Amcs 433 Documentation

8/8/2019 Amcs 433 Documentation

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Agriculture

Motor Control

Cum

Security system-433

(AMCS-433)

By-

A. Kalyan Chakravarthy (05M31A0419)

K. Arun Kumar

(05M31A0403)B. Shirisha (05M31A0446)

N. Mamatha

(05M31A0422)

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NISHITHA COLLEGE OF ENGINEERING &

TECHNOLOGY(Approved by AICTE, Govt. of AP, & Affiliated to JNT University,

Hyderabad)

Lemoor (v), kandukur (M) R.R.District-501 359. A.P. Ph: 08414 234399/234599.

Website: www.nishitha.com

__________________________________________________________________________________________________

DEPARTMENT OF ELECTRONIC AND

COMMUNICATION ENGINEERING

Certificate

This is to certify that this is the bonafide record of the project

carried out by.Roll no of

final year B.Tech. (Electronics & communication Engineering)

during the academic Year 2007 - 2008 in partial fulfilment of

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http://www.nishitha.com/http://www.nishitha.com/


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the requirements for the award of Degree of Bachelors of

Technology.

Guide Head of Dept.Principal

A PROJECT REPORT ON

NAME OF THE PROJECT

Submitted to

Jawaharlal Nehru Technological University

Hyderabad

In partial fulfillment for the award of degree of

BACHELOR OF TECHNOLOGY

In

ELECTRONICS & COMMUNICATION ENGINEERING

By

NAME ROLL NO.

Under the guidance of

MR. SHIVSHANKAR

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DEPARMENT OF ELECTRONICS &

COMMUNICATION ENGINEERING

NISHITHA COLLEGE OF ENGINEERING &

TECHNOLOGY

LEMOOR, KANDUKUR, R.R DIST, HYDERABAD- 50135

ACKNOWLEDGEMENT

I am indebted to my project guide Mr.Vikram.p, for his valuable suggestion and for

the motivation he provided. I owe my sincere thanks to him for sparing his valuable time and

his constant encouragement throughout the project.

I express my sincere thanks to Mr. Giriraju, head of department of electronics and

communication engineering, Nishitha College of engineering, lemoor, kandukur. For his

guidance and his encouragement and support and also I thank the cheerful staff working

under him for their support.

I express my sincere thanks to Mr. shivshanker asst. professor, accepting us and

guiding us in this project work. I also thank him for his encouragement support and imparting

technical skills. I owe my sincere thanks to him for sparing his valuable time and his constant

encouragement throughout the project.

I express my sincere thanks to Mr. Dr. Vijay Kumar, director of, Nishitha College of

engineering, lemoor, kandukur. For his guidance and his encouragement and support and also

I thank the cheerful staff working under him for their support.

I express my sincere thanks to Mr. Sheshadri shekar, Principal of, Nishitha College

of engineering, Lemoor, kandukur. For his encouragement and support and also I thank the

cheerful staff working under him for their support.

Acknowledgement are also due to the staff of the department of Electronics and

Communication Engineering, Nishitha College of Engineering and Technology, Classmates

and my friends who directly or indirectly or indirectly helped us in marking this project a

success.

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CONTENTS

Abstract

Block diagram

Components description

Introduction to controller

PCB Design

Power Supplies

Relays

RF Transmitter & Receiver

Decoder(HT 648)

Encoder(HT 640)

LM 324

Working

Applications

Advantages

Disadvantages

Solutions for disadvantages

Scope of the project

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ABSTRACT

Agriculture is the back bone of our country. Not only our country, it forms an

important aspect in every part of the world because, our dependency on that is greater. Hence,

technology must groove in to agriculture and thus improve the agriculture sector. Our main

aim of the project implies the same.

It is customary that a farmer has to walk miles to his farm, to water his

crop(to switch on the motor). He is also not aware about the power presence at the field. He

does not know whether the water level is low or high. Hes not aware when any unauthorized

persons may enter the field and he never knows if any fire breaks in his field which damagethe entire crop. The AMCS-433 provides exactly the solution for these problems.

By using this system, the farmer can directly switch ON the motor from his

house. He also gets the indication whether the power at field is present or not. Thus he does

not need to walk every time to his field in order to switch on the motor, at any time. He is

also indicated about the water level at the tank in his field is low or high. He is signalled

when any unauthorized person enters the field and most importantly, he is alarmed when any

fire breaks in the field so that he can switch on the motor to supply the water to put off the

fire. Hence this system provides full control of the water flow and offers high security to the

fields, remotely.

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7

CO

NTROLLER

DECODER

ENCODER

RFRX

RFTX

POWER

SUPPLY

MOTORCONTR

OL

LED INDICATIONS

MOTORON/OFF

POWERON/OFF

WATERLEVEL

FIRE

POWERSUPPLY

CONTROLL

ER

FIREINDICATO

R

DECODER

EN

CODER

WATERLEVEL

INDICATO

POWERFAILURECIRCUIT

RF

RX

RFTX

MOTOR


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COMPONENTS DESCRIPTION

INTRODUCTION TO MICROCONTROLLER:

PIN DIAGRAM

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A Microcontroller consists of a powerful CPU tightly coupled with memory RAM, ROM or

EPROM), various I / O features such as Serial ports, Parallel Ports, Timer/Counters,

Interrupt Controller, Data Acquisition interfaces-Analog to Digital Converter (ADC),

Digital to Analog Converter (ADC), everything integrated onto a single Silicon Chip.

It does not mean that any micro controller should have all the above said features on

chip, Depending on the need and area of application for which it is designed, the on chip

features present in it may or may not include all the individual section said above.

Any microcomputer system requires memory to store a sequence of instructions

making up a program, parallel port or serial port for communicating with an external system,

timer / counter for control purposes like generating time delays, Baud rate for the serial port,

apart from the controlling unit called the Central Processing Unit

ADVANTAGES OF MICROCONTROLLERS:

1. If a system is developed with a microprocessor, the designer has to go for external

memory such as RAM, ROM or EPROM and peripherals and hence the size of the

PCB will be large enough to hold all the required peripherals. But, the micro

controller has got all these peripheral facilities on a single chip so development of a

similar system with a micro controller reduces PCB size and cost of the design.

One of the major differences between a micro controller and a microprocessor is that

a controller often deals with bits , not bytes as in the real world application, for

example switch contacts can only be open or close, indicators should be lit or dark

and motors can be either turned on or off and so forth.

INTRODUCTION TO ATMEL MICROCONTROLLER

SERIES: 89C51 Family, TECHNOLOGY: CMOS

The major Features of 8-bit Micro controllerATMEL 89C51:

8 Bit CPU optimized for control applications

Extensive Boolean processing (Single - bit Logic) Capabilities.

On - Chip Flash Program Memory

On - Chip Data RAM

Bi-directional and Individually Addressable I/O Lines

Multiple 16-Bit Timer/Counters

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Full Duplex UART

Multiple Source / Vector / Priority Interrupt Structure

On - Chip Oscillator and Clock circuitry.

On - Chip EEPROM

SPI Serial Bus Interface

Watch Dog Timer

POWER MODES OF ATMEL 89C51 ICROCONTROLLER:

To exploit the power savings available in CMOS circuitry. Atmels Flash micro

controllers have two software-invited reduced power modes.

IDLE MODE:

The CPU is turned off while the RAM and other on - chip peripherals continue

operating. In this mode current draw is reduced to about 15 percent of the current drawn

when the device is fully active.

POWER DOWN MODE:

All on-chip activities are suspended while the on chip RAM continues to hold its

data. In this mode, the device typically draws less than 15 Micro Amps and can be as low as

0.6 Micro Amps

POWER ON RESET:

When power is turned on, the circuit holds the RST pin high for an amount of time

that depends on the capacitor value and the rate at which it charges.

To ensure a valid reset, the RST pin must be held high long enough to allow the

oscillator to start up plus two machine cycles. On power up, Vcc should rise within

approximately 10ms. The oscillator start-up time depends on the oscillator frequency. For a

10 MHz crystal, the start-up time is typically 1ms.With the given circuit, reducing Vcc

quickly to 0 causes the RST pin voltage to momentarily fall below 0V. However, this voltage

is internally l limited and will not harm the device.

MEMORY ORGANIZATION:

* Logical Separation of Program and Data Memory *

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All Atmel Flash micro controllers have separate address spaces for program and data memory as sh

in Fig 1.The logical separation of program and data memory allows the data memory to be accessed by

addresses. Which can be more quickly stored and manipulated by an 8 bit CPU Nevertheless 16 Bit

memory addresses can also be generated through the DPTR register?

Program memory can only be read. There can be up to 64K bytes of directly

addressable program memory. The read strobe for external program memory is the Program

Store Enable Signal (PSEN) Data memory occupies a separate address space from program

memory. Up to 64K bytes of external memory can be directly addressed in the external

data memory space. The CPU generates read and write signals, RD and WR during external

data memory accesses. External program memory and external data memory can be

combined by aapplying the RD and PSEN signal to the inputs of AND gate and using the

output of the fate as the read strobe to the external program/data memory.

PROGRAM MEMORY:

Fig 1.1 shows the map of the lower part of the program memory, after reset, the CPU

begins execution from location 0000h. As shown in Fig 1.1 each interrupt is assigned a fixed

location in program memory. The interrupt causes the CPU to jump to that location, where

it executes the service routine. External Interrupt 0 for example, is assigned to location0003h. If external Interrupt 0 is used, its service routine must begin at location 0003h. If the

interrupt in not used its service location is available as general-purpose program memory.

Fig.2: Program Memory.

0033h

Timer 2 002Bh

Serial Port 0023h

Timer 1 001Bh

External 8 Bytes

Interrupt 1 0013h

Timer 0 000Bh

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External

Interrupt 0 0003h

The interrupt service locations are spaced at 8 byte intervals 0003h for External

interrupt 0, 000Bh for Timer 0, 0013h for External interrupt 1,001Bh for Timer1, and so on.

If an Interrupt service routine is short enough (as is often the case in control applications) it

can reside entirely within that 8-byte interval. Longer service routines can use a jump

instruction to skip over subsequent interrupt locations. If other interrupts are in use. The

lowest addresses of program memory can be either in the on-chip Flash or in an external

memory. To make this selection, strap the External Access (EA) pin to either Vcc or GND.

For example, in the AT89C51 with 4K bytes of on-chip Flash, if the EA pin is strapped to

Vcc, program fetches to addresses 0000h through 0FFFh are directed to internal Flash.

Program fetches to addresses 1000h through FFFFh are directed to external memory.

DATA MEMORY:

The Internal Data memory is dived into three blocks namely,

The lower 128 Bytes of Internal RAM.

The Upper 128 Bytes of Internal RAM.

Special Function Register.

Internal Data memory Addresses are always 1 byte wide, which implies an

address space of only 256 bytes. However, the addressing modes for internal RAM can in

fact accommodate 384 bytes. Direct addresses higher than 7Fh access one memory space, andindirect addresses higher than 7Fh access a different Memory Space.

The lowest 32 bytes are grouped into 4 banks of 8 registers. Program instructions call

out these registers as R0 through R7. Two bits in the Program Status Word (PSW) Select,

which register bank, is in use. This architecture allows more efficient use of code space, since

register instructions are shorter than instructions that use direct addressing.

The next 16-bytes above the register banks form a block of bit addressable memory space.

The micro controller instruction set includes a wide selection of single - bit instructions

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and this instruction can directly address the 128 bytes in this area. These bit addresses are

00h through 7Fh. either direct or indirect addressing can access all of the bytes in lower

128 bytes. Indirect addressing can only access the upper 128. The upper 128 bytes of

RAM are only in the devices with 256 bytes of RAM.

The Special Function Register includes Posrt latches, timers, peripheral controls etc.,

direct addressing can only access these register. In general, all Atmel micro controllers have

the same SFRs at the same addresses in SFR space as the AT89C51 and other compatible

micro controllers. However, upgrades to the AT89C51 have additional SFRs. Sixteen

addresses in SFR space are both byte and bit Addressable. The bit Addressable SFRs are

those whose address ends in 000B. The bit addresses in this area are 80h through FFh.

FFFFh FFFFh

EXTERNAL

EXTERNAL

FFh

EA = 0 EA = 1

EXTERNAL EXTERNAL 0000h

-0000- 00h

PSEN RD WR

Fig.1.1 89C51 MEMORY STRUCTURE

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ADDRESSING MODES

DIRECT ADDRESSING:

In direct addressing, the operand specified by an 8-bit address field in the instruction.

Only internal data RAM and SFRs can be directly addressed.

INDIRECT ADDRESSING:

In Indirect addressing, the instruction specifies a register that contains the address of

the operand. Both internal and external RAM can indirectly address.

The address register for 8-bit addresses can be either the Stack Pointer or R0 or R1 of

the selected register Bank. The address register for 16-bit addresses can be only the 16-bit

data pointer register, DPTR.

INDEXED ADDRESSING:

Program memory can only be accessed via indexed addressing this addressing mode is

intended for reading look-up tables in program memory. A 16 bit base register (Either DPTR

or the Program Counter) points to the base of the table, and the accumulator is set up with the

table entry number. Adding the Accumulator data to the base pointer forms the address of the

table entry in program memory.

Another type of indexed addressing is used in the case jump instructions. In this

case the destination address of a jump instruction is computed as the sum of the base pointer

and the Accumulator data.

REGISTER INSTRUCTION:

The register banks, which contains registers R0 through R7, can be accessed by

instructions whose opcodes carry a 3-bit register specification. Instructions that access the

registers this way make efficient use of code, since this mode eliminates an address byte.

When the instruction is executed, one of four banks is selected at execution time by the

row bank select bits in PSW.

REGISTER - SPECIFIC INSTRUCTION:

Some Instructions are specific to a certain register. For example some instruction

always operates on the Accumulator, so no address byte is needed to point out. In these cases,

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the opcode itself points to the correct register. Instruction that regger to Accumulator as A

assemble as Accumulator - specific Opcodes.

IMMEDIATE CONSTANTS:

The value of a constant can follow the opcode in program memory For example.

MOV A, #100 loads the Accumulator with the decimal number 100. The same number could

be specified in hex digit as 64h.

PROGRAM STATUS WORD:

Program Status Word Register in Atmel Flash Micro controller:

CY AC F0 RS1 RS0 OV --- P

PSW 7 PSW 0

PSW 6 PSW 1

PSW 5 PSW 2

PSW 4 PSW 3

PSW 0:

Parity of Accumulator Set by Hardware to 1 if it contains an Odd number of 1s,

Otherwise it is reset to 0.

PSW1:

User Definable Flag

PSW2:

Overflow Flag Set By Arithmetic Operations

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PSW3:

Register Bank Select

PSW4:

Register Bank Select

PSW5:

General Purpose Flag.

PSW6:

Auxiliary Carry Flag Receives Carry Out from

Bit 1 of Addition Operands

PSW7:

Carry Flag Receives Carry Out From Bit 1 of ALU Operands.

The Program Status Word contains Status bits that reflect the current state of the

CPU. The PSW shown if Fig resides in SFR space. The PSW contains the Carry Bit, The

auxiliary Carry (For BCD Operations) the two - register bank select bits, the Overflow flag, a

Parity bit and two user Definable status Flags.

The Carry Bit, in addition to serving as a Carry bit in arithmetic operations also serves

the as the Accumulator for a number of Boolean Operations .The bits RS0 and RS1 select

one of the four register banks. A number of instructions register to these RAM locations as

R0 through R7.The status of the RS0 and RS1 bits at execution time determines which of

the four banks is selected.

The Parity bit reflect the Number of 1s in the Accumulator .P=1 if the Accumulator

contains an even number of 1s, and P=0 if the Accumulator contains an even number of 1s.

Thus, the number of 1s in the Accumulator plus P is always even. Two bits in the PSW are

uncommitted and can be used as general-purpose status flags.

INTERRUPTS

The AT89C51 provides 5 interrupt sources: Two External interrupts, two-timer

interrupts and a serial port interrupts. The External Interrupts INT0 and INT1 can each either

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level activated or transition - activated, depending on bits IT0 and IT1 in Register TCON.

The Flags that actually generate these interrupts are the IE0 and IE1 bits in TCON. When the

service routine is vectored to hardware clears the flag that generated an external interrupt

only if the interrupt WA transition - activated. If the interrupt was level - activated, then the

external requesting source (rather than the on-chip hardware) controls the requested flag. Tf0

and Tf1 generate the Timer 0 and Timer 1 Interrupts, which are set by a rollover in their

respective Timer/Counter Register (except for Timer 0 in Mode 3). When a timer interrupt is

generated, the on-chip hardware clears the flag that generated it when the service routine is

vectored to. The logical OR of RI and TI generate the Serial Port Interrupt. Neither of these

floag is cleared by hardware when the service routine is vectored to. In fact, the service

routine normally must determine whether RI or TI generated the interrupt an the bit must be

cleared in software.

In the Serial Port Interrupt is generated by the logical OR of RI and TI. Neither of

these flag is cleared by hardware when the service routine is vectored to. In fact, the service

routine normally must determine whether RI to TI generated the interrupt and the bit must be

cleared in software.

IE: Interrupt Enable Register

EA - ET2 ES ET1 EX1 ET0 EX0

Enable bit = 1 enabled the interrupt

Enable bit = 0 disables it.

OSCILLATOR AND CLOCK CIRCUIT:

XTAL1 and XTAL2 are the input and output respectively of an inverting amplifier

which is intended for use as a crystal oscillator in the pin configuration, in the frequency

range of 1.2 MHz to 12 Mhz. XTAL2 also the input to the internal clock generator.

To drive the chip with an internal oscillator, one would ground XTAL1 and XTAL2.

Since the input to the clock generator is divide by two flip flop there are no requirements on

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the duty cycle of the external oscillator signal. However, minimum high and low times must

be observed.

The clock generator divides the oscillator frequency by 2 and provides a tow phase

clock signal to the chip. The phase 1 signal is active during the first half to each clock period

and the phase 2 signals are active during the second half of each clock period.

CPU TIMING:

A machine cycle consists of 6 states. Each stare is divided into a phase / half, during

which the phase 1 clock is active and phase 2 half. Arithmetic and Logical operations take

place during phase1 and internal register - to register transfer take place during phase 2.

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PCB DESIGN

Design and Fabrication of Printed circuit boards:

INTRODUCTION:

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

industrial. Some of the areas where PCBs are intensively used are computers, process control,

telecommunications and instrumentation.

MANUFATCURING:

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

and etch.

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

sided plate through hole (PTH) boards are made by the print plate and etch method.

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

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

inner layers.

SOFTWARE:

The software used in our project to obtain the schematic layout is MICROSIM.

PANELISATION:

Here the schematic transformed in to the working positive/negative films. The circuit

is repeated conveniently to accommodate economically as many circuits as possible in a

panel, which can be operated in every sequence of subsequent steps in the PCB process. This

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

DRILLING:

PCB drilling is a state of the art operation. Very small holes are drilled with high

speed CNC drilling machines, giving a wall finish with less or no smear or epoxy, required

for void free through hole plating.

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PLATING:

The heart of the PCB manufacturing process. The holes drilled in the board are treated

both mechanically and chemically before depositing the copper by the electro less copper

platting process.

ETCHING:

Once a multiplayer board is drilled and electro less copper deposited, the image

available in the form of a film is transferred on to the outside by photo printing using a dry

film printing process. The boards are then electrolyticaly plated on to the circuit pattern with

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

is removed by the conveyorised spray etching machines with chemical etchants. The etching

machines are attached to an automatic dosing equipment, which analyses and controls

etchants concentrations.

SOLDERMASK:

Since a PCB design may call for very close spacing between conductors, a solder

mask has to be applied on the both sides of the circuitry to avoid the bridging of conductors.

The solder mask ink is applied by screening. The ink is dried, exposed to UV, developed in amild alkaline solution and finally cured by both UV and thermal energy.

HOT AIR LEVELLING:

After applying the solder mask, the circuit pads are soldered using the hot air leveling

process. The bare bodies fluxed and dipped in to a molten solder bath. While removing the

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

the machines, leaving the board soldered and levelled. This is one of the common finishes

given to the boards. Thus the double sided plated through whole printed circuit board is

manufactured and is now ready for the components to be soldered.

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POWER SUPPLIES

INTRODUCTION:

The present chapter introduces the operation of power supply circuits built using filters,

rectifiers, and then voltage regulators. Starting with an ac voltage, a steady dc voltage is

obtained by rectifying the ac voltage, then filtering to a dc level, and finally, regulating to

obtain a desired fixed dc voltage. The regulation is usually obtained from an IC voltage

regulator unit, which takes a dc voltage and provides a somewhat lower dc voltage, which

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

voltage changes.

A block diagram containing the parts of a typical power supply and the voltage at various

points in the unit is shown in fig 19.1. The ac voltage, typically 120 V rms, is connected to

a transformer, which steps that ac voltage down to the level for the desired dc output. A

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

simple capacitor filter to produce a dc voltage. This resulting dc voltage usually has some

ripple or ac voltage variation. A regulator circuit can use this dc input to provide a dc

voltage that not only has much less ripple voltage but also remains the same dc value even

if the input dc voltage varies somewhat, or the load connected to the output dc voltagechanges. This voltage regulation is usually obtained using one of a number of popular

voltage regulator IC units.

Transformer Rectifier Filter IC regulator Load

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IC VOLTAGE REGULATORS:

Voltage regulators comprise a class of widely used ICs. Regulator IC units contain the

circuitry for reference source, comparator amplifier, control device, and overload

protection all in a single IC. Although the internal construction of the IC is somewhat

different from that described for discrete voltage regulator circuits, the external operation

is much the same. IC units provide regulation of either a fixed positive voltage, a fixed

negative voltage, or an adjustably set voltage.

A power supply can be built using a transformer connected to the ac supply line to

step the ac voltage to desired amplitude, then rectifying that ac voltage, filtering with a

capacitor and RC filter, if desired, and finally regulating the dc voltage using an IC regulator.

The regulators can be selected for operation with load currents from hundreds of milli

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

THREE-TERMINAL VOLTAGE REGULATORS:

Fig shows the basic connection of a three-terminal voltage regulator IC to a load. The

fixed voltage regulator has an unregulated dc input voltage, Vi, applied to one input terminal,

a regulated output dc voltage, Vo, from a second terminal, with the third terminal connected

to ground. For a selected regulator, IC device specifications list a voltage range over which

the input voltage can vary to maintain a regulated output voltage over a range of load current.

The specifications also list the amount of output voltage change resulting from a change in

load current (load regulation) or in input voltage (line regulation).

Fixed Positive Voltage Regulators:

GND

22

IN

OUT

From

Transforme

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The series 78 regulators provide fixed regulated voltages from 5 to 24 V. Figure 19.26

shows how one such IC, a 7812, is connected to provide voltage regulation with output from

this unit of +12V dc. An unregulated input voltage Vi is filtered by capacitor C1 and

connected to the ICs IN terminal. The ICs OUT terminal provides a regulated + 12V which

is filtered by capacitor C2 (mostly for any high-frequency noise). The third IC terminal is

connected to ground (GND). While the input voltage may vary over some permissible voltage

range, and the output load may vary over some acceptable range, the output voltage remains

constant within specified voltage variation limits. These limitations are spelled out in the

manufacturers specification sheets. A table of positive voltage regulated ICs is provided in

table 19.1.

TABLE 19.1 Positive Voltage Regulators in 7800 series

IC PartOutput Voltage

(V)

Minimum Vi (V)

7805 +5 7.3

7806 +6 8.3

7

808

+8 10.5

7

810

+10 12.5

7

812

+12 14.6

7

815

+15 17.7

7

818

+18 21.0

7824 +24 27.1

RELAYS

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A relay is a switch worked by an electromagnet. It is useful if we want a small

current in one circuit to control another circuit containing a device such as a lamp or electric

motor which requires a large current, or if we wish several different switch contacts to be

operated simultaneously.

When the controlling current flows through the coil, the soft iron core is

magnetized and attracts the L-shaped soft iron armature. This rocks on its pivot and opens,

closes or changes over, the electrical contacts in the circuit being controlled it closes the

contacts.

The current needed to operate a relay is called the pull-in current and the

dropout current in the coil when the relay just stops working. If the coil resistance R of a

relay is 185 and its operating voltage V is 12V, the pull-in current I is given by:

I = V = 12 = 0.065A = 65mA

R 185

RELAY CONTROL

CIRCUIT DIAGRAM DESCRIPTION:

In this circuit transistor BC547 is used as a switch. The control signal is given to the

base terminal of the transistor. The collector is attached to the relay coil. Relays are

electromechanical devices. There are two types of relays.

1. Normally closed

2. Normally opened

We are using normally opened type relay. When the controller output from the PC is

high the transistor will be in the ON state, so relay is energized. When the controller outputfrom the PC is low the transistor will be in the OFF state, so relay is de-energized the valve

will open. When the relay is de-energized the valve will close. So according to the controller

output the valve will open or close and thus level is maintained.

RF TRANSMITTER & RECEIVER

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RF TRANSMITTER

Figure2.3: RF transmitter

Circuit operation

RF transmitter circuit is given. This circuit can be operated on a 9V D.C. Supply

source. The signals are passed on from the signal unit connected in the circuit to the base of

the transistor Q1 (BF494) through the capacitor C1 (0.1). Q1 is a NPN transistor and its

collector is given positive supply through the coil L1. Its emitter is connected to the ground

through the resistance R3 (100E) while its base is given the forward supply through the

resistance R2 (68k). Other than this, the signal unit is given the positive supply through the

resistance R1 (1k8). This resistance functions as the load resistance here and generates the

audio signals together with the signal unit. These audio signals are given to the base of the

transistor Q1 (BF494) through the capacitor C1 (0.1).

The coil L1 connected at its collector can be made by giving 5 turns of 24 SWG wire

on a base of 0.5cm diameter. A capacitor C3 (12pf) has also been connected between the

collector and the emitter of the transistor Q1. This capacitor triggers the oscillations. As soon

as the audio signal is received at the base then the transistor starts to oscillate and it generates

Radio frequency, which is given to the antenna through the capacitor C4 (1kpf) and

transmitted. The range of this transmitter lies between 100 meters to 500 meter

TRANSMITTER PIN DIAGRAM

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The TWS-434 and RWS-434 are extremely small, and are excellent for applications

requiring short-range RF remote controls. The transmitter module is only 1/3 the size of a

standard postage stamp, and can easily be placed inside a small plastic enclosure

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TWS-434: The transmitter output is up to 8mW at 433.92MHz with a range of

approximately 400 foot (open area) outdoors. Indoors, the range is approximately 200 foot,

and will go through most walls.

The TWS-434 transmitter accepts both linear and digital inputs can operate from 1.5 to 12

Volts-DC, and makes building a miniature hand-held RF transmitter very easy. The TWS-

434 is approximately the size of a standard postage stamp.

RF RECEIVER

RWS-434: The receiver also operates at 433.92MHz, and has a sensitivity of 3uV.

The RWS-434 receiver operates from 4.5 to 5.5 volts-DC, and has both linear and digital

outputs.

RWS-434 Receiver

Note: For maximum range, the recommended antenna should be approximately 35cmlong. To convert from centimeters to inchesmultiply by 0.3937. For 35cm, the length in

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inches will be approximately 35cm x 0.3937 = 13.7795 inches long. We tested these

modules using a 14, solid, 24 gauge hobby type wire, and reached a range of over 400 foot.

Your results may vary depending on your surroundings.

Sample Receiver Application Circuit

The example above shows the receiver section using the HT-12D decoder IC for a 4-bit RF

remote control system. The transmitter and receiver can also use the Holtek 8-bit HT-

640/HT-648L remote control encoder/decoder combination for an 8-bit RF remote control

system. Here are the schematics for an 8-bit RF remote control system:

No addressing or programming

The LS001 decoder IC can sink/source up to 25mA per output

Easy to use

Very low current consumption

Four data lines

Easy serial interface (encoder data out & decoder data in)

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Selectable baud rates (2400 or 9600 bps)

High noise immunity

Standard 8-Pin PDIP package

There are three Wireless RF Modules, Transmitter, Receiver and a Transceiver.

These RF Modules are designed to serve as a tool for electronic design engineers, developers,

hobbyists and students to perform wireless experiments. These modules make it easy for any

NON RF Experienced developer to add Wireless RF Remote Control to their project. NO RF

Knowledge required. The RF Modules are in a PCB (Printed Circuit Board) form with a 17

Pin 0.1 Inch spacing header that fits directly into most all prototyping boards. They are easy

to use boards that include encoders, decoders, addressing, RF data processing and even the

antenna, in a simple fully range tested board that is ready to plug right into your project. Just

apply +5VDC, ground, and the communication pins you require and enjoy hassle free

wireless communications. The Transmitter, Receiver and Transceiver all have 9600 baud

serial interfaces and stand-alone, 3 function switch inputs and outputs. The modules can

communicate over distances up to 250 feet. The boards operate on +5V and easily interface

to your Basic Stamp 2 or Basic Stamp 2sx

Two Modes of Operation:

Connecting GND to the Mode pin places the module in Switch Mode.

Connecting +5V to the Mode pin places the module in Serial Mode.

Switch Mode:

The transmitter, receiver and transceiver have 4 address pins (labeled ADDR1

ADDR4), providing 16 address combinations. Placing 0V or 5V on the 4 address pins sets the

units address (in a binary fashion). For example, placing 0V on all pins sets the address to

zero. Placing 5V on all pins sets the address to 15.The transmitter, receiver and transceiver

also have 3 switch data pins (labelled IN1 IN3). 0V or 5V logic levels placed on the input

pins of the transmitting module are automatically sent to the output pins (labeled OUT1

OUT3) on the receive module. In addition, 16 different modules can be addressed with the

built-in 4-bit address pins. The receiver will receive the switch data on its 3 switch output

pins only when its 4-bit address matches the transmitters 4-bit address. The 4-bit address

does not apply to serial mode.

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Serial Mode:

In serial mode (with +5V applied to the Mode pin) the modules can send and receive

serial data at 9600, N, 8, 1 with +5V and 0V logic levels. Simply connect a single wire to the

Transmit Data pin (labeled TXD) and send 9600 baud data into the module. The receivemodule outputs the same data at 9600 baud. All RF data processing is done automatically by

the modules. You cannot send a continuous 9600 baud stream; spacing between 9600 baud

bytes has to be at least 15 milliseconds. A flow control pin is provided for the transmitting

side to assist with achieving maximum efficient throughput. The Parallax Basic Stamp 2 and

BASIC Stamp 2sxhave built-in commands to do serial byte pacing and flow-control

handshaking in one single instruction (see source code examples).

Single direction communication requires at least:

Option a: 1 Transmitter and 1 Receiver.

Option b: 1 Transmitter and 1 Transceiver.

Option c: 1 Transceiver and 1 Receiver.

Bi-directional communication requires at least: 2 Transceivers.

Multi Point Communications can be achieved by:

Placing one transmitter at each node that needs to send information.

Placing one receiver at each node that needs to receive information.

Placing one transceiver at each node that needs to send and receive information.

DECODER (HT 648L)

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Features

Operating voltage: 2.4V~12V

Low power and high noise immunity CMOS technology

Low standby current

Capable of decoding 18 bits of information

Pairs with HOLTEKs 318 series of encoders

8~18 address pins

0~8 data pins

Trinary address setting

Two times of receiving check

Built-in oscillator needs only a 5% resistor

Valid transmission indictor

Easily interface with an RF or an infrared transmission medium

Minimal external components

Applications

Burglar alarm system

Smoke and fire alarm system

Garage door controllers

Car door controllers

Car alarm system

Security system

Cordless telephones

Other remote control systems

General Description

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The 318 decoders are a series of CMOS LSIs for remote control system applications. They

are paired with the 318 series of encoders. For proper operation a pair of encoder/decoder

pair with the same number of address and data format should be selected (refer to the

encoder/decoder cross reference tables). The 318 series of decoders receives serial address

and data from that series of encoders that are transmitted by a carrier using an RF or an IRtransmission medium. It then compares the serial input data twice continuously with its local

address. If no errors or unmatched codes are encountered, the input data codes are decoded

and then transferred to the output pins. The VT pin also goes high to indicate a valid

transmission. The 318 decoders are capable of decoding 18 bits of information that consists

of N bits of address and 18N bits of data. To meet various applications they are arranged to

provide a number of data pins whose range is from 0 to 8 and an address pin whose range is

from 8 to 18. In addition, the 318 decoders provide various combinations of address/data

number in different packages.

BLOCKDIAGRAM:

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PIN DIAGRAM

PIN DESCRIPTION:

Absolute Maximum Ratings*

Supply Voltage ............................... 0.3V to 13V

Storage Temperature................. 50C to 125C

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Input Voltage..................VSS0.3V to VDD+0.3V

Operating Temperature............... 20C to 75C

*Note: Stresses above those listed under Absolute Maximum Ratings may cause permanent

damage to the device. These are stress ratings only. Functional operation of this device at

these or any other conditions above those indicated in the operational sections of this

specification is not implied and exposure to absolute maximum rating conditions for extended

periods may affect device reliability.

Electrical characteristics:

Functional Description

Operation

The 318 series of decoders provides various combinations of address and data pins in

different packages. It is paired with the 318 series of encoders. The decoders receive data

transmitted by the encoders and interpret the first N bits of the code period as address and the

last 18N bits as data (where N is the address code number). A signal on the DIN pin then

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activates the oscillator which in turns decodes the incoming address and data. The decoders

will check the received address twice continuously. If all the received address codes match

the contents of the decoders local address, the 18N bits of data are decoded to activate the

output pins, and the VT pin is set high to indicate a valid transmission. That will last until the

address code is incorrect or no signal has been received. The output of the VT pin is highonly when the transmission is valid. Otherwise it is low always.

APPLICATION CIRCUIT

ENCODER (HT 640)

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Features:

Operating voltage: 2.4V~12V

Low power and high noise immunity CMOS technology

Low standby current Three words transmission

Built-in oscillator needs only 5% resistor

Easy interface with an RF or infrared transmission media

Minimal external components

Applications:

Burglar alarm system

Smoke and fire alarm system

Garage door controllers

Car door controllers

Car alarm system

Security system

Cordless telephones

Other remote control systems

General Description:

The encoders are a series of CMOS LSIs for remote control system applications. They

are capable of encoding 18 bits of information which consists of N address bits and 18_N

data bits. Each address/data input is externally trinary programmable if bonded out. It is

otherwise set floating internally. Various packages of the encoders offer flexible

combinations of programmable address/data to meet various application needs. Theprogrammable address/ data is transmitted together with the header bits via an RF or an

infrared transmission medium upon receipt of a trigger signal. The capability to select a TE

trigger type or a DATA trigger type further enhances the application

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PIN DIAGRAM

BLOCK DIAGRAM:

Absolute Maximum Ratings

Supply Voltage..............................._0.3V to 13V

Input Voltage ...................VSS_0.3 to VDD+0.3V

Storage Temperature................._50_C to 125_C

Operating Temperature .............._20_C to 75_C

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Note: These are stress ratings only. Stresses exceeding the range specified under _Absolute

Maximum Ratings_ may cause substantial damage to the device. Functional operation of this

device at other conditions beyond those listed in the specification is not implied and

prolonged exposure to extreme conditions may affect device reliability.

Functional Description

Operation:

The series of encoders begins a three-word transmission cycle upon receipt of a transmission

enable (TE for the HT600/HT640/HT680 or D12~D17 for the HT6187/HT6207/HT6247,

active high). This cycle will repeat itself as long as the transmission enable (TE or D12~D17)

is held high. Once the transmission enable falls low, the encoder output completes its final

cycle and then stops as shown below.

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Information word

An information word consists of 4 periods as shown:

Address/data waveform

Each programmable address/data pin can be externally set to one of the following three logic

states:

The _Open_ state data input is interpreted as logic low by the decoders since the decoder

output only have two states.

Address/data programming (preset)

The status of each address/data pin can be individually preset to logic _high_, _low_, or

_floating_. If a transmission enable signal is applied, the encoder scans and transmits the

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status of the 18 bits of address/data serially in the order A0 to AD17 for the

HT600/HT640/HT680 and A0 to D17 for the HT6187/HT6207/HT6247.There are some

packaging limitations. The 18-pin DIP HT680, for example, offers four external data bits and

eight external address bits. The remaining unpackaged bits or dummy codes are treated as

floating for A0~AD17 or as pull-low for D12~D17. During an information transmission these

bits are still located in their original position. But if the trigger signal is not applied, the chip

only consumes a standby current which is less than 1_A. The address pins are usually preset

to transmit data codes with particular security codes by the DIP switches or PCB wiring,

while the data is selected using push buttons or electronic switches.

Transmission enable

For the TE trigger type of encoders, transmission is enabled by applying a high signal to the

TE pin.

But for the Data trigger type of encoders, it is enabled by applying a high signal to one of the

data

pins D12~D17.

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HT640 application circuit

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LM324

Features

Internally frequency compensated for unity gain Large DC voltage gain: 100dB

Wide power supply range:

LM324 : 3V~32V (or 1.5 ~15V)

Input common mode voltage range includes ground

Large output voltage swing: 0V to VCC -1.5V

Power drain suitable for battery operation

DescriptionThe LM324 consist of four independent, high gain, internally frequency compensated

operational amplifiers which were designed specifically to operate from a single power

supply over a wide voltage range. Operation from split power supplies is also possible so

long as the difference between the two supplies is 3 volts to 32 volts. Application areas

include transducer amplifier, DC gain blocks and all the conventional OP amp circuits which

now can be easily implemented in single power supply systems.

INTERNAL BLOCK DIAGRAM

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WORKING

AMCS-433 works at 433 MHz frequency. The working of this system is simple, efficient and

reliable. This system consists of two modules, one at field and the other at home. Theworking of each module is described as follows.

FIELD MODULE:

This module consists of five circuits. Those are:

Power failure circuit

Fire sensor circuit

Water level indicator

Circuit breaker

All these circuits are controlled by microcontroller and the working of each circuit is as

follows

POWER FAILURE CIRCUIT:

This circuit is a power supply monitoring device that will trigger a led when the mains supply

cuts off. This device is helpful to inform the loss of power supply at a pump in the field. Once

the led is on, one will know that there is a loss of power supply and actions need to be taken

to rectify the situation by providing alternative power supply or relocating the installation.

CIRCUIT DISCRIPTION:

The circuit shown below consists of a AC relay. If the main input is 120V AC, use a 120V

AC relay. If the mains input is 240V AC, use a 240V AC relay. The relay is a Single Pole

Double Throw (SPDT) type where the COM will be connected to NC terminal if it is not

energised. Once energised, the COM terminal will be connected to the NO terminal.

When the mains power supply is available, the relay will be energised and the COM contact

will be connected to the NO terminal thus disconnecting the 9V power supply in the circuit.

When the mains supply cuts off, the COM will be connected to NC terminal and LED willlight up at home.

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Fig: Power failure indicator.

FIRE SENSOR CIRCUIT:

i/p

O/p O/p to controller

The working of flame circuit is very simple. It consists of a flame sensor. Its anode is

connected with 5v and cathode is connected to ground through 8.2k resister. The output is

collected at cathode. Whenever the fire is sensed by the sensor, it gives some voltage and it is

applied to IC LM324, a comparator. The reference voltage is set at the comparator andwhenever the output from sensor crosses this reference voltage, it gives 5v output to the

controller. This signal is transmitted to home and it triggers the buzzer and turns ON the

LED.

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FLAME SENSOR LM324


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WATER LEVEL INDICATOR:

The water level indicator uses a simple circuit to trap the water level in the tank at the field.

Its block diagram is given below

5v o/p

Fig: Base with 2 wires, centered with hole.

Fig: Rod with crossings

It uses a base with two wires tapped on it, one is connected to 5v and the other is connected

to output. The centre of the base is perforated to the radius of a rod. The low level of the

water is marked on the rod and at there conducting crossings are inserted as shown in the

figure. The edge of the rod is fixed with a light material such that it floats on water. Now this

rod is inserted through the hole of base and material attached to it should float on water. This

entire system is mounted on the base of the tank or well. When the material, floating on

water, touches the low level, the crossings on the rod make contact with the two wires on

base such that the 5v is shorted with output. This output is applied to controller, which

transmits this signal to home to turn ON the LED.

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CIRCUIT BREAKER:

The block diagram of the circuit breaker is shown below:

O/p

As shown in the figure, the circuit breaker uses IR transmitter and receiver pair for its

operation. In this circuit the IR transmitter and receiver are placed opposite to each other such

that the IR signals transmitted by the IR transmitter are always received by the IR receiver.

This pair is placed at the entrance of the field. Whenever any person or obstacle comes inbetween these pair, the signals are obstructed by the person and the receiver does not receive

the signals. Thus it does not produce any output. The output is collected at anode of the

receiver and it is given to LM324 comparator. Reference voltage is set at comparator and

whenever the output of receiver is low it is applied to controller through comparator and

transmitted to home which turns ON the LED and triggers the buzzer.

All these circuits are connected to controller and the controller is programmed to

transmit the desired signals to home for their indication. The transmitting signals from port

are applied to encoder (HT640) which encodes this data and the output from encoder is

applied to RF transmitter and then it is transmitted through antenna. Also the signals sent

from home are received at RF receiver through antenna and are decoded by HT648 (Decoder)and applied to ports for their operation. Remember that all the circuit in this module work

with 5v input.

HOME MODULE:

This module works with 5v and it is operated at 433MHz frequency. The microcontroller

controls all the functions in this module. The signals transmitted from Field are received

through RF receiver and decoded and applied to port of the controller. The controller is

programmed in such a way that, upon the received signals, required leds are turned ON.

This module has the switch to power ON the motor at field. Whenever the switch isturned on, this signal is transmitted through encoder, transmitter and received at field for its

operation.

Hence the module at field transmits the signals generated by each circuit in the field

module, as explained earlier. The module at home receives all these signals and indicated

through leds. By observing these signals, the farmer switch on the motor switch at home and

this signal is transmitted to field, received and thus the motor switch ON at field and the

water flow starts in to the field. Also, when fire breaks in the field the farmer can switch on

his motor to put off the fire. Thus this system form motor control cum security system.

Both the field and home modules are worked synchronously i.e. the transmission

is done one after the other. Hence this system is called as Half Duplex system.

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IR IR LM32


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APPLIC ATIONS

1) This system is mainly designed for the purpose of agriculture.

2) Apart from it, this system can be used in industries for various purposes such as

fire indication, water level indication etc.

3) When this system is installed at power transmission station and other places,

power on/off indication is received before it takes place and hence generators can

be switched on before the power goes off.

4) It can be used as the source of data transmission between remote places, without

any price.

5) It can be used in military for signalling, securely.

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ADVANTAGES

This system offers many advantages to the farmers and thus to

agriculture. Those are:

By using this system the farmers can remotely control the motor

in the field from his home at any time he requires, unlike walking

few distance to do that. This reduces his work.

The farmer also comes to know, whether the power at the field is

ON or so that he can switch on the motor. This facility really

requires in some areas as in INDIA, where farmers faceinterrupted power supply problems

The water level in the well or a tank when becomes very low,

indicated to the farmer, so that he can take necessary steps.

As we are using only 5v power supply to the system. Hence the

power consumption of the system is low. Also, we can install

batteries to operate the modules.

It alarms the farmer whenever fire breaks in the field such as inthe case of thunder storms etc and he can switch ON the motor

to supply the water to put off the fire. Also it alarms the farmer

when anyone enters the field. Thus it provides high security

Ease of use and readable to farmers.

The speed of operation of this system is very fast, thus providing

the fast communication for operation.

It has greater accuracy, since we are using electronic equipmentsand efficiency is good.

The cost of the system is low, hence affordable to farmers.

By using VLSI techniques the accuracy and efficiency of the

system increases and also cost decreases at greater extent.

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DISADVANTAGES

1) The transmission area of this system is less since we are

operating at 433MHz frequency.

2) The transmission is half duplex.

SOLUTIONS OFFERED BY US FOR THE DISADVANTAGES

MENTIONED ABOVE:

1) By using the RF modules or any other transmission modules greater

than this frequency, the transmission area increases.

2) By using transreceivers, this system can be made as full duplex.

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SCOPE OF THE PROJECT

a) By installing the soil moisture sensors in the field, the moisture levels of the soil

can be analysed by the farmer and thus can provide required water and fertilizers

if required, remotely.

b) Modern agriculture techniques follows powerful techniques like drip irrigation forbetter water flow into the fields. By using this system, we can also control and

implement those techniques, remotely.

c) We can also control the speed of the motor at the field by using this system,remotely.

d) We can connect some machines that are used in the field for various purposes and

can be operated and controlled accordingly.

e) This module is operated at 433.92 MHz frequency. By installing the transmitter

modules of greater frequency, transmission area increases.

f) We can also operate this system by using cell phones if signal strengths are good.

g) By installing cameras at field, farmer can visualize the field.

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Amcs 433 Documentation

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