Final Report

Campus Automation PROJECT REPORT ‘11

CHAPTER.1

INTRODUCTION

Dept. of ECE 1 VAST


1.1 INTRODUCTION

Now a day’s wired communication is outdated .Everywhere we are

trying to use wireless communication. But there are limitation in range of wireless

communication. Our aim is to develop a wireless transmitter receiver which is

capable of transmitting as well as receiving messages form similar devices. Main

objective of this project is make an efficient wireless transceiver is with very low

cost . Main application of this module is in big industries, and war fields , and it can

also be use for the communication between the guards in a train.

Dept. of ECE 2 VAST


CHAPTER.2

BLOCK DIAGRAM

Dept. of ECE 3 VAST


Campus automation system has mainly two sections, transmitter section and receiver

section.

2.1. TRANSMITTER SECTION

Dept. of ECE 4 VAST

BUZZER

PC

PIC

16F

877A

PIR

DRIVER CIRCUIT FAN

DRIVER CIRCUIT

COMPUTERINTERFACE

LIGHT

Fig.2.1


2.2. RECEIVER SECTION

RECEIVER SECTION:

Dept. of ECE 5 VAST

ZIGBEE MODULE

PIC 16F877A

LCD DISPLAY

Fig.2.2


CHAPTER.3

BLOCK DIAGRAM DESCRIPTION

Dept. of ECE 6 VAST


This chapter discuss about the blocks of transmitter and receiver section.

3.1.TRANSMITTER SECTION:

Transmitter section mainly consists of three sub sections:

*Message transmitting section

*Automatic bell

*Automatic fan and light controller

This section contains peripheral interface controller (PIC) 16F877A,

PIR sensor ,bell & ZIGBEE module. The 16F877A micro controller is the heart of

transmitter section, which controls the data transfer. Here we use wireless

transmission system for data transfer. PC is used to enter the data to the PIC with

the help of serial port.PIC controls the ZIGBEE module to transfer the data

serially.

The automatic bell works based on the program that we have stored

on the PIC. It consists of a LCD display to show the clock .The Program sets in

such a way that the bell rings at the end of each hour between 9am and 4pm.

A PIR (Passive Infrared) sensor detects infrared light that is emitted

from objects within its field of view. PIR sensors differ from other infrared sensors

because they can only receive infrared waves. Because all objects emit infrared

waves (electromagnetic waves that travel with heat), PIR sensors can detect objects

that are in front of them. In fact, PIR sensors can detect many things that humans

cannot. PIR sensors are used in many applications, such as night vision, motion

detection, and laser range finding.

Dept. of ECE 7 VAST


3.2.RECEIVER SECTION :

The receiver section mainly consists of a PIC microcontroller,

LCD display, Zigbee module and a buzzer .PIC receives the data serially through

ZIGBEE module and displays that data on LCD display. The buzzer is used to

indicate the arrival of new message. The program is set such that LCD will clear ,if

the message bit is greater than 16 bit.

Dept. of ECE 8 VAST


CHAPTER.4

CIRCUIT DIAGRAM

Dept. of ECE 9 VAST


The circuit diagrams of power supply, transmitter section and receiver section are

given below:

4.1.POWER SUPPLY

Dept. of ECE 10 VAST


4.2 TRANSMITTER SECTION



4.3 RECEIVER



CHAPTER.5

CIRCUIT DESCRIPTION



5.1.POWER SUPPLY

In this circuit Microcontroller, LCD, GPS and camera are uses +5 volt

supplies and MMC card uses +3.3 Volts. In the case of +5 Volt, we can use fixed

regulator ICs i.e., LM 7805(U5). The adjustable regulator LM 317 is used for 3.3 V.

A voltage regulator is an electronic device that supplies a constant voltage to a

circuit or load. The output voltage of the voltage regulator is regulated by the internal

circuitry of the regulator to the relatively independent of the current drawn by the

load, the supply or line voltage and the ambient temperature.

A voltage regulator may be part of some larger electronic circuit, but is often a

separate unit a module, unusually in the form of an integrated circuit. It is compressed

of three basic parts. A voltage reference circuit that produces a reference voltage that

is independent of temperature and supply voltage. An amplifier to compare the

reference voltage with the fraction of the output voltage that is fed back from the

voltage regulator output to the inverting input terminal of the amplifier. A series pass

transistor or combination of transistor to provide an adequate level of output current

to the load being driven.

The combination of the amplifier (often called an error amplifier) and the

series pass transistors, together with the resistive voltage divider to tap off a portion of

the output voltage, constitutes a feed back amplifier. The closed loop amplifier

configure act to maintain the traction of the output voltage feed back to the amplifier

inverting input terminal equal to the reference voltage that is supplied to the non-

inverting input terminal.

Three terminal voltage regulators are voltage regulators in which the output

voltage is set at some pre-determined value. They therefore, do not require any

external feed back connections. As a result, only three terminals are required for this

type of generator, input (Vin), output (Vo) and a ground terminal. Since these

regulators operate at a present out put voltage, the current limit resistor Rd is also

internal to the generator.



The principle advantage of three terminal regulators is the simplicity of

connection to the external circuit, with a minimum of external components required.

Indeed, in many applications no external components are required. The simplicity and

case of application is evident. The capacitor across the input terminals is required only

when the voltage regulator is located more than about 5cm.

From the power supply filter capacitor such that the lead inductance between

the supply and the regulator may cause stability problems and high frequency

oscillations. A very low Effective Series Resistance (ESR) should characterize the

capacitor. Acceptable values on generally 0.21 geF ceramic disks, 2mF or greater

tantalum, or 25 mF or greater aluminium electrolyte .A capacitor is generally not

needed across the output terminals. The use of a suitable capacitor will, however,

improve the regulator response to transient changes in the local conditions. and will

also reduce the noise present at the regulator output.

The device connected to 15 v DC supply (the input of the regulator IC always greater

than Vout+2). The diode D5 (1N4001) protects circuits from reveres current. If we

connect reveres polarity of the battery then a reveres current produces and damage the

regulator IC. The 15 volt DC pass to the 7812 IC. The output of the IC gives us

+12v.A 470 MFD/25v filter capacitor (C12) is used for smoothing purpose. A 47Mf

(C13) and 0.1 MF (C8) capacitors are used for surge voltage protection.

The output of the LM 7812 gives to the LM7805 IC for producing +5V dc. . A

47Mf (C14) and 0.1 MF (C9) capacitors are used for surge voltage protection. The

LM317 provides an internal reference voltage of 1.25V between the output and

adjustments terminals. This is used to set a constant current flow across an external

resistor divider show below, giving an output voltage VO of:

V0 = VREF ( 1 + R 2 /R 21 ) + IADJ R2

The device was designed to minimize the term IADJ ( 100 m A max) and to

maintain it very constant with line and load changes. Usually, the error term IADJ V

R2 can be neglected. VREF is 1.25v



V0= 1.25(1+R2/R21)

Here we want 3.3v. if R21 is 220 ohm we can get value of R2. Here a P1

(variable resistor ) is connected for adjusting output voltage.

R2+P1=360ohm

In summary,

OUTPUT VOLTAGE REQUIREMENTS: 3.3V, 5 V

CURRENT REQUIREMENTS: Upto 200 mA

SELECTION OF TRANSISTOR: Use 12-0-12 or 6-0-6 transformer to obtain 12V

AC supply from 230V AC mains supply.

SELECTION OF DIODES: Use 1N4007 diodes as it can withstand a maximum of 1

A.

SELECTION OF VOLTAGE REGULATORS: Use LM7805 to obtain the 5V DC

voltage and LM317 to obtain the 3.3V DC voltage.

SELECTION OF CAPACITOR C1:

The converted dc contains ac ripple components. Inorder to avoid this we use

a capacitive filter. C1 is used for filtering the rectifier output.

C=5I/(Vp x f)

I= 0.063A, f=50 Hz, Vp=12+1.2=13.2V.

Hence C=477.72µF. Use 470µF standard.

SELECTION OF CAPACITOR C2:

The capacitor C2 is used for filtering purpose. We require C2 << C1 .

Take C2 = C1 / 10


Campus Automation PROJECT REPORT ‘11 Use 47 µF std.

SELECTION OF R1 , R2, C3, C4:

C3 is used for filtering purpose. Use C3 = C2 = 47 µF std.

C4 is used for reducing noise at the output. Use C4= 0.1 µF std.

V0 = Vref [1 + (R2 / R1 )]

Vref = 1.25 V fixed value

Take R1 = 220 Ω std.

V0 = 3.3 V

Then R2 = 330 Ω std.

5.2Peripheral Interface Controller (PIC)

Peripheral Interface Controllers (PIC) is one of the advanced microcontrollers developed by microchip technologies. These microcontrollers are widely used in modern electronics applications. A PIC controller integrates all type


Campus Automation PROJECT REPORT ‘11 of advanced interfacing ports and memory modules. These controllers are more advanced than normal microcontroller like INTEL 8051. The first PIC chip was announced in 1975 (PIC1650). As like normal microcontroller, the PIC chip also combines a microprocessor unit called CPU and is integrated with various types of memory modules (RAM, ROM, EEPROM, etc), I/O ports, timers/counters, communication ports, etc. PIC 16F877 is one of the most advanced microcontroller from Microchip. PICs are popular with both industrial developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming (and re-programming with flash memory) capability. The figure of a PIC16F877 chip is shown below

All PIC microcontroller family uses Harvard architecture. This architecture has the program and data accessed from separate memories so the device has a program memory bus and a data memory bus (more than 8 lines in a normal bus). This improves the bandwidth (data throughput) over traditional von Neumann architecture where program and data are fetched from the same memory (accesses over the same bus). Separating program and data memory further allows instructions to be sized differently than the 8-bit wide data word. The PIC has number of advanced features, the important features of PIC16F877 series is given below.

5.2.1 General Features

It is a high performance RISC CPU. Only 35 simple word instructions. All single cycle instructions except for program branches which are two

cycles. Operating speed: clock input (200MHz), instruction cycle (200nS). Up to 368×8bit of RAM (data memory), 256×8 of EEPROM (data memory),

and 8k×14 of flash memory. Pin out compatible to PIC 16C74B, PIC 16C76, PIC 16C77. Eight level deep hardware stack. Interrupt capability (up to 14 sources).


Fig.5.1

http://www.circuitstoday.com/wp-content/uploads/2011/01/PIC-16F877.gif


Different types of addressing modes (direct, Indirect, relative addressing modes).

Power on Reset (POR). Power-Up Timer (PWRT) and oscillator start-up timer. Low power- high speed CMOS flash/EEPROM. Fully static design. Wide operating voltage range (2.0 – 5.56)volts. High sink/source current (25mA). Commercial, industrial and extended temperature ranges. Low power consumption (<0.6mA typical @3v-4MHz, 20µA typical @3v-

32MHz and <1 A typical standby).

5.2.2 Peripheral Features

Timer 0: 8 bit timer/counter with pre-scalar. Timer 1:16 bit timer/counter with pre-scalar. Timer 2: 8 bit timer/counter with 8 bit period registers with pre-scalar and

post-scalar. Two Capture (16bit/12.5nS), Compare (16 bit/200nS), Pulse Width Modules

(10bit). 10bit multi-channel A/D converter Synchronous Serial Port (SSP) with SPI (master code) and I2C (master/slave). Universal Synchronous Asynchronous Receiver Transmitter (USART) with 9

bit addresses detection. Parallel Slave Port (PSP) 8 bit wide with external RD, WR and CS controls

(40/46pin). Brown Out circuitry for Brown-Out Reset (BOR).

5.2.3 Key Features

Maximum operating frequency is 20MHz. Flash program memory (14 bit words), 8KB. Data memory (bytes) is 368. EEPROM data memory (bytes) is 256. 5 input/output ports. 3 timers. 2 CCP modules. 2 serial communication ports (MSSP, USART). PSP parallel communication port 10bit A/D module (8 channels)



5.2.4 Analog Features

10-bit, up to 8-channel Analog-to-Digital Converter (A/D) Brown-out Reset (BOR) Analog Comparator module with two analog comparators, programmable on-

chip voltage reference (VREF) module, programmable input multiplexing from device inputs and internal voltage reference & comparator outputs are externally accessible.

5.2.5 Special Features

100000 times erase/write cycle enhanced memory. 1000000 times erase/write cycle data EEPROM memory. Self programmable under software control. In-circuit serial programming and in-circuit debugging capability. Single 5V,DC supply for circuit serial programming WDT with its own RC oscillator for reliable operation. Programmable code protection. Power saving sleep modes. Selectable oscillator options.

Now we discuss the important parts of Peripheral Interface Controller

5.2.6 Central Processing Unit (CPU)

The function of CPU in PIC is same as a normal microcontroller CPU. A PIC CPU consists of several sub units such as instruction decoder, ALU, accumulator, control unit, etc. The CPU in PIC normally supports Reduced Instruction Set Computer (RISC) architecture (Reduced Instruction Set Computer (RISC), a type of microprocessor that focuses on rapid and efficient processing of a relatively small set of instructions. RISC design is based on the premise that most of the instructions a computer decodes and executes are simple. As a result, RISC architecture limits the number of instructions that are built into the microcontroller but optimizes each so it can be carried out very rapidly (usually within a single clock cycle). These RISC structure gives the following advantages.

The RISC structure only has 35 simple instructions as compared to others. The execution time is same for most of the instructions (except very few

numbers). The execution time required is very less (5 million instructions/second

approximately).

5.2.7 Memory Organization of PIC16F877



The memory of a PIC 16F877 chip is divided into 3 sections. They are Program memory Data memory and Data EEPROM

5.2.7.1 Program memory

Program memory contains the programs that are written by the user. The program counter (PC) executes these stored commands one by one. Usually PIC16F877 devices have a 13 bit wide program counter that is capable of addressing 8K×14 bit program memory space. This memory is primarily used for storing the programs that are written (burned) to be used by the PIC. These devices also have 8K*14 bits of flash memory that can be electrically erasable /reprogrammed. Each time we write a new program to the controller, we must delete the old one at that time. The program memory map and stack is shown in appendix

Program counters (PC) is used to keep the track of the program execution by holding the address of the current instruction. The counter is automatically incremented to the next instruction during the current instruction execution.

The PIC16F87XA family has an 8-level deep x 13-bit wide hardware stack. The stack space is not a part of either program or data space and the stack pointers are not readable or writable. In the PIC microcontrollers, this is a special block of RAM memory used only for this purpose.

5.2.7.2 Data Memory

The data memory of PIC16F877 is separated into multiple banks which contain the general purpose registers (GPR) and special function registers (SPR). According to the type of the microcontroller, these banks may vary. The PIC16F877 chip only has four banks (BANK 0, BANK 1, BANK 2, and BANK4). Each bank holds 128 bytes of addressable memory. The data memory bank organization is shown in appendix.

The banked arrangement is necessary because there are only 7 bits are available in the instruction word for the addressing of a register, which gives only 128 addresses. The selection of the banks are determined by control bits RP1, RP0 in the STATUS registers Together the RP1, RP0 and the specified 7 bits effectively form a 9 bit address. The first 32 locations of Banks 1 and 2, and the first 16 locations of Banks2 and 3 are reserved for the mapping of the Special Function Registers (SFR’s).

RP1:RP0 BANK



00 0

01 1

10 2

11 3

Table 5.1

A bit of RP1 & RP0 of the STATUS register selects the bank access. 5.2.7.3 Data EEPROM and FLASH

The data EEPROM and Flash program memory is readable and writable during normal operation (over the full VDD range). This memory is not directly mapped in the register file space. Instead, it is indirectly addressed through the Special Function Registers. There are six SFRs used to read and write this memory:

• EECON1

• EECON2

• EEDATA

• EEDATH

• EEADR

• EEADRH

The EEPROM data memory allows single-byte read and writes. The Flash program memory allows single-word reads and four-word block writes. Program memory write operations automatically perform an erase-before write on blocks of four words. A byte write in data EEPROM memory automatically erases the location and writes the new data (erase-before-write). The write time is controlled by an on-chip timer. The write/erase voltages are generated by an on-chip charge pump, rated to operate over the voltage range of the device for byte or word operations.

5.2.8 Input/output Ports

PIC16F877 has 5 basic input/output ports. They are usually denoted by PORT A (R A), PORT B (RB), PORT C (RC), PORT D (RD), and PORT E (RE). These ports are used for input/ output interfacing. In this controller, “PORT A” is only 6 bits wide (RA-0 to RA-7), ”PORT B” , “PORT C”,”PORT D” are only 8 bits wide (RB-0 to RB-7,RC-0 to RC-7,RD-0 to RD-7), ”PORT E” has only 3 bit wide (RE-0 to RE-7).



PORT-A RA0 to RA5 6 bit wide

PORT-B RB-0 to RB-7 8 bit widePORT-C RC-0 to RC-7 8 bit widePORT-D RD-0 to RD-7 8 bit widePORT-E RE-0 to RE-2 3 bit wide

Table 5.2

All these ports are bi-directional. The direction of the port is controlled by using TRIS(X) registers (TRIS A used to set the direction of PORT-A, TRIS B used to set the direction for PORT-B, etc.). Setting a TRIS(X) bit ‘1’ will set the corresponding

PORT(X) bit as input. Clearing a TRIS(X) bit ‘0’ will set the corresponding PORT(X) bit as output. (If we want to set PORT A as an input, just set TRIS(A) bit to logical ‘1’ and want to set PORT B as an output, just set the PORT B bits to logical ‘0’.)

5.2.8.1 Port A & TRIS A Register

PORTA is a 6-bit wide, bidirectional port. The corresponding data direction register is TRISA. Setting a TRISA bit (= 1) will make the corresponding PORTA pin an input (i.e., put the corresponding output driver in a High- Impedance mode). Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output (i.e., put the contents of the output latch on the selected pin). Reading the PORTA register reads the status of the pins, whereas writing to it will write to the port latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, the value is modified and then written to the port data latch. Pin RA4 is multiplexed with the Timer0 module clock input to become the RA4/T0CKI pin. The RA4/T0CKI pin is a Schmitt Trigger input and an open-drain output. All other PORTA pins have TTL input levels and full CMOS output drivers. Other PORTA pins are multiplexed with analog inputs and the analog VREF input for both the A/D converters and the comparators. The operation of each pin is selected by clearing/setting the appropriate control bits in the ADCON1 and/or CMCON registers.

The TRISA register controls the direction of the port pins even when they are being used as analog inputs. The user must ensure the bits in the TRISA register are maintained set when using them as analog inputs.

5.2.8.2 Port B & TRIS Register

PORTB is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISB. Setting a TRISB bit (= 1) will make the corresponding PORTB pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISB bit (= 0) will make the corresponding PORTB pin an output


Campus Automation PROJECT REPORT ‘11 (i.e., put the contents of the output latch on the selected pin). Three pins of PORTB are multiplexed with the In-Circuit Debugger and Low-Voltage Programming function: RB3/PGM, RB6/PGC and RB7/PGD. Each of the PORTB pins has a weak internal pull-up. A single control bit can turn on all the pull-ups. This is performed by clearing bit RBPU (OPTION_REG<7>). The weak pull-up is automatically turned off when the port pin is configured as an output. The pull-ups are disabled on a Power-on Reset. Four of the PORTB pins, RB7:RB4, have an interrupton- change feature. Only pins configured as inputs can cause this interrupt to occur (i.e., any RB7:RB4 pin configured as an output is excluded from the interrupton- change comparison). The input pins (of RB7:RB4) are compared with the old value latched on the last read of PORTB. The “mismatch” outputs of RB7:RB4 are OR’ed together to generate the RB port change interrupt with flag bit RBIF (INTCON<0>). This interrupt can wake the device from Sleep. The user, in the Interrupt Service Routine, can clear the interrupt in the following manner: Any read or write of PORTB. This will end the

Mismatch condition. Clear flag bit RBIF.

A mismatch condition will continue to set flag bit RBIF. Reading PORTB will end the mismatch condition and allow flag bit RBIF to be cleared. The interrupt-on-change feature is recommended for wake-up on key depression operation and operations where PORTB is only used for the interrupt-on-change feature. Polling of PORTB is not recommended while using the interrupt-on-change feature. This interrupt-on-mismatch feature, together with software configurable pull-ups on these four pins, allow easy interface to a keypad and make it possible for wake-up on key depression.

5.2.8.3 Port C & TRIS C Register

PORTC is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISC. Setting a TRISC bit (= 1) will make the corresponding PORTC pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISC bit (= 0) will make the corresponding PORTC pin an output (i.e., put the contents of the output latch on the selected pin). PORTC is multiplexed with several peripheral functions. PORTC pins have Schmitt Trigger input buffers. When the I2C module is enabled, the PORTC<4:3> pins can be configured with normal I2C levels, or with SMBus levels, by using the CKE bit (SSPSTAT<6>).

When enabling peripheral functions, care should be taken in defining TRIS bits for each PORTC pin. Some peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to make a pin an input. Since the TRIS bit override is in effect while the peripheral is enabled, read-modify write instructions (BSF, BCF, XORWF) with TRISC as the destination, should be avoided. The user should refer to the corresponding peripheral section for the correct TRIS bit settings.

5.2.8.4 Port D & TRIS D Register



PORTD is an 8-bit port with Schmitt Trigger input buffers. Each pin is individually configurable as an input or output. PORTD can be configured as an 8-bit wide microprocessor port (Parallel Slave Port) by setting control bit, PSPMODE (TRISE<4>). In this mode, the input buffers are TTL.

5.2.8.5 Port E & TRIS E Register

PORTE has three pins (RE0/RD/AN5, RE1/WR/AN6 and RE2/CS/AN7) which are individually configurable as inputs or outputs. These pins have Schmitt Trigger input buffers. The PORTE pins become the I/O control inputs for the microprocessor port when bit PSPMODE (TRISE<4>) is set. In this mode, the user must make certain that the TRISE<2:0> bits are set and that the pins are configured as digital inputs. Also, ensure that ADCON1 is configured for digital I/O. In this mode, the input buffers are TTL. Register 4-1 shows the TRISE register which also controls the Parallel Slave Port operation. PORTE pins are multiplexed with analog inputs. When selected for analog input, these pins will read as ‘0’s. TRISE controls the direction of the RE pins, even when they are being used as analog inputs. The user must make sure to keep the pins configured as inputs when using them as analog inputs.

5.2.9 USART

The Universal Synchronous Asynchronous Receiver Transmitter (USART) module is one of the two serial I/O modules. (USART is also known as a Serial Communications Interface or SCI). These ports are used for the transmission (TX) and reception (RX) of data. These transmissions possible with help of various digital data transceiver modules like RF, IR, Bluetooth, ZIGBEE etc. This is the one of the simplest way to communicate the PIC chip with other devices. The USART can be configured as a full-duplex asynchronous system that can communicate with peripheral devices, such as CRT terminals and personal computers, or it can be configured as a half-duplex synchronous system that can communicate with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs, etc.

The USART can be configured in the following modes:

Asynchronous (full-duplex) Synchronous – Master (half-duplex) Synchronous – Slave (half-duplex)

Bit SPEN (RCSTA<7>) and bits TRISC<7:6> have to be set in order to configure pins RC6/TX/CK and RC7/RX/DT as the Universal Synchronous Asynchronous Receiver Transmitter. The parameters for serial communication are

Data rate (Baud rate in bps) Data size (packet size)



Start bit (if any) Stop bit (if any) Parity bit (if any)

PIC 16F877A have no start bit, one stop bit & no parity bit. Therefore the transmitted or received information is 9-bit in size, where 8-bit is data & one bit is stop bit. The USART module also has a multi-processor communication capability using 9-bit address detection. 5.2.10 Pin Diagram of PIC 16F877A

The 40 pin PDIP pin- out of PIC 16F877A is shown below:

Fig.5.2

Some pins for these I/O ports are multiplexed with an alternate function for the peripheral features on the device. These are given in appendix.

5.2.11 Master Clear

PIC16F87XA devices have a noise filter in the MCLR Reset path. The filter will detect and ignore small pulses. Voltages applied to the pin that exceed its specification can result in both Resets and current consumption outside of device specification during the Reset event. For this reason, Microchip recommends that the MCLR pin no longer be tied directly to VDD. The use of an RCR network, as shown in Fig.6.5 is suggested. During normal operation this pin should be high. When reset it is low, during reset, the following conditions will occur



Queue will clear All registers will clear IP points to the first location of memory RAM will clear

Fig.5.3

5.2.12 Limitations of PIC Architecture

Peripheral Interface Controller has only one accumulator. Small instruction set. Register banking switch required to access RAM of other devices. Operations and registers are not orthogonal. Program memory is not accessible.

The PIC requires external clock generator. We use crystal oscillator for clock generation. The details of crystal oscillator are given in appendix-3.

5.2.13 Advantages of PIC Controlled System



• Reliability: The PIC controlled system often resides machines that are expected to run continuously for many years without any error and in some cases recover by themselves if an error occurs(with help of supporting firmware).

• Performance: Many of the PIC based embedded system use a simple pipelined RISC processor for computation and most of them provide on-chip SRAM for data storage to improve the performance.• Power consumption: A PIC controlled system operates with minimal power consumption without sacrificing performance. Power consumption can be reduced by independently and dynamically controlling multiple power platforms.• Memory: Most of the PIC based systems are memory expandable and will help in easily adding more and more memory according to the usage and type of application. In small applications the inbuilt memory can be used.

5.3 ZIGBEE Module

Fig.5.4 In this project the data will be transmitted from the attendance entering system to the main server using wireless technology. The past several years have witnessed a rapid growth of wireless networking. However, up to now wireless networking has been mainly focused on high-speed communications, and relatively long range applications such as the IEEE 802.11 Wireless Local Area Network (WLAN) standards. The first well known standard focusing on Low- Rate Wireless Personal Area Networks (LR-WPAN) was Bluetooth. However it has limited capacity for networking of many nodes. There are many wireless monitoring and control applications in industrial and home environments which require longer battery life, lower data rates and less complexity than those from existing standards. For such wireless applications, a new standard called IEEE 802.15.4 has been developed by IEEE. The new standard is also called ZigBee, when additional stack layers defined by the ZigBee Alliance are used.

ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4-2003 standard for


http://www.digi.com/products/morephotos.jsp?pfid=147&lid=EN

Campus Automation PROJECT REPORT ‘11 Low-Rate Wireless Personal Area Networks (LR-WPANs), such as wireless light switches with lamps, electrical meters with in-home-displays, consumer electronics equipment via short-range radio needing low rates of data transfer. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth. ZigBee is targeted at radio-frequency (RF) applications that require a low data rate, long battery life, and secure networking.

5.3.1 Wireless Personal Area Network (WPAN)

A WPAN (wireless personal area network) is a personal area network - a network for interconnecting devices centered on an individual person's workspace - in which the connections are wireless. Typically, a wireless personal area network uses some technology that permits communication within about 10 meters (33 ft) such as Bluetooth, which was used as the basis for a new standard, IEEE 802.15.

A WPAN could serve to interconnect all the ordinary computing and communicating devices that many people have on their desk or carry with them today - or it could serve a more specialized purpose such as allowing the surgeon and other team members to communicate during an operation.

A key concept in WPAN technology is known as "plugging in". In the ideal scenario, when any two WPAN-equipped devices come into close proximity (within several meters of each other) or within a few kilometers of a central server, they can communicate as if connected by a cable. Another important feature is the ability of each device to lock out other devices selectively, preventing needless interference or unauthorized access to information.

The technology for WPANs is in its infancy and is undergoing rapid development. Proposed operating frequencies are around 2.4 GHz in digital modes. The objective is to facilitate seamless operation among home or business devices and systems. Every device in a WPAN will be able to plug in to any other device in the same WPAN, provided they are within physical range of one another. In addition, WPANs worldwide will be interconnected.

5.3.2 The Name ZIGBEE

The name ZigBee is said to come from the domestic honeybee which uses a zig-zag type of dance to communicate important information to other hive members. This communication dance (the "ZigBee Principle") is what engineers are trying to emulate with this protocol _ a bunch of separate and simple organisms that join together to tackle complex tasks. The domestic honeybee, a colonial insect, lives in a hive that contains a queen, a few male drones, and thousands of worker bees. The survival, success, and future of the colony is dependent upon continuous communication of vital information between every member of the colony. The technique that honey bees use to communicate new-found food sources to other members of the colony is


Campus Automation PROJECT REPORT ‘11 referred to as the ZigBee Principle. Using this silent, but powerful communication system, whereby the bee dances in a zig-zag pattern, she is able to share information such as the location, distance, and direction of a newly discovered food source to her fellow colony members. Instinctively implementing the ZigBee Principle, bees around the world industriously sustain productive hives and foster future generations of colony members.

5.3.3 Trademark and Alliance

The ZigBee Alliance is an association of companies working together to enable reliable, cost-effective, and low-power wirelessly networked monitoring and control products based on an open global standard. The ZigBee Alliance is a group of companies that maintain and publish the ZigBee standard. The term ZigBee is a registered trademark of this group, not a single technical standard.

As per its main role, it standardizes the body that defines ZigBee, and also publishes application profiles that allow multiple OEM vendors to create interoperable products. The current list of application profiles either published, or in the works are:

ZigBee Home Automation ZigBee Smart Energy 1.0 ZigBee Telecommunication Services ZigBee Health Care ZigBee Remote Control

5.3.4 IEEE 802.15.4

Creating wireless networks can be done using a variety of RF protocols. Some protocols are proprietary to individual vendors, others are industry standards. This Application Note will explore the ZigBee protocol industry standard for data transmission, and the IEEE 802.15.4 protocol on which it was built. We will define the frequencies used, the bandwidth it occupies, and networking features unique to this protocol. ZigBee is a protocol that uses the 802.15.4 standard as a baseline and adds additional routing and networking functionality. What ZigBee is designed to do is add mesh networking to the underlying 802.15.4 radio.

The goal IEEE had when they specified the IEEE 802.15.4 standard was to provide a standard for ultra-low complexity, ultra-low cost, ultra-low power consumption and low data rate wireless connectivity among inexpensive devices.

802.15.4 is a standard for wireless communication put out by the IEEE (Institute for Electrical and Electronics Engineers). IEEE has published the standards that define communication in areas such as the Internet, PC peripherals, industrial communication and wireless technology. As a few examples, the IEEE 802.11


Campus Automation PROJECT REPORT ‘11 standard defines communication for wireless LAN and 802.16 define communication for broadband wireless Metropolitan Area Networks. While both of those wireless standards are concerned with higher bandwidth Internet access applications, 802.15.4 was developed with lower data rate, simple connectivity and battery application in mind.

The 802.15.4 standard specifies that communication can occur in the 868- 868.8MHz, the 902-928 MHz or the 2.400-2.4835 GHz Industrial Scientific and Medical (ISM) bands. While any of these bands can technically be used by 802.15.4 devices, the 2.4 GHz band is more popular as it is open in most of the countries worldwide.

The 868 MHz band is specified primarily for European use, whereas the 902-928 MHz band can only be used in the United States, Canada and a few other countries and territories that accept the FCC regulations. The 802.15.4 standard specifies that communication should occur in 5 MHz channels ranging from 2.405 to 2.480 GHz. In the 2.4 GHz band, a maximum over-the-air data rate of 250 kbps is specified, but due to the overhead of the protocol the actual theoretical maximum data rate is approximately half of that. While the standard specifies 5 MHz channels, only approximately 2 MHz of the channel is consumed with the occupied bandwidth.

At 2.4 GHz, 802.15.4 specifies the use of Direct Sequence Spread Spectrum and uses an Offset Quadrature Phase Shift Keying (O-QPSK) with half-sine pulse shaping to modulate the RF carrier.

The relationship between IEEE 802.15.4 and ZigBee is similar to that between IEEE 802.11 and the Wi-Fi Alliance. The ZigBee 1.0 specification was ratified on 14 December 2004 and is available to members of the ZigBee Alliance. Most recently, the ZigBee 2007 specification was posted on 30 October 2007. The first ZigBee Application Profile, Home Automation, was announced 2 November 2007. As amended by NIST, the Smart Energy Profile 2.0 specification will remove the dependency on IEEE 802.15.4. Device manufacturers will be able to implement any MAC/PHY, such as IEEE 802.15.4(x) and IEEE P1901, under an IP layer based on 6LoWPAN.

5.3.5 Components of the IEEE 802.15.4

IEEE 802.15.4 networks use three types of devices:

The network Coordinator maintains overall network knowledge. It is the most sophisticated one of the three types, and requires the most memory and computing power.

The Full Function Device (FFD) supports all IEEE 802.15.4 functions and features speci_ed by the standard. It can function as a network coordinator. Additional memory and computing power make it ideal for network router



functions or it could be used in network-edge devices (where the network touches the real world).

The Reduced Function Device (RFD) carries limited (as speci_ed by the standard) functionality to lower cost and complexity. It is generally found in network-edge devices. The RFD can be used where extremely low power consumption is a necessity.

5.3.6 ISM Band

The industrial, scientific and medical (ISM) radio bands were originally reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than communications. Examples of applications in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices were limited to certain bands of frequencies. In general, communications equipment operating in these bands must accept any interference generated by ISM equipment.

The ISM bands are defined by the ITU-R in 5.138, 5.150, and 5.280 of the Radio Regulations. Individual countries' use of the bands designated in these sections may differ due to variations in national radio regulations. Because communication devices using the ISM bands must tolerate any interference from ISM equipment, these bands are typically given over to uses intended for unlicensed operation, since unlicensed operation typically needs to be tolerant of interference from other devices anyway.

In the United States of America, uses of the ISM bands are governed by Part 18 of the FCC rules, while Part 15 contains the rules for unlicensed communication devices, even those that use the ISM frequencies.

For many people, the most commonly encountered ISM device is the home microwave oven operating at 2.45 GHz. However, in recent years these bands have also been shared with license-free error-tolerant communications applications such as Wireless Sensor Networks in the 868 MHz, 915 MHz and 2.450 GHz bands, as well as wireless LANs and cordless phones in the 915 MHz, 2.450 GHz, and 5.800 GHz bands. IEEE 802.15.4, ZigBee and other personal area networks may use the 915 MHz and 2450 MHz ISM bands.

5.3.7 General characteristics of ZIGBEE

ZigBee is a low-cost, low-power, wireless mesh networking standard. First, the low cost allows the technology to be widely deployed in wireless control and monitoring applications. Second, the low power-usage allows longer life with smaller batteries. Third, the mesh networking provides high reliability and more extensive range. Because ZigBee can activate (go from sleep to active mode) in 30 msec or less, the latency can be very low and devices can be very responsive — particularly


Campus Automation PROJECT REPORT ‘11 compared to Bluetooth wake-up delays, which are typically around three seconds. Because ZigBees can sleep most of the time, average power consumption can be very low, resulting in long battery life. The general characteristics of the zigbee are:

Data rates of 20 kbps and up to 250 kbps Star or Peer-to-Peer network topologies Support for Low Latency Devices CSMA-CA Channel Access Handshaking Low Power Usage consumption 3 Frequencies bands with 27 channels Extremely low duty-cycle (<0.1%)

5.3.8 Device Types

There are three different types of ZigBee devices:

ZigBee coordinator (ZC): The most capable device, the coordinator forms the root of the network tree and might bridge to other networks. There is exactly one ZigBee coordinator in each network since it is the device that started the

network originally. It is able to store information about the network, including acting as the Trust Center & repository for security keys.

ZigBee Router (ZR): As well as running an application function, a router can act as an intermediate router, passing on data from other devices.

ZigBee End Device (ZED): Contains just enough functionality to talk to the parent node (either the coordinator or a router); it cannot relay data from other devices. This relationship allows the node to be asleep a significant amount of the time thereby giving long battery life. A ZED requires the least amount of memory, and therefore can be less expensive to manufacture than a ZR or ZC.

5.3.9 Different Stacks of ZIGBEE

The first stack release is now called ZigBee 2004. The second stack release is called ZigBee 2006, and mainly replaces the MSG/KVP structure used in 2004 with a "cluster library". The 2004 stack is now more or less obsolete.

ZigBee 2007, now the current stack release, contains two stack profiles, stack profile 1 (simply called ZigBee), for home and light commercial use, and stack profile 2 (called ZigBee Pro). ZigBee Pro offers more features, such as multi-casting, many-to-one routing and high security with Symmetric-Key Key Exchange (SKKE), while


Campus Automation PROJECT REPORT ‘11 ZigBee (stack profile 1) offers a smaller footprint in RAM and flash. Both offer full mesh networking and work with all ZigBee application profiles. ZigBee 2007 is fully backward compatible with ZigBee 2006 devices: A ZigBee 2007 device may join and operate on a ZigBee 2006 network and vice versa. Due to differences in routing options, ZigBee Pro devices must become non-routing ZigBee End-Devices (ZEDs) on a ZigBee 2006 network, the same as for ZigBee 2006 devices on a ZigBee 2007 network must become ZEDs on a ZigBee Pro network. The applications running on those devices work the same, regardless of the stack profile beneath them.

5.3.10 ZIGBEE Protocols

The protocols build on recent algorithmic research (Ad-hoc On-demand Distance Vector, neuRFon) to automatically construct a low-speed ad-hoc network of nodes. In most large network instances, the network will be a cluster of clusters. It can also form a mesh or a single cluster. The current profiles derived from the ZigBee protocols support beacon and non-beacon enabled networks.

In non-beacon-enabled networks (those whose beacon order is 15), an unslotted CSMA/CA channel access mechanism is used. In this type of network, ZigBee Routers typically have their receivers continuously active, requiring a more robust power supply. However, this allows for heterogeneous networks in which some devices receive continuously, while others only transmit when an external stimulus is detected. The typical example of a heterogeneous network is a wireless light switch: The ZigBee node at the lamp may receive constantly, since it is connected to the mains supply, while a battery-powered light switch would remain asleep until the switch is thrown. The switch then wakes up, sends a command to the lamp, receives an acknowledgment, and returns to sleep.

In such a network the lamp node will be at least a ZigBee Router, if not the ZigBee Coordinator; the switch node is typically a ZigBee End Device. In beacon-enabled networks, the special network nodes called ZigBee Routers transmit periodic beacons to confirm their presence to other network nodes. Nodes may sleep between beacons, thus lowering their duty cycle and extending their battery life. Beacon intervals may range from 15.36 milliseconds to 15.36 ms * 214 = 251.65824 seconds at 250 kbit/s, from 24 milliseconds to 24 ms * 214= 393.216 seconds at 40 kbit/s and from 48 milliseconds to 48 ms * 214 = 786.432 seconds at 20 kbit/s. However, low duty cycle operation with long beacon intervals requires precise timing, which can conflict with the need for low product cost.

In general, the ZigBee protocols minimize the time the radio is on so as to reduce power use. In beaconing networks, nodes only need to be active while a beacon is being transmitted. In non-beacon-enabled networks, power consumption is decidedly asymmetrical: some devices are always active, while others spend most of their time sleeping.



Except for the Smart Energy Profile 2.0, which will be MAC/PHY agnostic, ZigBee devices are required to conform to the IEEE 802.15.4-2003 Low-Rate Wireless Personal Area Network (WPAN) standard. The standard specifies the lower protocol layers—the physical layer (PHY), and the media access control (MAC) portion of the data link layer (DLL). This standard specifies operation in the unlicensed 2.4 GHz (worldwide), 915 MHz (Americas) and 868 MHz (Europe) ISM bands. In the 2.4 GHz band there are 16 ZigBee channels, with each channel requiring 5 MHz of bandwidth. The center frequency for each channel can be calculated as, FC = (2405 + 5 * (ch - 11)) MHz, where ch = 11, 12,.....26.

The radios use direct-sequence spread spectrum coding, which is managed by the digital stream into the modulator. BPSK is used in the 868 and 915 MHz bands, and OQPSK that transmits four bits per symbol is used in the 2.4 GHz band. The raw, over-the-air data rate is 250 kbit/s per channel in the 2.4 GHz band, 40 kbit/s per channel in the 915 MHz band, and 20 kbit/s in the 868 MHz band. Transmission range is between 10 and 75 meters (33 and 246 feet) and up to 1500 meters for zigbee pro, although it is heavily dependent on the particular environment. The output power of the radios is generally 0 dBm (1 mW). The basic channel access mode is "carrier sense, multiple access/collision avoidance" (CSMA/CA). That is, the nodes talk in the same way that people converse; they briefly check to see that no one is talking before they start. There are three notable exceptions to the use of CSMA. Beacons are sent on a fixed timing schedule, and do not use CSMA. Message acknowledgments also do not use CSMA. Finally, devices in Beacon Oriented networks that have low latency real-time requirements may also use Guaranteed Time Slots (GTS), which by definition do not use CSMA. 5.3.11 Offset QPSK (OQPSK)

Offset quadrature phase-shift keying (OQPSK) is a variant of phase-shift keying modulation using 4 different values of the phase to transmit. It is sometimes called Staggered quadrature phase-shift keying (SQPSK).

Taking four values of the phase (two bits) at a time to construct a QPSK symbol can allow the phase of the signal to jump by as much as 180° at a time. When the signal is low-pass filtered (as is typical in a transmitter), these phase-shifts result in large amplitude fluctuations an undesirable quality in communication systems. By offsetting the timing of the odd and even bits by one bit-period, or half a symbol-period, the in-phase and quadrature components will never change at the same time. In the constellation diagram shown on the right, it can be seen that this will limit the phase-shift to no more than 90° at a time. This yields much lower amplitude fluctuations than non-offset QPSK and is sometimes preferred in practice. The picture on the right shows the difference in the behavior of the phase between ordinary QPSK and OQPSK. It can be seen that in the first plot the phase can change by 180° at once, while in OQPSK the changes are never greater than 90°.


Campus Automation PROJECT REPORT ‘11 The modulated signal is shown below for a short segment of a random binary data-stream. Note the half symbol-period offset between the two component waves. The sudden phase-shifts occur about twice as often as for QPSK (since the signals no longer change together), but they are less severe. In other words, the magnitude of jumps is smaller in OQPSK when compared to QPSK.

Fig.5.5 5.3.12 Mesh Networking

ZigBee is designed to do the mesh networking to the underlying 802.15.4 radio. Mesh networking is used in applications where the range between two points may be beyond the range of the two radios located at those points, but intermediate radios are in place that could forward on any messages to and from the desired radios.

Fig 5.6

As an example, in the figure above suppose we wanted to transmit data from point A to point B, but the distance was too great between the points. The message could be transmitted through point C and a few other radios to reach the destination.

5.3.13 ZIGBEE v/s Bluetooth

ZigBee Protocol was developed to serve very different applications than Bluetooth and leads to tremendous optimizations in power consumption. Some of the key protocol differentiators are:

ZigBee:


http://en.wikipedia.org/wiki/File:OQPSK_timing_diagram.png


Very low duty cycle, very long primary battery life, Static and dynamic star and mesh networks, >65,000 nodes, with low latency

available, Ability to remain quiescent for long periods without communications, Direct Sequence Spread Spectrum allows devices to sleep without the

requirement for close synchronization. Bluetooth:

Moderate duty cycle, secondary battery lasts same as master, Very high QoS and very low, guaranteed latency, Quasi-static star network up to seven clients with ability to participate in more

than one network, Frequency Hopping Spread Spectrum is extremely difficult to create extended

networks without large synchronization cost.

5.3.14 ZIGBEE Module

The ZigBee Module provides an alternative way to transfer data without the use of wires. ZigBee transceiver is developed by Digi. ZigBee was among the first transceivers that hit the market and came in a convenient to use casing.

The ZigBee uses a wireless 2.4GHz transceiver to communicate with another ZigBee module. Furthermore, ZigBee modules are capable of communicating with more than one ZigBee module. Thus, it means you can create a network of ZigBee modules all over the place as long as they are in range, of course.Some features of ZigBee are:

802.15.4 Protocol created by the IEEE foundation. Data rate of 250KBps (Kilobits per second). Can be used indoors and outdoors. Range is from 100ft-300 for standard XBee modules and 300ft-1 Mile for

XBee Pro Modules (depending on where it’s used and the line of sight from one XBee to the next XBee).

The standard XBee has a 1mW transmit power and the XBee Pro has a 60mW transmit power.

No configuration is required out of the box. Default baud rate is 9600bps. Although, you can change the configuration of

how fast you want to transmit but for this tutorial we will just leave the baud rate at default.

One of the great features of ZigBee networks is the low power operation. XBee makes sure you won’t be changing the batteries very often! It consumes about 35mA during transmission (38mA while receiving) while it keeps it below 1uA while sleeping. These are quite attractive specs. , XBee also allows invisible operation. That


Campus Automation PROJECT REPORT ‘11 means you don't have to care about exchanging complicated information with the module in order to send a packet. The invisible mode sets up a link of streaming data over the ZigBee network. So all you need to do is to serially send the information to the transmitter and the receiver module will output them the same way to your target machine. Quite simply, it replaces the serial communication cable. This can be very handy. Overall the XBee modules are easy to use and provide great features.

5.3.15 Pin Diagram of ZIGBEE

The pin out of the Zigbee module is shown below:

Fig.5.7

The details of each pin are given in appendix-4. For the data transmission & reception only pin 1 (supply), pin 2 (transmit), pin 3 (receive) and pin 10 (ground) are required.

5.4 PIR Sensor

Fig.5.8



A PIR sensor detects infrared light that is emitted from objects within its field of view. PIR sensors differ from other infrared sensors because they can only receive infrared waves. Because all objects emit infrared waves (electromagnetic waves that travel with heat), PIR sensors can detect objects that are in front of them. In fact, PIR sensors can detect many things that humans cannot. PIR sensors are used in many applications, such as night vision, motion detection, and laser range finding.

5.4.1 Working of PIR PIR sensors are made of pyroelectric (or thermoelectric) materials and usually contain lenses or mirrors in order to focus the infrared light for maximum reception. As infrared light comes in contact with the pyroelectric material, which is usually a thin sheet, it creates an electrical current that can be measured to determine the intensity of the infrared light (depth perception) and the direction that it came from. Because of these properties, PIR sensors are able to determine how far away someone is and whether he/she is approaching the sensor.

5.4.2 ApplicationsPIR sensors are used in many applications. They are used on television sets and television accessory devices, such as VCRs and DVD players, to detect infrared light coming from a television remote. PIR sensors are also used as motion detectors at most public doorways in grocery stores, hospitals, and libraries. PIR sensors can also be used for military purposes such as laser range-finding, night vision, and heat-seeking missiles.

5.4.3 AdvantagesPIR sensors have several important advantages. They detect infrared light from several feet/yards away, depending on how the device is calibrated. PIR sensors are generally compact and can be fitted into virtually any electronic device. Also, they do not need an external power source because they generate electricity as they absorb infrared light.

5.4.4 DisadvantagesAlthough PIR sensors can be advantageous, they also have several disadvantages. PIR sensors can only receive infrared light and cannot emit it like other types of infrared sensors. They can be expensive to purchase, install, and calibrate as well.

5.5 MAX232:

The MAX232 is a dual driver/receiver that includes a capacitive voltage

generator to supply EIA-232 voltage levels from a single 5-V supply. Each receiver

converts EIA-232 inputs to 5-V TTL/CMOS levels. These receivers have a typical

threshold of 1.3 V and a typical hysteresis of 0.5 V, and can accept ±30-V inputs.


Campus Automation PROJECT REPORT ‘11 Each driver converts TTL/CMOS input levels into EIA-232 levels. The driver,

receiver, and voltage-generator functions are available as cells in the Texas

Instruments Lin ASIC library.

Meets or Exceeds TIA/EIA-232-F and ITU Recommendation V.28

Operates From a Single 5-V Power Supply With 1.0-_F Charge-Pump

Capacitors

Operates Up To 120 kbit/s

Two Drivers and Two Receivers

±30-V Input Levels

Low Supply Current . . . 8 mA Typical

ESD Protection Exceeds JESD 22

− 2000-V Human-Body Model (A114-A)

Upgrade With Improved ESD (15-kV HBM) and 0.1-_F Charge-Pump

Capacitors is Available With the MAX202

Applications

− TIA/EIA-232-F, Battery-Powered Systems, Terminals, Modems,

and Computers

5.5.1 PIN DIAGRAM



Fig 5.9

5.6 LCD Display

Liquid crystal display (LCD) is an electronically-modulated optical device shaped into a thin, flat panel made up of any number of color or monochrome pixels filled with liquid crystals and arrayed in front of a light source (backlight) or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power. Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, and two polarizing filters, the axes of transmission of which are (in most of the cases) perpendicular to each other. With no actual liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer.

The surfaces of the electrodes that arAPPENDIXAPPEe in contact with the liquid crystal material are treated so as to align the liquid crystal molecules in a particular direction. This treatment typically consists of a thin polymer layer that is unidirectional rubbed using, for example, a cloth. The direction of the liquid crystal alignment is then defined by the direction of rubbing. Electrodes are made of a transparent conductor called Indium Tin Oxide (ITO).

An LCD is a small low cost display. It is easy to interface with a micro-controller because of an embedded controller (the black blob on the back of the board). This controller is standard across many displays (HD 44780) which means many micro-controllers (including the Arduino) have libraries that make displaying messages as easy as a single line of code. An HD44780 Character LCD is a de facto industry standard liquid crystal display (LCD) display device designed for interfacing with embedded systems. These screens come in a variety of configurations including 8x1, which is one row of eight characters, 16x2, and 20x4. The most commonly manufactured configuration is 40x4 characters, which requires two individually addressable HD44780 controllers with expansion chips as the HD44780 can only address up to 80 characters. In this project we use 16x2 LCD display.

These LCD screens are limited to text only and are often used in copiers, fax machines, laser printers, industrial test equipment, networking equipment such as routers and storage devices. Character LCDs can come with or without backlights, which may be LED, fluorescent, or electroluminescent. Character LCDs use a standard 14-pin interface and those with backlights have 16 pins.

5.6.1 Font


Campus Automation PROJECT REPORT ‘11 The character generator ROM contains 208 characters in a 5x8 dot matrix, and 32 characters in a 5x10 dot matrix. There is a Japanese version of the ROM which includes kana characters, and a European version which includes Cyrillic and Western European characters. The 7-bit ASCII subset for the Japanese version is non-standard: it supplies a Yen symbol where the backslash character is normally found, and left and right arrow symbols in place of tilde and the rub-out character.

A limited number of custom characters can be programmed into the device in the form of a bitmap using special commands. These characters have to be written to the device each time it is switched on, as they are stored in volatile memory.

5.6.2 Features

The features of the LCD display are given below:

16 Characters x 2 Lines 5x7 Dot Matrix Character + Cursor HD44780 Equivalent LCD Controller/driver Built-In 4-bit or 8-bit MPU Interface Standard Type Works with almost any Microcontroller Great Value Pricing

5.6.3 Pin Diagram

The pin diagram & description of pins of 16x2 LCD display is given below:



Fig. 5.10

1. Ground

2. VCC (+3.3 to +5V)

3. Contrast adjustment (VO)

4. Register Select (RS). RS=0: Command, RS=1: Data

5. Read/Write (R/W). R/W=0: Write, R/W=1: Read

5.7 RS 232 Serial Port

In telecommunications, RS-232 (Recommended Standard 232) is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports.

RS232 is the most known serial port used in transmitting the data in communication and interface. Even though serial port is harder to program than the parallel port, this is the most effective method in which the data transmission requires less wires that yields to the less cost. The RS232 is the communication line which enables the data transmission by only using three wire links. The three links provides ‘transmit’, ‘receive’ and common ground. The ‘transmit’ and ‘receive’ line on this connecter send and receive data between the computers. As the name indicates, the data is transmitted serially. The two pins are TXD & RXD. There are other lines on this port as RTS, CTS, DSR, DTR, and RTS, RI. The ‘1’ and ‘0’ are the data which defines a voltage level of 3V to 25V and -3V to -25V respectively. The electrical characteristics of the serial port as per the EIA (Electronics Industry Association) RS232C Standard specify a maximum baud rate of 20,000bps.


Campus Automation PROJECT REPORT ‘11 In RS-232, user data is sent as a time-series of bits. Both synchronous and asynchronous transmissions are supported by the standard. In addition to the data circuits, the standard defines a number of control circuits used to manage the connection between the DTE and DCE. Each data or control circuit only operates in one direction that is, signaling from a DTE to the attached DCE or the reverse. Since transmit data and receive data are separate circuits, the interface can operate in a full duplex manner, supporting concurrent data flow in both directions. The standard does not define character framing within the data stream, or character encoding.

5.7.1 Pin out Diagram

Fig.5.11

5.8 Working

Our project mainly consists of two sections:

TRANSMITTER SECTION which is placed in office room

RECEIVER SECTION which is placed in class room



The transmitter section mainly consists of:

Message transmitting section Automatic bell Automatic Fan & light Controller

5.8.1 Notice Display System

The Message Transmitting section transmits messages wirelessly through ZigBee module & PIC. The data has to be transmitted is entered from PC to PIC through serial port connector or RS232 connector. The USART communication is used for transmitting data. The data is send as RS232 protocols.

The USART is universal synchronous asynchronous receiver transmitter. Its main function is to transmit or receive serial data. It can transfer a frame of data with 8 or 9 data bits per transmission. USART uses two I/O pins to transmit and receive data. The I/O pins of USART is connected to Tx and Rx pin of ZigBee module.In the receiver side a ZigBee module, a PIC and an LCD display are used.

Generally ZigBee devices are of three types

Coordinator Router End device

In the transmitter side the ZigBee module acts as a co-ordinator.In the receiver side it acts as both router and end device. Transmitter data is received by the ZigBee module and PIC in the receiver side. The received data is displayed on LCD by interfacing it with PIC.A buzzer is connected in the circuit to indicate the arrival of new message.

5.8.2 Automatic Fan & Light Controller

A PIR (Passive Infrared) sensor detects infrared light that is emitted from objects within its field of view. PIR sensors differ from other infrared sensors because they can only receive infrared waves. PIR sensor is pyroelectric


Campus Automation PROJECT REPORT ‘11 materials and usually contains lenses in order to focus the infrared light for maximum reception. As infrared light comes in contact with the pyroelectric material, which is Usually a thin sheet, it creates an electrical current that can be measured to determine the intensity of the infrared light and direction it came from.

5.8.3 Automatic college Bell

The automatic bell works based on the program that we have stored on

the PIC. It consists of a LCD display to show the clock .The Program sets in such

a way that the bell rings at the end of each hour between 9am and 4pm.



CHAPTER 6

SOFTWARE SECTION



6.1 FLOWCHART

6.1.1TRANSMITTER SECTION


START

Initialize LCD,TIMER

Set the time using switch

Initialize time hh=0,mm=0,ss=0

If ss>=3?

If (hh>=9) && (hh<=16)&&(mm=0)

Print “alarm” with beep

A



Print “clock” andDisplay the time

REAPEAT

STOP

A


6.1.2 Receiver section


START

LCD initialization

If message>= 16 bit ?

STOP

Display the message on 16*2 bit LCD module

Clear the screen


6.2 Firmware

6.2.1 Transmitter section

#include <string.h>

#include <lcd.c>

#include <stdio.h>

#include <stdlib.h>

unsigned int hh=00,ss=00,mm=00,count=1;

#int_TIMER1

void TIMER1_isr()

{

if(input(pin_a2))

{

output_bit(pin_b6,1);

}

else

{


}

if(count==1)

{

if(input(pin_a0))

{

hh++;

if(hh==24)

{

hh=0;

}

}

if(input(pin_a1))

{



mm++;

if(mm==60)

{

mm=0;

}

}

count=0;

lcd_gotoxy(5,2);

printf(lcd_putc,"%02u",hh);

lcd_gotoxy(7,2);

printf(lcd_putc,":%02u",mm);

lcd_gotoxy(10,2);

printf(lcd_putc,":%02u",ss);

ss=ss+1;

if(ss==60)

{

ss=0;

mm++;

if(mm==60)

{

mm=0;

hh++;

if(hh==24)

{

hh=0;

}

if((hh>=9)&&(hh<=16)&&(mm==0))

{

lcd_gotoxy(7,1);

printf(lcd_putc,"alarm");


ss=ss+3;



delay_ms(30);

lcd_putc('\f');

lcd_gotoxy(7,1);

printf(lcd_putc,"CLOCK");


}

}

}

}

count++;

set_timer1(0xfffe);

}

void main()

{

char f;

lcd_init();

lcd_gotoxy(7,1);

printf(lcd_putc,"CLOCK");

setup_timer_1(T1_INTERNAL|T1_DIV_BY_8);

enable_interrupts(GLOBAL);

enable_interrupts(INT_TIMER1);

while(1)

{

f=getc();

putc(f);

}

}



6.2.2 RECEIVER SECTION

#include “c:\documents and settings\pjt\desktop\campus\cam.h”

#include<lcd.c>

Void main()

{

Char c;

int i=0;

lcd_intit();

l1:while(1)

{

i++;

c=getc();

printf (lcd_putc,”%c”,c);

if(i==16)

{

lcd_putc(‘\f’);

lcd_goto(1,1);

i=0;

}

else

{

go to l1;

}

}

}



CHAPTER 7

SOFTWARE DESCRIPTION



7.1 COMPONENT PCB LAYOUT



7.2 PCB LAYOUT



CHAPTER 8

THEORY OF PROJECT



8.1 ZIGBEE

Creating wireless networks can be done using a variety of RF protocols.

Some protocols are proprietary to individual vendors, others are industry standards.

This Application Note will explore the ZigBee protocol industry standard for data

transmission, and the IEEE 802.15.4 protocol on which it was built. Here defined

are the frequencies used, the bandwidth it occupies, and networking features unique

to this protocol. ZigBee is a protocol that uses the 802.15.4 standard as a baseline

and adds additional routing and networking functionality. What ZigBee is designed

to do is add mesh networking to the underlying 802.15.4 radio. Mesh networking is

used in applications where the range between two points may be beyond the range

of the two radios located at those points, but intermediate radios are in place that

could forward on any messages to and from the desired radios

As an example, in the figure above suppose we wanted to transmit data from

point A to point B, but the distance was too great between the points. The message

could be transmitted through point C and a few other radios to reach the

destination.

Another feature of ZigBee is its ability to self-heal. If the radio at point C

was removed for some reason, a new path would be used to route messages from A

to B. Devices in the ZigBee specification can either be used as End Devices,

Routers or Coordinators. Routers can also be used as End Devices. Since the

ZigBee protocol uses the 802.15.4 standard to define the PHY and MAC layers, the

frequency, signal bandwidth and modulation techniques are identical.

802.15.4

802.15.4 is a standard for wireless communication put out by the IEEE

(Institute for Electrical and Electronics Engineers). IEEE has published the

standards that define communication in areas such as the Internet, PC peripherals,

industrial communication and wireless technology. As a few examples, the IEEE

802.11 standard defines communication for wireless LAN and 802.16 defines

communication for broadband wireless Metropolitan Area Networks. While both of

those wireless standards are concerned with higher bandwidth Internet access

applications, 802.15.4 was developed with lower data rate, simple connectivity and


Campus Automation PROJECT REPORT ‘11 battery application in mind.

The 802.15.4 standard specifies that communication can occur in the 868-

868.8MHz, the 902-928 MHz or the 2.400-2.4835 GHz Industrial Scientific and

Medical (ISM) bands. While any of these bands can technically be used by

802.15.4 devices, the 2.4 GHz band is more popular as it is open in most of the

countries worldwide.

8.2 HOW-TO SET UP XBEE ZNET 2.5 (SERIES 2) MODULES ?

Step 1: Construct the circuit

Fig (13): Construction of the XBee circuit

Build the XBee Breakout board and plug one of the XBee’s into it. Set up

the circuit on your bread board using the diagram. Instead of using a reset switch, I

just plug one end of a jumper wire into the XBee reset pin and leave the other end

of that jumper hanging off the edge of the board; when I need to reset the XBee, I

just momentarily touch the bare end of the jumper to ground.

Step 2: Power-up the XBee and prep the software

After double checking your connections, use the USB-miniB cable to plug

the FT232 Breakout into a USB port on your computer. Both LEDs connected to

the XBee should light up and stay on (assuming your XBee shipped as a

Router/End Device and there is no Coordinator around to connect to).


Campus Automation PROJECT REPORT ‘11 Step 3: Run X-CTU and connect to the XBee:

Run the X-CTU software. You should see a screen like the one shown

below. Make a Single-click on the USB COM port that the XBee is connected to. If

you’re not sure, you can click the “Test/Query” button to read each COM port to

discover which one has the XBee.

Fig (14): Run X-CTU and connect to the XBee

Step 4: Update the firmware

Click on the “Modem Configuration” tab and then click on the “Download

new versions…” button to download all of the updated firmwares. After the



Fig (15): Update the firmware

firmware downloads have completed, click on the “Read” button. The window will

display all of the current settings of the attached XBee. Select “ZNet 2.5

Router/End Device AT” as the firmware in the pull-down menu.You may want to

change the “PAN ID” to a unique number if you plan to use your XBee in a place

where others will be using their own XBees. Check the box that says “Always

update firmware” and click the “Write” button. The X-CTU software may ask you

to push the reset button during the firmware upgrade process.

Step 5: Test the XBee

Read through this step before you do it since once you enter command

mode, you’ll need to enter a new command within 5 seconds or the Xbee will exit

command mode and you’ll need to start this step again. Click on the terminal tab

and type “+++” in the window to enter command mode. The XBee should respond

in a second or two with “OK”. Type “ATVR” to check the firmware version on the

XBee. This should match the firmware version that you upgraded to (1241 for

Router/End Device or 1041 for Coordinator). Type “ATID” to check the PAN

Network ID that the XBee is using. It should respond with“123” or whatever

unique PAN ID you set in step 4. Type “ATNI” to check the Node Identifier.



Fig (16): Run X-CTU and connect to the XBee

The XBee should respond with “router1” or whatever unique Node

Identifier you set in step 4. Type “ATCN” to exit command mode. The XBee will

respond with “OK”. If those commands returned the correct information, then

congratulations, you’ve successfully updated this XBee! Quit the X-CTU program

and disconnect the USB-miniB cable from the computer. If any of those commands

did not return the correct information, click back to the “Modem Configuration”

tab, change the desired settings, and click the “Write” button again.

8.3 USART:

The USART protocol is used for serial interfacing between the PIC and the

PC.

A USART usually contains the following components:

a clock generator, usually a multiple of the bit rate to allow sampling in the

middle of a bit period.

input and output shift registers

transmit/receive control

read/write control logic

transmit/receive buffers (optional)

parallel data bus buffer (optional)

First-in, first-out (FIFO) buffer memory (optional)



8.4 RS232 PROTOCOL:

The MAX232 is a dual driver/receiver that includes a capacitive voltage

generator to supply EIA-232 voltage levels from a single 5-V supply. Each receiver

converts EIA-232 inputs to 5-V TTL/CMOS levels. These receivers have a typical

threshold of 1.3 V and a typical hysteresis of 0.5 V, and can accept ±30-V inputs.

Each driver converts TTL/CMOS input levels into EIA-232 levels. The driver,

receiver, and voltage-generator functions are available as cells in the Texas

Instruments Lin ASIC library.

Fig (17): Circuit diagram of MAX 232

Fig (18): GPS module

8.5 PCB FABRICATION DETAILS


Campus Automation PROJECT REPORT ‘11 The PCB must be fabricated first. Then the components are

soldered carefully to PCB. We should keep in mind that the quality of soldering

affects the quantity of output. The procedure for fabricating the PCB for setting up

the circuit of any multipurpose project is described below.

8.5.1 PCB MAKING

Making of the PRINTED CIRCUIT BOARD is as much as art on a technique

particularly when they are fabricated in very small numbers. There are several ways

of drawing PCB patterns and making the final boards. The making of PCB patterns

and the PCB involves two steps:

1. Preparing the PCB drawing

2. Fabricating the PCB itself from the drawing.

The traditional method of drawing the PCB with complete placements of

parts, taking a photographic negative of the drawing, developing the image of

negative formed on photo sensitized copper plate and dissolving the excess copper

by etching is a standard practice being followed in large scale operations. However,

for small scale operations, the cost saving procedure adopted here may be adopted.

8.5.2 PCB DRAWING

Making of PCB drawing involves some preliminary considerations such as

placement of components on a piece of paper. Locating holes, deciding the

diameter of various holes, the optimum area of each component should occupy the

shape and location lands for connecting two or more components at a particular

place. There is no other way to arrive at a conclusion than by trial and error. For

anchoring leads of component 1mm diameter holes and for fixing PCB holding

screws to the 3mm diameter holes can be made. Thus a sketch of the PCB is made.

8.5.3 FABRICATION:

The copper clad PCB is now prepared by rubbing away the oxide, grease, etc.

With fine emery paper or sand paper on this, the final PCB drawing may be traced

by using a carbon paper. Clips are used to prevent the carbon paper from slipping

while PCB pattern is being traced on the laminate. Only the connecting lines in


Campus Automation PROJECT REPORT ‘11 PCBs, slants and holes should be traced. The component position can be marked on

the PCB reverse side if desired.

The marked holes in PCB may be drilled using 1mm or 3mm drill bits and

the traced PCB pattern created with black, quick drying enamel paint, using a thin

brush or a small metal case. In case of any shorting of lines due to spilling of paint,

they may be removed by scraping with blade or knife after the paint has dried.

After drying, 20-30 gms of ferric chloride in 75 ml of water may be heated to

about 60 degrees and over the PCB placed with its copper side upwards in a plastic

tray. Stirring the solution helps speedy etching. The dissolution of unwanted

copper would take about 45 minutes. If etching takes longer, the solution may be

heated again and the process is repeated. The paint on the pattern can be removed

by rubbing with a rag soaked in a thinner, turpentine or acetone. The PCB may

then be washed and dried. Depending on the wiring diagram, the resistors are taken

care at first, and then the IC’s are soldered. 8.5.4 SOFTWARE DESCRIPTION

MPLAB IDE is a Windows Operating System (OS) software program that runs

on a PC to develop applications for Microchip microcontrollers and digital signal

controllers. It is called an Integrated Development Environment, or IDE, because it

provides a single integrated "environment" to develop code for embedded

microcontrollers. Experienced embedded systems designers may want to skip

ahead to Components of MPLAB IDE. It is also recommended that MPLAB IDE

On-line Help and MPLAB IDE Updates and Version Numbering be reviewed. The

rest of this chapter briefly explains embedded systems development and how

MPLAB IDE is used.

DESCRIPTION OF AN "EMBEDDED SYSTEM"

An embedded system is typically a design making use of the power of a

small microcontroller, like the Microchip PIC MCU or dsPIC Digital Signal



Controller (DSCs). These microcontrollers combine a microprocessor unit (like the

CPU in a desktop PC) with some additional circuits called "peripherals", plus some

additional circuits on the same chip to make a small control module requiring few

other external devices. This single device can then be embedded into other

electronic and mechanical devices for low-cost digital control.

8.5.5 DEVICE PROGRAMMING

CCS SOFTWARE:

CCS provides a complete, integrated tool suite for developing and debugging

embedded applications running on Microchip PIC® MCUs and dsPIC® DSCs. This

suite includes an IDE for project management, a context sensitive C aware editor,

build tools and real time debugger...helping developers create, analyze, debug and

document project code.

The heart of this development tool suite is the CCS intelligent code optimizing

C compiler, which frees developers to concentrate on design functionality instead of

having to become an MCU architecture expert.

Maximize code reuse by easily porting from one MCU to another.

Minimize lines of new code with CCS provided peripheral drivers, built-in

functions and standard C operators.

Built in libraries are specific to PIC® MCU registers, allowing access to

hardware features directly from C.



CHAPTER 9

ADVANTAGES AND LIMITATIONS



9.1 ADVANTAGES

The energy can be saved by the use of the automatic light and fan controller.

Periods can be maintained correctly by the use of automatic bell.

Hardware implementation is simpler.

9.2 LIMITATIONS

The message is displayed using LCD display is not clear, when the observer is

far away from the display.

The bell rings at the end of each hour. Complex programming is required to

change the time interval as predetermined rule.

ZigBee module is very costly.



CHAPTER 10

FUTURE EXPANSION OF PROJECT



10.1 FUTURE EXPANSION OF THE PROJECT

The future development of the device lies in the fact that it uses a microcontroller and that could be programmed in a variety of ways to utilize the available pin connections.

Message can also be transmitted to many transceiver modules simultaneously by using network topologies.

Also data can be transmitted to selected ZigBee modules by using addressing schemes.

The range of transmission and reception can be increased by using more routers.



CHAPTER 11

CONCLUSION



11.1CONCLUSION

The project “campus automation system” was concluded to be of a great innovation

for the improvement of day to day life. Data was transmitted from one transceiver

module to another module wirelessly. It helps to transmit and receive data through

ZigBee module. This device adds to range of applications for which ZigBee

communication is being utilized today.

It has the advantages of being a wireless device besides the simpler hardware

implementation is required.

The automatic fan and light controller section is very useful to save energy.

The automatic bell is very useful to maintain the periods accurately.



APPENDIX



Multiplexed Functions of 16F877A Pins

Analog input port (AN0 TO AN7) : these ports are used for interfacing analog inputs.

TX and RX: These are the USART transmission and reception ports. SCK: these pins are used for giving synchronous serial clock input. SCL: these pins act as an output for both SPI and I2C modes. DT: these are synchronous data terminals. CK: synchronous clock input. SD0: SPI data output (SPI Mode). SD1: SPI Data input (SPI mode). SDA: data input/output in I2C Mode. CCP1 and CCP2: these are capture/compare/PWM modules. OSC1: oscillator input/external clock. OSC2: oscillator output/clock out. MCLR: master clear pin (Active low reset). Vpp: programming voltage input. THV: High voltage test mode controlling. Vref (+/-): reference voltage. SS: Slave select for the synchronous serial port. T0CK1: clock input to TIMER 0. T1OSO: Timer 1 oscillator output. T1OS1: Timer 1 oscillator input. T1CK1: clock input to Timer 1. PGD: Serial programming data. PGC: serial programming clock. PGM: Low Voltage Programming input. INT: external interrupt. RD: Read control for parallel slave port. CS: Select control for parallel slave. PSP0 to PSP7: Parallel slave port. VDD: positive supply for logic and input pins. VSS: Ground reference for logic and input/output pins.

DATA SHEET



ZIGBEE MODULE



Pin Details of RS 232



D-Type-9 pin no.

D-Type-25pin no.

Pin outs

Functions

3 2 RD Receive Data (Serial data input)2 3 TD Transmit Data (Serial data output)7 4 RTS Request to send (acknowledge to modem that

UART is ready to exchange data8 5 CTS Clear to send (i.e.; modem is ready to exchange

data)6 6 DSR Data ready state (UART establishes a link)5 7 SG Signal ground1 8 DCD Data Carrier detect (This line is active when

modem detects a carrier4 20 DTR Data Terminal Ready.9 22 RI Ring Indicator (Becomes active when modem

detects ringing signal from PSTN



COST ESTIMATION

ITEMS COST.Rs

Microcontroller IC-PIC 260

Zigbee 3500

PIR 550

LCD 260

PCB 800 MAX 232 IC 70

Serial port 70

Buzzer 60

IC socket 10 Crystal oscillator 10

Program coding 300

Basic components 340

TOTAL Rs: 6500 approx


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