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SMOKE DETECTOR WITH ALARM

1. INTRODUCTION

1.1 A BOUT FIRE DETECTION SYSTEMS:

There are many concerns in automatic fire detection, of which the most important ones are

about different sensor combinations and appropriate techniques for quick and noise-tolerant fire

detection. Researchers have been studying fires taking place in various places such as residential

area (Milke and McAvoy 1995), forest (Yu, Wang et al. 2005; Bagheri 2007) and mines (Tan,

Wang et al. 2007) to find some solutions for fire monitoring.

An important issue in automatic fire detection is separation of fire sources from noise

sources. For the residential fires, being flaming or non-flaming (smoldering smoke fires), the

general trend is to focus either on the sensor and sensor combinations or detection techniques. In

another word, researchers have focused either on identifying the best set of sensors which

collaboratively can detect fire using simple techniques (Milke and McAvoy 1995; Milke 1999;

Cestari, Worrell et al. 2005) or on designing complex detection techniques that use single or at best

very small set of simple sensors (Okayama 1991; Thuillard 2000).

Several decades of forestry research have resulted in many advances in field of forest fire

monitoring. The Fire Weather Index (FWI) system being developed by the Canadian Forest Service

(CFS; Bagheri 2007) and the National Fire Danger Rating System (NFDRS) introduced by the

National Oceanic and Atmospheric Administration (NOAA; Yu, Wang et al. 2005) are two

examples of such advances. Studying the state-of-the-art techniques reveals two main trends in fire

detection, i.e., existing techniques have either considered fire detection as an application of a certain

field (e.g., event detection for wireless sensor networks) or the main concern for which techniques

have been specifically designed (e.g., fire detection using remote sensing techniques).

The use of early warning fire and smoke detection systems results in significant reduction in

fire deaths. The sooner a fire is detected, the better the outcome for saving lives. This document

provides guidance for the proper operation of fire detection systems for those who apply, install,

and maintain them. Correct installation and maintenance of smoke detectors prevents unwanted

nuisance alarms. Occupants can become desensitized when repeated nuisance alarms occur. In

worst case scenarios, technicians could disconnect alarms from the system to avoid the unnecessary

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disruption. Either situation negates a detectors potential life saving benefit, making the proper

operation of an early warning fire and smoke detection system indispensable.

The purpose of this guide is to provide information concerning the proper application of

smoke detectors used in conjunction with fire alarm systems. The guide outlines basic principles

that should be considered in the application of early warning fire and smoke detection devices. It

presents operating characteristics of detectors and environmental factors, which may aid, delay, or

prevent their operation.

This document presents information for fire protection, mechanical, and electrical engineers;

fire service personnel, fire alarm designers; and installers. A key element in the effectiveness of

smoke detection systems is the latest version of NFPA 72 for installation and testing of systems.

Installation must comply with all code requirements and directions from Authorities Having

Jurisdiction (AHJs). AHJ directives always take precedence over other codes and exercise final

authority over installations and maintenance procedures.

1.2 BLOCK DIAGRAM:

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Figure 1.2 BLOCK DIAGRAM

2. MICRO CONTROLLER

3

AT89S52

Micro-controller

fan

Power supply

Unit

Driver unit

buzzer

LCD

ADC

Smoke

Sensor

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2.1 A BRIEF HISTORY OF 8051:

In 1981, Intel Corporation introduced an 8 bit microcontroller called 8051. This

microcontroller had 128 bytes of RAM, 4K bytes of chip ROM, two timers, one serial port, and four

ports all on a single chip. At the time it was also referred as A SYSTEM ON A CHIP

The 8051 is an 8-bit processor meaning that the CPU can work only on 8 bits data at

a time. Data larger than 8 bits has to be broken into 8 bits pieces to be processed by the CPU. The

8051 has a total of four I\O ports each 8 bit wide.

There are many versions of 8051 with different speeds and amount of on-chip ROM and

they are all compatible with the original 8051. This means that if you write a program for one it will

run on any of them.

The 8051 is an original member of the 8051 family. There are two other members in the

Family of 8051 microcontrollers. They are 8052 and 8031. All the three microcontrollers will have

the same internal architecture, but they differ in the following aspects.

8031 has 128 bytes of RAM, two timers and 6 interrupts.

8051 has 4K ROM, 128 bytes of RAM, two timers and 6 interrupts.

8052 has 8K ROM, 256 bytes of RAM, three timers and 8 interrupts.

Of the three microcontrollers, 8051 is the most preferable. Microcontroller supports both serial and

parallel communication.

In the concerned project 8052 microcontroller is used. Here microcontroller used is AT89S52,

which is manufactured by ATMEL laboratories.

2.2 NECESSITY OF MICROCONTROLLERS:

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Microprocessors brought the concept of programmable devices and made many

applications of intelligent equipment. Most applications, which do not need large amount of data

and program memory, tended to be costly.

The microprocessor system had to satisfy the data and program requirements so; sufficient

RAM and ROM are used to satisfy most applications .The peripheral control equipment also had to

be satisfied. Therefore, almost all-peripheral chips were used in the design. Because of these

additional peripherals cost will be comparatively high.

(a) An example:

8085 chip needs:

An Address latch enable is for separating address from multiplex address and data.32-KB RAM

and 32-KB ROM to be able to satisfy most applications. As also Timer / Counter, Parallel

programmable port, Serial port, and Interrupt controller are needed for its efficient applications.

In comparison a typical Micro controller 8051 chip has all that the 8051 board has except a

reduced memory as follows.

4K bytes of ROM as compared to 32-KB, 128 Bytes of RAM as compared to 32-KB.

Bulky:

On comparing a board with full of chips (Microprocessors), one chip with all components in

it (Microcontroller).

Debugging:

Lots of Microprocessor needs circuitry and program to debug. In Micro controller there is

no Microprocessor circuitry to debug.

Slower Development time:

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As we have observed Microprocessors need a lot of debugging at board level and at program level,

whereas, Micro controller do not have the excessive circuitry and the built-in peripheral chips are

easier to program for operation.

So peripheral devices like Timer/Counter, Parallel programmable port, Serial Communication Port,

Interrupt controller and so on, which were most often used were integrated with the Microprocessor

to present the Micro controller .RAM and ROM also were integrated in the same chip. The ROM

size was anything from 256 bytes to 32Kb or more. RAM was optimized to minimum of 64 bytes to

256 bytes or more.

Microprocessor has following instructions to perform:

1. Reading instructions or data from program memory ROM.

2. Interpreting the instruction and executing it.

3. Microprocessor Program is a collection of instructions stored in a Nonvolatile memory.

4. Read Data from I/O device

5. Process the input read, as per the instructions read in program memory.

6. Read or write data to Data memory.

7. Write data to I/O device and output the result of processing to O/P device.

2.3 Introduction to AT89S52:

The system requirements and control specifications clearly rule out the use of 16, 32 or 64 bit

micro controllers or microprocessors. Systems using these may be earlier to implement due to large

number of internal features. They are also faster and more reliable but, the above application is

satisfactorily served by 8-bit micro controller. Using an inexpensive 8-bit Microcontroller will

doom the 32-bit product failure in any competitive market place. Coming to the question of why to

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use 89S52 of all the 8-bit Microcontroller available in the market the main answer would be

because it has 8kB Flash and 256 bytes of data RAM32 I/O lines, three 16-bit timer/counters, a

Eight-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 hardware reset. The Flash program memory supports both parallel programming and in Serial

In-System Programming (ISP). The 89S52 is also In-Application Programmable (IAP), allowing the

Flash program memory to be reconfigured even while the application is running.

By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89S52 is a

powerful microcomputer which provides a highly flexible and cost effective solution to many

embedded control applications.

2.4 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

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

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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

2.5 PIN DIAGRAM:

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Fig 2.1 PIN DIAGRAM OF 89S52 IC

2.6 PIN DESCRIPTION:

Pin Description

VCC: Supply voltage.

GND: Ground.

Port 0

Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink

eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high- impedance

inputs. Port 0 can also be configured to be the multiplexed low- order address/data bus during

accesses to external pro-gram and data memory. In this mode, P0 has internal pull-ups

Port 0 also receives the code bytes during Flash programming and outputs the c o de bytes

during program m verification. External pull-ups are required during program verification.

Port 1

Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1 output buffers can

sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal

pull-ups 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 pull-ups. 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

Port 2




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source current (IIL) because of the internal pull-ups. Port 2 emits the high-order address byte during

fetches from external program memory and during accesses to external data memory that uses 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 uses 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




source current (IIL) because of the pull-ups. Port 3 also serves the functions of various special

features of the AT89C51, as shown in the following table.

Port 3 also receives some control signals for Flash programming and verification

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

P3.6 WR (external data memory write strobe)

P3.7 RD (external data memory read strobe)

Table-2.2 Port3

RST

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

device.

ALE/PROG

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Address Latch Enable 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 Note, however, that one ALE pulse is skipped during each

access to external data memory. If desired, ALE operation can be disabled by setting 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.

2.7 Internal Block diagram:

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Fig 2.2 AT89C51 internal block diagram

The 8052 Oscillator and Clock:

The heart of the 8051 circuitry that generates the clock pulses by which all the internal all

internal operations are synchronized. Pins XTAL1 and XTAL2 is provided for connecting a

resonant network to form an oscillator. Typically a quartz crystal and capacitors are employed. The

crystal frequency is the basic internal clock frequency of the microcontroller. The manufacturers

make 8051 designs that run at specific minimum and maximum frequencies typically 1 to 16 MHz

Fig-2.3 Oscillator and timing circuit

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2.8 MEMORIES:

Types of memory:

The 8052 have three general types of memory. They are on-chip memory, external Code memory

and external Ram. On-Chip memory refers to physically existing memory on the micro controller

itself. External code memory is the code memory that resides off chip. This is often in the form of

an external EPROM. External RAM is the Ram that resides off chip. This often is in the form of

standard static RAM or flash RAM.

a)Code memory

Code memory is the memory that holds the actual 8052 programs that is to be run. This memory is

limited to 64K. Code memory may be found on-chip or off-chip. It is possible to have 8K of code

memory on-chip and 60K off chip memory simultaneously. If only off-chip memory is available

then there can be 64K of off chip ROM. This is controlled by pin provided as EA

b)Internal RAM

The 8052 have a bank of 256 bytes of internal RAM. The internal RAM is found on-chip.

So it is the fastest Ram available. And also it is most flexible in terms of reading and writing.

Internal Ram is volatile, so when 8051 is reset, this memory is cleared. 256 bytes of internal

memory are subdivided. The first 32 bytes are divided into 4 register banks. Each bank contains 8

registers. Internal RAM also contains 256 bits, which are addressed from 20h to 2Fh. These bits are

bit addressed i.e. each individual bit of a byte can be addressed by the user. They are numbered 00h

to FFh. The user may make use of these variables with commands such as SETB and CLR.

Special Function registered memory:

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Special function registers are the areas of memory from the memory location indicated by

SP and then decrements the value of SP.

d) Data pointer

The SFRs DPL and DPH work together work together to represent a 16-bit value called the data

pointer. The data pointer is used in operations regarding external RAM and some instructions code

memory. It is a 16-bit SFR and also an addressable SFR.

e) Program counter

The program counter is a 16 bit register, which contains the 2 byte address, which tells the 8052

where the next instruction to execute to be found in memory. When the 8052 is initialized PC starts

at 0000h. And is incremented each time an instruction is executes. It is not addressable SFR.

f) PCON (power control, 87h)

The power control SFR is used to control the 8051s power control modes. Certain

operation modes of the 8051 allow the 8051 to go into a type of sleep mode which consumes

much lee power.

g) TCON (timer control, 88h)

The timer control SFR is used to configure and modify the way in which the 8051s two timers

operate. This SFR controls whether each of the two timers is running or stopped and contains a flag

to indicate that each timer has overflowed. Additionally, some non-timer related bits are located in

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TCON SFR. These bits are used to configure the way in which the external interrupt flags are

activated, which are set when an external interrupt occurs.

h) TMOD (Timer Mode, 89h)

The timer mode SFR is used to configure the mode of operation of each of the two timers. Using

this SFR your program may configure each timer to be a 16-bit timer, or 13 bit timer, 8-bit auto

reload timer, or two separate timers. Additionally you may configure the timers to only count whenan external pin is activated or to count events that are indicated on an external pin.

i) TO (Timer 0 low/high, address 8A/8C h)

These two SFRs taken together represent timer 0. Their exact behavior depends on how the

timer is configured in the TMOD SFR; however, these timers always count up. What is

configurable is how and when they increment in value.

j) T1 (Timer 1 Low/High, address 8B/ 8D h)

These two SFRs, taken together, represent timer 1. Their exact behavior depends on how the

timer is configured in the TMOD SFR; however, these timers always count up.

k) P0 (Port 0, address 90h, bit addressable)

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This is port 0 latch. Each bit of this SFR corresponds to one of the pins on a micro controller. Any

data to be outputted to port 0 is first written on P0 register. For e.g., bit 0 of port 0 is pin P0.0, bit 7

is pin p0.7. Writing a value of 1 to a bit of this SFR will send a high level on the corresponding I/O

pin whereas a value of 0 will bring it to low level.

l) P1 (port 1, address 90h, bit addressable)

This is port latch1. Each bit of this SFR corresponds to one of the pins on a micro controller.

Any data to be outputted to port 0 is first written on P0 register. For e.g., bit 0 of port 0 is pin P1.0,

bit 7 is pin P1.7. Writing a value of 1 to a bit of this SFR will send a high level on the

corresponding I/O pin whereas a value of 0 will bring it to low level

m) P2 (port 2, address 0A0h, bit addressable):

This is a port latch2. Each bit of this SFR corresponds to one of the pins on a micro controller. Any

data to be outputted to port 0 is first written on P0 register. For e.g., bit 0 of port 0 is pin P2.0, bit 7

is pin P2.7. Writing a value of 1 to a bit of this SFR will send a high level on the corresponding I/O

pin whereas a value of 0 will bring it to low level.

n) P3 (port 3, address B0h, bit addressable):

This is a port latch3. Each bit of this SFR corresponds to one of the pins on a micro

controller. Any data to be outputted to port 0 is first written on P0 register. For e.g., bit 0 of port 0 is

pin P3.0, bit 7 is pin P3.7. Writing a value of 1 to a bit of this SFR will send a high level on the

corresponding I/O pin whereas a value of 0 will bring it to low level.

o) IE (interrupt enable, 0A8h):

The Interrupt Enable SFR is used to enable and disable specific interrupts. The low 7 bits of

the SFR are used to enable/disable the specific interrupts, where the MSB bit is used to enable or

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disable all the interrupts. Thus, if the high bit of IE is 0 all interrupts are disabled regardless of

whether an individual interrupt is enabled by setting a lower bit.

p) IP (Interrupt Priority, 0B8h)

The interrupt priority SFR is used to specify the relative priority of each interrupt. On 8051,

an interrupt may be either low or high priority. An interrupt may interrupt interrupts. For e.g., if we

configure all interrupts as low priority other than serial interrupt. The serial interrupt alwaysinterrupts the system, even if another interrupt is currently executing. However, if a serial interrupt

is executing no other interrupt will be able to interrupt the serial interrupt routine since the serial

interrupt routine has the highest priority.

q) PSW (Program Status Word, 0D0h)

The program Status Word is used to store a number of important bits that are set and cleared

by 8052 instructions. The PSW SFR contains the carry flag, the auxiliary carry flag, the parity flag

and the overflow flag. Additionally, it also contains the register bank select flags, which are used to

select, which of the R register banks currently in use.

r) SBUF (Serial Buffer, 99h)

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SBUF is used to hold data in serial communication. It is physically two registers. One is

writing only and is used to hold data to be transmitted out of 8052 via TXD. The other is read only

and holds received data from external sources via RXD. Both mutually exclusive registers use

address 99h.

I/O ports:

One major feature of a microcontroller is the versatility built into the input/output (I/O)

circuits that connect the 8052 to the outside world. The main constraint that limits numerous

functions is the number of pins available in the 8051 circuit. The DIP had 40 pins and the success of

the design depends on the flexibility incorporated into use of these pins. For this reason, 24 of the

pins may each used for one of the two entirely different functions which depend, first, on what is

physically connected to it and, then, on what software programs are used to program the pins.

PORT 0

Port 0 pins may serve as inputs, outputs, or, when used together, as a bi directional low-order

address and data bus for external memory. To configure a pin as input, 1 must be written into the

corresponding port 0 latch by the program. When used for interfacing with the external memory, the

lower byte of address is first sent via PORT0, latched using Address latch enable (ALE) pulse and

then the bus is turned around to become the data bus for external memory.

PORT 1

Port 1 is exclusively used for input/output operations. PORTS 1 pin have no dual function.

When a pin is to be configured as input, 1 is to be written into the corresponding Port 1 latch.

PORT 2

Port 2 may be used as an input/output port. It may also be used to supply a high order address

byte in conjunction with Port 0 low-order byte to address external memory. Port 2 pins are

momentarily changed by the address control signals when supplying the high byte a 16-bit address.

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Port 2 latches remain stable when external memory is addressed, as they do not have to be turned

around (set to 1) for data input as in the case for Port 0.

PORT 3

Port 3 may be used to input /output port. The input and output functions can be programmed

under the control of the P3 latches or under the control of various special function registers. Unlike

Port 0 and Port 2, which can have external addressing functions and change all eight-port b se, each

pin of port 3 maybe individually programmed to be used as I/O or as one of the alternate functions.

The Port 3 alternate uses are:

Table-2.3 Port3 uses

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Pin (SFR) Alternate Use

P3.0-RXD (SBUF) Serial data input

P3.1-TXD (SBUF) Serial data output

P3.2-INTO 0 (TCON.1) External interrupt 0

P3.3 - INTO 1 (TCON.3) External interrupt 1

P3.4 - T0 (TMOD) External Timer 0 input

P3.5 T1 (TMOD) External timer 1 input

P3.6 - WR External memory write pulse

P3.7 - RD External memory read pulse

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2.9 INTERRUPTS:

The AT89S52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three

timers interrupts (Timers0, 1, and 2), and the serial port interrupt. These interrupts are all shown in

Figure 10. Each of these interrupt sources can be individually enabled or disabled by setting or

clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, which

disables all interrupts at once. Note that Table 5 shows that bit position IE.6 is unimplemented. 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.

Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register 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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3. POWER SUPPLY

3.1 INTRODUCTION:

There are many types of power supply. Most are designed to convert high voltage AC mains

electricity to a suitable low voltage supply for electronic circuits and other devices. A power supply

can by broken down into a series of blocks, each of which performs a particular function. For

example a 5V regulated supply can be shown as below

Fig 3.1: Block Diagram of a Regulated Power Supply System

Similarly, 12v regulated supply can also be produced by suitable selection of the individual

elements. Each of the blocks is described in detail below and the power supplies made from these

blocks are described below with a circuit diagram and a graph of their output:

3.2 Transformer:

A transformer steps down high voltage AC mains to low voltage AC. Here we are using a center-tap

transformer whose output will be sinusoidal with 36volts peak to peak value.

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The low voltage AC output is suitable for lamps, heaters and special AC motors. It is not suitable

for electronic circuits unless they include a rectifier and a smoothing capacitor. The transformer

output is given to the rectifier circuit.

3.3 Rectifier:

A rectifier converts AC to DC, but the DC output is varying. There are several types of rectifiers;

here we use a bridge rectifier.

The Bridge rectifier is a circuit, which converts an ac voltage to dc voltage using both half

cycles of the input ac voltage. The Bridge rectifier circuit is shown in the figure. The circuit has

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four diodes connected to form a bridge. The ac input voltage is applied to the diagonally opposite

ends of the bridge. The load resistance is connected between the other two ends of the bridge.

For the positive half cycle of the input ac voltage, diodes D1 and D3 conduct, whereas diodes D2

and D4 remain in the OFF state. The conducting diodes will be in series with the load resistance RL

and hence the load current flows through RL.

For the negative half cycle of the input ac voltage, diodes D2 and D4 conduct whereas, D1

and D3 remain OFF. The conducting diodes D2 and D4 will be in series with the load resistance RL

and hence the current flows through RL in the same direction as in the previous half cycle. Thus a

bi-directional wave is converted into unidirectional.

Figure 3.3 Rectifier circuit

Now the output of the rectifier shown in Figure 3.3 is shown below in Figure 3.4

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Fig-3.4 Output of the Rectifier

The varying DC output is suitable for lamps, heaters and standard motors. It is not suitable

for lamps, heaters and standard motors. It is not suitable for electronic circuits unless they include a

smoothing capacitor.

3.5 Smoothing:

The smoothing block smoothes the DC from varying greatly to a small ripple and the ripple voltage

is defined as the deviation of the load voltage from its DC value. Smoothing is also named as

filtering.

Filtering is frequently effected by shunting the load with a capacitor. The action of this system

depends on the fact that the capacitor stores energy during the conduction period and delivers this

energy to the loads during the no conducting period. In this way, the time during which the current

passes through the load is prolonging Ted, and the ripple is considerably decreased. The action of

the capacitor is shown with the help of waveform.

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Fig-3.5 Smoothing action of capacitor

Fig-3.6 Waveform of the rectified output smoothing

3.7 Regulator:

Regulator eliminates ripple by setting DC output to a fixed voltage. Voltage regulator ICs are

available with fixed (typically 5V, 12V and 15V) or variable output voltages. Negative voltage

regulators are also available

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Many of the fixed voltage regulator ICs has 3 leads (input, output and high impedance). They

include a hole for attaching a heat sink if necessary. Zener diode is an example of fixed regulator

which is shown here.

Fig 3.7 Regulator

Transformer + Rectifier + Smoothing + Regulator:

Fig-3.8 Power Supply

4. BUZZER

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4.1 INTRODUCTION:

A buzzer orbeeper is a signaling device, usually electronic, typically used in automobiles,

household appliances such as a microwave ovens, & game shows.

The word "buzzer" comes from the rasping noise that buzzers made when they were

electromechanical devices, operated from stepped-down AC line voltage at 50 or 60 cycles. Other

sounds commonly used to indicate that a button has been pressed are a ring or a beep.

4.1 Fig Buzzers

4.2 PRINCIPLE:

Basically, the sound source of a piezoelectric sound component is a piezoelectric

diaphragm. A piezoelectric diaphragm consists of a piezoelectric ceramic plate which has electrodeson both sides and a metal plate (brass or stainless steel, etc.).

A piezoelectric ceramic plate is attached to a metal plate with adhesives. Applying D.C.

voltage between electrodes of a piezoelectric diaphragm causes mechanical distortion due to the

piezoelectric effect. For a misshaped piezoelectric element, the distortion of the piezoelectric

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element expands in a radial direction. And the piezoelectric diaphragm bends toward the direction.

The metal plate bonded to the piezoelectric element does not expand. Conversely, when the

piezoelectric element shrinks, the piezoelectric diaphragm bends in the direction Thus, when AC

voltage is applied across electrodes, the bending is repeated and produces the sound waves in the

air.

Mainly it consists of a number of switches or sensors connected to a control unit that determines if

and which button was pushed or a preset time has lapsed, and usually illuminates a light on the

appropriate button or control panel, and sounds a warning in the form of a continuous or

intermittent buzzing or beeping sound.

Initially this device was based on an electromechanical system which was identical to an

electric bell without the metal gong (which makes the ringing noise). Often these units were

anchored to a wall or ceiling and used the ceiling or wall as a sounding board. Another

implementation with some AC-connected devices was to implement a circuit to make the AC

current into a noise loud enough to drive a loudspeaker and hook this circuit up to a cheap 8-ohm

speaker.

Nowadays, it is more popular to use a ceramic-based piezoelectric sounder like a Sonalert

which makes a high-pitched tone. Usually these were hooked up to "driver" circuits which varied

the pitch of the sound or triggered the sound ON and OFF. In game shows it is also known as a

"lockout system," because when one person signals ("buzzes in"), all others are locked out from

signaling. Several game shows have large buzzer buttons which are identified as "plungers".

In this project the Buzzer is used to alert the user. The user is alerted in the conditions such

as start of the system, an unhealthy condition being prevailed which is needed to be avoided, the

card inserted is not valid.

5. ADC 0808

5.1 DESCRIPTION:

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The ADC0808, ADC0808 data acquisition component is a monolithic CMOS device with

an 8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor compatible control

logic. The 8-bit A/D converter uses successive approximation as the conversion technique. The

converter features a high impedance chopper stabilized comparator, a 256R voltage divider with

analog switch tree and a successive approximation register. The 8-channel multiplexer can directly

access any of 8-single-ended analog signals.

The device eliminates the need for external zero and full-scale adjustments. Easy interfacing

to microprocessors is provided by the latched and decoded multiplexer address inputs and latched

TTL TRI-STATE outputs.

The design of the ADC0808 has been optimized by incorporating the most desirable aspects

of several A/D conversion techniques. The ADC0808, ADC0809 offers high speed, high accuracy,

minimal temperature dependence, excellent long-term accuracy and repeatability, and consumes

minimal power. These features make this device ideally suited to applications from process and

machine control to consumer and automotive applications.

5.2 FEATURES:

Easy interface to all microprocessors

Operates ratiometrically or with 5 VDC or analog span adjusted voltage reference

No zero or full-scale adjust required

8-channel multiplexer with address logic

0V to VCC input range

Outputs meet TTL voltage level specifications

ADC0808 equivalent to MM74C949

5.3 PIN DIAGRAM:

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Fig 5.3 Pin diagram of ADC0808 IC

6. LCD

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Fig 6 LCD diagramLCDs can add a lot to your application in terms of providing an useful interface for the user,

debugging an application or just giving it a "professional" look. The most common type of LCD

controller is the Hitachi 44780, which provides a relatively simple interface between a processor

and an LCD. Inexperienced designers do often not attempt using this interface and programmers

because it is difficult to find good documentation on the interface, initializing the interface can be a

problem and the displays themselves are expensive.

Table.6 LCD Pin Discription

7. MOSFET IRF 540

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Pins Description

1 Ground

2 Vcc

3 Contrast Voltage

4 "R/S" _Instruction/Register Select

5 "R/W" _Read/Write LCD Registers

6 "E" Clock

7 - 14 Data I/O Pins

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This device is a Robust device which can be used for Variety of applications where high

speed switching and high current is the requirement.

7.1 APPLICATIONS:

High Current, High Speedswitching

Solenoid and relay drivers

AC-DC & DC-AC Converter

Auto Motive Environment (Injection)

7.2 DESCRIPTION:

MOSFET, IRF540

Continuous Drain Current Id:27A

Drain Source Voltage Vds:100V

No. of Pins:3

On Resistance Rds(on):70mohm

Transistor Case Style:TO-220

Transistor Polarity:N Channel

Device Marking:IRF540

Package / Case:TO-220

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Fig 7.2 Mosfet IRF 540

a common type of transistor in which charge carriers, such as electrons, flow along channels. The

width of the channel, which determines how well the device conducts, is controlled by an electrode

called the gate, separated from channel by a thin layer of oxide insulation. The insulation keeps

current from flowing between the gate and channel.

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8. 555 TIMER IC

The 555 timer IC is an integrated circuit (chip) used in a variety oftimer, pulse generation

and oscillatorapplications. The IC design was proposed in 1970 by Hans R. Camenzind and Jim

Ball. After prototyping, the design was ported to the Monochip analogue array, incorporating

detailed design by Wayne Foletta and others from Qualidyne Semiconductors. Signetics (later

acquired by Philips) took over the design and production, and released the first 555s in 1971. The

full part numbers were NE555 (commercial temperature range, 0 C to +70 C) and SE555 (military

temperature range, 55 C to +125 C).

As with most parts of the era, These were available in both high-reliability metal can (T

package) and inexpensive epoxy plastic (V package) packages. Thus the full part numbers were

NE555V, NE555T, SE555V, and SE555T. It has been hypothesized that the 555 got its name from

the three 5 k resistors used within,[1] but Hans Camenzind has stated that the number was

arbitrary.[2]The part is still in widespread use, thanks to its ease of use, low price and good stability.

As of 2003, it is estimated that 1 billion units are manufactured every year.[2] The circuit

arrangement of the 555 is said to be even more common, being incorporated in the charge pump of

many single-voltage Flash and other electrically-erasable ICs

Fig 8 555 Timer

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http://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Timerhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/1970http://en.wikipedia.org/wiki/Hans_R._Camenzindhttp://en.wikipedia.org/wiki/Signeticshttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/1971http://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/555_timer_IC#cite_note-0http://en.wikipedia.org/wiki/555_timer_IC#cite_note-0http://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1http://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1http://en.wikipedia.org/wiki/1000000000_(number)http://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1http://en.wikipedia.org/wiki/Charge_pumphttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Timerhttp://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/1970http://en.wikipedia.org/wiki/Hans_R._Camenzindhttp://en.wikipedia.org/wiki/Signeticshttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/1971http://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/555_timer_IC#cite_note-0http://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1http://en.wikipedia.org/wiki/1000000000_(number)http://en.wikipedia.org/wiki/555_timer_IC#cite_note-semiconductormuseum.com-1http://en.wikipedia.org/wiki/Charge_pumphttp://en.wikipedia.org/wiki/Flash_memory

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9. DC FANS

9.1 Introduction:

9.1 DC Fan

A fan is a machine used to create flow within a fluid, typically a gas such as air. A fan consists of a

rotating arrangement of vanes or blades which act on the air. Usually, it is contained within some

form of housing or case. This may direct the airflow or increase safety by preventing objects fromcontacting the fan blades. Most fans are powered by electric motors, but other sources of power

may be used, including hydraulic motors and internal combustion engines and solar power. Fans

produce air flows with high volume and low pressure, as opposed to compressors which produce

high pressures at a comparatively low volume. A fan blade will often rotate when exposed to an air

stream, and devices that take advantage of this, such as anemometers and wind turbines, often have

designs similar to that of a fan.

9.2 TYPES OF FANS :

Mechanical revolving blade fans are made in a wide range of designs. In a home you can find fans

that can be put on the floor or a table, or hung from the ceiling, or are built into a window, wall,

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http://en.wikipedia.org/wiki/Machinehttp://en.wikipedia.org/wiki/Fluidhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Hydraulicshttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Gas_compressorhttp://en.wikipedia.org/wiki/Anemometerhttp://en.wikipedia.org/wiki/Wind_turbinehttp://en.wikipedia.org/wiki/Window_fanhttp://en.wikipedia.org/wiki/Machinehttp://en.wikipedia.org/wiki/Fluidhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Hydraulicshttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Gas_compressorhttp://en.wikipedia.org/wiki/Anemometerhttp://en.wikipedia.org/wiki/Wind_turbinehttp://en.wikipedia.org/wiki/Window_fan

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roof, chimney, etc. They can be found in electronic systems such as computers where they cool the

circuits inside, and in appliances such as hair dryers and space heaters. They are also used for

moving air in air-conditioning systems, and in automotive engines, where they are driven by belts

or by direct motor. Fans used for comfort create a wind chill, but do not lower temperatures

directly. Fans used to cool electrical equipment or in engines or other machines do cool the

equipment directly by forcing hot air into the cooler environment outside of the machine.

There are three main types of fans used

moving air, axial

centrifugal (also called radial)

cross flow (also called tangential)

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10. SENSOR.

This article includes a list of references, but its sources remain unclear because it hasinsufficient

inline citations.

Fig 10.1 Smoke Sensor

A sensor is a device that measures a physical quantity and converts it into a signal which

can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer

converts the measured temperature into expansion and contraction of a liquid which can be read on

a calibrated glass tube. Athermocouple converts temperature to an output voltage which can be read

by a voltmeter. For accuracy, most sensors are calibrated against known standards.

10.2 USES:

Sensors are used in everyday objects such as touch-sensitive elevator buttons ( tactile sensor) and

lamps which dim or brighten by touching the base. There are also innumerable applications for

sensors of which most people are never aware. Applications include cars, machines, aerospace,

medicine, manufacturing and robotics.

A sensor is a device which receives and responds to a signal. A sensor's sensitivity indicates how

much the sensor's output changes when the measured quantity changes. For instance, if the mercury

in a thermometer moves 1 cm when the temperature changes by 1 C, the sensitivity is 1 cm/C (it

is basically the slope Dy/Dx assuming a linear characteristic). Sensors that measure very small

changes must have very high sensitivities. Sensors also have an impact on what they measure; for

instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the

liquid heats the thermometer. Sensors need to be designed to have a small effect on what is

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http://en.wikipedia.org/wiki/Wikipedia:Citing_sourceshttp://en.wikipedia.org/wiki/Wikipedia:Citing_sources#Adding_the_citationhttp://en.wikipedia.org/wiki/Mercury-in-glass_thermometerhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Voltmeterhttp://en.wikipedia.org/wiki/Calibrationhttp://en.wikipedia.org/wiki/Standard_(metrology)http://en.wikipedia.org/wiki/Tactile_sensorhttp://en.wikipedia.org/wiki/Wikipedia:Citing_sourceshttp://en.wikipedia.org/wiki/Wikipedia:Citing_sources#Adding_the_citationhttp://en.wikipedia.org/wiki/Mercury-in-glass_thermometerhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Voltmeterhttp://en.wikipedia.org/wiki/Calibrationhttp://en.wikipedia.org/wiki/Standard_(metrology)http://en.wikipedia.org/wiki/Tactile_sensor

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measured, making the sensor smaller often improves this and may introduce other advantages.

Technological progress allows more and more sensors to be manufactured on a microscopic scale as

microsensors using MEMStechnology. In most cases, a microsensor reaches a significantly higher

speed and sensitivity compared with macroscopic approaches

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11. RESULT & APPLICATIONS

11.1 RESULT:

By this way we can use the kit in order to operate respective home appliances and day to

life which results in reduce of the man power in such a way that one can operate from a single place

with the help of the system.

11.2 APPLICATIONS:

Home

Offices

Railway stations

Textile mills

Hotels

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12. FUTURE ENHANCEMENT & CONCLUSION

12.1 FUTURE ENHANCEMENT:

Extensive experimental research conducted in the last decade has provided some insight into

the fundamentals of detection. Some areas of the detection problem, however, need better

understanding in order to select the right detector for the specific applications. The following items

are proposed for further study

The optimum location of a residential smoke detector should be investigated in order to

ensure that the warning signal isclearly audible inall rooms of adwelling.

Research is urgently needed to determine the best way of detecting smoke in a corridor

when the fire originates inside a room with the door closed.

Further research is required to investigate the contribution 0% heating and air-conditioning

system to the movement of smokeoriginating from flaming or smoldering fires.

12.2 CONCLUSION:

The project Smoke Detector With Alarm has been successfully designed and tested.

It has been developed by integrating features of all hardware components used presence of every

module has been reasoned out and placed carefully thus contributing to the best of the working unit.

Secondly, used highly advanced ICs and with the help of growing technology the project

has been successfully implemented.

13. BIBILOGRAPHY

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WWW.MITEL.DATABOOK.COM

WWW.ATMEL.DATABOOK.COM

WWW.FRANKLIN.COM

WWW.KEIL.COM

REFERENCES:

1. "The 8051 Microcontroller Architecture, Programming & Applications" by

Kenneth J Ayala.

2. "The 8051 Microcontroller & Embedded Systems by Mohammed Ali Mazidi and

Janice Gillespie Mazidi

3. "Power Electronics by M D Singh and K B Khanchandan

4. "Linear Integrated Circuits by D Roy Choudary & Shail Jain

5. "Electrical Machines by S K Bhattacharya

6. "Electrical Machines II by B L Thereja

7. www.8051freeprojectsinfo.com

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http://www.8051freeprojectsinfo.com/http://www.8051freeprojectsinfo.com/

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