An Intelligent Mobile Robot Navigation Technique PROJECT REPORT

AN INTELLIGENT MOBILE ROBOT NAVIGATION TECHNIQUE USING RFID TECHNOLOGY

TABLE OF CONTENTS
TITLE ABSTRACT INTRODUCTION BASIC BLOCK DIAGRAM RFID TAGS, READER & OPERATING PRINCIPLE THE ANTENNA MICROCONTROLLER EEPROM LIQUID CRYSTAL DISPLAY (LCD) KEYPAD RS232 SETUP POWER SUPPLY SECTION COMPLETE CIRCUIT DIAGRAM PCB DESIGN SOFTWARE TOOLS PROGRAM (SOURCE CODE) CONCLUSION FUTURE POSSIBILITIES REFERENCES PAGE No.

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LIST OF FIGURES & DIAGRAMS
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BASIC BLOCK DIAGRAM OVERALL CIRCUIT DIAGRAM POWER SUPPLY BLOCK DIAGRAM POWER SUPPLY CIRCUIT DIAGRAM MICROCONTROLLER CIRCUIT KEYPAD CIRCUIT EEPROM CIRCUIT 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

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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 datacarrying 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 ‘C 1’ 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 stepup 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: Distance: Dimensions: Weight: Memory: Data durability: 125 KHz Read only Up to 30 mm 75mm x 40mm 6.4g 16 bits 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 GND Supply voltage. Ground. 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

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

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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 XTAL2 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. 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 7 EXF2 6 RCLK 5 TCLK EXEN2 4 3 TR2 2 C/T2 1 CP/RL2 0

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Table 6.1 Interrupt registers

Function Timer 2 overflow flag set by a Timer 2 overflow and must be TF2 cleared by software. TF2 will not be set when either RCLK = 1 or TCLK = 1. 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 EXF2 to vector to the Timer 2 interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1). Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial port RCLK Modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock. Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial port TCLK Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock. Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if Timer EXEN2 2 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. Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 C/T2 = 1 for external event counter (falling edge triggered). Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2 = 0 causes automatic reloads to occur when Timer 2 overflows or CP/RL2 negative transitions occur at T2EX when EXEN2 = 1. When either 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

Symbol

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Dual Data Pointer Registers: 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 0 0 1 X CP/RL2 0 1 X X TR2 1 1 1 0 MODE 16-bit Auto-reload 16-bit Capture Baud Rate Generator (Off)

Table 6.3 Timer2 Operating Modes

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In the Counter function, the register is incremented in response to a 1-to0 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 30

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)

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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,
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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

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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.
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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.

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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)

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• Programmable duty cycles • 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.

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KEYPAD 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, Alt0169 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.

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Fig – Key Pad Architecture

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RS232-SETUP

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

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each circuit in the interface connector, standard subsets of interface circuits for selected telecom applications” 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

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in battery-powered systems, since their low-power shutdown mode reduces power dissipation to less than 5μW. The MAX225, MAX233, MAX235, and 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.

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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.

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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.

TRANSFORMER

RECTIFIER

FILTER

IC REGULATOR

LOAD

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.

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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.

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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

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COMPLETE CIRCUIT DIAGRAM

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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.

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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.

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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.

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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. Industrystandard 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 developing, maintaining, and improving your C programs) in

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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: 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: Lcd8_Display(0xc0," ",16);} if(s3==1&&c==1){l1=1;l2=0;r1=1;r2=0;} ",16);

",16);

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if(s4==0&&d==0) {d=1;Lcd8_Display(0x80,"CARD NO 4: Lcd8_Display(0xc0," ",16);} if(s4==1&&d==1){l1=1;l2=0;r1=1;r2=0;} if(i>8) { ES=0; Delay(30000);

",16);

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)) {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;}

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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 { if(RI==1)

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{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.

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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

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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/ http://www.howstuffworks.com/
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