very thick to support the whole population? Yes, but there is another solution. The voltage from the power station is very very high. Given a limited cable size, we can still deliver more power to the population by increasing the voltage. Power is the product of voltage and current. With the limit in cable size, hence the current, we can deliver more power by rising the voltage. That is why you can often see electrical sub-station around the place we live in. It is a big transformer inside which step down the very high voltage to a lower voltage that we can use. There are many stages of sub-station from a power station all the way to the end consumer.

You can think of the electrical system as the distribution for our water pipes. High voltage is similar to high pressure for the water pipe. Cable size or current is the water pipe size. Electrical power being the volume of the water. Having a limitation in the waterpipe size does not means that we cannot deliver more water to the population. We can still increase the water pressure so that the water is able to travel faster, hence deliver more water though the pipe out.

The Experiment

Now that we have know something about power factor correction, the following experiment setup will further illustrate the function of a power saver and how the thing works. I have done some reverse engineering work on the following 3 items shown in the picture consist of (from the left)

1) I have managed to salvage white cylindrical AC capacitor from an office fluorescent lighting using a magnetic ballast. I had remembered seeing such component connected to the setup and have dismantled one for the experiment. It is just an ordinary AC capacitor which electrical contractor sometimes used to correct the power factor of the lighting so that current flowing from the mains supply to the lamp can be minimum. The magnetic ballast is an inductive component. Having this counter balance capacitor load, the power factor can be improve, therefore reduce the current. This capacitor was connected to a 3 pin plug for the experiment. Using a multimeter, I managed to measure the capacitance to be 3.2uF, which is the same value as labelled on the component itself.

2) GAD1203 Extreme Power Saver (CX005). I have managed to open it up to understand further about it’s interior. The inside consist of a circuit and a black rectangular block. At a glance, it seems quite complicated circuit, but after careful examination, the circuit looks suspicious. The IC chip on-board is a logic gate IC which does not do any function. The black box is actually a 4.75uF capacitor component. The measured capacitance is 5.6uF which is quite close to the label. The incoming 2 pin Live and Neutral is connected parallel to the capacitor and the circuit. Without the circuit, the capacitor will be enough to act as a power factor correcting device.

3) GAD1202 Power Saver (CHT-001C), 2400W. This product is easier to do the reverse engineering. It consist of two black box connected in parallel to the AC Live & Neutral wire. The 2 black box is the capacitor measuring 5uF each which is the same as labelled on the component itself. Two capacitor means that the total capacitance is 10uF. There is a lamp indicator which is connected to the AC line, indicating that the device is connected to the AC mains.

I have this experiment and setup as below with help from saveOne Pte Ltd in Singapore. Their business is mainly in the Asia region Philippines, Thailand, Malaysia and China. This company sells a range of energy saving products, from energy saving lighting, energy saving electronic ballast to energy saving equipments. The picture shows a demonstration rack of their electronic ballast product for circular fluorescent lamp which I have also installed for my house. I like the product and have written an article about it quite some time ago. If you are interested, you can visit this link.

The reason I use this rack for the experiment because there was this magnetic ballast fluorescent lamp setup at the bottom of their rack. You can see from the picture, it is the lamp that is lighted up. Magnetic ballast component is an inductive load and is useful for our experiment.

The setup consist of 2x power meter to check on the wattage, current and power factor at 2 location along the power supply line from the mains to the magnetic ballast lamp. Right from the top, you can see a 4 way socket power extension. This is the point where I would tap the power from. The first thing that was connected is the power meter which was connected to the 2nd socket position. This power meter no.1 measures the electricity for the whole setup. The later setup that would be connected to this power meter will be measured. This means that we would be able to know the current flowing from the supply mains to this setup, and also the wattage consumption of the setup.

From the power meter no.1, a multi-plug socket was plugged on top of it to split the power outlet into 2. On the right side, it is where the power saver (capacitor under test) will be plugged. The front side is the 3pin plug which is from the cable extension drum. On top of the cable drum is power meter no.2. The magnetic ballast lamp is connected to this power meter no.2. Power meter no.2 measures the wattage, current and power factor for the lamp.

Measure Result from Power Meter no.1

0. Without any thing connected, the magnetic ballast lamp consume a wattage of 44.2W. Current is high at 0.432A. The power factor measured from the power meter is low at 0.42.

1. When the small 3.25uF capacitor is connected along the power line, the measurement from power meter no.1 shows that the power factor has improved to 0.76. The improve in power factor will also lead to a drop in the current. With this small capacitor, the current is now lower at 0.242A. The power consumption remains unchanged for the own setup.

2. Next comes the Extreme Power Saver GAD1203. The 5.6uF capacitance is higher than the previous 3.25uF. As shown in the measurement, the power factor is now exactly 1.0. This is a perfect match. The magnetic ballast requires 5.6uF capacitance to correct its power factor. The current is measured to be 0.198A. Since the power factor is perfect, this is the lowest current we can attain for the lamp. The power consumption goes slightly higher at 45.1W, probably due to the extra circuit that is in the Power Saver.

3. Next comes the GAD1202 Power Saver. The 10uF capacitance is among the highest of all the Power Saver under this test. When it is connected along the line, the power factor actually drop down to 0.47. This happens because we have over correct the power factor by putting in too high a capacitance value. The drop in power factor comes with an increase in the current flow of 0.403A. Putting too much Power Saver can degrade the performance. It is possible to create an even higher current than the original setup (without any thing connected along the line). This means that if too many Power Saver is connected along the line, you will expect an increase in current instead. You can try it out on the demonstration, requesting the salesman to install more Power Saver to the setup. The current will drop up to a certain point then increase more and more after that. The current will never drop back once the power factor is over corrected. You will need more inductive load to balance it back to a power factor of 1.0. I have tried it out before, and was able to see the increase in current once the second Power Saver was plugged in. The wattage is the highest among the rest at 45.3W. This might be due to the lamp indicator in the circuit which will also consume energy.

Measure Result from Power Meter no.2

Throughout the turning on and off of the Power Saver device, the reading remains the same. The reading is the same as the Power Meter no.1 as if no capacitor or power saver is connected. This shows that current from the Power Saver all the way to the inductive load (magnetic ballast fluorescent lamp) was not corrected and still remains high at 0.432A throughout the experiment.

Conclusion

The current was corrected only from the power supply mains to the Power Saver only. Current from the Power Saver to the inductive load remains the same. In order to keep the current minimum along the cable, the power saver will be better kept as close as possible to the load that requires power factor correction.

The use of a power factor correcting device helps to reduce current from the power mains to the device. Lower current means that the current carrying AC cable can be afford to be thinner. To put it in another way, more inductive appliances can be connected to the same AC cable if they are all power factor corrected. Lower current flowing through the cable also means less power loss on the cable it self. High current flowing through a thin cable can generate some heat (cable loss). However cable loss is usually insignificant.

To conclude, the power saver can help to reduce current flow. In order to reduce the current, you will need to understand your load and apply the correct counter load value. Over correcting an appliances will make it worst. In terms of energy saving, the saving will be insignificant. In fact, the experiment shows a slight increase in wattage. It is quite conclusive that the Power Saver product is a scam.

The following are some other sites from people who have similar knowledge and explaination. I have collected these website for your further understanding of how power saver works.

http://www.nlcpr.com/Deceptions1.php

Alternative name for Power Saver:

Energy Saver

Power Saving

Electric Saver

Current Stabilizers

Home Energy Saving Device

Power Factor Saver

Saving Saint

Forum comment:
http://www.janleow.com/life/electricity-energy-power-saving-device.html
http://ezinearticles.com/?Energy-Saving-Devices—Do-They-Work?&id=4556173
http://www.ideamarketers.com/?Energy_Saving_Devices_Do_They_Work&articleid=1210082&from=PROFILE
http://www.advancedenergy.org/buildings/knowledge_library/systems_approach/energy_saving_devices.html
http://www.physicsforums.com/archive/index.php/t-170023.html
http://www.nlcpr.com/Deceptions1.php
http://webdevsys.com/aussiePowerSaversScam.htm
http://forum.lowyat.net/topic/1071423/all
https://www.oag.state.tx.us/oagnews/release.php?id=2456
http://www.guardian.co.uk/money/2011/dec/01/trading-standards-bogus-energy-saving-plugs
http://forums.techarp.com/general-hardware/23800-electricity-saving-box.html
http://electricitysaver.com.au/home/index.php/how-does-it-work
http://forums.whirlpool.net.au/archive/1125316
http://forums.hardwarezone.com.sg/general-merchandise-bazaar-261/wts-gadget-save-electricity-mini-sun-power-saver-2191556.html

http://www.xtremeplace.com/yabbse/index.php?topic=78110.0

Mini Sun Power Saver

http://www.h2hgroup.org/

http://www.minisunsaver.com/

http://www.minisunpower.com/

http://powersaver.biz/

http://powersavermalaysia.blogspot.com/

Model: MS88, MS188, MS388

A German technology.

Tested by PSB (Singapore) & SIRIM (Malaysia)

click here to see PSB test report, click here to see SIRIM QAS test report

POWERGARD

http://homeenergysaver.net/

GaoYiNeng Energy Saving Device

http://www.szgyn.com/

THE GUARDIAN

http://eccobest.com/

Joinwe Electricity saving box

http://joinwe.net/en/products-01.htm

sd-001 Electricity saving box

The Electric Saver 1200

http://electricsaver1200.com

POWER PANDA

http://thepowerpanda.com

Ecobrand Power Savers and Current Stabilizers

http://www.saving-electrics.com/

EcoWatt Energy

http://ecowattenergy.com/residential.php

Ultima Imaging Systems Pvt Ltd.
Power Saving Device
http://www.ultimaimaging.co.in/powersaver.html

UBRIDGE Technology

http://ubridge.en.alibaba.com/product/358253955-206600002/Electric_Power_Saver_up_40_.html

Model: UBT6

Aztech ESAVER

www.esaver.net

brouchure

This is a possible microprocessor controlled power factor correcting equipment. It looks rather bulky. The automatic power factor correction should be real, but as for the electricity bill saving, I will doubt so.

Power Saver India

http://powersaverindia.com/

This product claims to be controlled by a microprocessor. I do have doubt if it has the intelligent to even correct the power factor.

http://aonepowersaver.com/

http://realpowersaver.com/

This product claims to be controlled by a microprocessor. I do have doubt if it has the intelligent to even correct the power factor.

References:

Microchip dsPic 30F Programming reference guide

PIC microcontroller Development Board

(Completed on 2006-10-28)

The ultimate PIC Microcontroller development board. After years of programming PIC microcontroller, I have finally design my super development board to program PIC microcontroller firmware. The automatic programming mode select and the 40 bits LED light bar display have ease my programming process and increase debugging speed by 10 times. I can easily do troubleshooting because of the 40 bits LED display. The LED allows display for 5 bytes of variables using only 3 bits of any output port. I used to allocate PORTD to display one byte of the memory. Debugging used to be slow and tedious. This board also features automatic select to programming mode when the board is powered down. This means that there is no need to do manual switching. The ICSP interface allows the firmware to be loaded to the microcontroller without inserting/removing IC chip.

Features

-Development for 18, 28, 40 pins DIP PIC microcontroller

-Serial Communication RS232, with Tx/Rx transmission activities indicator.

-Changeable microcontroller Crystal Clock

-ICSP programming pins

-Automatic switch to programming mode when board power is turned off.

-Proper labels and easy to view LED bar display, buffered from all the ports. Output pins from all the ports.

-Serial to parallel data latching to extend more output bits from 3 output pins. Output pins with easy to view LED bar display.

-Adjustable dc-dc power supply using LM2576-ADJ IC to cater for 5V and 3.3V power supply system.

-Features 74HC series logic family and Max232 IC for operating on 3.3V power supply. (see logic family selection guide)

-Fuse protection.

Click on the image for Circuit Schematic

For more information for extending microcontroller I/O (input/output) ports using “serial to parrallel” or “parallel to serial” circuit, you can refer to More Circuit Schematic.

The development board uses the following logic IC:

74HC595, serial to parallel with output latched

74HC244, octal logic buffer

MAX232, RS232 to TTL tranceiver

LM2576-adj, DC-DC voltage regulator

For more information on how to select logic family, see “Logic Selection Guide” from Texas Instrument.

Introduction: AUP, CBT-C, CB3T/Q, SSTU, VME, AUC, SSTV, GTLP, Little Logic, AVC, TVC, ALVT, CBTLV, ALVC, CBT, LVC, LV

Mature: AHC/AHCT, LVT-A, ABT, FCT, AC/ACT, HC/HCT, BCT, CD4000

Obsolescence: 74ALS, 74F, 74AS, 74LS, 74S, 74xx (oldest)

(Completed in the year 2005)

My first own build programmer system. Spent quite a lot of time designing and fabricating the plastic box chassis. It works, but I never really work much with it after I brought myself a commercial version.

(Completed in the year 2002-05-xx)

This is a interface board for fitting various model of PIC microcontroller to the programmer. The programming pins numer is different for every PIC microcontroller model. This interface board eliminate the need to build a new programmer board for different PIC microcontroller model.

(Completed in the year 2002-05-xx)

This board is design to be function as a multi purpose PIC microcontroller development board. I have build specially to trial run the microcontroller firmware I wrote. Bi-directional digital buffer are used, to protect the microcontroller from external device during interfacing. After working with microcontroller for some time, I find that this buffer interface is not necessary. Microcontroller I/O ports do not damage easily. When interfacing microcontroller with high powered or unknown devices, opto-coupler can be used instead. Opto-coupler provides maximum isolation as well as protection between the microcontroller and other devices.

Attached to the main PCB is a smaller PCB board. It consist of a MAX232 converting computer RS232 to microcontroller TTL serial signal. This small board also include a charge pump circuit that generate 12V from a 5V source for the purpose of programming the PIC microcontroller. This programmer design “Toolkit TK3 PIC programmer” was taken reference from my favourite hobby magazine “Everyday Practical Electronics“.

Development Board schematic & PCB layout

Programmer Board schematic & PCB layout

(Completed in the year 2002-05-xx)

Input switches and Output LED test board interface. It is very useful when doing microcontroller project, because it can help to indicate if the firmware is running correctly inside the microcontroller. A must have kit when doing digital project.

table updated in 26 May 2007

16
29
39

17
29
40

8
19
27

10