Fyp Human Detecting Robot RF

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CHAPTER 1

Introduction:

Development of a suitable system in which a sensor is for carrying out surveillance of

recognizable real time video information should be transmitted to the receiver point suitably

located in the observation area. Sensor should be able to detect man sized objects in above-

mentioned conditions.

The project aims at making the robot to move in any direction, connected at the receiver side,

specified by the user at the transmitter side using RF technology. The project uses the RF

technology, wireless camera and Embedded Systems to design this application. The main objective

of this project is to design a system that continuously checks for the data received from the

transmitter section and also monitor video captured by the and transmit the same to remotlely

placed or a PC.

1.1 Background of the project:

The software application and the hardware implementation help the microcontroller read the data

received from the transmitter section and accordingly change the direction of the robot. The

performance of the design is maintained by controlling unit.

1.2 Overview of the technologies used Embedded Systems:

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.

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, word

processing, accounting, software development and so on.

Following are the advantages of Embedded Systems:

1. They are designed to do a specific task and have real time performance constraints which must

be met.

2. They allow the system hardware to be simplified so costs are reduced.

3. They are usually in the form of small computerized parts in larger devices which serve a general

purpose.

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1.3 RF Technology:

RF refers to radio frequency, the mode of communication for wireless technologies of all kinds,

including cordless phones, radar, ham radio, GPS and radio and television broadcasts. RF waves are

electromagnetic waves which propagate at the speed of light, or 186,000 miles per second (300,000

km/s). The frequencies of RF waves, however, are slower than those of visible light, making RF

waves invisible to the human eye. The frequency of a wave is determined by its oscillations or

cycles per second.

1.4 Moving robot:

Robotics is a fascinating subject- more so, if you have to fabricate a robot yourself. The field of

robotics encompasses a number of engineering disciplines such as electronics (including electrical),

structural, pneumatics and mechanical. The electrical items include DC and Stepper motors,

actuators, electrical grips, clutches and their control. The electronic parts involves remote control,

sensors (touch sensors, light sensor, collision sensor, etc), there interface circuitry and a

microcontroller for overall control functions.

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CHAPTER 2

Literature review:

2.1 Methods of Programming a Microcontroller:

In System Programming Application development for embedded systems is usually done on a

desktop computer (PC), using a high level language like C or assembly language. After the

executable binary has been created by the cross development tools, these binary needs to be

uploaded to the target board. In most cases it will go to some kind of non-volatile memory,

requiring specific programming procedures.

While in earlier days a chip had been removed from the target board and placed in a programming

device, today's microcontrollers and external memory chips can be re-programmed without being

removed from the circuit. This is called in-circuit or in-system programming.

For in-system programming the following items are needed

1. A software tool running on the desktop computer, which is able to control the

programming interface via any standard port.

2. A programming adapter which allows to connect the programming interface to any

standard port available at the PC, like USB, RS-232, printer port etc.

3. A special programming interface like SPI (Serial Programming Interface),

Fig 2.1: In System Programming

All three requirements must be fulfilled somehow, but there is a large variety of real world

implementations. For example, the programming adapter may be integrated on the target board. In

http://en.wikipedia.org/wiki/In-System_Programming

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that case, for example, a USB cable may be used to directly connect the PC to the target board.

2.1.1 Parallel Programming Model

It is a concept that enables the expression of parallel programs which can be compiled and executed.

The value of a programming model is usually judged on its generality: how well a range of different

problems can be expressed and how well they execute on a range of different architectures. The

implementation of a programming model can take several forms such as libraries invoked from

traditional sequential languages, language extensions, or complete new execution models.

Consensus on a particular programming model is important as it enables software expressed within

it to be transportable between different architectures.

The main work of this project is to capture the real time image using as wireless camera. The

wireless camera is placed on a moving robot and the robot is controlled using a laptop. The

communication between the robot and the human interface is wireless using RF band.

This system involve to Monitoring and controlling the system using four different modules.

1) Sensing and Control Unit

2) PC and Control unit

3) Wireless control Unit

4) Moving Robot Control Unit

2.2 Project Overview and working:

What we present here is an elementary moving robot that can be controlled by laptop using

primarily the RF mode. The main work of this project is to capture the real time image using as

wireless camera. The wireless camera is placed on a moving robot and the robot is controlled using

a laptop. The communication between the robot and the human interface is wireless using RF band.

The RF remote control has the advantage of adequate range (up to 200m with proper antenna)

besides being Omni directional On the other hand, Rf receiver ,the proposed moving robot can

move in forward and reverse direction. You will also be able to steer it towards left and right

directions. While being turn to left and right, the corresponding blinking LEDs would blink indicate

the direction of its turning. Similarly, during reverse movement, reversing LEDs would be lit.

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CHAPTER 3

METHODOLOGY:

3.1 RF Transmitter:

Block diagram of RF transmitter:-

Transmitted signal

Fig 3.1 Block Diagram of RF Transmitter

POWERE SUPPLY

SYSTEM

RF TRANSMITTER

ENCODER HT 12 E

MICROCONTROLLER

(AT 89 C51)

RX.

TX.

USB (DB9)

MAX 232 TX.

RX.

RX.

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Circuit diagram of transmitter:

Fig 3.2 Circuit. Diagram of RF Transmitter

Working of Transmitter:

In this section, we are using RF transmitter module, microcontroller (AT 89C51) IC, encoder IC,

Max 232 IC and power supply. System is connected with transmitter by RS 232.When a signal is

send by system that is received at MAX 232.Then this signal is passes to microcontroller (AT

89C51).

Microcontroller process this signal and send it to encoder IC. Encoder IC encoded this signal and

transmit to RF module. RF module transmit this signal.

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3.2 RF receiver:

Block diagram of RF receiver:

Received Signal

Fig 3.3 Block Diagram of RF Receiver

RF RECEIVER

module

BATTERY

MICROCONTROLLER

(AT 89C 51)

MOTOR

DRIVE CKT

(L29 3D)

DECODER

(HT12 D)

M1

M2

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Circuit diagram of RF receiver:

Fig.3.4 Circuit Diagram of RF Receiver

Working of Receiver:

In this section, we are using RF receiver, microcontroller(AT 89C51), Decoder IC, Motor drive

IC,motor,battery. RF receiver received RF signal and send it to the decoder IC . Decoder IC decode

this signal and send it to the microcontroller at 89c51.

Microcontroller process this signal and send it to motor drive ckt IC. whenever we give command

signal from system , RF receiver ckt received the RF signal then moving robot drive by motor ckt,

perform some operation like forward , back, stop, left and right.

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3.3 MICROCONTROLLER AT89C51:

General Description:

The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of

Flash programmable and erasable read only memory (PEROM). The device is manufactured using

Atmels high-density nonvolatile memory technology and is compatible with the industry-standard

MCS-51 instruction set and pin out. The on-chip Flash allows the program memory to be

reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a

versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful

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

control applications.

3.3.1 Features of ATMEL 89C51 Microcontroller:

Compatible with MCS-51Products

2K Bytes of Reprogrammable Flash Memory

Endurance: 1,000 Write/Erase Cycles

2.7V to 6V Operating Range

Fully Static Operation: 0 Hz to 24 MHz

Two-level Program Memory Lock

128 x 8-bit Internal RAM

15 Programmable I/O Lines

Two 16-bit Timer/Counters

Six Interrupt Sources

Programmable Serial UART Channel

Direct LED Drive Outputs

On-chip Analog Comparator

Low-power Idle and Power-down Modes

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Block Diagram of ATMEL 89C51 Microcontroller:

Fig 3.5: Block Diagram of AT89C51 Microcontroller

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Pin Diagram of ATMEL 89C51 Microcontroller

Figure 3.6: Pin Diagram of AT89C51 Microcontroller

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3.3.2 Pin Description of ATMEL 89C51 Microcontroller:

VCC

Supply voltage.

GND

Ground.

Port 0

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

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

Port 0 may 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 0 also receives the code bytes during Flash programming, and outputs the code bytes during

program verification. External pull-ups are required during program

verification.

Port 1

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

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

the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. Port 1 also receives the low-

order address bytes during Flash programming and verification.

Port 2


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 use 16-bit

addresses (MOVX @DPTR). In this application, it uses strong internal pull-ups

when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI),

Port 2 emits the contents of the P2 Special Function Register.

Port 2 also receives the high-order address bits and some control signals during Flash programming

and verification.

Port 3

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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 also serves the functions of various special features of the AT89C51 as listed below:

Port Pin Alternate Functions

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

P3.6 WR (external data memory write strobe)

P3.7 RD (external data memory read strobe)

RST

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

device.

ALE/PROG

Address Latch Enable 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.

PSEN

Program Store Enable is the read strobe to external program memory.

When the AT89C51 is executing code from external program memory, PSEN is activated twice

each machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the device to fetch code

from external program memory locations starting at 0000H up to FFFFH. Note, however, that if

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lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for

internal program executions. This pin also receives the 12-volt programming enable voltage (VPP)

during Flash programming, for parts that require 12-volt VPP.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

3.4 Requirements for RF communication:

RF communication is required for the transmission of radio waves from RF transmitter (remote) to

RF receiver (robot) to enable the movement of the robot in this project. The basic requirements for

the RF communication used in this project are as follows:

RF Transmitter

RF Receiver

Encoder and Decoder

Microcontroller

3.4.1 RF Transmitter Module:

The RF TX-400 MHz is ideal for remote control applications where low cost and longer

range 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 RFTX-400mhz

suitable for high volume applications.

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Fig 3.7: RF Transmitter 400 MHz

Features:

400mhz Frequency

Low Cost

1.5-12V operation

Pin Description:

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 bypassed with should be a .01uF ceramic

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

degrade transmitter noise performance.

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

harmonic emissions.

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3.4.2 RF Receiver Module:

Fig 3.8: RF Receiver 434 MHz

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

pins. Two Data pins are provided in the receiver module. Thus, this data can be used for further

applications.

Fig 3.9: Pin Diagram of RF Receiver 434 MHz

Pin Description:

ANT- Antenna input.

GND-Receiver Ground. Connect to ground plane.

VCC- VCC pins are electrically connected and provide operating voltage for the receiver.

VCC can be applied to either or both. VCC should be bypassed with a .1F ceramic

capacitor. Noise on the power supply will degrade receiver sensitivity.

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

CMOS compatible output.

3.4.3 HT12E Encoder:

HT12E is an encoder integrated circuit of 212 series of encoders. They are paired with 212

series of decoders for use in remote control system applications. It is mainly used in interfacing

RF and infrared circuits. The chosen pair of encoder/decoder should have same number of

addresses and data format. Simply put, HT12E converts the parallel inputs into serial output. It

encodes the 12 bit parallel data into serial for transmission through an RF transmitter. These 12

bits are divided into 8 address bits and 4 data bits. HT12E has a transmission enable pin which is

active low. When a trigger signal is received on TE pin, the programmed addresses/data are

transmitted together with the header bits via an RF or an infrared transmission medium. HT12E

begins a 4-word transmission cycle upon receipt of a transmission enable.

Fig. 3.10 HT12E

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Pin Diagram of Encoder IC:

Fig 3.11 Pin Diagram of HT12E IC

How Does The Encoder Work?

The 318 (3 power of 18) 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

theHT6187/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.

Address/data programming (preset)

The status of each address/data pin can be individually preset to logic high, logic low, or floating. If

a transmission enable signal is applied, the encoder scans and transmits the status of the 18 bits of

address/data serially in the order A0 to AD17.

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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

3.4.4 HT12D Decoder :

HT12D IC comes from HolTek Company. HT12D is a decoder integrated circuit that belongs to

212 series of decoders. This series of decoders are mainly used for remote control system

applications, like burglar alarm, car door controller, security system etc. It is mainly provided to

interface RF and infrared circuits. They are paired with 212 series of encoders. The chosen pair of

encoder/decoder should have same number of addresses and data format. In simple terms, HT12D

converts the serial input into parallel outputs. It decodes the serial addresses and data received by,

say, an RF receiver, into parallel data and sends them to output data pins. The serial input data is

compared with the local addresses three times continuously. The input data code is decoded when

no error or unmatched codes are found. A valid transmission in indicated by a high signal at VT pin.

HT12D is capable of decoding 12bits, of which 8 are address bits and 4 are data bits.

Pin Diagram :

Fig 3.12 Pin Diagram of HT 12 D

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.

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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.

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. 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

Applications

Burglar alarm system

Smoke and fire alarm system

Garage door controllers

Car door controllers

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3.5 MAX 232 IC:

Fig 3.13 MAX 232 IC

The MAX232 IC is used to convert the TTL/CMOS logic levels to RS232 logic levels during serial

communication of microcontrollers with PC. The controller operates at TTL logic level (0-5V)

whereas the serial communication in PC works on RS232 standards (-25 V to + 25V). This makes it

difficult to establish a direct link between them to communicate with each other.

The intermediate link is provided through MAX232. It is a dual driver/receiver that includes a

capacitive voltage generator to supply RS232 voltage levels from a single 5V supply. Each receiver

converts RS232 inputs to 5V TTL/CMOS levels. These receivers (R1 & R2) can accept 30V inputs.

The drivers (T1 & T2), also called transmitters, convert the TTL/CMOS input level into RS232

level.

The transmitters take input from controllers serial transmission pin and send the output to RS232s

receiver. The receivers, on the other hand, take input from transmission pin of RS232 serial port and

give serial output to microcontrollers receiver pin. MAX232 needs four external capacitors whose

value ranges from 1F to 22F.

Microcontroller MAX232 RS232

Tx T1/2 In T1/2 Out Rx

Rx R1/2 Out R1/2 In Tx

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3.5.1 Pin Description of MAX 232:

Pin No Function Name

1

Capacitor connection pins

Capacitor 1 +

2 Capacitor 3 +

3 Capacitor 1 -

4 Capacitor 2 +

5 Capacitor 2 -

6 Capacitor 4 -

7 Output pin; outputs the serially transmitted data at RS232 logic level;

connected to receiver pin of PC serial port

T2 Out

8 Input pin; receives serially transmitted data at RS 232 logic level;

connected to transmitter pin of PC serial port

R2 In

9 Output pin; outputs the serially transmitted data at TTL logic level;

connected to receiver pin of controller.

R2 Out

10 Input pins; receive the serial data at TTL logic level; connected to

serial transmitter pin of controller.

T2 In

11 T1 In

12 Output pin; outputs the serially transmitted data at TTL logic level;

connected to receiver pin of controller.

R1 Out

13 Input pin; receives serially transmitted data at RS 232 logic level;

connected to transmitter pin of PC serial port

R1 In

14 Output pin; outputs the serially transmitted data at RS232 logic level;

connected to receiver pin of PC serial port

T1 Out

15 Ground (0V) Ground

16 Supply voltage; 5V (4.5V 5.5V) Vcc

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fig 3.14Pin Diagram Of MAX232

3.6 RS232:

Electronic data communications between elements will generally fall into two broad categories:

single-ended and differential. RS232 (single-ended) was introduced in 1962, and despite rumours

for its early demise, has remained widely used through the industry.

Independent channels are established for two-way (full-duplex) communications. The RS232

signals are represented by voltage levels with respect to a system common (power / logic ground).

The "idle" state (MARK) has the signal level negative with respect to common, and the "active"

state (SPACE) has the signal level positive with respect to common. RS232 has numerous

handshaking lines (primarily used with modems), and also specifies a communications protocol.

RS232 data is bi-polar.... +3 TO +12 volts indicate an "ON or 0-state (SPACE) condition" while A -

3 to -12 volts indicates an "OFF" 1-state (MARK) condition.... Modern computer equipment ignores

the negative level and accepts a zero voltage level as the "OFF" state. In fact, the "ON" state may be

achieved with lesser positive potential. This means circuits powered by 5 VDC are capable of

driving RS232 circuits directly, however, the overall range that the RS232 signal may be

transmitted/received may be dramatically reduced.

The output signal level usually swings between +12V and -12V. The "dead area" between +3v and -

3v is designed to absorb line noise. In the various RS-232-like definitions this dead area may vary.

For instance, the definition for V.10 has a dead area from +0.3v to -0.3v. Many receivers designed

for RS-232 are sensitive to differentials of 1v or less.

In telecommunication RS-232 is the traditional name for a series of standards

for serial binary single-ended data and control signals connecting between a DTE (Data Terminal

Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer

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serial ports. The standard defines the electrical characteristics and timing of signals, the meaning

of signals, and the physical size and pinout of connectors. The current version of the standard

is TIA-232-F Interface between Data Terminal Equipment and Data Circuit-Terminating Equipment

Employing Serial Binary Data Interchange, issued in 1997.An RS-232 port was once a standard

feature of a personal computer for connections to modems, printers, mice, data

storage, uninterruptible power supplies, and other peripheral devices. However, the low

transmission speed, large voltage swing, and large standard connectors motivated development of

the universal serial bus, which has displaced RS-232 from most of its peripheral interface roles.

Fig 3.15 USART

Fig 3.16: DB9 Port Pin Connections

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3.7 JMK WS -309 AS CAMERA AND Easy cap 002 USB2.0 DVR :-

In this project this camera is used for catching the real time image and send it to the pc or laptop by

using RF band, and that real time image received by laptop with the help of Easy cap 002 USB 2.0

interface 4 channel device.

Fig3.17 Physical appearance of camera,radio receiver and adapters

3.7.1 Technical Parameters of Transmitting Unit:

Video Camera Parts: 1/3" 1/4" Image Sensors

System: PAL/CCIR NTSC/EIA

Effective Pixel: PAL: 628X582 NTSC: 510X492

Image Area: PAL: 5.78X4.19mm NTSC: 4.69X3.45mm Horizontal Definition: 380 TV Lines

Scanning Frequency: PAL/CCIR: 50HZ NTSC/EIA: 60HZ Minimum Illumination: 3LUX

Sensitivity: +18DB-AGL ON-OFF

Output Electrical Level: 50MW

Output Frequency: 1.2G/2.4G

Transmission Signal: Video, Audio

Linear Transmission Distance: 50-100M

Voltage: DC+9V

Current: 300mA

Power Dissipation:

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Receiving Signal: Video, Audio

Voltage: DC 12V

Current: 500mA

3.8 Power Supply Part:

Fig.3.18 Power Supply Part

3.8.1 Power Supply Components:

LM 7805 voltage regulator

Bridge Rectifier:50V 1A

LED: green /red (3mm)

Resistors: 470

Capacitors : 2 220 F , 3 100 nF

3.9 Light Emitting Diode:

A light-emitting diode (LED) is a semiconductor light source.LEDs are used as indicator lamps in

many devices and are increasingly used for other lighting. Appearing as practical electronic

components in 1962, early LEDs emitted low-intensity red light, but modern versions are available

across the visible, ultraviolet, and infrared wavelengths, with very high brightness.

When a light-emitting diode is switched on, electrons are able to recombine with holes within the

device, releasing energy in the form of photons. This effect is called electroluminescence and the

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color of the light (corresponding to the energy of the photon) is determined by the energy band gap

of the semiconductor. An LED is often small in area (less than 1 mm2), and integrated optical

components may be used to shape its radiation pattern. LEDs present many advantages over

incandescent light sources including lower energy consumption, longer lifetime, improved physical

robustness, smaller size, and faster switching.

3.10 LM 7805 voltage regulator:

The LM78XX series of three terminal positive regulators are available in the TO-220 package and

with several fixed output voltages, making them useful in a wide range of applications. Each type

employs internal current limiting, thermal shut down and safe operating area protection, making it

essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output

current. Although designed primarily as fixed voltage regulators, these devices can be used with

external components to obtain adjustable voltages and currents.

The 7805 is a family of self-contained fixed linear voltage regulator integrated circuits. The 78xx

family is commonly used in electronic circuits requiring a regulated power supply due to their ease-

of-use and low cost. The 7805 line are positive voltage regulators: they produce a voltage that is

positive relative to a common ground. There is a related line of 79xx devices which are

complementary negative voltage regulators. 78xx and 79xx ICs can be used in combination to

provide positive and negative supply voltages in the same circuit.

Advantages:

7805 series ICs do not require additional components to provide a constant, regulated source

of power, making them easy to use, as well as economical and efficient uses of space. Other

voltage regulators may require additional components to set the output voltage level, or to

assist in the regulation process. Some other designs (such as a switched-mode power supply)

may need substantial engineering expertise to implement.

7805 series ICs have built-in protection against a circuit drawing too much power. They

have protection against overheating and short-circuits, making them quite robust in most

applications. In some cases, the current-limiting features of the 7805 devices can provide

protection not only for the 7805 itself, but also for other parts of the circuit.

7805 is easy to use.

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Disadvantages:

The input voltage must always be higher than the output voltage by some minimum amount

(typically 2 volts). This can make these devices unsuitable for powering some devices from

certain types of power sources (for example, powering a circuit that requires 5 volts using 6-

volt batteries will not work using a 7805).

As they are based on a linear regulator design, the input current required is always the same

as the output current. As the input voltage must always be higher than the output voltage,

this means that the total power (voltage multiplied by current) going into the 7805 will be

more than the output power provided. The extra input power is dissipated as heat. This

means both that for some applications an adequate heat sink must be provided, and also that

a (often substantial) portion of the input power is wasted during the process, rendering them

less efficient than some other types of power supplies. When the input voltage is

significantly higher than the regulated output voltage (for example, powering a 7805 using a

24 volt power source), this inefficiency can be a significant issue.

Even in larger packages, 78xx integrated circuits cannot supply as much power as many

designs which use discrete components, and are generally inappropriate for applications

requiring more than a few amperes of current.

Fig 3.19 : LM7805 Voltage Regulator

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3.11 MOTOR DRIVE CIRCUIT:

Components used:

For this project, well be using the following components:

One L293D H Bridge

One 7805 voltage regulator

One 7812 voltage regulator

Four capacitors, around 10uF

Two DC motors

The H-Bridge is the key component. To power this chip, we use the two voltage regulators. The

7805 is used for generating logic voltages (5V = logical 1). The 7812 will actually power the

motors.

Step 1: The power supply:

Well first work on the power supply for the motors and the chip. For

that, well be using the two voltage regulator ICs. Ideally, you could

connect a circuit like this:

Fig.3.20 Connection between two voltage regulator ICs

The two thick lines on the left are the main DC power supply (probably from some battery source or

maybe a DC adapter). Once the power is routed through this circuit, you get a 5 volt potential

difference across the ground and the line marked +5V. And you get 12 volts potential difference

across the +12V line and ground.

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However, there are always fluctuations in the input lines. To minimize these, we add capacitors

across the input terminals and the output terminals. So the final power supply circuit for our project

would be like this.

Fig 3.21 power supply

Step 2: Connecting power to the L293D:

There are a total of 8 pins on the L293D that relate to power. Four ground pins, three pins that need

the +5V and one pin that needs the +12V supply.

Doing the 4 ground connections might be messy if youre making this circuit for the first time.

Anyway, heres why were doing all these connections:

Fig .3.22 Connecting power to the L293D

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The four grounds have to connect to ground. No questions asked. Without that, the chip wont

function. The Vs is connected to +12V because well be running our DC motors at this voltage.

We put a +5V into Vss because thats the standard voltage for a logical 1. Based on this voltage, the

L293D will decide if a given voltage input is a logical 1 or a logical 0.

ENABLE1 and ENABLE2 are connected to +5V because we will be using both sides of the chip.

We put a logical 1 into these pins.

Step 3: Connecting the output:

Our outputs are motors. So we simply connect the two terminals of the motors across

OUTPU1/OUTPUT2 and OUTPUT3/OUTPUT4. As simple as that.

Fig 3.23 Connecting output

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Step 4: Connecting the input pins:

The only thing that now remains is connecting the INPUT pins. These pins connect to whatever

controller you have. If you have a microcontroller or a microcontroller, these four wires go there.

If you want to have it computer controller, they go into the parallel port of the computer, or

probably even the serial port. Or if you want, you could go a step further and even use some

wireless transmitter to wirelessly control the two motors.

Fig .3.24 Connecting input

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3.12 Programming of the Microcontroller :

#include

#define input P1

#define output P2

unsigned char logic(void);

void main()

{

unsigned char x;

input=0xff;

while(1)

{

x =logic();

switch(x)

{

case 0:

output=0xf5;

break;

case 1:

output=0xf1;

break;

case 2:

output=0xf4;

break;

case 3:

output=0xfa;

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break;

default:

output=0xf0;

break;

}

}

}

unsigned char logic(void)

{

if(input==0xfe)

return 0;

else if(input==0xfd)

return 1;

else if(input==0xfb)

return 2;

else if(input==0xf7)

return 3;

else

return 4;

}

#include

unsigned char recv(void);

//void trans(unsigned char);

35

void main()

{

unsigned char a;

SCON=0x50;

TMOD=0x20;

TH1=-3;

TR1=1;

while(1)

{

//trans('A');

a=recv();

switch(a)

{

case 'W':

P1=0xfe; //left

break;

case 'A':

P1=0xfd; //up

break;

case 'D':

P1=0xfb; // down

break;

case 'S':

P1=0xf7; // right

break;

default:

P1=0xff;

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break;

}

}

}

/*void trans(unsigned char value)

{

SBUF=value;

while(TI==0);

TI=0;

}*/

unsigned char recv(void)

{ unsigned char value;

RI=0;

while(RI==0);

value=SBUF;

return value;

}

37

CHAPTER 4

CONCLUSION AND FUTURE WORK:

This project presents a human being detecting robot using RF communication with wireless real

time image transmission and it is designed and implemented with Atmel 89C51 MCU in embedded

system domain.

The robot is moved in particular direction using switches and the images are captured and images

are watched on the laptop .Experimental work has been carried out carefully. The result shows that

higher efficiency is indeed achieved using the embedded system. The proposed method is verified to

be highly beneficial for the security purpose and industrial purpose.

The future aspect of our project we can use flying object and work on image processing technique.

38

CHAPTER 5

Advantage and disadvantage of the project:

advantages :

Less weight

Less Cost

Autonomous system

No sound and no external noise problem

DISADVANTAGES:

No safety equipment added

It would not detect perfect person details.

39

REFERENCES

Text Books:

[1] Raj Kamal, Embedded Systems, Pearson Education Publications, 2007.

[2] Mazzidi, 8051 Microcontroller and Embedded Systems, Prentice Hall

Publications, 2nd Edition, 2005.

Magazines:

[1] Electronics for you

[2] Electrikindia

Web portal:

[1] www.howstuffworks.com.

[2] http://www.atmel.com/dyn/resources/prod_documents/doc0265.pdf.

[3] www.intechopen.com/download/pdf/pdfs_id/68.pdf.

http://www.intechopen.com/download/pdf/pdfs_id/68.pdf

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1.1 Background of the project:1.2 Overview of the technologies used Embedded Systems:3.8 Power Supply Part:Fig.3.18 Power Supply Part3.8.1 Power Supply Components:

3.10 LM 7805 voltage regulator:Advantages:Disadvantages:

Fig 3.19 : LM7805 Voltage Regulator

Components used:Step 1: The power supply:Well first work on the power supply for the motors and the chip. For that, well be using the two voltage regulator ICs. Ideally, you could connect a circuit like this:

Step 2: Connecting power to the L293D:Step 3: Connecting the output:Step 4: Connecting the input pins:3.12 Programming of the Microcontroller :

Documents

Fyp Human Detecting Robot RF