: Introduction to project:-
This project contains its own hardware and software to control at most eight electric appliances via PC©s parallel [url removed, login to view]
project is independently developed by me.
Aim of project:-
Most of engineering industry using PC to control hardware with using additional I/O card but with my project you can use your default printer port controlling external device such as switching on/off light or control electronic devices. This project allows you to control appliance in your home or office like-turning on or off the air
conditioner, adjusting lighting, opening & closing windows, monitoring burglar alarms, and more.
System:- A PC working on MS-DOS/WINDOWS 98 ME
Software:-A program written in C++.
This material is about the parallel port on MS-DOS / Windows computers.
Imagine you are looking at the back of your pc, and that the parallel port socket is horizontal, with the long row of socket on top. The numbers of the sockets at the ends of the rows are...
13 . . . . . . . . . . 1
25 . . . . . . 14
The 'interesting' pins are: Data bits 0-7: Pins 2 to 9,
respectively. If you write to address 888 (decimal), you should see the
outputs on those pins change. Pins 18-25: Signal ground. (I.e. for a VERY
simple experiment, connect an LED to pin2, a 680ohm resistor to the LED,
and then the other end of the LED to pin 19.
The PCB contains eight identical switched relay positions,
Power input positions to the relays (either [url removed, login to view] jack
centre positive, or via the terminal block) and a Centronics
connector to the parallel port of a PC. To keep the kit
simple no input latches have been put on it. If your
application is important then you should use a UPS to keep
the computer operating in the case of a mains power supply
failure. If the board is accidentally disconnected from the
parallel port then the 10K pulldown resistors will turn the
relay off. The diodes protect the transistors from the backemf
which is occurs when the relay is turned off and its
magnetic field collapses.
The relays are under direct control of the output byte (8
bits) from the parallel port. When a pin is high a nominal
5V is presented to the base resistor R1.
Components Specification Numbers
Resistors 1Kohm 9
Capacitors 1uf,.1uf,1000uf 1,1,1
General Purpose Circuit Board 1
Relay 5 V. 8
25 Pin Male Connector D-Type 1
25 Pin Female Connector D-Type 1
L.E.D. Green 8
L.E.D. Red 9
I.C. LS7805 1
I.C. 74LS244 1
Transformer 6 V. 1
Diode IN4001 2
Wire Multicable 5 mt.
DESIGNE AND DEVLOPED BY AMIT KAUSHIK E-MAIL: amitjbl@[url removed, login to view] Phone no. 05122612909 Address 232 (MINI) M.I.G. BARRA-2 KANPUR U.P. 208027