AN INTELLIGENT MOBILE

ROBOT NAVIGATION

TECHNIQUE

USING RFID TECHNOLOGY

TABLE OF CONTENTS

TITLE PAGE No.

1 ABSTRACT

2 INTRODUCTION

3 BASIC BLOCK DIAGRAM

4 RFID TAGS, READER & OPERATING PRINCIPLE

5 THE ANTENNA

6 MICROCONTROLLER

7 EEPROM

8 LIQUID CRYSTAL DISPLAY (LCD)

9 KEYPAD

10 RS232 SETUP

11 POWER SUPPLY SECTION

12 COMPLETE CIRCUIT DIAGRAM

13 PCB DESIGN

14 SOFTWARE TOOLS

15 PROGRAM (SOURCE CODE)

16 CONCLUSION

17 FUTURE POSSIBILITIES

18 REFERENCES

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LIST OF FIGURES & DIAGRAMSPAGE No.

1 BASIC BLOCK DIAGRAM

2 OVERALL CIRCUIT DIAGRAM

3 POWER SUPPLY BLOCK DIAGRAM

4 POWER SUPPLY CIRCUIT DIAGRAM

5 MICROCONTROLLER CIRCUIT

6 KEYPAD CIRCUIT

7 EEPROM CIRCUIT

8 RS-232 SETUP CIRCUIT

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ABSTRACT

Existing techniques for autonomous indoor navigation are often

environment-specific and thus limited in terms of their applicability.

In this project, we take a fundamentally different approach to indoor

navigation and propose an active environment based navigation system. We

argue that for a versatile navigation system the environment itself should

provide spatial information.

In our proposed approach, navigation is based on the concept of space

partitions where the location of an agent is approximated by the closest

partition.

We show that Radio Frequency Identification (RFID) technology is a

viable option for generating space partitions. We present a cost effective

deployment strategy for passive RFID tags to construct a complete

partitioning of the environment.

Our experiments show that the deployment allows efficient path

planning even under a large degree of imprecision.

This project analyses potentials, challenges, and applications of using

passive, stationary RFID tags for marking routes for autonomous vehicles in

manufacturing environments.

Our approach promises to be flexible, robust, and inexpensive. A

prototype has been designed and developed. Two algorithms are

programmed and tested using four RFID tags.

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INTRODUCTION

Automatic Guided Vehicles (AGVs) are robots moving freely in

manufacturing environments or warehouses require a means of navigation.

Frequently transportation routes are marked with optical lines or electric

wires embedded into the floor. More recently, electric wires are replaced by

RFID tags returning static IDs in defined positions. All approaches share the

inflexibility if routes have to be changed or require to determine the exact

locations of all RFID tags.

This project is about a mobile robot navigation technique using Radio

Frequency Identification (RFID) technology. Navigation based on

processing some analog features of an RFID signal is a promising alternative

to different types of navigation methods in the state of the art. The main idea

is to exploit the ability of a mobile robot to navigate a priori unknown

Environments without a vision system and without building an approximate

map of the robot workspace, as is the case in most other navigation

algorithms.

This project achieved by placing RFID tags in the 3-D space so that

the lines linking their projections on the ground define the “free way’s”

along which the robot can (or is desired to) move. The algorithm is capable

of reaching a target point in its a priori unknown workspace, as well as

tracking a desired trajectory with a high precision. The proposed solution

offers a modular, computationally efficient, and cost-effective alternative to

other navigation techniques for a large number of mobile robot applications,

particularly for service robots, such as, for instance, in large offices and

assembly lines. The effectiveness of the proposed approach is practically

understood by designing a prototype of mobile robot.

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BASIC BLOCK DIAGRAM

6

RFID TAGS, READER & OPERATING PRINCIPLE

RFID Tags & Reader has three Components

Transponder – RFID tag

Transceiver – Tag Reader

Antenna

Transponder – RFID tag

There are two types of RFID tags: (1) Passive tags, (2) Active tags

Passive tags are those energized by the reader itself, they contain no power

source, typically have very long lifetimes (near indefinite) a drawback over

active tags is the read range, typically 2cm (1in) to 1.5m (4.5 ft), a strong

positive is individual tag cost. RFID Passive tag is composed of a integrated

electronic chip and a antenna coil that includes basic modulation circuitry

and non-volatile memory.

Fig 4.1 - Different types of tags

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Fig 4.2 – Real tags

For most general applications passive tags are usually the most cost

effective. These are made in a wide variety of sizes and materials: there are

durable plastic tags for discouraging retail theft, wafer thin tags for use

within "smart" paper labels, tiny tracking tags which are inserted beneath an

animal's skin and credit card sized tags for access control. In most cases the

amount of data storage on a passive tag is fairly limited - capacity often

being measured in bits as opposed to bytes.

However for most applications only a relatively small amount of data

usually needs to be codified and stored on the tag, so the limited capacity

does not normally pose a major limitation. Most tags also carry an

unalterable unique electronic serial number, which makes RFID tags

potentially very useful in applications where item tracking is needed or

where security aspects are important.

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Fig 4.3 - Interaction between tag and reader

The reader powers the tag (transponder), by emitting a radio frequency

wave. The tag then responds by modulating the energizing field. This

modulation can be decoded to yield the tags unique code, inherent in the tag.

The resultant data can be the passed to a computer from processing. Tags

have various salient features apart from their physical size: Other available

features are: Read Only, Read Write, Anti-Collision.

Operating principles of RFID systems

There are a huge variety of different operating principles for RFID

systems. The most important principle is inductive coupling, which is

described in detail below.

Inductive coupling

An inductively coupled transponder comprises of an electronic data-

carrying device, usually a single microchip and a large area coil that

functions as an antenna.

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Fig 4.4 - Inductive Coupling

Inductively coupled transponders are almost always operated passively.

This means that all the energy needed for the operation of the microchip has

to be provided by the reader. For this purpose, the reader's antenna coil

generates a strong, high frequency electro-magnetic field, which penetrates

the cross-section of the coil area and the area around the coil. Because the

wavelength of the frequency range used (< 135 kHz: 2400 m, 13.56 MHz:

22.1 m) is several times greater than the distance between the reader's

antenna and the transponder, the electro-magnetic field may be treated as a

simple magnetic alternating field with regard to the distance between

transponder and antenna.

A small part of the emitted field penetrates the antenna coil of the

transponder, which is some distance away from the coil of the reader. By

induction, a voltage ‘VI’ is generated in the transponder's antenna coil. This

voltage is rectified and serves as the power supply for the data-carrying

device (microchip). A capacitor ‘C1’ is connected in parallel with the

reader's antenna coil, the capacitance of which is selected such that it

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combines with the coil inductance of the antenna coil to form a parallel

resonant circuit, with a resonant frequency that corresponds with the

transmission frequency of the reader. Very high currents are generated in the

antenna coil of the reader by resonance step-up in the parallel resonant

circuit, which can be used to generate the required field strengths for the

operation of the remote transponder.

The antenna coil of the transponder and the capacitor ‘C1’ to form a

resonant circuit tuned to the transmission frequency of the reader. The

voltage V at the transponder coil reaches a maximum due to resonance step-

up in the parallel resonant circuit.

As described above, inductively coupled systems are based upon a

transformer-type coupling between the primary coil in the reader and the

secondary coil in the transponder. This is true when the distance between the

coils does not exceed 0.16 times the wavelength, so that the transponder is

located in the near field of the transmitter antenna.

If a resonant transponder (i.e. the self-resonant frequency of the

transponder corresponds with the transmission frequency of the reader) is

placed within the magnetic alternating field of the reader's antenna, then this

draws energy from the magnetic field. This additional power consumption

can be measured as voltage drop at the internal resistance in the reader

antennae through the supply current to the reader's antenna. The switching

on and off of a load resistance at the transponder's antenna therefore effects

voltage changes at the reader's antenna and thus has the effect of an

amplitude modulation of the antenna voltage by the remote transponder. If

the switching on and off of the load resistor is controlled by data, then this

data can be transferred from the transponder to the reader. This type of data

transfer is called load modulation.

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To reclaim the data in the reader, the voltage measured at the

reader's antenna is rectified. This represents the demodulation of an

amplitude-modulated signal.

Technical Specifications of the tags used

Frequency: 125 KHz Read only

Distance: Up to 30 mm

Dimensions: 75mm x 40mm

Weight: 6.4g

Memory: 16 bits

Data durability: 20 Years or more

The advantages of a passive tag are:

The tag functions without a battery; these tags have a useful life of

twenty years or more. The tag is typically much less expensive to

manufacture

The tag is much smaller (some tags are the size of a grain of rice). These

tags have almost unlimited applications in consumer goods and other areas.

Tags can be read through a variety of substances such as snow, fog, ice,

paint, crusted grime, and other visually and environmentally challenging

conditions, where barcodes or other optically read technologies would be

useless.

RFID tags can also be read in challenging circumstances at remarkable

speeds, in most cases responding in less than 100 millisecond

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Fig 4.5 – RFID Reader Module

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THE ANTENNA

A reader reads identifiers from tags on pallets conveyed past the

reader. The reader includes two interleaved linear arrays of antennas with

circularly polarized fields. Each antenna is composed of a pair of crossed

rods phased to have adjacent antennas of an array generate circularly

polarized fields of opposite rotation.

Fig 5.1 – Some Antennas

The vector components of the polarization in the direction across

the width of the conveyor have peaks and nulls, and the interleaved arrays

are arranged such that the nulls of one array's fields are covered with the

peaks of the other array's fields. This arrangement allows the reader to the

identifier from the tag when the tag is at any orientation. A tag at the side of

the reader is aligned in the direction of travel by rails on the conveyor. The

reader has antennas aligned in the direction of travel to read such tags.

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Loop antenna would provide better gain and also a larger bandwidth.

The inductance and capacitance of the antenna can be calculated from the

equations below:

N = number of turns

w = length of one side (inches)

a = wire radius (inches)

A simple loop antenna was made in order to enhance the reading

distance of the reader. This distance was in fact increased for about half an

inch. Antenna matching was unnecessary as the reader and antenna had

close impedance. It was concluded that antenna constructs two oblong

shapes both in front and rear, which is the case in most square loop antennas.

Fig 5.2 – Radiation Pattern

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MICROCONTROLLER(AT89S52)

The AT89S52 is a low-power, high-performance CMOS 8-bit

microcontroller with 8K bytes of in-system programmable Flash memory.

The device is manufactured using Atmel’s high-density nonvolatile memory

technology and is compatible with the industry- standard 80C51 instruction

set and pinout. The on-chip Flash allows the program memory to be

reprogrammed in-system or by a conventional nonvolatile memory

programmer. By combining a versatile 8-bit CPU with in-system

programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful

microcontroller which provides a highly-flexible and cost-effective solution

to many embedded control applications.

The AT89S52 provides the following standard features: 8K bytes of

Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers,

three 16-bit timer/counters, a six-vector two-level interrupt architecture, a

full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the

AT89S52 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/counters, serial port, and

interrupt system to continue functioning. The Power-down mode saves the

RAM contents but freezes the oscillator, disabling all other chip functions

until the next interrupt or hardware reset.

Features:

• Compatible with MCS-51® Products

• 8K Bytes of In-System Programmable (ISP) Flash Memory

[Endurance: 1000 Write/Erase Cycles]

• 4.0V to 5.5V Operating Range

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• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Three 16-bit Timer/Counters

• Eight Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

• Dual Data Pointer

• Power-off Flag

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Fig 6.1 – Microcontroller (AT 89S52) Block Diagram

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Fig 6.2 – Microcontroller (AT 89S52) Pin Details

Pin Description

VCC - Supply voltage.

GND - Ground.

Port 0 - Port 0 is an 8-bit open drain bidirectional I/O port. As an output

port, each pin can sink eight TTL inputs. When 1s are written to

port 0 pins, the pins can be used as high impedance inputs. Port

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0 can also be configured to be the multiplexed low order

address/data bus during accesses to external program and data

memory. In this mode, P0 has internal pullups. Port 0 also

receives the code bytes during Flash programming and outputs

the code bytes during program verification. External pullups are

required during program verification.

Port 1 - Port 1 is an 8-bit bidirectional I/O port with internal pullups.

The Port 1 output buffers can sink/source four TTL inputs.

When 1s are written to Port 1 pins, they are pulled high by the

internal pullups and can be used as inputs. As inputs, Port 1

pins that are externally being pulled low will source current

(IIL) because of the internal pullups. In addition, P1.0 and P1.1

can be configured to be the timer/counter 2 external count input

(P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX),

respectively, as shown in the following table. Port 1 also

receives the low-order address bytes during Flash programming

and verification.

Table 6.1 – Microcontroller (AT 89S52) Port 1 Alternate Functions

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Port 2 - Port 2 is an 8-bit bidirectional I/O port with internal pullups.

The Port 2 output buffers can sink/source four TTL inputs.

When 1s are written to Port 2 pins, they are pulled high by the

internal pullups and can be used as inputs. As inputs, Port 2

pins that are externally being pulled low will source current

(IIL) because of the internal pullups. Port 2 emits the high-order

address byte during fetches from external program memory and

during accesses to external data memory that use 16-bit

addresses (MOVX @ DPTR). In this application, Port 2 uses

strong internal pull-ups when emitting 1s. During accesses to

external data memory that use 8-bit addresses (MOVX @ RI),

Port 2 emits the contents of the P2 Special Function Register.

Port 2 also receives the high-order address bits and some

control signals during Flash programming and verification.

Port 3 - Port 3 is an 8-bit bidirectional I/O port with internal pullups.

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 pullups and can be used as inputs. As inputs, Port 3

pins that are externally being pulled low will source current

(IIL) because of the pullups. Port 3 also serves the functions of

various special features of the AT89S52, as shown in the

following table. Port 3 also receives some control signals for

Flash programming and verification.

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Table 6.2 – Microcontroller (AT 89S52) Port 3 Alternate Functions

RST - Reset input. A high on this pin for two machine cycles while

the oscillator is running resets the device. This pin drivesHigh

for 96 oscillator periods after the Watchdog times out. The

DISRTO bit in SFR AUXR (address 8EH) can be used to

disable this feature. In the default state of bit DISRTO, the

RESET HIGH out feature is enabled.

ALE/PROG - Address Latch Enable (ALE) is an 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. Note, however, that

one ALE pulse is skipped during each access to external data

memory. If desired, ALE operation can be disabled by setting

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bit 0 of SFR location 8EH. With the bit set, ALE is active only

during a MOVX or MOVC instruction. Otherwise, the pin is

weakly pulled high. Setting the ALE-disable bit has no effect if

the microcontroller is in external execution mode.

PSEN - Program Store Enable (PSEN) is the read strobe to external

program memory. When the AT89S52 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, 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.

XTAL1 - Input to the inverting oscillator amplifier and input to the

internal clock operating circuit.

XTAL2 - Output from the inverting oscillator amplifier

Special Function Registers (SFR)

A map of the on-chip memory area called the Special Function Register

(SFR). Note that not all of the addresses are occupied, and unoccupied

addresses may not be implemented on the chip. Read accesses to these

addresses will in general return random data, and write accesses will have an

indeterminate effect. User software should not write 1s to these unlisted

locations, since they may be used in future products to invoke new features.

In that case, the reset or inactive values of the new bits will always be 0.

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Table 6. – Microcontroller (AT 89S52) SFR Map & Reset values

Timer 2 Registers

Control and status bits are contained in registers T2CON and T2MOD

for Timer 2. The register pair (RCAP2H, RCAP2L) is the Capture/Reload

registers for Timer 2 in 16-bit capture mode or 16-bit auto-reload mode.

Interrupt Registers

The individual interrupt enable bits are in the IE register. Two priorities

can be set for each of the six-interrupt sources in the IP register.

T2CON – Timer/Counter 2 Control Register

TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL2

7 6 5 4 3 2 1 0

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Table 6.1 Interrupt registers

Symbol Function

TF2Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either RCLK = 1 or TCLK = 1.

EXF2

Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and EXEN2 = 1.When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must becleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1).

RCLK

Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial portModes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock.

TCLK

Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial portModes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.

EXEN2

Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if Timer2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX.

TR2 Start/Stop control for Timer 2. TR2 = 1 starts the timer.

C/T2Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge triggered).

CP/RL2

Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2 = 0causes automatic reloads to occur when Timer 2 overflows or negative transitions occur at T2EX when EXEN2 = 1. Wheneither RCLK or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow.

Table 6.2 T2CON Timer/Counter 2 Control Register

Dual Data Pointer Registers:

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To facilitate accessing both internal and external data memory, two banks

of 16-bit Data Pointer Registers are provided: DP0 at SFR address locations

82H-83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0

and DPS = 1 selects DP1.

The user should always initialize the DPS bit to the appropriate value

before accessing the respective Data Pointer Register.

Power Off Flag:

The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON

SFR. POF is set to “1” during power up. It can be set and rest under software

control and is not affected by reset.

Memory Organization

MCS-51 devices have a separate address space for Program and Data

Memory. Up to 64K bytes each of external Program and Data Memory can

be addressed.

Program Memory

If the EA pin is connected to GND, all program fetches are directed to

external memory. On the AT89S52, if EA is connected to VCC, program

fetches to addresses 0000H through 1FFFH are directed to internal memory

and fetches to addresses 2000H through FFFFH are to external memory.

Data Memory

The AT89S52 implements 256 bytes of on-chip RAM. The upper 128

bytes occupy a parallel address space to the Special Function Registers. This

means that the upper 128 bytes have the same addresses as the SFR space

but are physically separate from SFR space. When an instruction accesses an

internal location above address 7FH, the address mode used in the

instruction specifies whether the CPU accesses the upper 128 bytes of RAM

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or the SFR space. Instructions, which use direct addressing access of the

SFR space.

For example, the following direct addressing instruction accesses the

SFR at location 0A0H (which is P2). MOV 0A0H, #data Instructions that

use indirect addressing access the upper 128 bytes of RAM.

For example, the following indirect addressing instruction, where R0

contains 0A0H, accesses the data byte at address 0A0H, rather than P2

(whose address is 0A0H). MOV @R0, #data Note that stack operations are

examples of indirect addressing, so the upper 128 bytes of data RAM are

available as stack space.

Watchdog Timer (WDT)(One-time Enabled with Reset-out)

The WDT is intended as a recovery method in situations where the CPU

may be subjected to software upsets. The WDT consists of a 13-bit counter

and the Watchdog Timer Reset (WDTRST) SFR. The WDT is defaulted to

disable from exiting reset. To enable the WDT, a user must write 01EH and

0E1H in sequence to the WDTRST register (SFR location 0A6H). When the

WDT is enabled, it will increment every machine cycle while the oscillator

is running. The WDT timeout period is dependent on the external clock

frequency. There is no way to disable the WDT except through reset (either

hardware reset or WDT over-flow reset). When WDT overflows, it will

drive an output RESET HIGH pulse at the RST pin.

Using the WDT

To enable the WDT, a user must write 01EH and 0E1H in sequence to

the WDTRST register (SFR location 0A6H). When the WDT is enabled, the

user needs to service it by writing 01EH and 0E1H to WDTRST to avoid a

WDT over-flow.

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The 13-bit counter overflows when it reaches 8191 (1FFFH), and this

will reset the device. When the WDT is enabled, it will increment every

machine cycle while the WDT at least every 8191-machine cycles.

To reset the WDT the user must write 01EH and 0E1H to WDTRST.

WDTRST is a write-only register. The WDT counter cannot be read or

written. When WDT overflows, it will generate an output RESET pulse at

the RST pin. The RESET pulse duration is 96xTOSC, where

TOSC=1/FOSC. To make the best use of the WDT, it should be serviced in

those sections of code that will periodically be executed within the time

required to prevent a WDT.

WDT During Power-down and Idle

In Power-down mode the oscillator stops, which means the WDT also

stops. While in Power-down mode, the user does not need to service the

WDT. There are two methods of exiting Power-down mode: by a hardware

reset or via a level-activated external interrupt, which is enabled prior to

entering Power-down mode. When Power-down is exited with hardware

reset, servicing the WDT should occur as it normally does whenever the

AT89S52 is reset. Exiting Power-down with an interrupt is significantly

different. The interrupt is held low long enough for the oscillator to stabilize.

When the interrupt is brought high, the interrupt is serviced. To prevent

the WDT from resetting the device while the interrupt pin is held low, the

WDT is not started until the interrupt is pulled high. It is suggested that the

WDT be reset during the interrupt service for the interrupt used to exit

Power-down Mode. To ensure that the WDT does not overflow within a few

states of exiting Power-down, it is best to reset the WDT just before entering

Power-down mode. Before going into the IDLE mode, the WDIDLE bit in

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SFR AUXR is used to determine whether the WDT continues to count if

enabled.

The WDT keeps counting during IDLE (WDIDLE bit = 0) as the default

state. To prevent the WDT from resetting the AT89S52 while in IDLE

mode, the user should always set up a timer that will periodically exit IDLE,

service the WDT, and reenter IDLE mode. With WDIDLE bit enabled, the

WDT will stop to count in IDLE mode and resumes the count upon exit

from IDLE.

Timer 2

Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an

event counter. The type of operation is selected by bit C/T2 in the SFR

T2CON. Timer 2 has three operating modes: capture, auto-reload (up or

down counting), and baud rate generator. The modes are selected by bits in

T2CON. Timer 2 consists of two 8-bit registers, TH2 and TL2. In the Timer

function, the TL2 register is incremented every machine cycle. Since a machine cycle

consists of 12 oscillator periods, the count rate is 1/12 of the oscillator frequency.

RCLK +TCLK CP/RL2 TR2 MODE

0 0 1 16-bit Auto-reload

0 1 1 16-bit Capture

1 X 1 Baud Rate Generator

X X 0 (Off)

Table 6.3 Timer2 Operating Modes

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In the Counter function, the register is incremented in response to a 1-to-

0 transition at its corresponding external input pin, T2. In this function, the

external input is sampled During S5P2 of every machine cycle. When the

samples show a high in one cycle and a low in the next cycle, the count is

incremented. The new count value appears in the register during S3P1 of the

cycle following the one in which the transition was detected. Since two

machine cycles (24 oscillator periods) are required to recognize a 1-to-0

transition, the maximum count rate is 1/24 of the oscillator frequency. To

ensure that a given level is sampled at least once before it changes, the level

should be held.

Capture Mode

In the capture mode, two options are selected by bit EXEN2 in T2CON.

If EXEN2 = 0, Timer 2 is a 16-bit timer or counter which upon overflow sets

bit TF2 in T2CON. This bit can then be used to generate an interrupt. If

EXEN2 = 1, Timer 2 performs the same operation, but a 1- to-0 transition at

external input T2EX also causes the current value in TH2 and TL2 to be

captured into RCAP2H and RCAP2L, respectively. In addition, the

transition at T2EX causes bit EXF2 in T2CON to be set. The EXF2 bit, like

TF2, can generate an interrupt.

Fig 6.2 Timer2 in capture mode

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Auto-reload (Up or Down Counter)

Timer 2 can be programmed to count up or down when configured in its

16-bit auto-reload mode. This feature is invoked by the DCEN (Down

Counter Enable) bit located in the SFR T2MOD (see Table 4). Upon reset,

the DCEN bit is set to 0 so that timer 2 will default to count up. When

DCEN is set, Timer 2 can count up or down, depending on the value of the

T2EX pin.

Fig 6.3 - Timer 2 Auto Reload mode

Figure 6.3 shows Timer 2 automatically counting up when DCEN=0. In

this mode, two options are selected by bit EXEN2 in T2CON.

If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets the TF2 bit

upon overflow. The overflow also causes the timer registers to be reloaded

with the 16-bit value in RCAP2H and RCAP2L. The values in Timer in

Capture ModeRCAP2H and RCAP2L are preset by software. If EXEN2 = 1,

a 16-bit reload can be triggered either by an overflow or by a 1-to-0

transition at external input T2EX.

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This transition also sets the EXF2 bit. Both the TF2 and EXF2 bits can

generate an interrupt if enabled. Setting the DCEN bit enables Timer 2 to

count up or down. In this mode, the T2EX pin controls the direction of the

count. Logic 1 at T2EX makes Timer 2 count up. The timer will overflow at

0FFFFH and set the TF2 bit.

This overflow also causes the 16-bit value in RCAP2H and RCAP2L to

be reloaded into the timer registers, TH2 and TL2, respectively. Logic 0 at

T2EX makes Timer 2 count down. The timer underflows when TH2 and

TL2 equal the values stored in RCAP2H and RCAP2L. The underflow sets

the TF2 bit and causes 0FFFFH to be reloaded into the timer registers. The

EXF2 bit toggles whenever Timer 2 overflows or underflows and can be

used as a 17th bit of resolution. In this operating mode, EXF2 does not flag

an interrupt.

Fig 6.4 Timer 2 Auto reload mode (DCEN=1)

32

Baud Rate Generator

Timer 2 is selected as the baud rate generator by setting TCLK and/or

RCLK in T2CON.Note that the baud rates for transmit and receive can be

different if Timer 2 is used for the receiver or transmitter and Timer 1 is

used for the other function. Setting RCLK and/or TCLK puts Timer 2 into

its baud rate generator mode. The baud rate generator mode is similar to the

auto-reload mode, in that a rollover in TH2 causes the Timer 2 registers to

be reloaded with the 16-bit value in registers RCAP2H and RCAP2L, which

are preset by software. The baud rates in Modes 1 and 3 are determined by

Timer 2’s overflow rate according to the following equation. Mode 1 and 3

Baud Rates = Timer 2 Overflow Rate/16 The Timer can be configured for

either timer or counter operation. In most applications, it is configured for

timer operation (CP/T2 = 0). The timer operation is different for Timer 2

when it is used as a baud rate generator. Normally, as a timer, it increments

every machine cycle (at 1/12 the oscillator frequency). As a baud rate

generator, however, it increments every state time (at 1/2 the oscillator

frequency).

The baud rate formula is given below.

(Mode 1 and 3)/Baud Rate =

Oscillator Frequency/(32*[65536- RCAP2H, RCAP2L])

Where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L

taken as a 16-bit unsigned integer. This figure is valid only if RCLK or

TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will

not generate an interrupt. Note too, that if EXEN2 is set, a 1-to-0 transition

in T2EX will set EXF2 but will not cause a reload from (RCAP2H,

33

RCAP2L) to (TH2, TL2). Thus, when Timer 2 is in use as a baud rate

generator, T2EX can be used as an extra external interrupt. Note that when

Timer 2 is running (TR2 = 1) as a timer in the baud rate generator mode,

TH2 or TL2 should not be read from or written to. Under these conditions,

the Timer is incremented every state time, and the results of a read or write

may not be accurate. The RCAP2 registers may be read but should not be

written to, because a write might overlap a reload and cause write and/or

reload errors. The timer should be turned off (clear TR2) before accessing

the Timer 2 or RCAP2 registers.

Fig 6.5 Timer 2 in Baud Rate Generator Mode

Interrupts

The AT89S52 has a total of six interrupt vectors: two external interrupts

(INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial

port interrupt. Each of these interrupt sources can be individually enabled or

disabled by setting or clearing a bit in Special Function Register IE. IE also

34

contains a global disable bit, EA, which disables all interrupts at once. In the

AT89S52, bit position IE.5 is also unimplemented.

User software should not write 1s to these bit positions, since they may

be used in future AT89 products.

Fig 6.6 Interrupt Sources

Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in

registers T2CON. Neither of these flags is cleared by hardware when the

service routine is vectored to. In fact, the service routine may have to

determine whether it was TF2 or EXF2 that generated the interrupt, and that

bit will have to be cleared in software. The Timer 0 and Timer 1 flags, TF0

and TF1, are set at S5P2 of the cycle in which the timers overflow. The

values are then polled by the circuitry in the next cycle. However, the Timer

2 flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer

overflows.

35

LIQUID CRYSTAL DISPLAY (LCD)

Liquid crystal displays (LCDs) have materials, which combine the

properties of both liquids and crystals. Rather than having a melting point,

they have a temperature range within which the molecules are almost as

mobile as they would be in a liquid, but are grouped together in an ordered

form similar to a crystal.

An LCD consists of two glass panels, with the liquid crystal material

sand witched in between them. The inner surface of the glass plates are

coated with transparent electrodes which define the character, symbols or

patterns to be displayed polymeric layers are present in between the

electrodes and the liquid crystal, which makes the liquid crystal molecules to

maintain a defined orientation angle.

One each polarizes are pasted outside the two glass panels. These

polarizes would rotate the light rays passing through them to a definite

angle, in a particular direction. When the LCD is in the off state, light rays

are rotated by the two polarizes and the liquid crystal, such that the light rays

come out of the LCD without any orientation, and hence the LCD appears

transparent.

When sufficient voltage is applied to the electrodes, the liquid crystal

molecules would be aligned in a specific direction. The light rays passing

through the LCD would be rotated by the polarizes, which would result in

activating / highlighting the desired characters. The LCD’s are lightweight

with only a few millimeters thickness. Since the LCD’s consume less power,

they are compatible with low power electronic circuits, and can be powered

for long durations.

36

The LCD does not generate light and so light is needed to read the

display. By using backlighting, reading is possible in the dark. The LCD’s

have long life and a wide operating temperature range. Changing the display

size or the layout size is relatively simple which makes the LCD’s more

customers friendly.

The LCDs used exclusively in watches, calculators and measuring

instruments are the simple seven-segment displays, having a limited amount

of numeric data. The recent advances in technology have resulted in better

legibility, more information displaying capability and a wider temperature

range. These have resulted in the LCDs being extensively used in

telecommunications and entertainment electronics. The LCDs have even

started replacing the cathode ray tubes (CRTs) used for the display of text

and graphics, and also in small TV applications.

Crystalonics dot–matrix (alphanumeric) liquid crystal displays are

available in TN, STN types, with or without backlight. The use of C-MOS

LCD controller and driver ICs result in low power consumption. These

modules can be interfaced with a 4-bit or 8-bit microprocessor /Micro

controller.

The built-in controller IC has the following features:

Correspond to high speed MPU interface (2MHz)

80 x 8 bit display RAM (80 Characters max)

9,920-bit character generator ROM for a total of 240 character

fonts. 208 character fonts (5 x 8 dots) 32 character fonts (5 x 10

dots)

64 x 8 bit character generator RAM 8 character generator RAM 8

character fonts (5 x 8 dots) 4 characters fonts (5 x 10 dots)

Programmable duty cycles

37

1/8 – for one line of 5 x 8 dots with cursor

1/11 – for one line of 5 x 10 dots with cursor

1/16 – for one line of 5 x 8 dots with cursor

Wide range of instruction functions display clear, cursor home,

display on/off, cursor on/off, display character blink, cursor shift,

display shift.

Automatic reset circuit, which initializes the controller / driver ICs

after power on.

KEYPAD

38

A numeric keypad, or numpad for short, is the small, palm-sized,

seventeen key section of a computer keyboard, usually on the very far right.

The numeric keypad features digits 0 to 9, addition (+), subtraction (-),

multiplication (*) and division (/) symbols, a decimal point (.) and Num

Lock and Enter keys. Laptop keyboards often do not have a numpad, but

may provide numpad input by holding a modifier key (typically lapelled

"Fn") and operating keys on the standard keyboard. Particularly large

laptops (typically those with a 17 inch screen or larger) may have space for a

real numpad, and many companies sell separate numpads which connect to

the host laptop by a USB connection.

Numeric keypads usually operate in two modes: when Num Lock is off,

keys 8, 6, 2, 4 act like an arrow keys and 7, 9, 3, 1 act like Home, PgUp,

PgDn and End; when Num Lock is on, digits keys produce corresponding

digits. These, however, differ from the numeric keys at the top of the

keyboard in that, when combined with the Alt key on a PC, they are used to

enter characters which may not be otherwise available: for example, Alt-

0169 produces the copyright symbol. These are referred to as Alt codes. On

Apple Computer Macintosh computers, which lack a Num Lock key, the

numeric keypad always produces only numbers. The num lock key is

replaced by the clear key.

39

Fig – Key Pad Architecture

RS232-SETUP

40

Fig 10.1 – RS 232 Communication Setup

RS232:

In telecommunications, RS-232 is a standard for serial binary data

interconnection between a DTE (Data terminal equipment) and a DCE (Data

Circuit-terminating Equipment). It is commonly used in computer serial

ports.

Scope of the Standard:

The Electronic Industries Alliance (EIA) standard RS-232-C [3] as of

1969 defines:

“Electrical signal characteristics such as voltage levels, signaling rate,

timing and slew-rate of signals, voltage withstand levels, short-circuit

behavior, maximum stray capacitance, cable length, interface mechanical

characteristics, pluggable connectors and pin identification Functions of

each circuit in the interface connector, standard subsets of interface circuits

for selected telecom applications”

41

The standard does not define such elements as character encoding (for eg.

ASCII,or EBCDIC), or the framing of characters in the data stream (bits per

character, start/stop bits, parity).

The standard does not define protocols for error detection or algorithms

for data compression.

The standard does not define bit rates for transmission, although the

standard says it is intended for bit rates lower than 20,000 bits per second.

Many modern devices can exceed this speed (38,400 and 57,600 bit/s being

common, and 115,200 and 230,400 bit/s making occasional appearances)

while still using RS-232 compatible signal levels.

Details of character format and transmission bit rate are controlled by the

serial port hardware, often a single integrated circuit called a UART that

converts data from parallel to serial form. A typical serial port includes

specialized driver and receiver integrated circuits to convert between internal

logic levels and RS-232 compatible signal levels.

Interfacing the hard ware with the PC has the following advantages:

Storing and retrieval of data becomes easier.

Networking can be done and hence the entire system can be

monitored online.

Access can be user friendly.

Interfacing the hard ware with the PC is done using MAX232 (rs232)

The MAX220–MAX249 family of line drivers/receivers is intended for all

EIA/TIA-232E and V.28/V.24 communications interfaces, particularly

applications where ±12V is not available. These parts are especially useful

in battery-powered systems, since their low-power shutdown mode reduces

power dissipation to less than 5μW. The MAX225, MAX233, MAX235, and

42

MAX245/MAX246/MAX247 use no external components and are

recommended for applications where printed circuit board space is critical.

Features:

Operate from Single +5V Power Supply (+5V and +12V—

MAX231/MAX239)

Low-Power Receive Mode in Shutdown (MAX223/MAX242)

Meet All EIA/TIA-232E and V.28 Specifications

Multiple Drivers and Receivers

3-State Driver and Receiver Outputs

Open-Line Detection (MAX243)

Circuit working Description:

In this circuit the MAX 232 IC used as level logic converter. The

MAX232 is a dual driver/receiver that includes a capacive voltage generator

to supply EIA 232 voltage levels from a single 5v supply. Each receiver

converts EIA-232 to 5v TTL/CMOS levels. Each driver converts

TLL/CMOS input levels into EIA-232 levels.

43

Fig 10.2 – RS 232 Function Tables & Logic Diagram

In this circuit the microcontroller transmitter pin is connected in the

MAX232 T2IN pin which converts input 5v TTL/CMOS level to RS232

level. Then T2OUT pin is connected to reviver pin of 9 pin D type serial

connector which is directly connected to PC.

In PC the transmitting data is given to R2IN of MAX232 through

transmitting pin of 9 pin D type connector which converts the RS232 level

to 5v TTL/CMOS level. The R2OUT pin is connected to receiver pin of the

microcontroller. Likewise the data is transmitted and received between the

microcontroller and PC or other device vice versa.

44

POWER SUPPLY SECTION

The ac voltage, typically 220V rms, is connected to a transformer,

which steps that ac voltage down to the level of the desired dc output. A

diode rectifier then provides a full-wave rectified voltage that is initially

filtered by a simple capacitor filter to produce a dc voltage. This resulting dc

voltage usually has some ripple or ac voltage variation.

A regulator circuit removes the ripples and also remains the same dc

value even if the input dc voltage varies, or the load connected to the output

dc voltage changes. This voltage regulation is usually obtained using one of

the popular voltage regulator IC units.

Figure: 11.1 Block diagram (Power supply)

Working principle

Transformer: The transformer will step down the power supply voltage

(0-230V) to (0-12V) level. Then the secondary of the potential transformer

will be connected to the bridge rectifier.

Bridge rectifier: When four diodes are connected as shown in figure, the

circuit is called as bridge rectifier.

Let us assume that the transformer is working properly and there is a

positive potential, at terminal ‘0’ and a negative potential at terminal ‘9’. the

positive potential at terminal ‘0’ will forward bias D1 and reverse bias D2.

45

TRANSFORMER RECTIFIER FILTER IC REGULATOR LOAD

The negative potential at terminal ‘9’ will forward bias D4 and reverse

D3. At this time D1 and D4 are forward biased and will allow current flow

to pass through them; D2 and D3 are reverse biased and will block current

flow.

Figure: 11.2 Circuit diagram (Power supply)

One-half cycle later the polarity across the secondary of the transformer

reverses, forward biasing D2 and D3 and reverse biasing D1 and D4.

One advantage of a bridge rectifier over a conventional full-wave

rectifier is that with a given transformer the bridge rectifier produces a

voltage output that is nearly twice that of the conventional full-wave circuit.

IC voltage regulators

Voltage regulators comprise a class of widely used ICs. 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 adjustably set voltage. The regulators can be selected

for operation with load currents from hundreds of milli amperes to tens of

amperes, corresponding to power ratings from milli watts to tens of watts.

46

A fixed three-terminal voltage regulator has an unregulated dc input

voltage, Vi, applied to one input terminal, a regulated dc output voltage, Vo,

from a second terminal, with the third terminal connected to ground.

The series 78 regulators provide fixed positive regulated voltages

from 5 to 24 volts. Similarly, the series 79 regulators provide fixed negative

regulated voltages from 5 to 24 volts.

For ICs, microcontroller, LCD --------- 5 volts

For alarm circuit, op-amp, relay circuits ---------- 12 volts

.

47

COMPLETE CIRCUIT DIAGRAM

48

PCB DESIGN

Printed circuit boards, or PCBs, form the core of electronic equipment

domestic and industrial. Some of the areas where PCBs are intensively used

are computers, process control, telecommunications and instrumentation.

The manufacturing process consists of two methods; print and etch, and

print, plate and etch.

The single sided PCBs are usually made using the print and etch method.

The double sided plate through – hole (PTH) boards are made by the print

plate and etch method.

The production of multi layer boards uses both the methods. The inner

layers are printed and etch while the outer layers are produced by print, plate

and etch after pressing the inner layers.

SOFTWARE: There are plenty of software packages available which

can convert a schematic into PCB layouts. The software used in our project

to obtain the layout is MICROSIM.

PANELISATION: Here the schematic transformed in to the working

positive/negative films. The circuit is repeated conveniently to accommodate

economically as many circuits as possible in a panel, which can be operated

in every sequence of subsequent steps in the PCB process. This is called

penalization. For the PTH boards, the next operation is drilling.

DRILLING: PCB drilling is a state of the art operation. Very small

holes are drilled with high speed CNC drilling machines, giving a wall finish

with less or no smear or epoxy, required for void free through hole plating.

PLATING: The heart of the PCB manufacturing process. The holes

drilled in the board are treated both mechanically and chemically before

depositing the copper by the electro less copper platting process.

49

ETCHING: Once a multiplayer board is drilled and electro less

copper deposited, the image available in the form of a film is transferred on

to the out side by photo printing using a dry film printing process. The

boards are then electrolytic plated on to the circuit pattern with copper and

tin. The tin-plated deposit serves an etch resist when copper in the unwanted

area is removed by the conveyor’s spray etching machines with chemical

enchants. The etching machines are attached to an automatic dosing

equipment, which analyses and controls enchants concentrations.

SOLDERMASK: Since a PCB design may call for very close

spacing between conductors, a solder mask has to be applied on the both

sides of the circuitry to avoid the bridging of conductors. The solder mask

ink is applied by screening. The ink is dried, exposed to UV, developed in a

mild alkaline solution and finally cured by both UV and thermal energy.

HOT AIR LEVELLING: After applying the solder mask, the circuit

pads are soldered using the hot air leveling process. The bare bodies fluxed

and dipped in to a molten solder bath. While removing the board from the

solder bath, hot air is blown on both sides of the board through air knives in

the machines, leaving the board soldered and leveled. This is one of the

common finishes given to the boards. Thus the double sided plated through

whole printed circuit board is manufactured and is now ready for the

components to be soldered.

50

SOFTWARE TOOLS

Keil C compiler:

Keil development tools for the 8051 Microcontroller Architecture support

every level of software developer from the professional applications

engineer to the student just learning about embedded software development.

The industry-standard Keil C Compilers, Macro Assemblers, Debuggers,

Real-time Kernels, Single-board Computers, and Emulators support all 8051

derivatives and help you get your projects completed on schedule.

The Keil 8051 Development Tools are designed to solve the complex

problems facing embedded software developers.

When starting a new project, simply select the microcontroller you use

from the Device Database and the µVision IDE sets all compiler, assembler,

linker, and memory options for you.

Numerous example programs are included to help you get started with

the most popular embedded 8051 devices.

The Keil µVision Debugger accurately simulates on-chip peripherals

(I²C, CAN, UART, SPI, Interrupts, I/O Ports, A/D Converter, D/A

Converter, and PWM Modules) of your 8051 device.

Simulation helps you understand hardware configurations and avoids

time wasted on setup problems. Additionally, with simulation, you can write

and test applications before target hardware is available.

When you are ready to begin testing your software application with target

hardware, use the MON51, MON390, MONADI, or FlashMON51 Target

Monitors, the ISD51 In-System Debugger, or the ULINK USB-JTAG

Adapter to download and test program code on your target system.

51

It's been suggested that there are now as many embedded systems in

everyday use as there are people on planet Earth. Domestic appliances from

washing machines to TVs, video recorders and mobile phones, now include

at least one embedded processor. They are also vital components in a huge

variety of automotive, medical, aerospace and military systems. As a result,

there is strong demand for programmers with 'embedded' skills, and many

desktop developers are moving into this area.

Embedded C is designed for programmers with desktop experience in C,

C++ or Java who want to learn the skills required for the unique challenges

of embedded systems.

Key techniques required in all embedded systems are covered in detail,

including the control of port pins and the reading of switches.

A complete embedded operating system was available with the compiler,

with full source code.

All code is written in C, so no assembly language is required. Industry-

standard C compiler from Keil software is used to write the programs.

MICROSIM.

For PCB design (explained in the earlier chapter)

C SCOPE & LINT

For learning C (There are a number of tools available to aid in

developing, maintaining, and improving your C programs)

.

52

PROGRAM (SOURCE CODE)

#include <at89x52.H>#include "smcl_lcd8.h"#include "AT_serial.h"sbit buz=P1^0;sbit s1=P2^0;sbit s2=P2^1;sbit s3=P2^2;sbit s4=P2^3;sbit s5=P2^4;sbit l1=P1^1;sbit l2=P1^2;sbit r1=P1^3;sbit r2=P1^4;unsigned char dat[10],i,a=0;b=0,c=0,d=0,sec,j,k,z=0;void LLLL();void main(){

buz=0;Lcd8_Init();Serial_Init(9600);Receive(1);r1=r2=l1=l2=1; Lcd8_Display(0x80,"RFID MOBILE ",16);Lcd8_Display(0xC0,"ROBOT NAVIGATION",16);

while(1)/*to retain in the loop when turn on & reset con*/{

if(s1==0&&a==0){a=1;Lcd8_Display(0x80,"CARD NO 1: ",16);Lcd8_Display(0xc0," ",16);}

if(s1==1&&a==1){l1=1;l2=0;r1=1;r2=0;}

if(s2==0&&b==0){b=1;Lcd8_Display(0x80,"CARD NO 2: ",16);Lcd8_Display(0xc0," ",16);}

if(s2==1&&b==1){l1=1;l2=0;r1=1;r2=0;}

if(s3==0&&c==0){c=1;Lcd8_Display(0x80,"CARD NO 3: ",16); Lcd8_Display(0xc0," ",16);}

53

if(s3==1&&c==1){l1=1;l2=0;r1=1;r2=0;}

if(s4==0&&d==0){d=1;Lcd8_Display(0x80,"CARD NO 4: ",16);Lcd8_Display(0xc0," ",16);}

if(s4==1&&d==1){l1=1;l2=0;r1=1;r2=0;}

if(i>8) { ES=0; Delay(30000);

if((dat[7]=='4'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='1')&&(a==1)){r1=1;r2=1;l1=1;l2=1;a=0;Lcd8_Display(0xC0,"CARD:1

DETECTED ",16);buz=1;}

else if((dat[7]=='D'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='4')&&(a==1)){l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 2: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='1'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='F')&&(a==1)){l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 3: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='C'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='C')&&(a==1))

{l1=1;l2=0;r1=0;r2=1;Delay(65000);Delay(65000);Delay(65000); l1=1;l2=0;r1=1;r2=0;}

else is if((dat[7]=='4'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='1')&&(b==1)){r1=1;r2=0;l1=0;l2=1;Lcd8_Display(0x80,"CARD NO 1: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='D'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='4')&&(b==1))

{l1=1;l2=1;r1=1;r2=1;b=0;Lcd8_Display(0xC0,"CARD:2 DETECTED " ,16); buz=1;}

else if((dat[7]=='1'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='F')&&(b==1))

{l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 3: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='C'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='C')&&(b==1))

{l1=1;l2=0;r1=0;r2=1;Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='4'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='1')&&(c==1))

54

{r1=1;r2=0;l1=0;l2=1;Lcd8_Display(0x80,"CARD NO 1: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='D'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='4')&&(c==1))

{l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 2: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='1'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='F')&&(c==1)){l1=1;l2=1;r1=1;r2=1;c=0;Lcd8_Display(0xC0,"CARD:3 DETECTED ",16);buz=1;}

else if((dat[7]=='C'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='C')&&(c==1))

{l1=1;l2=0;r1=0;r2=1;Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='4'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='1')&&(d==1)){r1=1;r2=0;l1=0;l2=1;Lcd8_Display(0x80,"CARD NO 1:",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='D'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='4')&&(d==1))

{l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 2: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='1'||dat[7]=='F')&&(dat[8]=='F'||dat[8]=='F')&&(d==1)){l1=1;l2=0;r1=0;r2=1;Lcd8_Display(0x80,"CARD NO 3: ",16);Delay(65000);Delay(65000);Delay(65000);l1=1;l2=0;r1=1;r2=0;}

else if((dat[7]=='C'||dat[7]=='9')&&(dat[8]=='9'||dat[8]=='C')&&(d==1))

{l1=1;l2=1;r1=1;r2=1;d=0;Lcd8_Display(0xC0,"CARD:4 DETECTED ",16);buz=1;}

for(i=0;i<=8;i++)dat[i]=0;

i=0;ES=1;

} }

}

void receiver(void) interrupt 4

55

{ if(RI==1)

{dat[i]=SBUF;i++;RI=0;}

}ADVANTAGES

1. Low power consumption.

2. This project is viable and cost effective.

3. Navigation path can be easily redefined

4. Less complex navigation program

5. infrastructural changes in the navigation path Doesn’t affect as in

the case of visual based navigation systems

6. Simple on its design

7. Easy to use

8. Reliability.

56

APPLICATION:

This project can be used in places for

1. Industrial companies,

2. Colleges, Schools, Offices for Library Management

3. Warehousing etc.

4. Application areas of RFID technology is many and a few are

5. Logistics

6. Toll Collection

7. Animal Tracking

8. Vehicle Identification

57

CONCLUSION

Completion of this project brings a new product to the world of industry

to increase speed and efficiency while reducing the loss. To implement

the idea, project was divided into four different parts: RFID system and

antenna, RFID system communication, Navigation algorithm, and Robot.

Each part was handled by a member of a group.

In developing this project, new and innovative solutions were needed to

tackle the design challenges that were encountered. Each problem was

dealt with further research and trial and error method in a timely manner.

Various objective of electrical engineering was used in developing this

project including radio frequency, digital design, and signal processing.

Overall the learning objective of this project provided an opportunity to

research beyond the academic requirements.

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FUTURE POSSIBILITIES

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REFERENCES

1 Mill Man J and Hawkies c.c. “Integrated

Electronics” Mcgraw Hill 1972

2 Roy Choudhury D, Shail Jain, “ Linear Integrated Circuit”, New

Age International Publishers, New Delhi,2000

3 Referred Websites Such As wikipeidia, atmel.com,

howstuffworks.com, ieee.projects.robotics Etc.,

4 “The 8051 Microcontroller and Embedded system” by

Mohammad Ali Mazidi.

WEBSITES:

http://www.sparrel.com/ http://www.atmel.com/

http://www.rfid - handbook.com/

http://www.microchip.com/

http://www.philips.com/

http://www.rfidjournal.com/

http://www.aimglobal.org/

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http://www.howstuffworks.com/

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