Pc Based Appliances Controller Ag 111508

7/31/2019 Pc Based Appliances Controller Ag 111508

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PC BASED APPLIANCES CONTROLLER

Submitted by:


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CONTENTS:

S.NO. TOPICS

1. INTRODUCTION

2. DESRIPTION OF PROJECT

3. BRIEF INTRODUCTION TO PARALLEL PORT

4. DESCRIPTION FOR REGISTERS

5. POWER SUPPLY

6. OPTOCOUPLER

7. PROGRAMMING FOR THE REQUIRED CIRCUIT

8. FUTURESCOPE

9. CONCLUSION

10. REFERENCES


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INTRODUCTION

This project can be used for the controlling of various appliances using PC.

It consist a circuit for using the printer port of a PC, for control application

using software and some interface hardware. The interface circuit along with

the given software can be used with the printer port of any PC for

controlling up to eight equipment. Parallel port is a simple and inexpensive

tool for building computer controlled devices and projects. The simplicity

and ease of programming makes parallel port popular.

DESRIPTION OF PROJECT

BASIC COMPONENTS REQUIRED

1. Personal Computer

2. Optocoupler

3. ULN 2803

4. Electro-mechanical Relay(SPDT)

5. Transformer(15v)

6. Voltage Regulator 78XX

7. Diode(IN4007), Resistors, capacitors


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BASIC CIRCUIT DIAGRAM


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BRIEF INTRODUCTION TO PARALLEL PORT

Parallel port modes

The IEEE 1284 Standard which has been published in 1994 defines five modes of data

transfer for parallel port. They are:

1. Compatibility Mode

2. Nibble Mode

3. Byte Mode

4. EPP

5. ECP

The programs, circuits, and other information found in this tutorial are compatible to

almost all types of parallel ports and can be used without any problems (Not tested, just

because of confidence!).

Hardware

The pin outs of DB25 connector is shown in the picture below:

The lines in DB25 connector are divided into three groups, they are:

1. Data lines (data bus)2. Control lines

3. Status lines.


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As the name refers, data is transferred over data lines. Control lines are used to control the

peripheral, and of course, the peripheral returns status signals back to the computer through

Status lines. These lines are connected to Data, Control and Status registers internally.

Pin No

(DB25)

Signal

name

DirectionRegister

- bit

Inverted

1 nStrobe Out Control-0 Yes

2 Data0 In/Out Data-0 No








10 nAck In Status-6 No

11 Busy In Status-7 Yes

12 Paper-Out In Status-5 No

13 Select In Status-4 No

14 Linefeed Out Control-1 Yes

15 nError In Status-3 No

16 nInitialize Out Control-2 No

17nSelect-

PrinterOut Control-3 Yes

18-25 Ground - - -

Parallel port registers

The Data, Control and Status lines are connected to there corresponding registers inside the

computer. So, by manipulating these registers in program, one can easily read or write to

parallel port with programming languages like 'C' and BASIC.


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The registers found in a standard parallel port are:

1. Data register

2. Status register3. Control register

As their names specify, Data register is connected to Data lines, Control register is

connected to Control lines and Status register is connected to Status lines. (Here the word

connection does not mean that there is some physical connection between

data/control/status lines. The registers are virtually connected to the corresponding lines.)

So, whatever you write to these registers will appear in the corresponding lines as voltages.

Of course, you can measure it with a multimeter. And whatever you give to Parallel port as

voltages can be read from these registers (with some restrictions). For example, if we write

'1' to Data register, the line Data0 will be driven to +5v. Just like this, we can

programmatically turn on and off any of the Data lines and Control lines.

Description for registers

In an IBM PC, these registers are IO mapped and will have an unique address. We have to

find these addresses to work with the parallel port. For a typical PC, the base address of

LPT1 is 0x378 and of LPT2 is 0x278. The Data register resides at this base address, Status

register at base address + 1 and the control register is at base address + 2. So, once we have

the base address, we can calculate the address of each register in this manner. The table

below shows the register addresses of LPT1 and LPT2.

Register LPT1 LPT2


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Data register (baseaddress + 0) 0x378 0x278

Status register (baseaddress + 1) 0x379 0x279

Control register (baseaddress + 2) 0x37a 0x27a

POWER SUPPLY

REGULATOR IC (78XX)

It is a three pin IC used as a voltage regulator. It converts unregulated DC

current into regulated DC current.

BRIDGE RECTIFIER

A bridge rectifier makes use of four diodes in a bridge arrangement to

achieve full-wave rectification. This is a widely used configuration, both

with individual diodes wired as shown and with single component bridges

where the diode bridge is wired internally.

CIRCUIT DIAGRAM OF POWER SUPPLY


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OPTOCOUP LERThere are many situations where signals and data need to be transferred from

one subsystem to another within a piece of electronics equipment, or from

one piece of

equipment to another, without making a direct ohmic contact electrical

connection. Often this is because the source and destination are (or may be

at times) at very different voltage levels, like a microprocessor which is

operating from 5V DC but being used to control a triac which is switching

240V AC. In such situations the link between the two must be an isolatedone, to protect the microprocessor from over-voltage damage.


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HIGH VOLTAGE HIGH CURRENT DARLINGTON

TRANSISTOR ARRAY (ULN2803)

The eight NPN Darlington connected transistors in this family of arrays are

ideally suited for interfacing between low logic level digital circuitry (such

as TTL, CMOS or PMOS/NMOS) and the higher current/voltage

requirements of lamps, relays, printer hammers or other similar loads for abroad range of computer, industrial, and consumer applications. All devices

feature opencollector outputs and free wheeling clamp diodes for transient

suppression.

The ULN2803 is designed to be compatible with standard TTL families

while the ULN2804 is optimized for 6 to 15 volt high level CMOS or PMOS


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ULN 2803

RELAY

A relay is an electrical switch that opens and closes under the control of another electricalcircuit. In the original form, the switch is operated by an electromagnet to open or close

one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay isable to control an output circuit of higher power than the input circuit, it can be consideredto be, in a broad sense, a form of an electrical amplifier.

Here relay is used for the isolation of various heavy appliances to the PC. Since the PC

operates on very low current, but the current in various appliances is in Amperes therefore

isolation is necessary and relay is required. Here we have used single pole dual throughrelay for the purpose.


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CIRCUIT DIAGRAM OF PROJECT


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PROGRAMMING FOR THE REQUIRED CIRCUIT

/*program to control devices using PC parallel port

The devices are controlled by pressing the keys 1-8

that corresponds to each of the 8 possible devices

*/

#include

#include#include

#define PORT 0x378 /* This is the parallel port address */

main()

{

char val=0,key=0;

char str1[]="ON ";

char str2[]="OFF";char *str;

clrscr();printf("Press the appropriate number key to turn on/off devices:\n\n");

printf("Here Device1 is connected to D0 of parallel port and so on\n\n");

printf("Press \"x\" to quit\n\n");gotoxy(1,8);

printf("Device1:OFF Device2:OFF Device3:OFF Device4:OFF\n");

printf("Device5:OFF Device6:OFF Device7:OFF Device8:OFF");

while(key!='x' && key!='X')

{gotoxy(1,12);printf("Value in hex sent to the port:");

key=getch();

switch(key){

case '1':

gotoxy(9,8);

val=(val&0x01)?(val&(~0x01)):val|0x01;

str=(val&0x01)?str1:str2;

printf("%s",str);outportb(PORT,val);

gotoxy(1,13);

printf("%x",val);break;

case '2':


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gotoxy(21,8);


str=(val&0x02)?str1:str2;printf("%s",str);

outportb(PORT,val);

gotoxy(1,13);printf("%x",val);

break;

case '3':

gotoxy(33,8);

val=(val&0x04)?(val&(~0x04)):val|0x04;str=(val&0x04)?str1:str2;

printf("%s",str);

outportb(PORT,val);


break;

case '4':

gotoxy(45,8);




gotoxy(1,13);

printf("%x",val);break;

case '5':

gotoxy(9,9);



outportb(PORT,val);


break;

case '6':

gotoxy(21,9);



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printf("%s",str);

outportb(PORT,val);gotoxy(1,13);

printf("%x",val);

break;

case '7':

gotoxy(33,9);




gotoxy(1,13);

printf("%x",val);

break;

case '8':gotoxy(45,9);



outportb(PORT,val);

gotoxy(1,13);

printf("%x",(unsigned char)val);break;

}

}

}


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ESTIMATED COST OF PROJECT

The estimate cost of project is rupees 8000

FUTURE SCOPE OF PROJECT

This project can be used in industries as well as in houses to control the

various appliances through PC. Devices can be controlled from the desktop

while working on it.

You can use voice recognition (or DTMF) to control your house by this

method (Smart House).


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CONCLUSION

The greatest learning experience in this project comes from the design and

construction of PC Based Appliance Controller which answer a lot of

questions regarding the real implementation of Embedded system, Electro-

mechanical relays and Opto-couper, ULN 2803, Parallel Port of PC .

During the development of our project we studied and analyzed many real

world applications

of Electronics and Software Engineering. Some of the theoretical knowledge

that was inculcated in us within our engineering program, which we have

applied practically, are:

1. Use of voltage regulation and filtering in power supply.

2. Study of parallel ports.

3. Study of C-Language.

4. Study of ULN.

5. Understanding of single pole dual through relay.

6. Study of Optocoupler.


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REFERENCES

http://www.sparkfun.com/tutorials/57

http://www.codeproject.com/KB/cs/control_e_appliances.aspx

http://www.electronic-circuits-

diagrams.com/computersimages/computersckt1.shtml

http://www.ehow.com/how_5993533_use-computer-control-household-

appliances.html
http://www.sparkfun.com/tutorials/57http://www.codeproject.com/KB/cs/control_e_appliances.aspxhttp://www.electronic-circuits-diagrams.com/computersimages/computersckt1.shtmlhttp://www.electronic-circuits-diagrams.com/computersimages/computersckt1.shtmlhttp://www.ehow.com/how_5993533_use-computer-control-household-appliances.htmlhttp://www.ehow.com/how_5993533_use-computer-control-household-appliances.htmlhttp://www.sparkfun.com/tutorials/57http://www.codeproject.com/KB/cs/control_e_appliances.aspxhttp://www.electronic-circuits-diagrams.com/computersimages/computersckt1.shtmlhttp://www.electronic-circuits-diagrams.com/computersimages/computersckt1.shtmlhttp://www.ehow.com/how_5993533_use-computer-control-household-appliances.htmlhttp://www.ehow.com/how_5993533_use-computer-control-household-appliances.html

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Pc Based Appliances Controller Ag 111508

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