weather monitoring using rf

8/2/2019 Weather Monitoring Using Rf

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ABSTRACT

The project deals with the design and development of hardware and software for

eight channelweather monitoringsystem.

A weather monitoring(also data logger ordata recorder) is an electronic device

that records data over time or in relation to location either with a built in instrument or

sensor or by using external instruments and sensors. One of the primary advantages of

using these data loggers is the ability to automatically and continuously collect data on a

24-hour basis.

The data which are recorded continuously in this project are Temperature, Intensity.

These analog quantities are taken and converted into corresponding digital values using an

eight channel ADC. These converted digital values are transmitted from the

microcontroller using RF transmitter and an encoder. These same values are received at the

receiver end using RF receiver and a decoder.

The RF modules used here are STT-433 MHz Transmitter, STR-433 MHz

Receiver, HT640 RF Encoder and HT648 RF Decoder. The processed data from ADC is

sent to microcontroller. The microcontroller passes this data to the RF transmitter through

RF Encoder. The encoder continuously receives the data from the microcontroller, passes

the data to the RF transmitter and the transmitter transmits the data. The encoder encodes

the 8-bit data into a single data and then presents it to RF transmitter.

At the receiving end, the RF receiver receives this data, gives it to RF decoder. This

decoder converts the single bit data into 8-bit data and presents it to the microcontroller.

Now, it is the job of the controller to read the data and display the same data on LCD.

CHAPTER 1

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INTRODUCTION

The project deals with the design and development of hardware and software for

eight channel weather monitoringsystem.

A weather monitoring(also data logger ordata recorder) is an electronic device

that records data over time or in relation to location either with a built in instrument or

sensor or by using external instruments and sensors. One of the primary advantages of

using these data loggers is the ability to automatically and continuously collect data on a

24-hour basis.

The data which are recorded continuously in this project are Temperature, Intensity.

These analog quantities are taken and converted into corresponding digital values using an

eight channel ADC. These converted digital values are transmitted from the

microcontroller using RF transmitter and an encoder. These same values are received at the

receiver end using RF receiver and a decoder.

The RF modules used here are STT-433 MHz Transmitter, STR-433 MHz

Receiver, HT640 RF Encoder and HT648 RF Decoder. The processed data from ADC is

sent to microcontroller. The microcontroller passes this data to the RF transmitter through

RF Encoder. The encoder continuously receives the data from the microcontroller, passes

the data to the RF transmitter and the transmitter transmits the data. The encoder encodes

the 8-bit data into a single data and then presents it to RF transmitter.

At the receiving end, the RF receiver receives this data, gives it to RF decoder. This

decoder converts the single bit data into 8-bit data and presents it to the microcontroller.

Now, it is the job of the controller to read the data and display the same data on LCD.

CHAPTER2

EMBEDDED SYSTEMS

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An embedded system can be defined as a computing device that does a specific

focused job. Appliances such as the air-conditioner, VCD player, DVD player, printer, fax

machine, mobile phone etc. are examples of embedded systems. Each of these appliances

will have a processor and special hardware to meet the specific requirement of the

application along with the embedded software that is executed by the processor for meeting

that specific requirement. The embedded software is also called firm ware. The

desktop/laptop computer is a general purpose computer. You can use it for a variety of

applications such as playing games, wordprocessing, accounting, software development

and so on. In contrast, the software in the embedded systems is always fixed listed below:

Embedded systems do a very specific task, they cannot be programmed to do

different things. . Embedded systems have very limited resources, particularly the memory.

Generally, they do not have secondary storage devices such as the CDROM or the floppy

disk. Embedded systems have to work against some deadlines. A specific job has to be

completed within a specific time. In some embedded systems, called real-time systems, the

deadlines are stringent. Missing a deadline may cause a catastrophe-loss of life or damage

to property. Embedded systems are constrained for power. As many embedded systems

operate through a battery, the power consumption has to be very low.

2.1 Application Areas

Nearly 99 per cent of the processors manufactured end up in embedded systems.

The embedded system market is one of the highest growth areas as these systems are used

in very market segment- consumer electronics, office automation, industrial automation,

biomedical engineering, wireless communication, data communication,

telecommunications, transportation, military and so on.

2.1.1 Consumer appliances

At home we use a number of embedded systems which include digital camera,

digital diary, DVD player, electronic toys, microwave oven, remote controls for TV and

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air-conditioner, VCO player, video game consoles, video recorders etc. Todays high-tech

car has about 20 embedded systems for transmission control, engine spark control, air-

conditioning, navigation etc. Even wristwatches are now becoming embedded systems.

2.1.2Office automation

The office automation products using em embedded systems are copying machine,

fax machine, key telephone, modem, printer, scanner etc.

2.1.3Industrial automation

Today a lot of industries use embedded systems for process control. These include

pharmaceutical, cement, sugar, oil exploration, nuclear energy, electricity generation and

transmission. The embedded systems for industrial use are designed to carry out specific

tasks such as monitoring the temperature, pressure, humidity, voltage, current etc., and then

take appropriate action based on the monitored levels to control other devices or to send

information to a centralized monitoring station.

2.1.4Medical electronics

Almost every medical equipment in the hospital is an embedded system. These

equipments include diagnostic aids such as ECG, EEG, blood pressure measuring

devices, X-ray scanners; equipment used in blood analysis, radiation, colonoscopy,

endoscopy etc. Developments in medical electronics have paved way for more accurate

diagnosis of diseases.

2.1.5 Computer networking

Computer networking products such as bridges, routers, Integrated Services Digital

Networks (ISDN), Asynchronous Transfer Mode (ATM), X.25 and frame relay switches

are embedded systems which implement the necessary data communication protocols. For

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example, a router interconnects two networks. The two networks may be running different

protocol stacks. The routers function is to obtain the data packets from incoming pores,

analyze the packets and send them towards the destination after doing necessary protocol

conversion. Most networking equipments, other than the end systems (desktop computers)

we use to access the networks, are embedded systems

2.1.6 Telecommunications

In the field of telecommunications, the embedded systems can be categorized as

subscriber terminals and network equipment. The subscriber terminals such as key

telephones, ISDN phones, terminal adapters, web cameras are embedded systems. The

network equipment includes multiplexers, multiple access systems, Packet Assemblers

Dissemblers (PADs), sate11ite modems etc. IP phone, IP gateway, IP gatekeeper etc. are

the latest embedded systems that provide very low-cost voice communication over the

Internet.

2.1.7 Wireless technologies

Advances in mobile communications are paving way for many interesting

applications using embedded systems. The mobile phone is one of the marvels of the last

decade of the 20h century. It is a very powerful embedded system that provides voice

communication while we are on the move

.

2.2 Overview of Embedded System Architecture

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Every embedded system consists of custom-built hardware built around a Central

Processing Unit (CPU). This hardware also contains memory chips onto which the

Fig2.2 (a): layered Architecture of Embedded system

Software is loaded. The software residing on the memory chip is also called the

firm ware The embedded system architecture can be represented as a layered architecture

as shown in Fig.

The operating system runs above the hardware, and the application software runs

above the operating system. The same architecture is applicable to any computer including

a desktop computer. However, there are significant differences. It is not compulsory to

have an operating system in every embedded system. For small appliances such as remote

control units, air conditioners, toys etc., there is no needforan operating system and you

can write only the software specific to that application. Once the software is transferred

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to the memory chip, the software will continue to runfora long time you dont need to

reload new software.

Now, let us see the details of the various building blocks of the hardware of an embedded

system. As shown in Fig. the building blocks are;

Central Processing Unit (CPU)

Memory (Read-only Memory and Random Access Memory)

Input Devices

Output devices

Communication interface

Application-specific circuitry

Fig2.2 (b): building blocks of the hardware of an embedded system

2.2.1 Central Processing Unit (CPU)

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The Central Processing Unit (processor, in short) can be any of the following:

microcontroller, microprocessor or Digital Signal Processor (DSP). A micro-controller is a

low-cost processor. Its main attraction is that on the chip itself, there will be many other

components such as memory, serial communication interface, analog-to digital converter

etc. So, for small applications, a micro-controller is the best choice as the number of

external components required will be very less. On the other hand, microprocessors are

more powerful, but you need to use many external components with them. D5P is used

mainly for applications in which signal processing is involved such as audio and video

processing.

2.2.2 Memory

The memory is categorized as Random Access 11emory (RAM) and Read Only

Memory (ROM). The contents of the RAM will be erased if power is switched off to the

chip, whereas ROM retains the contents even if the power is switched off. So, the firmware

is stored in the ROM. When power is switched on, the processor reads the ROM; the

program is program is executed.

2.2.3 Input devices

Unlike the desktops, the input devices to an embedded system have very limited

capability. There will be no keyboard or a mouse, and hence interacting with the embedded

system is no easy task. Many embedded systems will have a small keypad-you press one

key to give a specific command. A keypad may be used to input only the digits. Many

embedded systems used in process control do not have any input deviceforuser

interaction; they take inputsfrom sensors or transducers 1fnd produce electrical signals

that are in turn fed to other systems.

2.2.4 Output devices

The output devices of the embedded systems also have very limited capability.8


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Some embedded systems will have afew Light Emitting Diodes (LEDs) to indicate the

health status of the system modules, orforvisual indication of alarms. A small Liquid

Crystal Display (LCD) may also be used to displaysome important parameters.

2.2.5Communication interfaces

The embedded systems may need to, interact with other embedded systems at they

may have to transmit data to a desktop. To facilitate this, the embedded systems are

provided with one or a few communication interfaces such as RS232, RS422, RS485,

Universal Serial Bus (USB), IEEE 1394, Ethernet etc.

2.2.6 Application-specific circuitry

Sensors, transducers, special processing and control circuitry may be required fat an

embedded system, depending on its application. This circuitry interacts with the processor

to carry out the necessary work. The entire hardware has to be given power supply either

through the 230 volts main supply or through a battery. The hardware has to design in such

a way that the power consumption is minimized

CHAPTER 3

HARDWARE IMPLEMENTATION OF THE PROJECT

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This chapter briefly explains about the Hardware Implementation of the project. It

discusses the design and working of the design with the help of block diagram and circuit

diagram and explanation of circuit diagram in detail. It explains the features, timer

programming, serial communication, interrupts of AT89S52 microcontroller. It also

explains the various modules used in this project.

3.1 Project Design

The implementation of the project design can be divided in two parts.

Hardware implementation

Firmware implementation

Hardware implementation deals in drawing the schematic on the plane paper

according to the application, testing the schematic design over the breadboard using the

various ICs to find if the design meets the objective, carrying out the PCB layout of the

schematic tested on breadboard, finally preparing the board and testing the designed

hardware.

The firmware part deals in programming the microcontroller so that it can control

the operation of the ICs used in the implementation. In the present work, we have used the

Orcad design software for PCB circuit design, the Keil v3 software development tool to

write and compile the source code, which has been written in the C language. The Proload

programmer has been used to write this compile code into the microcontroller. The

firmware implementation is explained in the next chapter.

The project design and principle are explained in this chapter using the block

diagram and circuit diagram. The block diagram discusses about the required components

of the design and working condition is explained using circuit diagram and system wiring

diagram.

3.2 INTRODUCTION TO MICROCONTROLLER

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Based on the Processor side Embedded Systems is mainly divided into 3 types

1. Micro Processor : - are for general purpose eg: our personal computer

2. Micro Controller:- are for specific applications, because of cheaper cost we will gofor these

3. DSP (Digital Signal Processor):- are for high and sensitive application purpose

3.3 MICROCONTROLLER VERSUS MICROPROCESSOR

A system designer using a general-purpose microprocessor such as the Pentium or

the 68040 must add RAM, ROM, I/O ports, and timers externally to make them functional.

Although the addition of external RAM, ROM, and I/O ports makes these systems bulkier

and much more expensive,

A Microcontroller has a CPU (a microprocessor) in addition to a fixed amount of

RAM, ROM, I/O ports, and a timer all on a single chip. In other words, the processor, the

RAM, ROM, I/O ports and the timer are all embedded together on one chip; therefore, the

designer cannot add any external memory, I/O ports, or timer to it.

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Fig3.3 (a): Block diagram of microprocessor

Fifffffffff

Fig3.3 (b): Block diagram of microcontroller

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MICRO CONTROLLER: is a chip through which we can connect many other devices

and also those are controlled by the program the program which burn into that chip

3.4 Block Diagram of the Project and its Description

The block diagram of the design is as shown in Fig 3.4. It consists of power supply

unit, microcontroller, sensor module, ADC, LCD, and the cooling system with its driver

circuit. The brief description of each unit is explained as follows

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Transmitter section

Fig3.4 (a): block diagram of the project and its description

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Receiver section

Fig3.4 (b): block diagram of the project and its description

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3.4.1 Power Supply

The input to the circuit is applied from the regulated power supply. The a.c. input

i.e., 230V from the mains supply is step down by the transformer to 12V and is fed to a

rectifier. The output obtained from the rectifier is a pulsating d.c voltage. So in order to get

a pure d.c voltage, the output voltage from the rectifier is fed to a filter to remove any a.c

components present even after rectification. Now, this voltage is given to a voltage

regulator to obtain a pure constant dc voltage.

Fig3.4.1 (a): components of a regulated power supply

3.4.2 Transformer

Usually, DC voltages are required to operate various electronic equipment and

these voltages are 5V, 9V or 12V. But these voltages cannot be obtained directly. Thus the

a.c input available at the mains supply i.e., 230V is to be brought down to the required

voltage level. This is done by a transformer. Thus, a step down transformer is employed to

decrease the voltage to a required level.

3.4.3 Rectifier

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The output from the transformer is fed to the rectifier. It converts A.C. into pulsating D.C.

The rectifier may be a half wave or a full wave rectifier. In this project, a bridge rectifier is

used because of its merits like good stability and full wave rectification.

3.4.4 Filter

Capacitive filter is used in this project. It removes the ripples from the output of

rectifier and smoothens the D.C. Output received from this filter is constant until the mains

voltage and load is maintained constant. However, if either of the two is varied, D.C.

voltage received at this point changes. Therefore a regulator is applied at the output stage.

3.4.5 Voltage regulator

As the name itself implies, it regulates the input applied to it. A voltage regulator is

an electrical regulator designed to automatically maintain a constant voltage level. In this

project, power supply of 5V and 12V are required. In order to obtain these voltage levels,

7805 and 7812 voltage regulators are to be used. The first number 78 represents positive

supply and the numbers 05, 12 represent the required output voltage levels.

3.4.6 Microcontrollers

Fig3.4.7 (a):8051 microcontroller

Microprocessors and microcontrollers are widely used in embedded systems

products. Microcontroller is a programmable device. A microcontroller has a CPU in

addition to a fixed amount of RAM, ROM, I/O ports and a timer embedded all on a single

chip. The fixed amount of on-chip ROM, RAM and number of I/O ports in

microcontrollers makes them ideal for many applications in which cost and space are

critical.

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The Intel 8051 is Harvard architecture, single chip microcontroller (C) which was

developed by Intel in 1980 for use in embedded systems. It was popular in the 1980s and

early 1990s, but today it has largely been superseded by a vast range of enhanced devices

with 8051-compatible processor cores that are manufactured by more than 20 independent

manufacturers including Atmel, Infineon Technologies and Maxim Integrated Products.

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

a time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by th

CPU. 8051 is available in different memory types such as UV-EPROM, Flash and NV-

3.4.7 Features of AT89S51

8K Bytes of Re-programmable Flash Memory.

RAM is 256 bytes.

4.0V to 5.5V Operating Range.

Fully Static Operation: 0 Hz to 33 MHzs

Three-level Program Memory Lock.

256 x 8-bit Internal RAM.

32 Programmable I/O Lines.

Three 16-bit Timer/Counters.

Eight Interrupt Sources.

Full Duplex UART Serial Channel.

Low-power Idle and Power-down Modes.

Interrupt recovery from power down mode.

Watchdog timer.

Dual data pointer.

Power-off flag.

Fast programming time.

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3.4.8 Description

The AT89S52 is a low-voltage, high-performance CMOS 8-bit microcomputer with

8K bytes of Flash programmable memory. The device is manufactured using Atmels high

density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. The on chip flash allows the program memory to be reprogrammed in

system or by a conventional non volatile memory programmer. 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.

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.

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Fig3.4.9 (a): pin diagram of 8052

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Fig3.4.9 (b): block diagram of 8052

3.4.9 Pin description

Vcc Pin 40 provides supply voltage to the chip. The voltage source is +5V.

GND: Pin 20 is the ground

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Port 0

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

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

impedance inputs. Port 0 can also be configured to be the multiplexed low-order

address/data bus during accesses to external program and data memory. In this mode, P0

has internal pull-ups.

.Port 1

Port 1 is an 8-bit bidirectional 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.

Table

Port 2

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Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output

buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled

high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are

externally being pulled low will source current (IIL) because of the internal 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. The port also receives the high-order address bits and

some control signals during Flash programming and verification.

Port 3Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can

sink/source four TTL inputs. When 1s are written to Port 3 pins, they are

pulled high by the internal pull-ups and can be used as inputs. As inputs,

Port 3 pins that are externally being pulled low will source current (IIL)

because of the pull-ups. Port 3 receives some control signals for Flash

programming and verification.

Port 3 also serves the functions of various special features of the AT89S52, as shown in the

following table.

Table (2)

RST

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

running resets the device. This pin drives high for 98 oscillator periods after the Watchdog

times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this

feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG

Address Latch Enable

(ALE) is an output pulse for latching the low byte of the address during accesses

to external memory. This pin is also the program pulse input (PROG)

during Flash programming.

In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator

frequency and may be used for external timing or clocking purposes. Note, however, that

one ALE pulse is skipped during each access to external data memory.

If desired, ALE operation can be disabled by setting 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.

PSENProgram Store Enable: (PSEN) is the read strobe to external program memory.

When the AT89S52 is executing code from external program memory,

PSEN is activated twice each machine cycle, except that two PSEN

activations are skipped during each access to external data memory.

EA/VPP

External Access Enable

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EA must be strapped to GND in order to enable the device to fetch code from

external program memory locations starting at 0000H up to FFFFH. Note,

however, that if lock bit 1 is programmed, EA will be internally latched on

reset.

XTAL1:Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

XTAL2:

Output from the inverting oscillator amplifier

Fig3.4.10 (a): oscillator connection

Fig3.4.10 (b): External clock drive connection

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

that can be configured for use as an on-chip oscillator. Either a quartz crystal or ceramic

resonator may be used. To drive the device from an external clock source, XTAL2 should

be left unconnected while XTAL1 is driven. There are no requirements on the duty cycle of

the external clock signal, since the input to the internal clocking circuitry is through a

divide-by-two flip-flop, but minimum and maximum voltage high and low time

specifications must be observed.

3.5 Special Function Registers

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

space is shown in the following table.

It should be noted that not all of the addresses are occupied and unoccupied

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

general return random data, and write accesses will have an indeterminate effect.

User software should not write 1s to these unlisted locations, since they may be

used in future products to invoke new features. In that case, the reset or inactive values of

the new bits will always be 0.

3.5.1 Timer 2 Registers

Control and status bits are contained in registers T2CON and T2MOD for Timer 2.

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

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

3.5.2 Interrupt Registers

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

for each of the six interrupt sources in the IP register.

3.5.3 Dual Data Pointer Registers

To facilitate accessing both internal and external data memory, two banks of 16-bit

Data Pointer Registers are provided: DP0 at SFR address locations 82H-83H and DP1 at

84H and 85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1.

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3.5.4 Power off Flag

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

set to 1 during power up. It can be set and rest under software control and is not affected

by reset.

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

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

subjected to software upsets. The WDT consists of a 14-bit counter and the Watchdog

Timer Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To

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

(SFR location 0A6H).

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

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

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

or WDT overflow reset). When WDT overflows, it will drive an output RESET HIGH

pulse at the RST pin.

3.5.6 UART

The Atmel 8051 Microcontrollers implement three general purpose, 16-bit timers/

counters. They are identified as Timer 0, Timer 1 and Timer 2 and can be independently

configured to operate in a variety of modes as a timer or as an event counter. When

operating as a timer, the timer/counter runs for a programmed length of time and then

issues an interrupt request.

A basic operation consists of timer registers THx and TLx (x= 0, 1) connected in

cascade to form a 16-bit timer. Setting the run control bit (TRx) in TCON register turns the

timer on by allowing the selected input to increment TLx. When TLx overflows it

increments THx; when THx overflows it sets the timer overflow flag (TFx) in TCON

register. Setting the TRx does not clear the THx and TLx timer registers. Timer registers

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can be accessed to obtain the current count or to enter preset values. They can be read at

any time but TRx bit must be cleared to preset their values, otherwise the behavior of the

timer/counter is unpredictable.

The C/T control bit (in TCON register) selects timer operation or counter operation,

by selecting the divided-down peripheral clock or external pin Tx as the source for the

counted signal. TRx bit must be cleared when changing the mode of operation, otherwise

the behavior of the timer/counter is unpredictable. For timer operation (C/Tx# = 0), the

timer register counts the divided-down peripheral clock. The timer register is incremented

once every peripheral cycle (6 peripheral clock periods). The timer clock rate is FPER / 6,

i.e. FOSC / 12 in standard mode or FOSC / 6 in X2 mode. For counter operation (C/Tx# =

1),

Since it takes 2 cycles (12 peripheral clock periods) to recognize a negative

transition, the maximum count rate is FPER / 12, i.e. FOSC / 24 in standard mode or FOSC

/ 12 in X2 mode. There are no restrictions on the duty cycle of the external input signal, but

to ensure that a given level is sampled at least once before it changes, it should be held for

at least one full peripheral cycle. In addition to the timer or counter selection, Timer 0

and Timer 1 have four operating modes from which to select which are selected by bit-

pairs (M1, M0) in TMOD. Modes 0, 1and 2 are the same for both timer/counters. Mode 3

is different.

The four operating modes are described below. Timer 2, has three modes of

operation: capture, auto-reload and baud rate generator.

3.6 Crystal Oscillator

The 8051 uses the crystal for precisely that: to synchronize its operation.

Effectively, the 8051 operates using what are called "machine cycles." A single machine

cycle is the minimum amount of time in which a single 8051 instruction can be executed.

Although many instructions take multiple cycles. 8051 has an on-chip oscillator. It needs

an external crystal that decides the operating frequency of the 8051. The crystal is

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connected to pins 18 and 19 with stabilizing capacitors. 12 MHz (11.059MHz) crystal is

often used and the capacitance ranges from 20pF to 40pF.

A cycle is, in reality, 12 pulses of the crystal. That is to say, if an instruction takes

one machine cycle to execute, it will take 12 pulses of the crystal to execute. Since we

know the we can calculate how many instruction cycles the 8051 can execute per second:

11,059,000 / 12 = 921,583

11.0592 MHz crystals are often used because it can be divided to give you exact clock rates

for most of the common baud rates for the UART, especially for the higher speeds (9600,

19200).

Fig3.6 (a): block diagram of crystal oscillator

3.7 Reset

RESET is an active High input When RESET is set to High, 8051 goes back to the

power on state. The 8051 is reset by holding the RST high for at least two machine cycles

and then returning it low. Initially charging of capacitor makes RST High, When capacitor

charges fully it blocks DC.

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Fig3.7 (a): diagram of reset

3.8 WHAT ARE THE MAIN REQUIREMENTS FOR THE COMMUNICATION

USING RF

RF Transmitter

RF Receiver

Encoder and Decoder

3.8.1 RF TRANSMITTER STT-433MHz

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Fig3.8.1(a):STT-433 MHz TRANSMITTER

3.8.1.1 FACTORS INFLUENCED TO CHOOSE STT-433MHz

ABOUT THE TRANSMITTER

The STT-433 is ideal for remote control applications where low cost and longerrange is required.

The transmitter operates from a1.5-12V supply, making it ideal for battery-powered

applications.

The transmitter employs a SAW-stabilized oscillator, ensuring accurate frequency

control for best range performance.

The manufacturing-friendly SIP style package and low-cost make the STT-433

suitable for high volume applications.

3.8.1.2 Features

433.92 MHz Frequency

Low Cost

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1.5-12V operation

Small size

3.8.2 PIN DESCRIPTION

FIG3.8.2 (a): PIN DISCRIPTION

GND: Transmitter ground:Connect to ground plane

DATA: Digital data input. This input is CMOS compatible and should be driven with

CMOS level inputs.

VCC: Operating voltage for the transmitter. VCC should be bypassed with a .01uF

ceramic capacitor and filtered with a 4.7uF tantalum capacitor. Noise on the power supply

will degrade transmitternoise performance.

ANT: 50 ohm antenna output. The antenna port impedance affects output power and

harmonic emissions. Antenna can be single core wire of approximately 17cm length or

PCBtrace antenna.

3.8.3 APPLICATION

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Fig3.8.3 (a): Connection between the transmitter and microcontroller

The typical connection shown in the above figure cannot work exactly at all times

because there will be no proper synchronization between the transmitter and the

microcontroller unit. i.e., whatever the microcontroller sends the data to the transmitter, the

transmitter is not able to accept this data as this will be not in the radio frequency range.

The encoder used here is HT640 from HOLTEK SEMICONDUCTORS INC.

3.8.4 ENCODER HT640

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Fig3.8.4 (a): PIN DIAGRAM OF HT640 ENCODER

PIN DESCRIPTION:

Table (3)

3.8.5 DEMO CIRCUIT: Transmission Circuit

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Fig3.8.5 (a): Bock diagram of Transmission circuit

The data sent from the microcontroller is encoded and sent to RF transmitter. The

data is transmitted on the antenna pin. Thus, this data should be received on the destination

i.e, on RF receiver.

3.8.6 RF RECEIVER STR-433 MHz

Fig3.8.6 (a): RF RECEIVER STR-433 MHz

The data is received by the RF receiver from the antenna pin and this data is

available on

the datpins . Two Data pins are provided in the receiver module.

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Fig3.8.6 (b): PIN DISCRIPTION OF STR-433

PINOUT

ANT: Antenna input.

GND: Receiver Ground. Connect to ground plane.

VCC (5V): VCC pins are electrically connected and provide operating voltage for the

receiver.

DATA: Digital data output. This output is capable of driving one TTL or CMOS load. It

is a CMOS compatible output.

3.9 HOW DOES THE DECODER WORK?

The 3^18 decoders are a series of CMOS LSIs for remote control system

applications. They are paired with the 3^18 series of encoders.

For proper operation, a pair of encoder/decoder pair with the same number of

address and data format should be selected.

The 3^18 series of decoders receives serial address and data from that series of

encoders that are transmitted by a carrier using an RF medium.

A signal on the DIN pin then activates the oscillator which in turns decodes the

incoming address and data.

The VT pin also goes high to indicate a valid transmission. That will last until the

address code is incorrect or no signal has been received.

The 3^18 decoders are capable of decoding 18 bits of information that consists of N

bits of address and 18N bits of data.

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Fig3.9 (a): flow chart of the decoder work

3.9.1 BASIC APPLICATION CIRCUIT OF HT648L DECODER

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Fig3.9.1 (a): BASIC APPLICATION CIRCUIT OF HT648L DECODER

3.9.2 DEMO CIRCUIT: Reception circuit

Fig3.9.2 (a); block diagram of Reception circuit

The data transmitted into the air is received by the receiver. The received data is

taken from the data line of the receiver and is fed to the decoder .The output of decoder is

given to microcontroller and then data is processed according to the application.

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3.10 Light Dependent Resistor

LDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits.

Normally the resistance of an LDR is very high, sometimes as high as 1,000,000 ohms, butwhen they are illuminated with light, the resistance drops dramatically. Thus in this project,

LDR plays an important role in switching on the lights based on the intensity of light i.e., if

the intensity of light is more (during daytime) the lights will be in off condition. And if the

intensity of light is less (during nights), the lights will be switched on.

Fig3.10 (a): Light Dependent Resister

The output of the LDR is given to ADC which converts the analog intensity value into

corresponding digital data and presents this data as the input to the microcontroller

3.10.1 Features

Calibrated directly in Celsius (Centigrade)

Linear + 10.0 mV/C scale factor

0.5C accuracy guaranteed (at +25C)

Rated for full 55 to +150C range

Suitable for remote applications

Low cost due to wafer-level trimming Operates from 4 to 30 volts

Less than 60 A current drain

Low self-heating, 0.08C in still air

Nonlinearity only 14C typical

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Low impedance output, 0.1 W for 1 mA load

3.11 Temperature Sensor (LM35)

LM35 converts temperature value into electrical signals. LM35 series sensors are

precision integrated-circuit temperature sensors whose output voltage is linearlyproportional to the Celsius temperature. The LM35 requires no external calibration since it

is internally calibrated. . The LM35 does not require any external calibration or trimming to

provide typical accuracies of 14C at room temperature and 34C over a full 55 to

+150C temperature range.

Fig3.11 (a): diagrams of LM35

3.11.1 The characteristic of this LM35 sensor is

For each degree of centigrade temperature it outputs 10milli volts

ADC0808

The ADC0808, ADC0809 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.

3.11.2 Key Specifications

Resolution 8 Bits

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Total Unadjusted Error 12 LSB and 1 LSB

Single Supply 5 VDC

Low Power 15 m

3.11.3 Features

Easy interface to all microprocessors

Operates ratio metrically 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 5V input range with single 5V power supply

Outputs meet TTL voltage level specifications

Standard hermetic or molded 28-pin DIP package

28-pin molded chip carrier package

ADC0808 equivalent to MM74C949

ADC0809 equivalent to MM74C949-1

3.11.4 BLOCK DIAGRAM OF LM35

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Fig3.11.4(a): block diagram LM35

3.11.5 PIN DISCRIPTION OF LM35 SENSOR

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FIG3.11.5 (a): Block and Pin Diagram of LM35

3.12 CONVERTER CHARACTERISTICS

3.12.1 The Converter

The heart of this single chip data acquisition system is its 8-bit analog-to-digital

converter. The converter is designed to give fast, accurate, and repeatable conversions over

a wide range of temperatures. The converter is partitioned into 3 major sections: the 256R

ladder network, the successive approximation register, and the comparator. The converters

digital outputs are positive true. The 256R ladder network approach (Figure 1) was chosen

over the conventional R/2R ladder because of its inherent monotonicity.

The A/D converters successive approximation register (SAR) is reset on the

positive edge of the start conversion (SC) pulse. The conversion is begun on the falling

edge of the start conversion pulse. A conversion in process will be interrupted by receipt of

a new start conversion pulse. Continuous conversion may be accomplished by tying the end

of conversion (EOC) output to the SC input. If used in this mode, an external start

conversion pulse should be applied after power up. End-of-conversion will go low between

0 and 8 clock pulses after the rising edge of start conversion. influence on the repeatability

of the device.

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I/O Pins

Table (4)

ADDRESS LINE A, B, C:The device contains 8-channels. A particular channel is selected

by using the address decoder line. The above table shows the input states for address lines

to select any channel.

Address Latch Enable ALE:The address is latched on the Low High transition of ALE.

START: The ADCs Successive Approximation Register (SAR) is reset on the positive

edge i.e. Low- High of the Start Conversion pulse.

Output Enable:Whenever data has to be read from the ADC, Output Enable pin has to

be pulled high thus enabling the TRI-STATE outputs, allowing data to be read from the

data pins D0-D7.

End of Conversion (EOC):This Pin becomes high when the conversion has ended,

so the controller comes to know that the data can now be read from the data pins.

Clock:External clock pulses are to be given to the ADC; this can be given either from

LM 555 in Astable mode or the controller can also be used to give the pulses.

3.12.2 ADC interface with the Microcontrollers

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Fig3.12.2 (a): ADC interface with the Microcontrollers

3.13 LIQUID CRYSTAL DIS PLAY

LCD stands forLiquid Crystal Display. LCD is finding wide spread use replacing LEDs

(seven segment LEDs or other multi segment LEDs) because of the following reasons:

1. The declining prices of LCDs.

2. The ability to display numbers, characters and graphics. This is in contrast to LEDs,

which are limited to numbers and a few characters.

3. Incorporation of a refreshing controller into the LCD,

4. Ease of programming for characters and graphics.

These components are specialized for being used with the microcontrollers, which

means that they cannot be activated by standard IC circuits. They are used for writing

different messages on a miniature LCD.

Fig3.13 (a): LCD display

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A model described here is for its low price and great possibilities most frequently

used in practice. It is based on the HD44780 microcontroller (Hitachi) and can display

messages in two lines with 16 characters each. It displays all alphabets, Greek letters,

punctuation marks, mathematical symbols etc. In addition, it is possible to display symbols

that user makes up on its own.

Automatic shifting message on display (shift left and right), appearance of the

pointer, backlight etc. are considered as useful characteristics.

3.13.1 Pins Functions

There are pins along one side of the small printed board used for connection to the

microcontroller. There are total of 14 pins marked with numbers. Their function is

described in the table below:

Function Pin Number Name Logic State Description

Ground 1 Vss - 0V

Power supply 2 Vdd - +5V

Contrast 3 Vee - 0 Vdd

Control of

operating4 RS

0

1

D0 D7 are interpreted as

commands

D0 D7 are interpreted as data

Control of

operating

4 RS0

1

D0 D7 are interpreted as

commands

D0 D7 are interpreted as data

5 R/W0

1

Write data (from controller to LCD)

Read data (from LCD to controller)

6 E

0

1

From 1 to 0

Access to LCD disabled

Normal operating

Data/commands are transferred to

LCD

Data / commands 7 D0 0/1 Bit 0 LSB

8 D1 0/1 Bit 1

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9 D2 0/1 Bit 2

10 D3 0/1 Bit 3

11 D4 0/1 Bit 4

12 D5 0/1 Bit 5

13 D6 0/1 Bit 6

14 D7 0/1 Bit 7 MSB

Table (8)

3.13.2 LCD screen

LCD screen consists of two lines with 16 characters each. Each character consists of

5x7 dot matrix. Contrast on display depends on the power supply voltage and whether

messages are displayed in one or two lines. For that reason, variable voltage 0-Vdd is

applied on pin marked as Vee. Trimmer potentiometer is usually used for that purpose.

Some versions of displays have built in backlight (blue or green diodes). When used during

operating, a resistor for current limitation should be used (like with any LE diode).

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Fig3.13.2 (a): LCD screen

3.13.3 LCD Basic Commands

All data transferred to LCD through outputs D0-D7 will be interpreted as

commands or as data, which depends on logic state on pin RS:

RS = 1 - Bits D0 - D7 are addresses of characters that should be displayed. Built in

processor addresses built in map of characters and displays corresponding symbols.

Displaying position is determined by DDRAM address. This address is either previously

defined or the address of previously transferred character is automatically incremented.

RS = 0 - Bits D0 - D7 are commands which determine display mode. List of commands

which LCD recognizes are given in the table below:

Command RS RW D7 D6 D5 D4 D3 D2 D1 D0Execution

Time

Clear display 0 0 0 0 0 0 0 0 0 1 1.64Ms

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Cursor home 0 0 0 0 0 0 0 0 1 x 1.64mS

Entry mode set 0 0 0 0 0 0 0 1 I/D S 40uS

Display on/off control 0 0 0 0 0 0 1 D U B 40uS

Cursor/Display Shift 0 0 0 0 0 1 D/C R/L x x 40uS

Function set 0 0 0 0 1 DL N F x x 40uS

Set CGRAM address 0 0 0 1 CGRAM address 40uS

Set DDRAM address 0 0 1 DDRAM address 40uS

Read BUSY flag (BF) 0 1 BF DDRAM address -

Write to CGRAM or DDRAM 1 0 D7 D6 D5 D4 D3 D2 D1 D0 40uS

Read from CGRAM or DDRAM 1 1 D7 D6 D5 D4 D3 D2 D1 D0 40uS

Table (9)

I/D 1 = Increment (by 1) R/L 1 = Shift right

0 = Decrement (by 1) 0 = Shift left

S 1 = Display shift on DL 1 = 8-bit interface

0 = Display shift off 0 = 4-bit interface

D 1 = Display on N 1 = Display in two lines

0 = Display off 0 = Display in one line

U 1 = Cursor on F 1 = Character format 5x10 dots

0 = Cursor off 0 = Character format 5x7 dot

B 1 = Cursor blink on D/C 1 = Display shift

0 = Cursor blink off 0 = Cursor shift

3.13.\4 LCD Initialization

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Once the power supply is turned on, LCD is automatically cleared. This process

lasts for approximately 15mS. After that, display is ready to operate. The mode of

operating is set by default. This means that:

1. Display is cleared

2. Mode

DL = 1 Communication through 8-bit interface

N = 0 Messages are displayed in one line

F = 0 Character font 5 x 8 dots

3. Display/Cursor on/off

D = 0 Display off

U = 0 Cursor off

B = 0 Cursor blink off

4. Character entry

ID = 1 Addresses on display are automatically incremented by 1

S = 0 Display shift off

Automatic reset is mainly performed without any problems. If for any reason power

supply voltage does not reach full value in the course of 10mS, display will start perform

completely unpredictably.

If voltage supply unit cannot meet this condition or if it is needed to provide

completely safe operating, the process of initialization by which a new reset enabling

display to operate normally must be applied.

Algorithm according to the initialization is being performed depends on whether

connection to the microcontroller is through 4- or 8-bit interface. All left over to be done

after that is to give basic commands and of course- to display messages.

3.13.5 LCD interface with the microcontroller (4-bit mode)

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Fig3.13.4 (a): LCD interface with the microcontroller (4-bit mode)

CHAPTER 4

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SOFTWARE IMPLEMENTATION OF THE PROJECT

DESIGN

This chapter briefly explains about the firmware implementation of the project. The

required software tools are discussed in section 4.2. Section 4.3 shows the flow diagram of

the project design. Section 4.4 presents the firmware implementation of the project design.

4.1 Software Tools Required

Keil v3, Proload are the two software tools used to program microcontroller. The

working of each software tool is explained below in detail.

4.1.1 Programming Microcontroller

Vision3

Vision3 is an IDE (Integrated Development Environment) that helps you write,

compile, and debug embedded programs. It encapsulates the following components:

A project manager.

A make facility.

Tool configuration.

Editor.

A powerful debugger.

To help you get started, several example programs (located in the \C51\Examples,

\C251\Examples, \C166\Examples, and \ARM\...\Examples) are provided.

HELLO is a simple program that prints the string "Hello World" using the Serial

Interface.

Building an Application in Vision2

To build (compile, assemble, and link) an application in Vision2, you must:

1. Select Project - (for example, 166\EXAMPLES\HELLO\HELLO.UV2).

2. Select Project - Rebuild all target files or Build target.

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Vision2 compiles, assembles, and links the files in your project.

Creating Your Own Application in Vision2

To create a new project in Vision2, you must:

1. Select Project - New Project.

2. Select a directory and enter the name of the project file.

3. Select Project - Select Device and select an 8052, 251, or C16x/ST10 device from

the Device Database.

4. Create source files to add to the project.

5. Select Project - Targets, Groups, Files, Add/Files, select Source Group1, and add

the source files to the project.

6. Select Project - Options and set the tool options. Note when you select the target

device from the Device Database all special options are set automatically. You

typically only need to configure the memory map of your target hardware. Default

memory model settings are optimal for most applications.

7. Select Project - Rebuild all target files or Build target.

Debugging an Application in Vision2

To debug an application created using Vision2, you must:

1. Select Debug - Start/Stop Debug Session.

2. Use the Step toolbar buttons to single-step through your program. You may enter

G, main in the Output Window to execute to the main C function.

3. Open the Serial Window using the Serial #1 button on the toolbar.

Debug your program using standard options like Step, Go, Break, and so on.

Starting Vision2 and creating a Project

Vision2 is a standard Windows application and started by clicking on the program

icon. To create a new project file select from the Vision2 menu

Project New Project. This opens a standard Windows dialog that asks you for the

new project file name.

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Building Projects and Creating a HEX Files

Typical, the tool settings under Options Target are all you need to start a new

application. You may translate all source files and line the application with a click on the

Build Target toolbar icon. When you build an application with syntax errors, Vision2 will

display errors and warning messages in the Output

Window Build page.

Database selection

You have made when you create your project target. Refer to page 58 for more

Information about selecting a device. You may select and display the on-chip peripheral

components using the Debug menu. You can also change the aspects of each peripheral

using the controls in the dialog boxes.

Start Debugging

You start the debug mode of Vision2 with the Debug Start/Stop Debug Session

command. Depending on the Options for Target Debug Configuration, Vision2 will

load the application program and run the startup code Vision2 saves the editor screen

layout and restores the screen layout of the last debug session.

Disassembly Window

The Disassembly window shows your target program as mixed source and

assembly program or just assembly code. A trace history of previously executed

instructions may be displayed with Debug View Trace Records. To enable the trace

history, set Debug Enable/Disable Trace Recording.

If you select the Disassembly Window as the active window all program step

commands work on CPU instruction level rather than program source lines. You can select

a text line and set or modify code breakpoints using toolbar buttons or the context menu

commands.

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4.2 SOURCE CODE:

1. Click on the Keil uVision Icon on Desktop

2. The following fig will appear.

3. Click on the Project menu from the title bar

4. Then Click on New Project

5. Save the Project by typing suitable project name with no extension in u r ownfolder sited in either C:\ or D:\

6. Then Click on save button above.

7. Select the component for u r project. i.e. Atmel

8. Click on the + Symbol beside of Atmel

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9. Select AT89C51

10. Then Click on OK

11. The Following fig will appear

12. Then Click either YES or NOmostly NO

13. Now your project is ready to USE

14. Now double click on the Target1, you would get another option Source group

1

15. Click on the file option from menu bar and select new

16. The next screen will be as shown in next page, and just maximize it by double

clicking on its blue boarder.

17. Now start writing program in either in C or ASM

18. For a program written in Assembly, then save it with extension . asm and for

C based program save it with extension .C

19. Now right click on Source group 1 and click on Add files to Group Source

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20. Now you will get another window, on which by default C files will appear.

21. Now select as per your file extension given while saving the file

22. Click only one time on option ADD

23. Now Press function key F7 to compile. Any error will appear if so happen.

24. If the file contains no error, then press Control+F5 simultaneously.

25. The new window is as follows

26. Then Click OK

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27. Now Click on the Peripherals from menu bar, and check your required port.

28. Drag the port a side and click in the program file.

29. Now keep Pressing function key F11 slowly and observe.

30. You are running your program successfully

4.3 PROLOAD

Proload is software which accepts only hex files. Once the machine code is

converted into hex code, that hex code has to be dumped into the microcontroller and this

is done by the Proload. Proload is a programmer which itself contains a microcontroller in

it other than the one which is to be programmed. This microcontroller has a program in it

written in such a way that it accepts the hex file from the Keil compiler and dumps this hexfile into the microcontroller which is to be programmed. As the Proload programmer kit

requires power supply to be operated, this power supply is given from the power supply

circuit designed above. It should be noted that this programmer kit contains a power supply

section in the board itself but in order to switch on that power supply,

Fig 4.3(a): Atmel 8052 compiler

4.4 Features

Supports major Atmel 89 series devices

Auto Identify connected hardware and devices

Error checking and verification in-built

Lock of programs in chip supported to prevent program copying

20 and 40 pin ZIF socket on-board

Auto Erase before writing and Auto Verify after writing

Informative status bar and access to latest programmed file

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Simple and Easy to use

Works on 57600 speed

4.5 Description

It is simple to use and low cost, yet powerful flash microcontroller programmer for

the Atmel 89 series. It will Program, Read and Verify Code Data, Write Lock Bits, Erase

and Blank Check. All fuse and lock bits are programmable. This programmer has

intelligent onboard firmware and connects to the serial port. It can be used with any type of

computer and requires no special hardware. All that is needed is a serial communication

ports which all computers have.

Fig 4.3(b): dumping of program

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CHAPTER 5

RESULTS

Assemble the circuit on the PCB as shown in Fig below. After assembling the

circuit on the PCB, check it for proper connections before switching on the power supply.

5.1 Transmitter kit

Fig (a): transmission kit

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The above fig shows the overall view of the kit. We have two sensors light

dependent resister and temperature sensor(LM35).The LM35 converts temp value into

electrical signal and LDRs senses intensity of light.555 Timer generates the pulse and

given to ADC which converts analog signal into digital signal and provides to

microcontroller.

We have the arc input available at the mains supply i.e., 230V is to be brought

down to the required voltage level. This is done by a step down transformer. The output

from the transformer is fed to the rectifier. It converts A.C. into pulsating D.C. The rectifier

may be a half wave or a full wave rectifier. Capacitive filter is used in this project. It

removes the ripples from the output of rectifier and smoothens the D.C. Output received

from this filter is constant until the mains voltage and load is maintained constant. Power

supply of 5V is required. In order to obtain the voltage level, 7805 voltage regulators is to

be used. The microcontroller has a CPU in addition to a fixed amount ofRAM, ROM, I/O

ports and a timer embedded all on a single chip. It controls the kit.

The microcontroller provides the converted digital values to HT640 RF Encoder.

STT-433 MHz RF transmitter transmits the digital values using transmitting antenna.

5.2 Receiver kit

Fig (b): reception kit

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These same values received at the STR-433 MHz Receiver and a HT648 RF

Decoder .this decoder converts signal bit data into 8.bit data and presents it to the

microcontroller. Now it is the job of the controller to read the data and display the same

data on LCD

5.3 Wireless weather monitoring kit

Fig(c): wireless weather monitoring kit

The working of wireless weather monitoring system kit is shown while it is in working. If

it exceeds the limit then buzzer will ON. If its not so then it will be in OFF condition and

LEDs continuously blinks.LCD also continuously shows the LDR and TEMP as shown in

above figure

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CHAPTER 6

CONCLUSIONThe implementation of weather monitoring system using RF is done successfully.

The communication is properly done without any interference between different modules

in the design. Design is done to meet all the specifications and requirements. Software tools

like Keil Uvision Simulator, Proload to dump the source code into the microcontroller,

Orcad Lite for the schematic diagram have been used to develop the software code before

realizing the hardware.

Circuit is implemented in Orcad and implemented on the microcontroller board.

The performance has been verified both in software simulator and hardware design. The

total circuit is completely verified functionally and is following the application software.

It can be concluded that the design implemented in the present work provide

portability, flexibility and the data transmission is also done with low power consumption

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CHAPTER 7

REFERENCES

1. Muhammad Ali Mazidi, Janice Gillispie Mazidi, and Rolin D.McKinla,The 8051 Microcontroller and Embedded Systems Using Assembly and C;

Pearson Education Inc.., 2006.

2. Kenneth J.Ayala , The 8051 Microcontroller Architecture, Programming, and

Application; West Publishing Company, USA.,1991

3. B.Ram, Computer Fundamentals Architecture and Organization; New Age

International (P) Ltd., Publishers, 2000.

4. Horn, and Delton T, Electronic Components A Complete Reference for Project

Builders; McGraw-Hill/Tab Electronics, 1991.

5. E Balagurusamy , Programming In ANSI C;Tata McGraw-Hill Publishing

Company Ltd,2008.

Websites

1. http://www.google.com

2. http://books.google.com

3. http://www.atmel.com

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4. http://www.datasheets4u.com

10. http://www.8051projects.net
http://www.datasheets4u.com/http://www.8051projects.net/http://www.datasheets4u.com/http://www.8051projects.net/

weather monitoring using rf

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