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RF ATTENDNCE

 

Introduction

In this project we will make project on RF attendance using RF ID. For RF attendance we will transfer Roll no of student wirelessly and on rxer end we will mark his/her attendance in mircontroller. We have option to check the attendance of each student.

We will use RF technology for this purpose.

RF remote control which is built using HT12E and HT12D chips. The remote control is built using RF encoder chip HT12E that will generate different codes. These codes will be transmitted by 434 MHz RF transmitter. At the receiving side these codes will be received by 434 MHz RF receiver and decoded by RF decoder chip HT12D. in the transmitter side which will attach with car we will sensor for accident detection. Sensors will give signal to HT12E . HT12E is a 18 pin ic. It converts  bit data input to serial output. It has 12 address lines to send data to particular receiver.

In this project we make attendance system using RFID. In this project we used 433Mhz RF transmitter and Receiver. We used 89s51 . LCD 16*2 connected to MCU at port 0 of MCU. Output of HT12D connected to MCU at port pin no 1 tp 4. Pot 1 pin 5 to 8 connected to four switches to check total attendance of each candidate. In this project we are using UHF frequencies of RF. LEDs connected at port 2 pin p2.0,p2.1,p2.2,and p2.6. LCD rs, rw ,en connected to p2.5,p2.4 and p2.3.HT12 E and HT12D s pin 1 to 9 connected to ground giving low. These are address pins of HT12E and HT12D. Pin no 10 to 14 of HT12 E are inputs of IC and 17 no pin is output pin. Pin no 10 -14 of  HT12D is ouput pin and 14 is input pin. Crystal pin of HT12E is 15 and 16 .this  project we will  make one transmitter and RF receiver. RF remote control which is built using HT12E and HT12D chips. The remote control is built using RF encoder chip HT12E that will generate different codes. These codes will be transmitted by 434 MHz RF transmitter. At the receiving side these codes will be received by 434 MHz RF receiver and decoded by RF decoder chip HT12D. These codes are fed to 89C51 to take a controlling action on moon walker. We will use 16*2 LCD display.there will be RFID for each  transmitter. RF transmitter will give signal to

For the regulated power supply we use ic 7805 as a regulator to provide a fix 5 volt power supply.

. Here we use pc 817 ( 4 pin opto coupler) to interface the micro controller with  the HT12E

Pin no 1of RF tx module is ground . second is for data , third for VCC and fourth for antenna Transmitter

For energy Zone we will get output at pin p3.4,5,6,7 of mircontroller.

 

It gives low signal to MCU. For in LED will glow and for out LED will not glow or stop glowing.

 

 

 

                  POWER SUPPLY FOR DIGITAL CIRCUITS

 

 

Summary of circuit features

 

      Brief description of operation: Gives out well regulated +9V output, output current capability of 100 mA.

      Circuit protection: Built-in overheating protection shuts down output when regulator IC gets too hot.

      Circuit complexity: Simple and easy to build.

      Circuit performance: Stable +9V output voltage, reliable operation.

      Availability of components: Easy to get, uses only common basic components.

      Design testing: Based on datasheet example circuit, I have used this circuit successfully as part of other electronics projects.

      Applications: Part of electronics devices, small laboratory power supply.

      Power supply voltage: Unregulated DC 8-18V power supply.

      Power supply current: Needed output current 1A.

      Components cost: Few rupees for the electronic components plus the cost of input transformer.

 

 

 

 

DESCRIPTION OF POWER SUPPLY

 

This circuit is a small +12 volts power supply, which is useful when experimenting with digital electronics. Small inexpensive wall transformers with variable output voltage are available from any electronics shop. Those transformers are easily available, but usually their voltage regulation is very poor, which makes them not very usable for digital circuit experimenter unless a better regulation can be achieved in some way. The following circuit is the answer to the problem.

 

This circuit can give +12V output at about 1A current. The circuit has overload and terminal protection.

IC

 

 

PIN 1 :  Unregulated voltage input

PIN 2 :  Ground

PIN 3  :  Regulated voltage output  

 

 

Component list

 

1.      7812 regulator IC.

2.      4700 uf electrolytic capacitor, at least 25V voltage rating.

3.      1000 uf electrolytic capacitor, at least 25V voltage rating.

 

Block Diagram of Transmitter

 

 

 

 

LCD DETAIL .

 

Frequently, an 8051 program must interact with the outside world using input and output devices that communicate directly with a human being. One of the most common devices attached to an 8051 is an LCD display. Some of the most common LCDs connected to the 8051 are 16x2 and 20x2 displays. This means 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively.

Fortunately, a very popular standard exists which allows us to communicate with the vast majority of LCDs regardless of their manufacturer. The standard is referred to as HD44780U, which refers to the controller chip which receives data from an external source (in this case, the 8051) and communicates directly with the LCD.

44780 BACKGROUND

The 44780 standard requires 3 control lines as well as either 4 or 8 I/O lines for the data bus. The user may select whether the LCD is to operate with a 4-bit data bus or an 8-bit data bus. If a 4-bit data bus is used, the LCD will require a total of 7 data lines (3 control lines plus the 4 lines for the data bus). If an 8-bit data bus is used, the LCD will require a total of 11 data lines (3 control lines plus the 8 lines for the data bus).

The three control lines are referred to as EN, RS, and RW.

The EN line is called "Enable." This control line is used to tell the LCD that you are sending it data. To send data to the LCD, your program should first set this line high (1) and then set the other two control lines and/or put data on the data bus. When the other lines are completely ready, bring EN low (0) again. The 1-0 transition tells the 44780 to take the data currently found on the other control lines and on the data bus and to treat it as a command.

The RS line is the "Register Select" line. When RS is low (0), the data is to be treated as a command or special instruction (such as clear screen, position cursor, etc.). When RS is high (1), the data being sent is text data which should be displayed on the screen. For example, to display the letter "T" on the screen you would set RS high.

The RW line is the "Read/Write" control line. When RW is low (0), the information on the data bus is being written to the LCD. When RW is high (1), the program is effectively querying (or reading) the LCD. Only one instruction ("Get LCD status") is a read command. All others are write commands--so RW will almost always be low.

Finally, the data bus consists of 4 or 8 lines (depending on the mode of operation selected by the user). In the case of an 8-bit data bus, the lines are referred to as DB0, DB1, DB2, DB3, DB4, DB5, DB6, and DB7.

 

AN EXAMPLE HARDWARE CONFIGURATION

As we've mentioned, the LCD requires either 8 or 11 I/O lines to communicate with. For the sake of this tutorial, we are going to use an 8-bit data bus--so we'll be using 11 of the 8051's I/O pins to interface with the LCD.

Let's draw a sample psuedo-schematic of how the LCD will be connected to the 8051.

 

As you can see, we've established a 1-to-1 relation between a pin on the 8051 and a line on the 44780 LCD. Thus as we write our assembly program to access the LCD, we are going to equate constants to the 8051 ports so that we can refer to the lines by their 44780 name as opposed to P0.1, P0.2, etc

 

 

 

 

 

 

 

 

 

Planning

 

STEPS

TIME

RESPONSIBILTY

PROJECTS SELECTION

 

 

CIRCUIT AND THEORY ARRANGEMENT

 

 

CHECKING AVAILABILITY OF COMPONENTS

 

 

TESTING CIRCUIT

 

 

PCB DESIGN

 

 

COMPONENT INSERTION AND SOLDERING

 

 

TESTING

 

 

REWORK  OR TROOUBLE SHOOTING

 

 

 

 

 

 

 

 

 

 

 

component

qty

rate

IC89C051,

 

1

60

ULN2003, 

 

1

30

Diodes in4001,

 

4

1

IC 7805

1

15

Optocoupler PC817

 

4

12

Tr548

4

3

Tr 558

4

3

Motors 12v

2

250

IC base 20 pin

1

10

Crystal 12 Mhz

1

25

Resiatncec 10k

4

.25

4k

4

.25

Cap 10f

1

5

Connecting wires

1

20

Ir sensors

3

120

 

        Software:-

Keil compiler or UMPS for programming

Window xp