AUTOMATIC SLOT INDICATOR CAR

PARKING USING AT89C51

MICROCONTROLLER

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content

CONTENTS Page No.

Abstract 4

1. Introduction 5

2. Flow diagram 8

3. Hardware description

(i). AT89C51 microcontroller

(ii). IR Sensors

(iii). Amplifying circuit

(a). NPN 547 Transistor

(b).Resistor

(c).Voltage supply

(iv). 16X2 LCD

4. Software description 39

5. Schematic connections 47

6. Advantages 49

7. Uses and implementation 50

8. Future scope 51

9. Conclusion 52

10. Reference 53

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ABSTRACT

Due to the increase in the number of vehicles on the road, traffic

problems are bound to exist. This is due to the fact that the current

transportation infrastructure and car park facility developed are unable to

cope with the influx of vehicles on the road. To alleviate the fore

mentioned problems, the smart card parking system has been developed.

With the implementation of the parking system, patrons can easily locate

and secure a vacant parking space at any car park deemed convenient to

them.

In this car parking system slots are allocated to the cars. Empty and filled

slots can be displayed on the LCD and the various problems related to

parking can be easily solved. There would be no traffic jam and no

wasting of time in searching of different parking areas.

This system is effectively in use in most of the European countries and

many of the American states. This design is mainly comprised of low

manual operation as well as efficient equipment can be installed any of

the commercial, industrial, apartments, institutions/universities, etc.

Hence it is a low cost apparatus as it mainly uses a microcontroller which

is programmable, which is easy to install in any of the above places

mentioned

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INTRODUCTION

Automobiles are synonyms for mobility and freedom. An amazing

increase in the growth of population in this world leads to the rapid

increase in the number of vehicle being used. With the growing number

of vehicles and the consequent shortage of parking space, there is

haphazard and totally unregulated parking of vehicles all over. In densely

populated areas they are real challenge for city planners, architects and

developers. The need to offer sufficient parking spaces is a task for

specialists. This situation calls for the need for an automated parking

system that not only regulates parking in a given area but also keeps the

manual control to a minimum. Automatic car parking systems is the sole

solution to park as many cars as possible in as little space as possible.

Automatic car parking systems are based on the most modern technology

of storage systems.

Our demonstration facility presents a miniature model of an automated

car parking system that regulates the number of cars that can be parked in

a given space at any given time based on the parking space availability. 

It requires no attendants and is more cost-effective than conventional

garages, and allows more cars to be parked in less space. The automation

technology is used to typically double to triple the capacity of

conventional parking garages. The main objective of this system is to

optimize the ground space available, for parking. In places where more

than 100 cars need to be parked, this system proves to be very useful.

Automatic Car Parking System enables the parking of vehicles, floor after

floor, by displaying the available slots thus reducing the ground space

used. Here any number of cars can be parked according to the

requirement, making the system modernized and a space-saving one.

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TYPES OF CAR PARKING

(a) Fully automated

(b) Semi automated

Fully Automated:

Fully automated parking systems operate much like robotic valet parking.

The driver drives the car into an APS entry (transfer) area. The driver and

all passengers exit the car. The driver uses an automated terminal nearby

for payment and receipt of a ticket. When driver and passengers have left

the entry area, the mechanical system lifts the car and transports it to a

pre-determined parking space in the system. More sophisticated fully

automated APS will obtain the dimensions of cars on entry in order to

place them in the smallest available parking space. The driver retrieves a

car by inserting a ticket or code into an automated terminal. The APS lifts

the car from its parking space and delivers it to an exit area. Most often,

the retrieved car has been oriented to eliminate the need for the driver to

back out. Fully automated APS theoretically eliminate the need for

parking attendants.

Semi Automated:

Semi-automated APS also use a mechanical system of some type to move

a car to its parking space, however putting the car into and/or the

operation of the system requires some action by an attendant or the

driver.

The choice between fully and semi-automated APS is often a matter of

space and cost, however large capacity (> 100 cars) tend to be fully

automated

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Characteristics of automatic car parking system suitable for Indian

environment

On the basis of critical study of automatic and semi automatic car parking

systems, it can be concluded that automatic car Parking System Suitable

for Indian Environment should have following Characteristics:

1. The car parking system should be semi automatic to minimize the cost.

2. The car parking system should multistoried to minimize the floor space

required per car.

3. A lift has to be provided to take the car to the upper stories.

4. Two doors have to be provided in the car lift for entry and exit of

vehicle.

5. LED and LCD display screen on each floor will be provided to display

data about available and non available parking slots.

6. An addition lift is provided which connects all the floors for the driver

to return to ground floor after parking the car.

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2. FLOW DIAGRAM

TTT

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Transmitter- Receiver Sensor

Amplifier Circuit

Microcontroller Circuit

Display Unit

3. HARDWARE DESCRIPTION

In this project we use many hardware materials. Every hardware

component have its own functions and own specifications. Every

component performs different functions. These components can be

implanted in many instruments by different means. Now, here we will

discuss the different hardware components used in our project.

(i). AT89C51 Microcontroller

(ii). IR Sensors

(iii). Amplifying circuit

(a). NPN transistor

(b). Resistors

(c). Voltage supply

iv. 16X2 LCD

Now we will describe every component used in project in detail.

(i) MICROCONTROLLER - AT89C51

Microcontroller is a single chip computer or A CPU with all peripherals

like RAM,ROM,I/O PORTS,ADC,TIMERS etc. on same chip. For ex:

intel's 8051, Motorola's 6811 etc.

The block diagram of the 8051 shows all of the features unique to

microcontrollers:

1. Internal ROM and RAM

2. I/O ports with programmable pins

3. Timers and counters

4. Serial data communication

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The block diagram also shows the usual CPU components program

counter, ALU, working registers, and the clock circuits.

The 8051 architecture consists of these specific features:

1. 8 bit CPU with registers A and B

2. 16 bit PC &data pointer (DPTR)

3. 8 bit program status word (PSW)

4. 8 bit stack pointer (SP)

5. Internal ROM or EPROM (8751) of 0(8031)to 4k(8051)6. Internal RAM of 128 bytes.

7. 4 register banks, each containing 8 registers

8. 80 bits of general purpose data memory

9. 32 input/output pins arranged as four 8 bit ports: P0-P3

10. Two 16 bit timer/counters: T0-T1

11. Two external and three internal interrupt sources

12. Oscillator and clock circuits

Pin diagram of AT89C51 microcontroller is shown as:

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Figure1: Pin diagram of AT89C51

Now we will briefly describe every part of the microcontroller:

AT89C51 is an 8-bit microcontroller and belongs to Atmel's 8051 family.

ATMEL 89C51 has 4KB of Flash programmable and erasable read only

memory (PEROM) and 128 bytes of RAM. It can be erased and program

to a maximum of 1000 times.

In 40 pin AT89C51, there are four ports designated as P1, P2, P3 and P0.

All these ports are 8-bit bi-directional ports, i.e., they can be used as both

input and output ports. Except P0 which needs external pull-ups, rest of

the ports have internal pull-ups. When 1s are written to these port pins,

they are pulled high by the internal pull-ups and can be used as inputs.

These ports are also bit addressable and so their bits can also be accessed

individually port P0 and P2 are also used to provide low byte and high

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byte addresses, respectively, when connected to an external memory. Port

3 has multiplexed pins for special functions like serial communication

hardware interrupts, timer inputs and read/write operation from external

memory. AT89C51 has an inbuilt UART for serial communication. It can

be programmed to operate at different baud rates. Including two timers&

hardware interrupts, it has a total of six interrupts. Pins can be described

as follows:

VCC

Positive (+ve) Dc Supply voltage which is normally between 3V to 5V

Dc.

GND

0 Volt ground. This pin is connected to -ve dc supply voltage.

PORTS

Ports are generally used by computers to communicate to the outside

world. Microcontrollers use port to read input from another device or to

send output to another device. At89C51 has four ports for

communication.

Port 0, Port 1, Port 2, Port 3

These ports are 8-bit bi-directional I/O ports. They can be used for both

input and output ports. As an output port, each pin can sink eight TTL

inputs. Port can be used as an input when they are made to read data from

another device (which can be a component or a sensor) or as an output

when they are used to send a signal to another device. They basically

understand two logic states that are 1s and 0s.

RST

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Reset input. This pin is used to reset the microcontroller. If a high

remains on this pin for two machine cycles while the oscillator is running,

the microcontroller is reset.

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. This pin is used to

control microcontroller. Setting the ALE-disable bit has no effect if the

microcontroller is in external execution mode.

PSEN

Program Store Enable is the read strobe to external program memory.

When the AT89C51 is executing code 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.

EA/VPP

External Access Enable (EA) must be strapped to GND in order to enable

the device to fetch code from external program memory locations starting

at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed,

EA will be internally latched on reset. EA should be strapped to VCC for

internal program executions. This pin also receives the 12-volt

programming enable voltage (VPP) during Flash programming, for parts

that require 12 volt VPP.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock

operating circuit. This pin is connected to the external crystal oscillator

together with XTAL2.

XTAL2

Output from the inverting oscillator amplifier

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Registers

In the CPU, registers are used to store information temporarily. That

information could be a byte of data to be processed, or an address

pointing to the data to be fetched. The vast majority of 89C51 register an

address pointing to the data to be fetched. The vast majority of 89C51

registers are 8-bit registers. In the 8051 there is only one data type: 8 bits.

The 8 bits of a register are shown in the diagram from the MSB (most

significant bit) D7 to the LSB (least significant bit) D0. With an 8-bit data

type, any data larger than 8 bits must be broken into 8-bit chunks before it

is processed. The most widely used registers of the 89C51 are A

(accumulator), B, R0, R1, R2, R3, R4, R5, R6, R7, DPTR (data pointer),

and PC (program counter). All of the above registers are 8-bits, except

DPTR and the program counter. The accumulator, register A, is used for

all arithmetic and logic instructions.

Figure 2: Registers of 8951

All the registers of 89C51 are:

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Timers:

Both timer 0 and timer 1 are 16 bits wide. Since the 89C51 has an 8-bit

architecture, each 16-bit timer is accessed as two separate registers of low

byte and high byte. Each timer is discussed separately.

Timer 0 Register:

The 16-bit register of time 0 is accesses as low byte and high byte. The

low byte register is called TL0 (timer 0 low byte) and the high byte

register is referred to as th0 (timer 0 high byte). These registers can be

access d like any other register, such as A,B, R0, R1, R2 etc. For

example, the instruction “TLO= 20” moves the value 500 into TL0, the

low byte of timer 0. These registers can also be read like any other

register.

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Figure 3: Timer 0 register

Timer 1 Register:

Timer 1 is also 16 bits, and its 16- bit register is split into two bytes,

referred to as TL1 (timer 1 low byte) and TH1 (timer 1 high byte). These

registers are accessible in the same way as the registers of timer 0.

Figure 4: Timer 1 register

TMOD (Timer Mode) Register:

Both timers 0 and 1 uses the same register, called TMOD, to set the

various timer operation modes. TMOD is an 8-bit register in which the

lower 4 bits are set aside for timer 0 and the upper 4 bits are set aside for

timer 1. In each case, the lower 2 bits are used to set the timer mode and

the upper 2 bits to specify the operation.

Mode 2 Programming:

The following are the characteristics and operations of mode 2.

1-It is an 8-bit timer; therefore, it allows only values of 00 to FFH to be

loaded into the timer’s register TH.

2-After TH is loaded with the 8-bit value, the 8051 gives a copy of it to

TL. Then the timer must be started. This is done by the instruction

“SETB TR0” for timer 0 and “SETB TR1” for timer 1. This is just like

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mode 1.

3-After the timer started, it starts to count up by incrementing the TL

register. It counts up until it reaches its limit of FFH. When it rolls over

from FFH to 00, it sets high the TF (timer flag). If we are using timer 0,

TF0 goes high; if we are using timer 1, TF1 is raised.

4-When the TL registers rolls from FFH to 0 and TF is set to 1, TL is

reloaded automatically with the original value kept by the TH register. To

repeat the process, we must simply clear TF and let it go without any

need by the programmer to reload the original value. This makes mode 2

and auto-reload, in contrast with mode 1 in which the programmer has to

reload TH and TL.

It must be emphasized that mode 2 is an 8-bit timer. However, it has an

auto-reloading capability in auto reload. TH is loaded with the initial

count and a copy of it is given to TL. This reloading leaves TH

unchanged, still holding a copy of original value. This mode has many

applications, including setting the baud rate in serial communication.

SBUF (Serial Buffer) Register:

SBUF is an 8-bit register used solely for serial communication in the

89C51. For a byte of data to be transferred via the TxD line, it must be

placed in the SBUF register. Similarly, SBUF holds the byte of data when

it is received by the 89C51 RxD line. SBUF can be accessed like any

other register in the 89C51.The moment a byte is written into SBUF, it is

framed with the start and stop bits and transferred serially via the TxD

pin. Similarly, when the bits are received serially via RxD, the 89C51

deframes it by eliminating the stop and start bits, making a byte out of the

data received, and then placing it in the SBUF. Some baud rates are

shown below:

Baud Rate= 9600 TH1(Decimal)=-3 TH1(HEX)=FD

Baud Rate= 4800 TH1(Decimal)=-6 TH1(HEX)=FA

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Baud Rate= 2400 TH1(Decimal)=-12 TH1(HEX)=F4

Baud Rate= 1200 TH1(Decimal)=-24 TH1(HEX)=E8

SCON (Serial Control) Register:

The SCON register is an 8-bit register used to program the start bit, stop

bit, and data bits of data framing, among other things. Following SCON

bits are explained; SMO SCON.7 Serial port mode specifier

SM1/ SCON.6= Serial port mode specifier

SM2/ SCON.5= Used for multiprocessor communication (Make it 0)

REN/ SCON.4= Set / cleared by software to enable / disable reception.

TB8/ SCON.3= Not widely used.

RB8/ SCON.2= Not widely used.

T1/ SCON.1= Transmit interrupt flag. Set by hardware at the beginning

of the stop bit in mode1must by cleared by software.

R1/ SCON.0= Receive interrupt flag. Set by hardware halfway through

the stop bit time in mode1must be cleared by software.

Bit-Addressable RAM:

Of the 128-byts internal RAM of the 8051, only 16 bytes of it are bit

addressable. The rest must be accessed in byte format. The bit –

addressable RAM locations are 20H to 2FH. These 16 bytes provide 128

bits of RAM bit – address ability since 16 x 8 = 128. They are addressed

as 0 to 127 (in decimal) or 00 to 7FH. Therefore, the bit addresses 0 to 7

are for the first byte of internal RAM location 20H, and 8 to 0FH are the

bit addresses of the second byte, RAM location 21H, and so on. The last

byte of 2FH has bit address byte of 2FH has bit addresses of 78H to 7FH.

Note that internal RAM locations 20-2FH are both byte-addressable and

bit addressable. Notice from figure that bit addresses 00 – 7FH belong to

RAM byte addresses 20 – 2FH, and bit addresses 80 – F7H belong to

SFR P0, P1 etc.

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Block diagram of 8951 can viewed as:

Figure 5: Block diagram of 8951

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(ii) IR SENSORS

In this receiver transmitter infrared sensor is used. These sensors are

available in pairs. One acts as receiver and other acts as transmitter.

These are designated as TX-RX.

Figure 6: TX-RX sensor

Infrared (IR) transmitters and receivers are present in many different

devices, though they are most commonly found in consumer electronics.

The way this technology works is that one component flashes an infrared

light in a particular pattern, which another component can pick up and

translate into an instruction. These transmitters and receivers are found in

remote controls and all different types of devices, such as televisions and

DVD players. Peripheral devices that include this technology can also

allow a computer to control various other consumer electronics. Since

infrared remotes are limited to line of sight operation, some products can

be used to extend the signals over a hardwired line or radio frequency

(RF) transmissions.

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Most common consumer electronic remote controls use infrared light.

They typically generate infrared using light emitting diodes (LEDs), and

the main component of a receiver unit is usually a photodiode. A remote

control flashes a pattern of invisible light, which is picked up and then

turned into an instruction by the receiver module. The parts necessary to

construct transmitter and receiver are typically inexpensive, but these

systems are limited to line of sight operation.

Infrared Sensors are of two types: Thermal & Quantum:

Thermal type sensors have no wavelength dependence. They use the

infrared energy as heat and their photosensitivity is independent of

wavelength. Thermal detectors don’t require cooling but have

disadvantages that response time is slow & detection time is low.

 Common types of thermal type IR detectors are:

Thermocouple-Thermopile:

A detector that converts temperature into an electrical signal is commonly

known as a thermocouple. The junction of dissimilar metals generates a

voltage potential, which is directly proportional to the temperature. This

junction can be made into multiple junctions to improve sensitivity. Such

a configuration is called a thermopile. The active or ‘Hot’ junctions are

blackened to efficiently absorb radiation. The reference or ‘Cold’

junctions are maintained at the ambient temperature of the detector. The

absorption of radiation by the blackened area causes a rise in temperature

in the ‘hot’ junctions as compared to the ‘cold’ junctions of the

thermopile. This difference in temperature across the thermocouple

junction causes the detector to generate a positive voltage. If the active or

‘hot’ junction were to cool to a temperature less than the reference or

‘cold’ junction the voltage output would be negative.These detectors has

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a relatively slow response time, but offers the advantages of DC stability,

requiring no bias, and responding to all wavelengths.

 Bolometer:

A bolometer is a simple thermal or total power detector. A bolometer

changes resistance when incident infrared radiation interacts with the

detector. This thermally sensitive semiconductor is made of a sintered

metal oxide material. It has a high temperature coefficient of resistance

It essentially consists of two main elements: a sensitive thermometer and

an absorptive element and a heat sink. Absorber is connected by a weak

thermal link to a heat sink (at temperature T0). Incoming energy increases

the temperature of the absorptive element above that of a heat sink and

rise in temperature is measured by a thermometer.

Delta T = T - T0 = E/C

Figure 7: Bolometer

Bolometer use metals or semiconductor/superconductors as absorptive

elements.

 Pyroelectric detector:

Pyroelectric detectors use PZT having pyroelectric effect, a high resistor

and a low noise FET, hermetically sealed in a package. Pyroelectric

materials are crystals, such as lithium tantalate, which exhibit

spontaneous polarization, or a concentrated electric charge that is

temperature dependent. PZT is spontaneously polarized in dark state. As

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infrared radiation strikes the detector surface, the change in temperature

causes a current to flow. This results in change of polarization state which

is reflected in terms of voltage change at the output.

 This detector exhibits good sensitivity and good response to a wide range

of wavelengths, and does not require cooling of the detector. It is the

most commonly used detector for gas monitors. Quantum type offer

higher detection performance and a faster response speed although their

photosensitivity is wavelength dependant. Quantum type detectors require

cooling for accurate measurements (except for those in near IR region).

Quantum type detectors are further classified into two categories:

Intrinsic type:

i) Photoconductive

Photoconductive type of IR detectors makes use of photoconductive

effect. This effect causes change in resistance when IR radiation falls

upon detecting elements.Examples are PbS, PbSe, MCT (HgCdTe)

Bandgap of PbS, PbSe have negative temperature coefficient and hence

their spectral response characteristics shift to long wavelength region

when cooled. However, bandgap of HgCdTe depends upon the

composition and therefore, spectral response characteristics can be

tailored to suit the requirements.

 ii) Photovoltaic

Photoconductive type of IR detectors makes use of photovoltaic effect.

Incident IR light cause increase in voltage output of these detectors.

Examples are InGaAs PIN photodiodes, InAs, InSb

Extrinsic type:

Various types of detectors like Ge:Au, Ge:Hg, Ge:Cu, Ge:Zn, Si:Ga,

Si:As and are used depending upon the requirements of the application-

spectral response, D*, etc.A photoelectric sensor,or photo eye, is a device

used to detect the distance, absence, or presence of an object by using a

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light transmitter, often infrared, and a photoelectric receiver.

For our purpose we use photoelectric sensor. A photoelectric sensor or

photo eye is a device used to detect the distance, absence, or presence of

an object by using a light transmitter, often infrared, and a photoelectric

receiver.

Types:

A self-contained photoelectric sensor contains the optics, along with the

electronics. It requires only a power source. The sensor performs its own

modulation, demodulation, amplification, and output switching. Some

self-contained sensors provide such options as built-in control timers or

counters. Because of technological progress, self-contained photoelectric

sensors have become increasingly smaller.

Remote photoelectric sensors used for remote sensing contain only the

optical components of a sensor. The circuitry for power input,

amplification, and output switching are located elsewhere, typically in a

control panel. This allows the sensor, itself, to be very small. Also, the

controls for the sensor are more accessible, since they may be bigger.

When space is restricted or the environment too hostile even for remote

sensors, fiber optics may be used. Fiber optics are passive mechanical

sensing components. They may be used with either remote or self-

contained sensors. They have no electrical circuitry and no moving parts,

and can safely pipe light into and out of hostile environments.

Sensing Modes:

An opposed (through beam) arrangement consists of a receiver located

within the line-of-sight of the transmitter. In this mode, an object is

detected when the light beam is blocked from getting to the receiver from

the transmitter.

A retroreflective arrangement places the transmitter and receiver at the

same location and uses a reflector to bounce the light beam back from the

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transmitter to the receiver. An object is sensed when the beam is

interrupted and fails to reach the receiver.

A proximity-sensing (diffused) arrangement is one in which the

transmitted radiation must reflect off the object in order to reach the

receiver. In this mode, an object is detected when the receiver sees the

transmitted source rather than when it fails to see it.

Some photoeyes have two different operational types, light operate and

dark operate. Light operatephotoeyes become operational when the

receiver "receives" the transmitter signal. Dark operate photoeyes become

operational when the receiver "does not receive" the transmitter signal.

The detecting range of a photoelectric sensor is its "field of view", or the

maximum distance the sensor can retrieve information from, minus the

minimum distance. A minimum detectable object is the smallest object

the sensor can detect. More accurate sensors can often have minimum

detectable objects of minuscule size.

(iii) Amplifying circuit

The amplifier consists of a npn transistor connected in Common emitter

mode. It is used as an interface between the sensors set and the

microcontroller circuit. It amplifies the signal received from the sensor

set and gives the amplified output to the microcontroller.

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Figure 8: Amplifying circuit layout

Amplifying circuit consist of following parts

a. NPN 547 Transistor

b. Resistors

c. Voltage supply

We will briefly describe about these parts of circuit:

a.NPN 547 Transistor:

An NPN transistor is the most common type of bipolar junction

transistor, or BJT for short. BJTs are often referred to simply as

transistors, and come in two main types: the NPN and the PNP. The "N"

represents a negatively charged layer of material and the "P" represents a

positively charged layer. NPN transistors have a positive layer located in-

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between two negative layers. Transistors are typically used in circuits for

amplifying or switching electrical signals that pass through them.

The NPN transistor has a shared base used by both the collector and the

emitter layers. The collector and emitter layers are also asymmetrical,

meaning the amount of impurity in one layer does not match the amount

in the other. Impurities are created when forming the material for the

layers because these impurities create the required positive or negative

charge. This process of creating a certain charge by producing impurities

in the material is known as doping.The NPN transistor is commonly used

because it is so easy to produce. For a transistor to work properly, it needs

to be formed from a semiconductor material. Semiconductors include

materials that fall somewhere near the middle on a scale measuring good

and bad conducting materials. Semiconductors can carry some electric

current, but not as much as extremely conductive materials such as metal.

Silicon is one of the most commonly used semiconductors, and NPN

transistors are the easiest transistors to make out of silicon.One

application for an NPN transistor is on a computer's circuit board.

Computers require all their information be translated into binary code,

and this process is accomplished through a plethora of tiny switches

flipping on and off on the computer’s circuit boards. NPN transistors can

be used for these switches. A strong electric signal turns the switch on

while a lack of a signal turns the switch off. Here we use BC547 NPN

Transistor. BC547 is an NPN bi-polar junction transistor. A transistor,

stands for transfer of resistance, is commonly used to amplify current. A

small current at its base controls a larger current at collector & emitter

terminals.BC547 is mainly used for amplification and switching

purposes. It has a maximum current gain of 800. Its equivalent transistors

are BC548 and BC549.The transistor terminals require a fixed DC

voltage to operate in the desired region of its characteristic curves. This is

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known as the biasing. For amplification applications, the transistor is

biased such that it is partly on for all input conditions. The input signal at

base is amplified and taken at the emitter. BC547 is used in common

emitter configuration for amplifiers. The voltage divider is the commonly

used biasing mode. For switching applications, transistor is biased so that

it remains fully on if there is a signal at its base. In the absence of base

signal, it gets completely off.

 Figure 9: Pin diagram of BC547 NPN Transistor

b. Resistors:

A resistor is a passive two terminal electric component that implementsas

electrical resistance a circuit element. Resistors act to reduce current

flow, and, at the same time, act to lower voltage levels within circuits.

Resistors may have fixed resistances or variable resistances, such as those

found in thermistor, varistors, trimmers, photoresistors etc.

The current through a resistor is in direct proportion to the voltage across

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the resistor's terminals. This relationship is represented by Ohm’s Law:

Where I is the current through the conductor in units of amperes, V is the

potential difference measured across the conductor in units of volts, and R

is the resistance of the conductor in units of ohms(symbol: Ω).

The ratio of the voltage applied across a resistor's terminals to the

intensity of current in the circuit is called its resistance, and this can be

assumed to be a constant (independent of the voltage) for ordinary

resistors working within their ratings.

Resistors are common elements of electrical networks and electronic

circuits and are ubiquitous in electronic equipment. Practical resistors can

be composed of various compounds and films, as well as resistance wires

(wire made of a high-resistivity alloy, such as nickel-chrome). Resistors

are also implemented within integrated circuits, particularly analog

devices, and can also be integrated into hybrid and printed circuits. The

electrical functionality of a resistor is specified by its resistance: common

commercial resistors are manufactured over a range of more than nine

orders of magnitude. When specifying that resistance in an electronic

design, the required precision of the resistance may require attention to

the manufacturing tolerance of the chosen resistor, according to its

specific application. The temperature coefficient of the resistance may

also be of concern in some precision applications. Practical resistors are

also specified as having a maximum power rating which must exceed the

anticipated power dissipation of that resistor in a particular circuit: this is

mainly of concern in power electronics applications. Resistors with

higher power ratings are physically larger and may require heat sinks. In

a high-voltage circuit, attention must sometimes be paid to the rated

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maximum working voltage of the resistor. While there is no minimum

working voltage for a given resistor, failure to account for a resistor's

maximum rating may cause the resistor to incinerate when current is run

through it.

Practical resistors have a series inductance and a small parallel

capacitance; these specifications can be important in high-frequency

applications. In a low noise amplifier or pre-amp, the noise characteristics

of a resistor may be an issue. The unwanted inductance, excess noise, and

temperature coefficient are mainly dependent on the technology used in

manufacturing the resistor. They are not normally specified individually

for a particular family of resistors manufactured using a particular

technology[1].A family of discrete resistors is also characterized

according to its form factor, that is, the size of the device and the position

of its leads (or terminals) which is relevant in the practical manufacturing

of circuits using them.

Units used for resistance: The ohm(symbol:Ω) is the SI unit of electrical

resistance, named after Georg Simon Ohm. An ohm is equivalent to a volt

per ampere. Since resistors are specified and manufactured over a very

large range of values, the derived units of milliohm (1 mΩ = 10−3 Ω),

kilohm (1 kΩ = 103 Ω), and megohm (1 MΩ = 106 Ω) are also in common

usage.The reciprocal of resistance R is called conductance G = 1/R and is

measured in Siemens (SI unit), sometimes referred to as a mho. Hence,

siemens is the reciprocal of an ohm: . Although the concept of

conductance is often used in circuit analysis, practical resistors are always

specified in terms of their resistance (ohms) rather than conductance.

29

Figure 10: Resistors

For amplifying circuit resistors of 10 ohm and 1.5 kilo ohms are used.

c. Voltage supply:

A voltage source is a two terminal device which can maintain a fixed

voltage. An ideal voltage source can maintain the fixed voltage

independent of the load resistance or the output current. However, a real-

world voltage source cannot supply unlimited current. A voltage source is

the dual of a current source. Real-world sources of electrical energy, such

as batteries, generators, and power systems, can be modeled for analysis

purposes as a combination of an ideal voltage source and additional

combinations of impedence element.

Voltage supply can be applied to the circuit by using batteries or adapters.

A 5V supply is given to the circuit.

(iv) 16X2 LCD

An HD44780 Character LCD is a de facto industry standard liquid crystal

display (LCD) display device designed for interfacing with embedded

systems. These screens come in a variety of configurations including 8x1,

which is one row of eight characters, 16x2, and 20x4. The most

commonly manufactured configuration is 40x4 characters, which requires

30

two individually addressable HD44780 controllers with expansion chips

as the HD44780 can only address up to 80 characters. These LCD screens

are limited to text only and are often used in copiers, fax machines, laser

printers, industrial test equipment, networking equipment such as routers

and storage device

F F

Figure 11: 16X2 LCD

These LCD screens are limited to text only and are often used in

copiers, fax machines, laser printers, industrial test equipment,

networking equipment such as routers and storage devices. Character

LCDs can come with or without backlights, which may be LED,

fluorescent, or electroluminescent.

31

Character LCDs use a standard 14-pin interface and those with backlights have 16 pins. The pin numbers, their name and corresponding functions

are shown in the table  below:

32

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

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 current limiting resistor.

LED- is the cathode of the back light LED and this pin must be connected

to ground.

LCD INITIALIZATION:

 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.

33

Send 01H for clearing the display and return the cursor.

SENDING DATA TO LCD:

The steps for sending data to the LCD module is given below. We have

already said that the LCD module has pins namely RS, R/W and E. It is

the logic state of these pins that make the module to determine whether a

given data input  is a command or data to be displayed.

Make R/W low.

Make RS=0 if data byte is a command and make RS=1 if the data byte

is a data to be displayed.

Place data byte on the data register.

Pulse E from high to low.

Repeat above steps for sending another data.

Now, we will discuss general interfacing of 16X2 LCD with AT89C51:

Figure 12: Circuit diagram of interfacing LCD to AT89C51

34

Follow these simple steps for displaying a character or data:

E=1; enable pin should be high

RS=1; Register select should be high

R/W=0; Read/Write pin should be low.

To send a command to the LCD just follows these steps:

E=1; enable pin should be high

RS=0; Register select should be low

R/W=1; Read/Write pin should be high.

Commands: There are some preset commands which will do a specific

task in the LCD. These commands are very important for displaying data

in LCD. The list of commands given:

Command Function

0F For switching on LCD, blinking the cursor.

1 Clearing the screen

2 Return home.

4 Decrement cursor

6 Increment cursor

E Display on and also cursor on

80 Force cursor to beginning of the first line

C0 Force cursor to beginning of second line

38 Use two lines and 5x7 matrix

35

Command Function

83 Cursor line 1 position 3

3C Activate second line

0C3 Jump to second line position 3

0C1 Jump to second line position1

Circuit Explanation:

The crystal oscillator is connected to XTAL1 and XTAL2 which will

provide the system clock to the microcontroller the data pins and

remaining pins are connected to the microcontroller as shown in the

circuit.  The potentiometer is used to adjust the contrast of the LCD. You

can connect data pins to any port. If you are connecting to port0 then you

have to use pull up registers. The enable, R/W and RS pins are should be

connected to the 10, 11 and 16 (P3.3, P3.4 and P3.5).

Programming LCD to 8951:

Coming to the programming you should follow these steps:

STEP1: Initialization of LCD.

STEP2: Sending command to LCD.

STEP3: Writing the data to LCD.

Initializing LCD: To initialize LCD to the 8051 the following instruction

and commands are to be embed in to the functions

0×38 is used for 8-bit data initialization.

36

0X6H for incrementing the cursor which will help to display another

character in the LCD

0x1H for clearing the LCD.

Sending data to the LCD:

E=1; enable pin should be high

RS=1; Register select should be high for writing the data

Placing the data on the data registers

R/W=0; Read/Write pin should be low for writing the data.

Uses of LCD:

Clocks: Alarm clocks and wall clocks commonly use LCDs to create

simplistic, easy-to-read screens. Modern LCD clocks use the liquid crystal

display to create decorative colors and images behind the date and time.

While the numbers are typically simplistic, LCD alarm clocks often offer

customization options for a stylized display.

Calculators: Calculators use LCDs because of its light and compact

design. This allows the screen to be as large as practical while requiring

little casing space and keeping the weight to a minimum. According to

IEEE, LCD is the most common form of display in modern hand-held

calculator devices.

Television: LCD technology is common in television screens for its light-

weight design and cost effectiveness. According to MSNBC, since 2007,

LCD sales have surpassed that of the traditional vacuum tube televisions

and offer competition to plasma television sales as well. In addition, Flat

Panel TV.org states that an LCD TVs screen lifespan is upward of 60,000

hours, making it more cost effective than other TV screens. LCD

37

4. SOFTWARE DESCRIPTION

Figure 14: Block diagram

The software used for the procedure is KIEL. The software codes used

are as follows:

//Program for Automatic Parking Slot Indicator

//using AT89C51

#include<reg51.h>

sbit slot1=P1^0;

38

sbit slot2=P1^1;

sbit slot3=P1^2;

sbit slot4=P1^3;

sbit led1=P3^0;

sbit led2=P3^1;

sbit led3=P3^2;

sbit led4=P3^3;

sbit rs=P0^0;

sbit rw=P0^1;

sbit en=P0^2;

void delay(int itime)

{

int i,j;

for(i=0;i<=itime;i++)

for(j=0;j<=1275;j++);

}

");

lcdcmd(0x39); void lcdcmd(unsigned char value)

{

rs=0;

rw=0;

en=1;

P2=value;

39

delay(1);

en=0;

}

void lcddata(unsigned char *value)

{

int i;

for(i=0;value[i]!='\0';i++)

{

rs=1;

rw=0;

en=1;

P2=value[i];

delay(1);

en=0;

}

}

void lcdnum(unsigned char slot)

{

rs=1;

rw=0;

en=1;

P2=slot;

delay(1);

en=0;

}

void main()

{

int x;

unsigned char a[4]={'1','2','3','4'};

40

unsigned char b[4]={'1','2','3','4'};

unsigned int c[4];

P3=0x00;

P1=0x00;

lcdcmd(0x08);

delay(1);

lcdcmd(0x38);

delay(1);

lcdcmd(0x0e);

delay(1);

lcdcmd(0x01);

delay(1);

lcdcmd(0x06);

delay(1);

lcdcmd(0x39);

delay(1);

lcddata("Welcome to

lcdcmd(0x80);

lcddata("Automatic Parking Indicator");

delay(500);

lcdcmd(0x01);

lcddata("Initialising.");

delay(50);

lcddata(".");

delay(50);

lcddata(".");

delay(50);

while(1)

{

41

if(slot1==0)

{

led1=1;

delay(1);

c[0]=1;

delay(10);

}

else

{

led1=0;

delay(1);

c[0]=0;

delay(10);

}

If (slot2==0)

{

led2=1;

delay(1);

c[1]=1;

delay(10);

}

else

{

led2=0;

delay(1);

c[1]=0;

delay(10);

}

if(slot3==0)

42

delay(1);

c[2]=1;

delay(10);

}

else

{

led3=0;

delay(1);

c[2]=0;

delay(10);

}

if(slot4==0)

{

led4=1;

delay(1);

c[3]=1;

delay(10);

}

else

{

led4=0;

delay(1);

c[3]=0;

delay(10);

}

lcdcmd(0x01);

lcdcmd(0x0e);

lcddata("Filled:");

delay(50);

43

lcdcmd(0x01);

lcdcmd(0x39);

for(x=0;x<=4;x++)

{

if(c[x]==1)

{

lcdnum(a[x]);

lcddata(",");

delay(50);

}

}

delay(50);

lcdcmd(0x01);

lcdcmd(0x0e);

lcddata("Available:");

delay(50);

lcdcmd(0x01);

lcdcmd(0x39);

for(x=0;x<=4;x++)

{

if(c[x]==0)

{

lcdnum(b[x]);

lcddata(",");

delay(20);

}

}

y: if(P1==0x00)

{

44

P3=0xFF;

lcdcmd(0x01);

lcddata("Parking Full");

delay(50);

lcdcmd(0x01);

goto y;

}

} //while(1) ends here

} //main() ends here

45

5. SCHEMATIC CONNECTIONS

FIGURE 14: Schematic layout

46

The connections are made in Proteus software. The C file id first

compiled in Keil Software and a hex file is created from Keil. The Hex

file is embedded in the microcontroller in the simulation work and also

virtually. In proteus sensors are replaced by switches and data is

displayed by using LED’S and LCD.

In the schematic layout circuit of AT89C51 the ports P1.0 – P1.3 are

connected to the output of the receiver transmitter sensors. These sensors

will detect the coming obstacle and will send information to

microcontroller using these ports. When the sensor is blocked by any

obstacle it will send 1 to the ports i.e it is in off state which indicates that

the car entered the parking area and one of the slots is filled. When there

is no obstacle, the sensors are in on state and will send 0 to the

microcontroller. The pins P3 are connected to the LCD which will

indicate the availability of space in the parking area. If parking is full it

will show that there is no space for incoming vehicle. LED connected to

the port P2 are used as indicator for the empty slots. It shows the

available space for incoming cars.

General circuit of amplifier circuit:

Figure 15: Amplifier circuit

47

Amplifier circuit amplifies the voltage and the output of the circuit is

given to the microcontroller. The input from the IR sensors is given to the

amplifier circuit. Main components of the amplifier circuit are

1. NPN Transistor

2. Resistances of 100 Ohm and 1.5 KiloOhm

3. Sensors

6. ADVANTAGES

Advance car parking is becoming famous day by day. It is far better than the

old methods of parking as it is helpful in many ways. here are some

advantages of advance car parking using slot indicator:

1.Efficiency:

Automatic Car Parking System provides car parking solutions

accommodating maximum cars in minimum space

 

2. Cost effective:

Automatic Car Parking System improves financial viability of

commercial and residential developments

 3. Saves Time: Automatic Car Parking System reduces parking and

retrieval time. Saves time spend in searching for empty parking slots and

48

time spend is searching the parked car. Retrieval on average is 2 to 3

minutes

4.Easy and cost effective maintenance

Automatic Car Parking System is cost effective in terms of maintenance

over the conventional parking systems.

5 Car safety

Automatic Car Parking System provides improved security, safety for the

cars. Cars parked are free from theft and damages that can e caused while

parking and retrieving.

6. Safer for drivers

Drivers collect their cars from secure waiting areas; thus they do not have

to walk through a car park alone and are less vulnerable 

7.Environment friendly

Automatic Car Parking System is environment friendly. As the car

engines are shut during the automatic parking process there is no

pollution. 

8.Aesthetics

State of the art modular design makes the system look very attractive.

9. Rush

Automatic car parking avoids rush and traffic jams in the parking area as

searching for empty parking slots become easy.

7. USES AND IMPLANTATION IN

VARIOUS CITIES

Automatic car parking can be used in:

Malls

49

Multistory buildings

Cinema halls

Offices

Implantation in cities:

As automatic car parking is very beneficial it is used in many countries of

world. Initially it was developed in Paris, France. Then other countries

had adopted their idea and use this system to make their life easy and

comfortable. America, England, China, Singapore etc. have this

automatic car parking facility. India also have automatic car parking

system in some cities. These cities are Delhi, Chennai and Pune

.

8. FUTURE SCOPE

Advance car parking has many benefits over normal parking system. So

due to its unlimited benefits and very few disadvantages it will become

famous in every city and every town in next few years.

Automatic Car Parking System enables the parking of vehicles, floor after

floor, by displaying the available slots thus reducing the ground space

used. Here any number of cars can be parked according to the

requirement, making the system modernized and a space-saving one.

When a vehicle arrived for parking, there is a chance of probability to

extend this system along with the identity cards .The LCD

displays the empty spaces availability of that  particular rack.

Then user has to enter his password, provided the first digit must be the

empty space in which he wishes to park his vehicle thus ensuring

protection. Again if he entered correct password then only the exit

50

gate will be opened for him. If the person

removes another vehicle then the sensors that are provided

beneath every parking place gives a buzzer sound which is being

provided and automatically the exit gate gets closed providing security to

vehicle owner. B y t h i s i m p l e m e n t a t i o n i n t h e c i r c u i t ,

p a r k i n g p r o b l e m i s s o l v e d a n a l s o i t p r e v e n t s vehicle

thefts. Person can also use its credit card to pay parking fee. The

criteria of advance booking of parking slots can also be

implanted to save the time of public.

9. CONCLUSION

By the end of this project

1. Connections and testing in Proteus is studied.

2. Coding and compiling of a C program in Keil u Vision software is

studied.

3. Hardware implementation by connecting Schematic

4. The hardware kit is tested successfully by embedding the C program –

Hex file in the AT89C51 Microcontroller.

5. The operation of microcontroller is analyzed in simulation and

practically.

At the end of this project hence we concluded that automatic car parking

is very beneficial and can be easily implanted.

51

REFERENCES

1. The 8051 microcontroller and embedded system by Muhammad Ali

Mazidi

2. en.wikipedia.org/wiki/Car_Parking_System

3. www.roboticparking.com/robotic_parking_how_it_works.html

4. www.slideshare.net/.../automatic-car-parking-system-16237748

5. en.wikipedia.org/wiki/Automated_parking_system

6. www.scribd.com

7. www.sgrlaw.com › Our Clients › Client Profiles

8.www.studymode.com/.../scope-and-delimitation-in-parking-

systemww.edgefxkits.com/rfid

9.www.eccos.com.hr/.../partneri/.../Skidata._!Brochure._Car_Parks-

EN.pd

10.www.scribd.com/doc/29013195/Automatic-Car-Parkingconcept-

based-paid-car-parking

11. www.projectsof8051.com/automatic-car-parking-indicator-system/

grietinfo.in/projects/MINI/EEE/DOC-A.8-Automatic%20parking.pdf

12. embedded-electronics.blogspot.com/p/at89c51-programming.html

13. www.savepageaspdf.com

14. projectus.freehost7.com

52

APPENDIX A

53

APPENDIX B

54