1 User Defined Project Report on AUTOMETIC BUS REGISTRATION AT BUS DEPOT USING 8051

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User Defined Project Report on
AUTOMETIC BUS REGISTRATION AT BUS DEPOT
USING 8051&RF MODULE
By:
SHINGALA BHARAT PANCHAL BRIJAL MAISURIYA ANKITA
(160233111019) (160233111010) (160233111006)
E.C.Department
Dr. S and S.S Ghandhi Government Engineering College
Surat

In partial fulfillment of the requirements
For the award of the degree
of
DEGREE IN ELECTRONICS & COMMUNICATION ENGINEERING

GUJARAT TECHNOLOGICAL UNIVERSITY
AHMEDABAD

Guided By : Submitted By:
TEJASH PATEL SHINGALA BHARAT (160233111019)
PANCHAL BRIJAL (160233111010)
MAISURIYA ANKITA (160233111006 )

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CERTIFICATE

This is certify that Shingala Bharat (160233111019), Panchal Brijal
(160233111010), Maisuriya Ankita (160233111006).has completed Part-I IDP
project work having title AUTOMATIC BUS REGISTRATION AT BUS
DEPOT USING 8051&RFMODULE. They have undergone the process of
shodh yatra, literature survey and problem definition. They are supposed to
carry out the residue UDP part-II work on same problem during semester-VI
for the final fulfillment of the UDP work which is prerequisite to complete
Degree Engineering

Guide- UDP Part-I
(TEJASH PATEL)
E.C. Department
Dr. S and S.S Ghandhi Government Engineering College
Surat

3

CERTIFICATE

This is certify that Mr. SHINGALA BHARAT having EnrolmentNo:-
(160233111019) has completed Part-I UDP project work having title
AUTOMATIC BUS REGISTRATION AT BUS DEPOT USING 8051&RF
MODULE.He has undergone the process ofshodhyatra, literature survey and
problem definition. He is supposed to carry out the residue UDP part-II work on
same problem during semester-VI for the final fulfillment of the UDP work which
is prerequisite to complete Degree Engineering.

4

CERTIFICATE

This is certify that PANCHAL BRIJAL having Enrolment No:(160233111010)
has completed Part-I UDP project work having title AUTOMATIC BUS
REGISTRATION AT BUS DEPOT USING 8051&RF MODULE.He has
undergone the process of shodh yatra, literature survey and problem definition. she
is supposed to carry out the residue UDP part-II work on same problem during
semester-VI for the final fulfillment of the UDP work which is prerequisite to
complete Degree Engineering.

5

CERTIFICATE

This is certify that MAISURIYA ANKITA having Enrolment No:
(160233111006)has completed Part-I UDP project work having title
AUTOMATIC BUS REGISTRATION AT BUS DEPOT USING 8051&RF
MODULE.He has undergone the process of shodh yatra, literature survey and
problem definition. sheis supposed to carry out the residue UDP part-II work on
same problem during semester-VI for the final fulfillment of the UDP work which
is prerequisite to complete Degree Engineering.

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ACKNOWLEDGEMENT

For providing this precious opportunity to us, we would like to
acknowledge the management of DR. S AND S.S GANDHI GOVERNMENT
ENGG. COLLEGE,SURAT
and my internal guide. Who had provided guidance of my complete
projectwork. We would like to thanks to all staff members for providing
information about which we had needed for developing this project
andlast, we are really grateful to all whose ideas have been helpful in
preparing this report.He has undergone the process ofshodhyatra, literature
survey and problem definition. They have supposed to carry out the residue UDP
part-II work on same problem during semester-VI for the final fulfillment of the
UDP work which is prerequisite to complete Degree Engineering.

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ABSTRACT

AUTOMATIC BUS REGISTRATION AT DEPOT is a system which replaces the
manual process of bus registration at registration window. The entry of bus is done
by using a RF module which is interfaced with 8051 microcontroller. The RF
module has a transmitter and receiver which are attached to bus and registration
window respectively. RTC (Real Time Clock) is interfaced with 8051, which gives
date and time. The data of bus is stored in 8051 and it is displayed via LCD.

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INDEX

Sr.no subject page no
1 Introduction…..…………………………………………… 10
2 Block Diagram …………………………………………… 11
3 Circuit diagram ……………………………………… 12
4 Microcontroller ………………………………..………… 14
4.1 Block diagram
4.2 Pin description
4.3 Features
5 LCD (Liquid Crystal Display) …… ………….…………… 20
5.1 Interfacing with 8051
6 RTC (Real Time Clock) ……….…………..……………….. 27
6.1 RTC Pin Diagram
6.2Pin description
6.3 Features
6.2Application
7 RF module…………………………..……………………. .33
7.1Decoder (HT12D)
• Pin Diagram
• Features
• Application
7.2 Encoder (HT12E)

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• Pin Diagram
• Features
• Application
8 Power supply ……………………………………………….. 38
• Block diagram

9 Project
………………………………………………………………………… 40
• Application
• Advantages
• Limitation
• Features scope

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INTRODUCTION:

We all are surrounded with different technologies which have effects on our work
and all activities.
Today’s world is emerging with new technologies every day and these
technologies not only save our time but makes our task easy. We have heard about
the idea of smart cities and initiatives are been taken to lead us there. The very
much known example is in our state Gujarat, is of smart stations.
Our project is AUTOMATIC BUS REGISTRATION AT DEPOT using 8051 and
RF module. In bus depot, when any bus enters its registration is done manually
with takes some time. Bus conductor goes to the registration window and then the
bus gets registered. With the help of our project this process can be made easy and
time can be saved.
Here we have used a RF module which consist of transmitter and receiver, 8051
microcontroller. A transmitter is attached at bus and receiver is placed at the
registration window. Whenever any bus enters the station it gets automatically
registered and the data is saved in 8051 and displayed in LCD.Along with it we
have used RTC(Real Time Clock) which shows the date and time at which the bus
enters the station.
Following tasks are done by this system
(i) Automatic registration of bus,
(ii) Number of passenger boarding in bus,
(iii) Time at which bus entered and left the depot.

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BLOCK DIAGRAM:-

Fig.(1)BLOCK DIAGARM

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CIRCUIT DIAGRAM:

Fig: (2) CIRCUIT DIAGRAM

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TRANSMITTER:

FIG: (2.a) CIRCUIT DIAGRAMTRANSMITTER

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? MICROCONTROLLER ARCHITECTURE BLOCK DIAGRAM:-

FIG:(3) 8051 MICROCONTROLLER ARCHITECTURE

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? Memory: Microcontroller requires a program which is a collection of instructions.This
program tells Microcontroller to do specific tasks. These programs requires a memory on
which these can be saved and read by Microcontroller to perform specific operation. The
memory which is used to store the program of Microcontroller, is known as code memory
or Program memory. It is known as ‘ROM'(Read Only Memory).

? Microcontroller also requires a memory to store data or operands temporarily. The
memory which is used to temporarily store data for operation is known as Data Memory
and we uses ‘RAM'(Random Access Memory) for this purpose. Microcontroller 8051 has
4K of Code Memory or Program memory that is it has 4KB Rom and it also have 128
bytes of data memory i.e. RAM.

? Bus: Basically Bus is a collection of wires which work as a communication channel or
medium for transfer of Data. These buses consists of 8, 16 or more wires. Thus these can
carry 8 bits, 16 bits simultaneously.

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? Advantages and Applications of Microcontroller:-

? Address Bus: Microcontroller 8051 has a 16 bit address bus. It used to address memory
locations. It is used to transfer the address from CPU to Memory
.
? Data Bus: Microcontroller 8051 has 8 bits data bus. It is used to carry data.

? Oscillator: As we know Microcontroller is a digital circuit device, therefore it requires
clock for its operation. For this purpose, Microcontroller 8051 has an on-chip oscillator
which works as a clock source for Central Processing Unit. As the output pulses of
oscillator are stable therefore it enables synchronized work of all parts of
8051 Microcontroller.

? Input/output Port: As we know that Microcontroller is used in embedded systems to
control the operation of machines. Therefore to connect it to other machines, devices or
peripherals we requires I/O interfacing ports in Microcontroller. For this
purpose Microcontroller 8051 has 4 input output ports to connect it to other peripherals.

? Timers/Counters: Microcontroller 8051 has 2 16 bit timers and counters. The counters
are divided into 8 bit registers. The timers are used for measurement of intervals, to
determine pulse width etc.

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? PIN DAIGRAM 8051:

Fig :(4) PIN DIAGRAM

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? PIN DESCRIPTION:
? VCC = Supply voltage.
? GND = Ground.
? Port0=Port 0 is an 8-bit open-drain bi-directional I/O port.

? PORT1, PORT2:
? Port 1 is an 8-bit bi-directional I/O port with internal pull-ups.
? The Port 1 output buffers can sink/source four TTL input. As input, Port 1 pins that are
externally being pulled low will source current (IIL) because of the internal pull-ups.
? Port 1 also receives the low-order address bytes during Flash programming and
verification.

? Port2:
? Port 2 is an 8-bit bi-directional I/O port with internal pull-ups.
? The Port 2 output buffers can sink/source four TTL inputs.
? When 1s are written to Port 2 pins they are pulled high the internal pull-ups and can be
used as inputs.

? Port3:
? Port 3 is an 8-bit bi-directional I/O port with internal pull-ups.
? The Port 3 output buffers can sink/source four TTL inputs.
? When 1s are written to Port 3 pins they are pulled high by the internal pull-ups and can be
used as inputs.

? RST:
? Reset input. A high on this pin for two machine cycles while the oscillator is running
resets device.

? ALE/PROG:
? Address Latch Enable output pulse for latching the low byte of the address during
Accesses to external memory.
? This pin is also the program pulse input (PROG) during Flash programming.
? In normal operation ALE is emitted at a constant rate of 1/6 the oscillator frequency,and
may be used for external timing or clocking purposes.

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? PSEN:
? Program Store Enable is the read strobe to external program memory. When the
AT89C51 is from external program memory, PSEN is activated twice each machine
cycle, except that two PSEN activations are skipped during each access to external data
memory.
? The AT89C51 provides the following standard features: 4Kbytes of Flash, 128 bytes of
RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt
architecture, a full duplex serial port, on- chip oscillator and clock circuitry .In addition,
the AT89C51 is designed with static logic for
? Operation down to zero frequency and supports two software selectable power saving
modes.
? The Idle Mode stops the CPU while allowing the RAM, timer/counter, serial executing
code
? Port and interrupt system to continue functioning.

? FEATURES:
? 4K Bytes of In-System Reprogrammable Flash Memory
? Fully Static Operation: 0 Hz to 24 MHz
? 128 x 8-bit Internal RAM
? 32 Programmable I/O Lines
? Two 16-bit Timer/Counters
? Six Interrupt Source

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? 1.6 LCD:

? These LCD screens are limited to monochrome text and are often used in copiers, fax
machines, laser printers, industrial test equipment, networking equipment such
as routers and storage devices.

? The screens come in a small number of standard configurations. Common sizes are 8×1
(one row of eight characters), 16×2, 20×2 and 20×4. Larger custom sizes are made with
32, 40 and 80 characters and with 1, 2, 4 or 8 lines.

? The most commonly manufactured larger configuration is 40×4characters, which
requires two individually addressable HD44780 controllers with expansion chips as a
single HD44780 chip can only address up to 80 characters.

? A common smaller size is 16×2, and this size is readily available as surplus stock for
hobbyist and prototyping work. Character LCDs can come with or without backlights,
which may be LED, fluorescent, or electroluminescent.

FIG: 5 16*2 LCD
? LCD INTERFACING 16*2 LCD WITH 8051
MICROCONTROLLER

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FIG: 6 LCD INTERFACING WITH 8051

? LCD display is an inevitable part in all embedded project and this article is about
interfacing 16*2 LCD with 8051 microcontroller.

? It is easy to interface LCD module with the 8051 but the fact is that you learn it properly,
it a very easy job and by knowing it you can easily design embedded projects like digital
voltmeter / ammeter, digital clock, home automation displays, status indicator display,
digital code locks, digital speedometer/ odometer, display for music players.

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? The circuit diagram given above shows how to interface a 16×2 LCD module with
AT89S1 microcontroller. Capacitor C3, resistor R3 and push button switch S1
forms the reset circuitry.Ceramic capacitors C1, C2 and crystal X1 is related to
the clock circuitry which produces the system clock frequency.

? P1.0 to P1.7 pins of the microcontroller is connected to the DB0 to DB7 pins of
the module respectively and through this route the data goes to the LCD module.

? P3.3, P3.4 and P3.5 are connected to the E, R/W, RS pins of the microcontroller
and through this route the control signals are transffered to the LCD
module.Resistor R1 limits the current through the back light LED and so do the
back light intensity. POT R2 is used for adjusting the contrast of the display.

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? 16*2 LCD MODULE:

? 16×2 LCD module is a very common type of LCD module that is used in 8051
based embedded projects. It consists of 16 rows and 2 columns of 5×7 or 5×8
LCD dot matrices. The module were are talking about here is type number
JHD162A which is a very popular one. It is available in a 16 pin package with
back light, contrast adjustment function and each dot matrix has 5×8 dot
resolution. The pin numbers, their name and corresponding functions are shown
in the table below.

Pin No: Name Function
1 VSS This pin must be connected to the ground
2 VCC Positive supply voltage pin (5V DC)
3 VEE Contrast adjustment
4 RS Register selection
5 R/W Read or write
6 E Enable
7 DB0 Data
8 DB1 Data
9 DB2 Data
10 DB3 Data
11 DB4 Data
12 DB5 Data

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13 DB6 Data
14 DB7 Data
15 LED+ Back light LED+
16 LED- Back light LED-

? VEE pin is meant for adjusting the contrast of the LCD display and the contrast
can be adjusted by varying the voltage at this pin. This is done by connecting one
end of a POT to the Vcc (5V), other end to the Ground and connecting the center
terminal (wiper) of the POT to the VEE pin. See the circuit diagram for better
understanding.

? The JHD162A has two built in registers namely data register and command
register. Data register is for placing the data to be displayed, and the command
register is to place the commands.

? The 16×2 LCD module has a set of commands each meant for doing a particular
job with the display. We will discuss in detail about the commands later. High
logic at the RS pin will select the data register and Low logic at the RS pin will
select the command register. If we make the RS pin high and the put a data in
the 8 bit data line (DB0 to DB7), the LCD module will recognize it as a data to be
displayed. If we make RS pin low and put a data on the data line, the module will
recognize it as a command.

? R/W pin is meant for selecting between read and write modes. High level at this
pin enables read mode and low level at this pin enables write mode.

? E pin is for enabling the module. A high to low transition at this pin will enable the
module.

? DB0 to DB7 are the data pins. The data to be displayed and the
command instructions are placed on these pins. LED+ is the anode of the back
light LED and this pin must be connected to Vcc through a suitable series
currentlimiting resistor. LED- is the cathode of the back light LED and this pin
must be connected to ground.

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? 16*2 LCD COMMANDS:

? 16×2 LCD module has a set of preset command instructions. Each command will
make the module to do a particular task. The commonly used commands and
their function are given in the table below.

Command Function
0F LCD ON, Cursor ON, Cursor blinking ON
01 Clear screen
02 Return home
04 Decrement cursor
06 Increment cursor
0E Display ON ,Cursor blinking OFF
80 Force cursor to the beginning of 1st line
C0 Force cursor to the beginning of 2nd line
38 Use 2 lines and 5×7 matrix
83 Cursor line 1 position 3
3C Activate second line
08 Display OFF, Cursor OFF
C1 Jump to second line, position1
OC Display ON, Cursor OFF

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C1 Jump to second line, position1
C2 Jump to second line, position2

? LCD INTIALIZATION:

? The steps that has to be done for initializing the LCD display is given below and
these steps are common for almost all applications.
– Send 38H to the 8 bit data line for initialization
– Send 0FH for making LCD ON, cursor ON and cursor blinking ON.
– Send 06H for incrementing cursor position.
– Send 01H for clearing the display and return the cursor.

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? RTC-Real Time Clock:
? PIN DIAGRAM:

FIG: 7 PIN DIAGRAM

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? PIN DESCRIPTION:-
? AD0–AD7 – Multiplexed Address/Data Bus
? NC – No Connection
? MOT – Bus Type Selection
? CS – Chip Select
? AS – Address Strobe
? R/W – Read/Write Input
? DS – Data Strobe
? RESET – Reset Input
? IRQ – Interrupt Request Output
? SQW – Square Wave Output
? VCC – +5 Volt Supply
? GND – Ground

? GND, VCC– DC power is provided to the device on these pins.VCC is the +5V input.
When 5V are applied within normal limits, the device is fully accessible and data can be
written and read.When VCC is below 4.25V typical, reads and writes are inhibited.
However, the timekeeping function continues unaffected by the lower input voltage. As
VcC falls below 3V typical, the RAM and timekeeper are switched over to an internal
lithium energy source. The timekeeping function maintains an accuracy of 1minute per
month at +25C, regardless of the voltage input on the VCC pin.

? MOT (Mode Select) – The MOT pin offers the flexibility to choose between two
bus types. When connected to VCC, Motorola bus timing is selected. When connected to
GND or left disconnected, Intel bus timing is selected. The pin has an internal pull-down
resistance of approximately 20k

? SQW (Square-Wave Output) – The SQW pin can output a signal from one of 13
taps provided by the15 internal divider stages of the RTC. The frequency of the SQW pin
can be changed by programming Register A, as shown in Table 1. The SQW signal can
be turned on and off using the SQWE bit inRegister B. The SQW signal is not available
when VCC is less than 4.25V, typically.

? AD0–AD7 (Multiplexed Bidirectional Address/Data Bus) – Multiplexed
buses save pins because address information and data information time-share the same
signal paths. The addresses are present during the first portion of the bus cycle and the
same pins and signal paths are used for data in the second portion of the cycle.
Address/data multiplexing does not slow the access time of the DS12887 since the bus
change from address to data occurs during the internal RAM access time.Addresses must
be valid prior to the falling edge of AS/ ALE, at which time the DS12887 latches the
address from AD0 to AD6.Valid write data must be present and held stable during the

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latter portion of the DS or WR pulses. In a read cycle the DS12887 outputs 8 bits of data
during the latter portion of the DS or RD pulses.

? AS (Address Strobe Input) – A positive-going address-strobe pulse serves to
demultiplex the bus. The falling edge of AS/ALE causes the address to be latched within
the DS12887. The next rising edge that occurs on the AS bus clears the address
regardless of whether CS is asserted. Access commands should be sent in pairs.

? DS (Data Strobe or Read Input) – The DS/RD pin has two modes of operation
depending on the level of the MOT pin. When the MOT pin is connected to VCC,
Motorola bus timing is selected. In this mode, DS is a positive pulse during the latter
portion of the bus cycle and is called Data Strobe. During read cycles, DS signifies the
time that the DS12887 is to drive the bidirectional bus. In write cycles the trailing edge of
DS causes the DS12887 to latch the written data. When the MOT pin is connected to
GND, Intel Bus timing is selected. In this mode the DS pin is called Read (RD).RD
identifies the time period when the DS12887 drives the bus with read data. The RD signal
is the same definition as the output-enable (OE) signal on a typical memory.

? R/W (Read/Write Input) – The R/W pin also has two modes of operation. When the
MOT pin is connected to VCC for Motorola timing, R/W is at a level that indicates
whether the current cycle is a read or write. A read cycle is indicated with a high level on
R/W while DS is high. A write cycle is indicated when R/W is low during DS.When the
MOT pin is connected to GND for Intel timing, the R/W signal is an active-low signal
called WR. In this mode, the R/W pin has the same meaning as the write-enable signal
(WE) on generic RAMs.

? CS (Chip-Select Input) -The chip select signal must be asserted low for a bus cycle
in the DS12887 to be accessed. CS must be kept in the active state during DS and AS for
Motorola timing and during RD and WR for Intel timing. Bus cycles that take place
without asserting CS latch addresses but no access occur. When VCC is below 4.25V, the
DS12887 internally inhibits access cycles by internally disabling the CS input. This
action protects both the RTC data and RAM data during power outages.

? IRQ (Interrupt Request Output) – The IRQ pin is an active-low output of the
DS12887 that can be used as an interrupt input to a processor. The IRQ output remains
low as long as the status bit causing the interrupt is present and the corresponding
interrupt-enable bit is set. To clear the IRQ pin, the processor program normally reads the
C register. The RESET pin also clears pending interrupts.When no interrupt conditions
are present, the IRQ level is in the high-impedance state. Multiple interrupting devices

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can be connected to an IRQ bus. The IRQ bus is an open drain output and requires an
external pull-up resistor.

? RESET (Reset Input) – The RESET pin has no effect on the clock, calendar, or
RAM. On power-up, the RESET pin can be held low for a time to allow the power supply
to stabilize. The amount of time that RESET is held low is dependent on the application

FIG: 8 RTC CONNECTION WITH 8051

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? ACTIVITY 1- Connect the DS12887 RTC to the 8051 as shown in Chapter 16. Write
a program to display time and date on PC screen or an LCD.

? ACTIVITY 2 – Connect a buzzer to the RTC12887. After finishing ACTIVITY 1,
write a program sound the buzzer every 25 seconds past the minute. The Buzzer
should stop after 10 seconds.

? 1. In connecting the RTC12887, indicate the direction of pins AS, DS, MOT, and RW
from the point of view of the 8051.

? 2. Give the steps for setting the time and date in RTC.

? 3.Give the steps for reading the time and date in RTC.

? 4. In the DS12887 give the address for the following.
(a) Seconds
(b) Minutes
(c) Hours
(d) Day of the week
(e) Day of the Month
(f) Month
(g) Year
? 5.In the DS12887 give the address for the following.

(a) Seconds Alarm
(b) Minutes Alarm
(c) Hours Alarm

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? FEATURES:

? Drop-in replacement for IBM AT computer clock/calendar
? Totally non-volatile with over 10 years ofoperation in the absence of power
? Self-contained subsystem includes lithium , quartz, and support circuitry
? Counts seconds, minutes, hours, days, day of the week, date, month, and
year with leap-year compensation valid up to 2100
? Binary or BCD representation of time, calendar, and alarm
? 12-hour or 24-hour clock with AM and PM in 12-hour mode
? Daylight Savings Time option
? Selectable between Motorola and Intel bus timing
? Multiplex bus for pin efficiency
? Interfaced with software as 128 RAM locations
– 14 bytes of clock and control registers
– 114 bytes of general-purpose RAM
? Programmable square-wave output signal
? Bus-compatible interrupt signals (IRQ)Three interrupts are separately
software-mask able and testable
– Time-of-day alarm once/second to once/day
– Periodic rates from 122ms to 500ms
– End-of-clock update cycle

? APPLICATION:

1) It is useful for particular time and date indicate

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? RF MODULE:
? DECODER HT12D:

FIG: 9 PIN DAIGRAM
? Pins 1-8: Are the address bits. This 8bit address is sent along with the data and the
data is accepted only at the receiver where address is same as the address of encoder.
Hence we must make sure that both encoder and decoder have the same address.

? Pin 9:Is the Ground
?
? Pin 10-13: Are the data pins from where we receive DATA but only after it is
made sure that data received is ERROR free.

? Pin 14: Is the DATA IN pin which is connected to the DATA pin of receiver (RX).

? Pin 15-16:We need to connect a resistance between these pins and the value of
resistance is dependent upon the voltage applied and the frequency of transmission
which is described later on.

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? Pin 17: Is VALID TRANSMISSION pin. The data received is put at the output
DATA pins only when data is found error free and only then this VT pin is made
HIGH i.e. a HIGH at the VT pin indicates that DATA intended to be transmitted is
received properly.

? Pin 18: is the pin where we need to supply the voltage (V).

? FEATURES:
1) Low power and high noise immunity CMOS technology.
2) Low stand-by current.
3) Three times of receiving check Address/Data number combination.
4) HT12D: 8 address bits and 4 data bits.
5) HT12F: 12 address bits and 0 data bit.
6) A built-in oscillator with only a 5% resistor.
7) A valid transmission indicator.
8) Operating voltage: 2.4V~12V
9) Easy interface with an RF or an infrared transmission medium
-Minimal external components
-Pair with Holtek 212 series of encoders
10) 18-pin DIP, 20-pin SOP package

? APPLICATIONS:
1) Burglar alarm system.
2) Smoke and fire alarm system.
3) Garage door controllers.
4) Car door controllers.
5) Car alarm system.
6) Security system.
7) Cordless telephones
8) Other remote control systems

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? ENCODER (HT12E):

FIG: 10 PIN DIAGRAM

? Pins 1-8:Are the address bits. This 8bit address is sent along with the data and the
data is accepted only at the receiver where address is same as the address of encoder.

? Pin 9: Is the Ground
? Pin 10-13:Are the address/data pins which we can use as DATA or extended
ADDRESS Pins. On the DATA pins we put the DATA to be transmitted.

? Pin 14:Is TRANSMIT ENABLE pin. The data is transmitted only when there is a
LOW at this pin
.
? Pin 15-16:we need to connect a resistance between these pins and the value of
resistance is dependent upon the voltage applied and the frequency of transmission
which is described later on.

? Pin 17: Is the DATA OUT pin which is connected to the DATA pin of transmitter
(TX).
? Pin 18: Is the pin where we need to supply the voltage ( V)

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? FEATURES:

1) Operating voltage 2.4V~5V for the HT12A.
2) 2.4V~12V for the HT12E
3) Low power and high noise immunity CMOS technology
4) Low standby current: 0.1A (typ.) at VDD=5V
5) HT12A with a 38kHz carrier for infrared transmission medium
6) Built-in oscillator needs only 5% resistor
7) Data code has positive polarity
8) Minimal external components
9) Minimum transmission word
– Four words for the HT12E
– One word for the HT12A

? APPLICATIONS:

1) Burglar alarm system
2) Smoke and fire alarm system
3) Garage door controllers
4) Car door controllers

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? Power supply (5v):
? Voltage regulators comprise a class of widely used Ices. Regulator IC units
contain the circuitry for reference source, comparator amplifier, control
device, and overload protection all in a single IC. IC units provide regulation
of either a fixed positive voltage, a fixed negative voltage, or an adjustable
set voltage. The regulators can be selected for operation with load currents
from hundreds of mills amperes to tens of amperes, corresponding to power
ratings from mills watts to tens of watts.

FIG: 11 POWER SUPPLY

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PROJECT:-
? APPLICATIONS:
1) It system is useful every smart bus station.
2) This system useful for bus registration in bus station.

? ADVANTEGES :-
1) It can replace old manually managed bus depot system with automatic bus
detecting, registration and information handling.
2) Better time ; bus management can be possible.
3) Good passenger service can be possible.

? LIMITATION:-
1) Every bus require one transmitter module.
2) Limiting distance 70m coverage area.

? FEATURES SCOPE:
1) In this system include people counter system.
2) Large coverage area increasing you can must be use advanced protocol zig
bee.

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REFEREANCE BOOK AND WEBSITES:-
1. The 8051 Microcontroller and Embedded Systems by Muhammad Ali Mazidi.
2. Fundamentals Of Embedded Software By Daniel W Lewis
3..www.howsstuffworks.com
4. www.alldatasheets.com
5. www.electronicsforu.com
6. www.knowledgebase.com
7. www.8051 projectsinfo.com
8. Datasheets of Microcontroller AT89S52
9. WWW.digikey.com
10. www.jameco.com
11. www.elexp.com
12. www.engineergarage.com