Here is a code to controle an led through parallel port.

Introduction:
PC parallel port can be very useful I/O channel for connecting your own circuits to PC. The PC's parallel port can be used to perform some very amusing hardware interfacing experiments. The port is very easy to use when you first understand some basic tricks. This document tries to show those tricks in easy to understand way.

Download:
1:download the "Blink Led" from Software menue"

WARNING: PC parallel port can be damaged quite easily if you make mistakes in the circuits you connect to it. If the parallel port is integrated to the motherboard (like in many new computers) repairing damaged parallel port may be expensive (in many cases it it is cheaper to replace the whole motherborard than repair that port).

How to connect circuits to parallel port PC parallel port is 25 pin D-shaped female connector in the back of the computer. It is normally used for connecting computer to printer,

pin function


2 D0
3 D1
4 D2
5 D3
6 D4
7 D5
8 D6
9 D7


Pins 18,19,20,21,22,23,24 and 25 are all ground pins.

1. Step 1 : First, you should have copied the jnpout32pkg.dll downloaded from above software menu the system32 directory.
   Follow up,include libraries System.Runtime. InteropServices in the top portion of your codes.
   
   
2. Step 2 : Create a new class for the .dll that you will be using. jnpout32pkg.dll (it has been created in that downloaded folder  " jnpout32" dir).
   
   

       3. step 3 : copy that jnpout32pkg.dll in your syatem32 dir.

            step 4 : download  BULB EXECUTED PROGRAM from software menu & copy that directory in your c:/
                     it consist of jnpout32 dir in which jnpout32.dll class function have been defined.
                     there is an ioTest.java file it's a actual program which uses a jnpout class file to read or write a data to parallel port.

          step 5 : you need to install java(j2sdk 2.5) or higher and run that ioTest.java file in j2sdk2.5. you will see the blinking led behind Ur machine.
          instead of led u can connect bulp also all u need is one particular circuit to control the voltage.
          here is an image bellow.

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