RFID BASED VOICE BANK ALERT SYSTEM FOR BLIND PEOPLE

ABSTRACT

We propose a new technology based assistive material reading

framework to help blind persons and product packaging from hand-held objects

in their daily lives. First we propose a camera input database which is processed

by mat labs. The proof-of-concept prototype is also evaluated on a dataset

collected using ten blind persons to evaluate the effectiveness of the system’s

hardware. There are few devices that can provide good access to common

hand-held objects such as product packages, and objects printed with text such

as prescription medication bottles.

Then we propose a Voice bank APR 9600 IC for voice recording and

playback solution. It can record voice with the help of on-board microphone or

via any audio input. Camera acts as main vision in detecting the lable image of

the product or board then image is processed internally and separates label from

image by using open CV library and finally identifies the product and identified

product name is pronounced through voice. Now it identifies received label

image is converted to text by using tesseract library. Once the identified label

name is converted to text and converted text is displayed on display unit

connected to controller. Now converted text should be converted to voice to

hear label name as voice through ear phones connected to audio jack port using

file library.

1

CHAPTER 1

INTRODUCTION

Although many research done in historical document collection analysis

and recognition has focused on detection and analyzing scanned document.

Obstruct readability and decrease the performance because of large degradation

in document text images. Documents text reading is become difficult due to

aging of document, poor quality of ink, physical deterioration, blur. To avoid

the researches must be choose advance techniques for historical document

image text analysis. This document images text analysis not limited to only

historical document analysis one can have license number plate image, street

name, sign recognition and translation, electricity meters and so many area

where text reorganization is essential.

Reading is obviously essential in today’s society. Printed text is

everywhere in the form of reports, receipts, bank statements, restaurant menus,

classroom handouts, product packages, instructions on medicine bottles, etc.

And while optical aids, video magnifiers, and screen readers can help blind

users and those with low vision to access documents, there are few devices that

can provide good access to common hand-held objects such as product

packages, and objects printed with text such as prescription medication bottles.

The ability of people who are blind or have significant visual

impairments to read printed labels and product packages will enhance

independent living and foster economic and social self-sufficiency. Today, there

are already a few systems that have some promise for portable use, but they

cannot handle product labeling. For example, portable bar code readers

designed to help blind people identify different products in an extensive product

database can enable users who are blind to access information about these

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products through speech. But a big limitation is that it is very hard for blind

users to find the position of the bar code and to correctly point the bar code

reader at the bar code.

Some reading-assistive systems such as pen scanners might be employed

in these and similar situations. However, these systems are generally designed

for and perform best with document images with simple backgrounds, standard

fonts, a small range of font sizes, and well-organized characters rather than

commercial product boxes with multiple decorative patterns. Most state-of-the-

art OCR software cannot directly handle scene images with complex

background.

However, the document to be read must be nearly flat, placed on a clear,

dark surface, and contains mostly text. Furthermore, Reader Mobile accurately

reads black print on a white background, but has problems recognizing coloured

text or text on a coloured background. It cannot read text with complex

backgrounds, text printed on cylinders with warped or incomplete images (such

as soup cans or medicine bottles).

Furthermore, these systems require a blind user to manually localize areas

of interest and text regions on the objects in most cases. Although a number of

reading assistants have been designed specifically for the visually impaired, to

our knowledge, no existing reading assistant can read text from the kinds of

challenging patterns and backgrounds found on many everyday commercial

products.such text information can appear in multiple scales, fonts, colours, and

orientations.

Our proposed algorithm can effectively handle complex background and

multiple patterns, and extract text information from both hand-held objects and

nearby signage, In assistive reading systems for blind persons, it is very

3

challenging for users to position the object of interest within the centre of the

camera’s view. As of now, there is still no acceptable solution.

We approach the problem in stages. To make sure the hand-held object

appears in the camera view, we use a camera with sufficiently wide angle to

accommodate users with only approximate aim. This may often result in other

text objects appearing in the camera’s view (for example, while shopping at a

supermarket). To extract the hand-held object from the camera image.

We can use text detection, localization, and extraction interchangeably. In

this paper differentiate between these terms. Text detection consist of

determination of the presence of text in a given images. Text localization is the

process of determining the location of text in the image. Although the specific

location of text in an image can be getting, the text still needs to be segmented

from the background to make possible its recognition. In stage of text extraction

where the text components in images are segmented from the background. The

text region usually has low-resolution that’s why enhancement of the

components is essential. After, the extracted text images can be converted

variable text patterns, we here propose a text localization algorithm that

combines rule based layout analysis and learning-based text classifier training,

which define novel feature maps based on stroke orientations and edge

distributions. These, in turn, generate representative and discriminative text

features to distinguish text characters from background outliers.

This system receives an input in the form of an image or video. The

images can be in color or gray scale, un-compressed or compressed, orientation.

This problem can be divided into the following sub-problems: (i) detection, (ii)

localization, (iii) extraction and enhancement and (iv) recognition.

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CHAPTER 2

LITERATURE REVIEW

2. 1 Detecting and Reading Text in Natural Scene

It gives an algorithm for detecting and reading text in natural images. The

algorithm is intended for use by blind and visually impaired subjects walking

through city scenes. We first obtain a dataset of city images taken by blind and

normally sighted subjects. From this dataset, we manually label and extract the

text regions. Next we perform statistical analysis of the text regions to

determine which image features are reliable indicators of text and have low

entropy (i.e. feature response is similar for all text images).We obtain weak

classifiers by using joint probabilities for feature responses on and off text.

These weak classifiers are used as input to an AdaBoost machine learning

algorithm to train a strong classifier. In practice, we trained a cascade with 4

strong classifiers containing 79 features. An adaptive binarization and extension

algorithm is applied to those regions selected by the cascade classifier. A

commercial software is used to read the text or reject it as a non-text region. The

overall algorithm has a success rate of over 90%.

2.2 Automatic Detection and Recognition

We present an approach to automatic detection and recognition of signs

from natural scenes, and its application to a sign translation task. The proposed

approach embeds multiresolution and multiscale edge detection, adaptive

searching, colour analysis, and affine rectification in a hierarchical framework

for sign detection, with different emphases at each phase to handle the text in

different sizes, orientations, colour distributions and backgrounds. We use

5

affine rectification to recover deformation of the text regions caused by an

inappropriate camera view angle.

The procedure can significantly improve text detection rate accuracy.

Instead of using binary information, we extract features from an intensity image

directly.

We propose a local intensity normalization method to effectively handle

lighting variations, followed by a Gabor transform to obtain local features, and

finally a linear discriminator analysis (LDA) method for feature selection. We

have applied the approach in developing a Chinese sign translation system,

which can automatically detect and recognize Chinese signs as input from a

camera, and translate the recognized text into English.

2.3 Wearable Obstacle Avoidance

The last decades a variety of portable or wearable navigation systems

have been developed to assist visually impaired people during navigation in

known or unknown, indoor or outdoor environments. There are three main

categories of these systems: electronic travel aids (ETAs), electronic orientation

aids (EOAs), and position locator devices (PLDs). This paper presents a

comparative survey among portable/wearable obstacle detection/avoidance

systems (a subcategory of ETAs) in an effort to inform the research community

and users about the capabilities of these systems and about the progress in

assistive technology for visually impaired people. The survey is based on

various features and performance parameters of the systems that classify them

in categories, giving qualitative-quantitative measures.

Finally, it offers a ranking, which will serve only as a reference point and

not as a critique on these systems. Texture-based approach for text detection in

images using support vector machines and continuously adaptive mean shift

algorithm.The current paper presents a novel texture-based method for detecting

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texts in images. A support vector machine (SVM) is used to analyze the textural

properties of texts. No external texture feature extraction module is used, but

rather the intensities of the raw pixels that make up the textural pattern are fed

directly to the SVM, which works well even in high-dimensional spaces. Next,

text regions are identified by applying a continuously adaptive mean shift

algorithm (CAMSHIFT) to the results of the texture analysis.

The combination of CAMSHIFT and SVMs produces both robust and

efficient text detection, as time-consuming texture analyses for less relevant

pixels are restricted, leaving only a small part of the input image to be texture-

analyzed.

Context-based Indoor Object Detection as an Aid to Blind Persons

Accessing Unfamiliar Environments.Independent travel is a well known

challenge for blind or visually impaired persons. In this paper, we propose a

computer vision based indoor way finding system for assisting blind people to

independently access unfamiliar buildings. In order to find different rooms (i.e.

an office, a lab, or a bathroom) and other building amenities (i.e. an exit or an

elevator), we incorporate door detection with text recognition. First we develop

a robust and efficient algorithm to detect doors and elevators based on general

geometric shape, by combining edges and corners.

The algorithm is generic enough to handle large intra-class variations of

the object model among different indoor environments, as well as small inter-

class differences between different objects such as doors and elevators. Next, to

distinguish an office door from a bathroom door, we extract and recognize the

text information associated with the detected objects. We first extract text

regions from indoor signs with multiple colours.

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CHAPTER 5

PROJECT DESCRIPTION

BLOCK DIAGRAM PROPOSED SYSTEM

Fig 4.1 Circuit Diagram of Proposed System

Our main contributions in this prototype system are a novel motion-

based algorithm to solve the aiming problem for blind users by their simply

shaking the object of interest for a brief period; a novel algorithm of automatic

text localization to extract text regions from complex background and multiple

text pattern.

8

To walk safely and confidently without any human assistance in urban or

unknown environments is a difficult task for blind people. Visually impaired

people generally use either the typical white cane or the guide dog to travel

independently. But these methods are used only to guide blind people for safe

path movement.

Then received label image is converted to text. Once the identified label

name is converted to text and converted text is displayed on display unit

connected to controller. Now converted text should be converted to voice to

hear label name as voice through ear phones connected to audio. Reading is

obviously essential in today’s society. Printed text is everywhere in the form of

reports, receipts, bank statements, restaurant menus, classroom handouts,

product packages, instructions on medicine bottles, etc. And while optical aids,

video magnifiers, and screen readers can help blind users and those with low

vision to access documents, there are few devices that can provide good access

to common hand-held objects such as product packages, and objects printed

with text such as prescription medication bottles.

There are already a few systems that have some promise for portable use,

but they cannot handle product labelling. For example, portable bar code

readers designed to help blind people identify different products in an extensive

product database can enable users who are blind to access information about

these products through speech.

Atmel 89c51 microcontroller is used RFID based technology was used.It

is a challenging problem to automatically trap captured images with complex

backgrounds ,Usually the text in captured images is most likely surrounded by

multiple scales, fonts, and colors.

9

10

POWER SUPPLY UNIT

In most of our electronic products or projects we need a power supply for

converting mains AC voltage to a regulated DC voltage. For making a power

supply designing of each and every component is essential. Here I’m going to

discuss the designing of  regulated 5V Power Supply.

Let’s start with very basic things the choosing of components

Component List :

1. Step down transformer

2. Voltage regulator

3. Capacitors

4. Diodes

Voltage regulator :

As we require a 5V we need LM7805 Voltage Regulator IC.

7805 IC Rating :

Input voltage range 7V- 35V

Current rating Ic = 1A

Output voltage range   VMax=5.2V ,VMin=4.8V 

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OPERATION OF REGULATED POWER SUPPLY

STEP DOWN TRANSFORMER

A step down transformer will step down the voltage from the ac mains to

the required voltage level. The turn’s ratio of the transformer is so adjusted such

as to obtain the required voltage value. The output of the transformer is given as

an input to the rectifier circuit.

RECTIFICATION

Rectifier is an electronic circuit consisting of diodes which carries out the

rectification process. Rectification is the process of converting an alternating

voltage or current into corresponding direct (dc) quantity. The input to a

rectifier is ac whereas its output is unidirectional pulsating dc. Usually a full

wave rectifier or a bridge rectifier is used to rectify both the half cycles of the ac

supply (full wave rectification). Figure below shows a full wave bridge rectifier.

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A bridge rectifier consists of four p-n junction diodes connected in the

above shown manner. In the positive half cycle of the supply the voltage

induced across the secondary of the electrical transformer i.e. VMN is positive.

Therefore point E is positive with respect to F. Hence, diodes D3 and D2 are

reversed biased and diodes D1 and D4 are forward biased. The diode D3 and D2

will act as open switches (practically there is some voltage drop) and diodes D1

andD4 will act as closed switches and will start conducting.

Hence a rectified waveform appears at the output of the rectifier as shown

in the first figure. When voltage induced in secondary i.e. VMN is negative than

D3 and D2 are forward biased with the other two reversed biased and a positive

voltage appears at the input of the filter.

The rectified voltage from the rectifier is a pulsating dc voltage having

very high ripple content. But this is not we want, we want a pure ripple free dc

waveform. Hence a filter is used. Different types of filters are used such as

capacitor filter, LC filter, Choke input filter, π type filter. Figure below shows a

capacitor filter connected along the output of the rectifier and the resultant

output waveform.

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As the instantaneous voltage starts increasing the capacitor charges, it

charges till the waveform reaches its peak value. When the instantaneous value

starts reducing the capacitor starts discharging exponentially and slowly through

the load (input of the regulator in this case). Hence, an almost constant dc value

having very less ripple content is obtained.

REGULATION

This is the last block in a regulated DC power supply. The output voltage

or current will change or fluctuate when there is change in the input from ac

mains or due to change in load current at the output of the regulated power

supply or due to other factors like temperature changes. This problem can be

eliminated by using a regulator. A regulator will maintain the output constant

even when changes at the input or any other changes occur.

Transistor series regulator, Fixed and variable IC regulators or a zener

diode operated in the zener region can be used depending on their applications.

IC’s like 78XX and 79XX are used to obtained fixed values of voltages at the

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output. With IC’s like LM 317 and 723 etc we can adjust the output voltage to a

required constant value. Figure below shows the LM317 voltage regulator. The

output voltage can be adjusted with adjusting the values of resistances R1 and

R2. Usually coupling capacitors of values about 0.01µF to 10µF needs to be

connected at the output and input to address input noise and output transients.

Ideally the output voltage is given by

Figure below shows the complete circuit of a regulated +5V DC power

supply using transformer, bridge rectifier, filter (smoothing) and a fixed +5 V

voltage regulator. Here we can use IC 7803(for 3V),7809(for 9 V),7812(for

12V) etc.

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Application of Regulated Power Supply

Regulated power supply is the main component of electrical,electronics

and as well as automation equipment. Mobile phone charger, oscilator, amplifier

are needed the regulated power supply

Understanding 7805 IC Voltage Regulator

A regulated power supply is very much essential for several electronic

devices due to the semiconductor material employed in them have a fixed rate

of current as well as voltage. The device may get damaged if there is any

deviation from the fixed rate. The AC power supply gets converted into

constant DC by this circuit. By the help of a voltage regulator DC, unregulated

output will be fixed to a constant voltage.

The circuit is made up of linear voltage regulator 7805 along with

capacitors and resistors with bridge rectifier made up from diodes. From giving

an unchanging voltage supply to building confident that output reaches

uninterrupted to the appliance, the diodes along with capacitors handle elevated

efficient signal conveyal.

As we have previously talked about that regulated power supply is a

device that mechanized on DC voltages and also it can uphold its output

accurately at a fixed voltage all the time  although if there is a significant

alteration in the DC input voltage.ICs regulator is mainly used in the circuit to

maintain the exact voltage which is followed by the power supply. A regulator

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is mainly employed with the capacitor connected in parallel to the input

terminal and the output terminal of the IC regulator.

For the checking of gigantic alterations in the input as well as in the

output filter, capacitors are used. While the bypass capacitors are used to check

the small period spikes on the input and output level. Bypass capacitors are

mainly of small values that are used to bypass the small period pulses straightly

into the Earth.A circuit diagram having regulator IC and all the above discussed

components arrangement revealed in the figure below.

As we have made the whole circuit till now to be operated on the 5V DC

supply, so we have to use an IC regulator for 5V DC. And the most generally

used IC regulators get into the market for 5V DC regulation use is 7805. So we

are connecting the similar IC in the circuit as U1.

IC 7805 is a DC regulated IC of 5V. This IC is very flexible and is widely

employed in all types of circuit like a voltage regulator. It is a three terminal

device and mainly called input , output and ground. Pin diagram of the IC 7805

is shown in the diagram below.

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The output generated from the unregulated DC output is susceptible to

the fluctuations of the input signal.IC voltage regulator  is connected with

bridge rectifier in series in these project so to steady the DC output against the

variations in the input DC voltage.To obtain a stable output of 5V, IC 7805 is

attached with 6-0-6V along with 500mA step down transformer as well as with

rectifier.To suppress the oscillation which might generate in the regulator IC,

C2 capacitor of 0.1 uF value is used.

When the power supply  filter  is far away from the regulated IC capacitor

C2 is used.Ripple rejection in the regulator is been improved by C4

capacitor(35uf) by avoiding the ripple voltage to be amplified at the regulator

output.The output voltage is strengthen and deduction of the output voltage is

done capacitor C3(0.1uF). To avoid the chance of the input get shorted D5

diode is used to save the regulator. If D5 is not presented in the circuit, the

output capacitor can leave its charge  immediately during low impedance course

inside  the regulators.

ARDUINO MICROCONTROLLER

The Arduino microcontroller is an easy to use yet powerful single board

computer that has gained considerable traction in the hobby and professional

18

market. The Arduino is open-source, which means hardware is reasonably

priced and development software is free. This guide is for students in ME 2011,

or students anywhere who are confronting the Arduino for the first time. For

advanced Arduino users, prowl the web; there are lots of resources.

The Arduino project was started in Italy to develop low cost hardware for

interaction design. An overview is on the Wikipedia entry for Arduino. The

Arduino hardware comes in several flavors. In the United States, Sparkfun

(www.sparkfun.com) is a good source for Arduino hardware. The Arduino

board, you can write programs and create interface circuits to read switches and

other sensors, and to control motors and lights with very little effort. Many of

the pictures and drawings in this guide were taken from the documentation on

the Arduino site, the place to turn if you need more information. The Arduino

section covers more on interfacing the Arduino to the real world.

The Duemilanove board features an Atmel ATmega328 microcontroller operating

at 5 V with 2 Kb of RAM, 32 Kb of flash memory for storing programs and 1 Kb

of EEPROM for storing parameters. The clock speed is 16 MHz, which translates

to about executing about 300,000 lines of C source code per second. The board has

14 digital I/O pins and 6 analog input pins. There is a USB connector for talking to

the host computer and a DC power jack for connecting an external 6-20 V power

source, for example a 9 V battery, when running a program while not connected to

the host computer. Headers are provided for interfacing to the I/O pins using 22 g

solid wire or header connectors.

An Arduino board historically consists of an Atmel 8-, 16- or

32-bit AVR microcontroller (although since 2015 other makers' microcontrollers

have been used) with complementary components that facilitate programming and

incorporation into other circuits. An important aspect of the Arduino is its standard

19

connectors, which lets users connect the CPU board to a variety of interchangeable

add-on modules known as shields.

Some shields communicate with the Arduino board directly over various

pins, but many shields are individually addressable via an I²C serial bus—so many

shields can be stacked and used in parallel. Prior to 2015 Official Arduinos had

used the AtMel megaAVR series of chips, specifically

the ATmega8, ATmega168, ATmega328, ATmega1280, and ATmega2560 and in

2015 units by other manufacturers were added. A handful of other processors have

also been used by Arduino compatibles. Most boards include a 5 V linear

regulator and a 16 MHz crystal oscillator (or ceramic resonator in some variants),

although some designs such as the LilyPad run at 8 MHz and dispense with the

onboard voltage regulator due to specific form-factor restrictions.

An Arduino's microcontroller is also pre-programmed with a boot

loader that simplifies uploading of programs to the on-chip flash memory,

compared with other devices that typically need an external programmer. This

makes using an Arduino more straightforward by allowing the use of an ordinary

computer as the programmer. Currently, optiboot bootloader is the default

bootloader installed on Arduino UNO.

At a conceptual level, when using the Arduino integrated development

environment, all boards are programmed over a serial connection. Its

implementation varies with the hardware version. Some serial Arduino boards

contain a level shifter circuit to convert between RS-232 logic levels and TTL-level

signals. Current Arduino boards are programmed via Universal Serial Bus (USB),

implemented using USB-to-serial adapter chips such as the FTDI FT232.

Some boards, such as later-model Uno boards, substitute the FTDI chip with a

separate AVR chip containing USB-to-serial firmware, which is reprogrammable

via its own ICSP header. Other variants, such as the Arduino Mini and the

unofficial Boarduino, use a detachable USB-to-serial adapter board or

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cable, Bluetooth or other methods, when used with traditional microcontroller tools

instead of the Arduino IDE, standard AVR ISP programming is used.

The Arduino board exposes most of the microcontroller's I/O pins for use

by other circuits. The Diecimila, Duemilanove, and current Uno provide 14 digital

I/O pins, six of which can produce pulse-width modulated signals, and six analog

inputs, which can also be used as six digital I/O pins. These pins are on the top of

the board, via female 0.10-inch (2.5 mm) headers. Several plug-in application

shields are also commercially available.

The Arduino Nano, and Arduino-compatible Bare Bones Board[9] and Boarduino

boards may provide male header pins on the underside of the board that can plug

into solderless breadboards.

There are many Arduino-compatible and Arduino-derived boards. Some

are functionally equivalent to an Arduino and can be used interchangeably. Many

enhance the basic Arduino by adding output drivers, often for use in school-level

education to simplify the construction of buggies and small robots. Others are

electrically equivalent but change the form factor, sometimes retaining

compatibility with shields, sometimes not. Some variants use completely different

processors, with varying levels of compatibility.

21

Digital Pins

In addition to the specific functions listed below, the digital pins on an

Arduino board can be used for general purpose input and output via the

pinMode(), digitalRead(), and digitalWrite() commands. Each pin has an

internal pull-up resistor which can be turned on and off using digitalWrite() (w/

a value of HIGH or LOW, respectively) when the pin is configured as an input.

The maximum current per pin is 40 mA.

Serial: 0 (RX) and 1 (TX).

Used to receive (RX) and transmit (TX) TTL serial data. On the Arduino

Diecimila, these pins are connected to the corresponding pins of the FTDI USB-

to-TTL Serial chip. On the Arduino BT, they are connected to the

corresponding pins of the WT11 Bluetooth module. On the Arduino Mini and

LilyPad Arduino, they are intended for use with an external TTL serial module

(e.g. the Mini-USB Adapter). External Interrupts: 2 and 3. These pins can be

configured to trigger an interrupt on a low value, a rising or falling edge, or a

change in value. See the attachInterrupt() function for details.

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PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite()

function. On boards with an ATmega8, PWM output is available only on pins 9,

10, and 11.

BT Reset: 7. (Arduino BT-only) Connected to the reset line of the bluetooth

module.

SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI

communication, which, although provided by the underlying hardware, is not

currently included in the Arduino language.

LED: 13. On the Diecimila and LilyPad, there is a built-in LED connected to

digital pin 13. When the pin is HIGH value, the LED is on, when the pin is

LOW, it's off.

Analog Pins

In addition to the specific functions listed below, the analog input pins

support 10-bit analog-to-digital conversion (ADC) using the analogRead()

function. Most of the analog inputs can also be used as digital pins: analog input

0 as digital pin 14 through analog input 5 as digital pin 19. Analog inputs 6 and

7 (present on the Mini and BT) cannot be used as digital pins.

I2C: 4 (SDA) and 5 (SCL). Support I2C (TWI) communication using the Wire

library .

Power Pins

VIN (sometimes labelled "9V"). The input voltage to the Arduino board when

it's using an external power source (as opposed to 5 volts from the USB

connection or other regulated power source). You can supply voltage through

this pin, or, if supplying voltage via the power jack, access it through this pin.

Note that different boards accept different input voltages ranges, please

see the documentation for your board. Also note that the LilyPad has no VIN

pin and accepts only a regulated input. 5V. The regulated power supply used to

power the microcontroller and other components on the board. This can come

either from VIN via an on-board regulator, or be supplied by USB or another

23

regulated 5V supply. 3V3. (Diecimila-only) A 3.3 volt supply generated by the

on-board FTDI chip. GND. Ground pins.

Other Pins

AREF. Reference voltage for the analog inputs. Used with analogReference().

Reset. (Diecimila-only) Bring this line LOW to reset the

microcontroller.Typically used to add a reset button to shields which block the

one on the board.

DRIVER CIRCUIT

A relay is an electrically operated switch. Many relays use an

electromagnet to operate a switching mechanism mechanically, but other

operating principles are also used. Relays are used where it is necessary to

control a circuit by a low-power signal (with complete electrical isolation

between control and controlled circuits), or where several circuits must be

controlled by one signal.

The first relays were used in long distance telegraph circuits, repeating

the signal coming in from one circuit and re-transmitting it to another. Relays

were used extensively in telephone exchanges and early computers to perform

logical operations.

A type of relay that can handle the high power required to directly control

an electric motor or other loads is called a contactor. Solid-state relays control

power circuits with no moving parts, instead using a semiconductor device to

perform switching. Relays with calibrated operating characteristics and

sometimes multiple operating coils are used to protect electrical circuits from

24

overload or faults; in modern electric power systems these functions are

performed by digital instruments still called "protective relays".

Basic Design and Operation:

A simple electromagnetic relay consists of a coil of wire wrapped around

a soft iron core, an iron yoke which provides a low reluctance path for magnetic

flux, a movable iron armature, and one or more sets of contacts (there are two in

the relay pictured). The armature is hinged to the yoke and mechanically linked

to one or more sets of moving contacts.

It is held in place by a spring so that when the relay is de-energized there

is an air gap in the magnetic circuit. In this condition, one of the two sets of

contacts in the relay pictured is closed, and the other set is open. Other relays

may have more or fewer sets of contacts depending on their function. The relay

in the picture also has a wire connecting the armature to the yoke. This ensures

continuity of the circuit between the moving contacts on the armature, and the

circuit track on the printed circuit board (PCB) via the yoke, which is soldered

to the PCB.

25

When an electric current is passed through the coil it generates a

magnetic field that activates the armature, and the consequent movement of the

movable contact(s) either makes or breaks (depending upon construction) a

connection with a fixed contact. If the set of contacts was closed when the relay

was de-energized, then the movement opens the contacts and breaks the

connection, and vice versa if the contacts were open.

When the current to the coil is switched off, the armature is returned by a

force, approximately half as strong as the magnetic force, to its relaxed position.

Usually this force is provided by a spring, but gravity is also used commonly in

industrial motor starters.

Most relays are manufactured to operate quickly. In a low-voltage

application this reduces noise; in a high voltage or current application it reduces

arcing.

When the coil is energized with direct current, a diode is often placed

across the coil to dissipate the energy from the collapsing magnetic field at

deactivation, which would otherwise generate a voltage spike dangerous to

semiconductor circuit components. Some automotive relays include a diode

inside the relay case.

26

Alternatively, a contact protection network consisting of a capacitor and

resistor in series (snubber circuit) may absorb the surge. If the coil is designed

to be energized with alternating current (AC), a small copper "shading ring" can

be crimped to the end of the solenoid, creating a small out-of-phase current

which increases the minimum pull on the armature during the AC cycle.[1]

A solid-state relay uses a thyristor or other solid-state switching device,

activated by the control signal, to switch the controlled load, instead of a

solenoid. An optocoupler (a light-emitting diode (LED) coupled with a photo

transistor) can be used to isolate control and controlled circuits.

Applications:

Relays are used for:

Amplifying a digital signal, switching a large amount of power with a

small operating power. Some special cases are:

o A telegraph relay, repeating a weak signal received at the end of a

long wire

o Controlling a high-voltage circuit with a low-voltage signal, as in

some types of modems or audio amplifiers,

o Controlling a high-current circuit with a low-current signal, as in

the starter solenoid of an automobile.

Detecting and isolating faults on transmission and distribution lines by

opening and closing circuit breakers (protection relays),Switching to a

standby power supply.

27

SWITCHS

In electrical engineering, a switch is an electrical component that can

break an electrical circuit, interrupting the current or diverting it from one

conductor to another.[1][2] The mechanism of a switch may be operated directly

by a human operator to control a circuit (for example, a light switch or a

keyboard button), may be operated by a moving object such as a door-operated

switch, or may be operated by some sensing element for pressure, temperature

or flow. A relay is a switch that is operated by electricity. Switches are made to

handle a wide range of voltages and currents; very large switches may be used

to isolate high-voltage circuits in electrical substations.

The most familiar form of switch is a manually

operated electromechanical device with one or more sets of electrical contacts,

28

which are connected to external circuits. Each set of contacts can be in one of

two states: either "closed" meaning the contacts are touching and electricity can

flow between them, or "open", meaning the contacts are separated and the

switch is nonconducting.

The mechanism actuating the transition between these two states (open or

closed) can be either a "toggle" or "momentary" type.

A switch may be directly manipulated by a human as a control signal to a

system, such as a computer keyboard button, or to control power flow in a

circuit, such as a light switch. Automatically operated switches can be used to

control the motions of machines, for example, to indicate that a garage door has

reached its full open position or that a machine tool is in a position to accept

another workpiece.

Switches may be operated by process variables such as pressure,

temperature, flow, current, voltage, and force, acting assensors in a process and

used to automatically control a system. For example, a thermostat is a

temperature-operated switch used to control a heating process. A switch that is

operated by another electrical circuit is called a relay.

Large switches may be remotely operated by a motor drive mechanism.

Some switches are used to isolate electric power from a system, providing a

visible point of isolation that can be padlocked if necessary to prevent

29

accidental operation of a machine during maintenance, or to prevent electric

shock.

An ideal switch would have no voltage drop when closed, and would

have no limits on voltage or current rating. It would have zero rise time and fall

time during state changes, and would change state without "bouncing" between

on and off positions.

Practical switches fall short of this ideal; they have resistance, limits on

the current and voltage they can handle, finite switching time, etc. The ideal

switch is often used in circuit analysis as it greatly simplifies the system of

equations to be solved, but this can lead to a less accurate solution. Theoretical

treatment of the effects of non-ideal properties is required in the design of large

networks of switches, as for example used in telephone exchanges.

Connections

In the simplest case, a switch has two conductive pieces, often metal,

called contacts, connected to an external circuit, that touch to complete (make)

the circuit, and separate to open (break) the circuit. The contact material is

chosen for its resistance to corrosion, because most metals

form insulating oxidesthat would prevent the switch from working. Contact

materials are also chosen on the basis of electrical

30

conductivity, hardness (resistance to abrasive wear),mechanical strength, low

cost and low toxicity.

Sometimes the contacts are plated with noble metals. They may

be designed to wipe against each other to clean off any contamination.

Nonmetallicconductors, such as conductive plastic, are sometimes used. To

prevent the formation of insulating oxides, a minimum wetting current may be

specified for a given switch design.

In electronics, switches are classified according to the arrangement of

their contacts. A pair of contacts is said to be "closed" when current can flow

from one to the other. When the contacts are separated by an insulating air gap,

they are said to be "open", and no current can flow between them at normal

voltages. The terms "make" for closure of contacts and "break" for opening of

contacts are also widely used.

The terms pole and throw are also used to describe switch contact

variations. The number of "poles" is the number of electrically separate

switches which are controlled by a single physical actuator. For example, a "2-

pole" switch has two separate, parallel sets of contacts that open and close in

unison via the same mechanism. The number of "throws" is the number of

separate wiring path choices other than "open" that the switch can adopt for

each pole. A single-throw switch has one pair of contacts that can either be

closed or open. A double-throw switch has a contact that can be connected to

31

either of two other contacts, a triple-throw has a contact which can be connected

to one of three other contacts, etc.

In a switch where the contacts remain in one state unless actuated, such as

a push-button switch, the contacts can either benormally open (abbreviated

"n.o." or "no") until closed by operation of the switch, or normally closed ("n.c."

or "nc") and opened by the switch action. A switch with both types of contact is

called a changeover switch. These may be "make-before-break" which

momentarily connects both circuits, or may be "break-before-make" .which

interrupts one circuit before closing the other.

Types of switches

Inductive loads

Incandescent loads

Wetting current

Biased switches

Rotary switch

Toggle switch

Mercury tilt switch

UART

A UART (Universal Asynchronous Receiver and Transmitter) is a device

allowing the reception and transmission of information, in a serial and

asynchronous way. A UART allows the communication between a computer

and several kinds of devices (printer, modem, etc), interconnected via an RS-

232 cable.

32

This setup has other implications. When the Uno is connected to

either a computer running Mac OS X or Linux, it resets each time a connection

is made to it from software (via USB). For the following half-second or so, the

bootloader is running on the Uno. While it is programmed to ignore malformed

data (i.e. anything besides an upload of new code), it will intercept the first few

bytes of data sent to the board after a connection is opened.

Fig 5.2 UART Serial Communication

5.2.1 SERIAL TRANSMISSION

Data transmission is made by the UART in a serial way, by 11-bit blocks:

A 0 bit marks the starting point of the block.

Eight bits for data.

One parity bit.

A 1 bit marking the end of the block.

The transmission and reception lines should hold a 1.

Data is transmitted.

The first transmitted bit is the LSB (least significant bit).

33

PROCESSOR UART RS232

CONNECTOR

The parity bit is set to 1 or 0, depending on the number of 1's transmitted.

if even parity is used, this number should be even .If odd parity is used, this

number should be odd. If the chosen parity is not respected in the block, a

transmission error should be detected .The transmission speed is fixed,

measured in bauds .The meaning of signals is:

parityerr: error during the block reception

Framingerr: format error during the block reception

Overrun: a new data is arrived before reading of the

precedent data

Rxrdy: a new data is arrived and it's ready for reading

TXRDY: a new data is ready for sending

Read: reading of the receiver's data is activated

Write: writing of the emitter's data is activated

Data: 8-bit data, read or written

Tx: output bit

Rx: input bit

5.2.2 DIVISION OF UART

Data Emission

Data Reception

5.2.2.1 DATA EMISSION

To test signal TXRDY is active. If yes, a 8-bit data can be written in the

emitter. Place the 8-bit data in the input and to active the write signal .The

UART sends the 8 bits, via the TX signal. During transmission, the TXRDY

signal should be inactive. At the end of the emission, TXRDY should be active

again et TX set to 1.

5.2.2.2 DATA RECEPTION

34

The 8 bits of information arrive in a serial way, at any moment, via the

RX Signal. The starting point is given par a 0 value of RX. The UART places

the 8 bits in a parallel way over Data out, and announces their availability

setting rxrdy active .The information reading is made active with the read

signal.

5.2.3 RS-232 CONNECTOR

The J3 connector provides a standard RS-232 connection .The pins of J3

are directly connected to the FPGA, allowing an internal implementation of the

serial controller. It's possible to implement two UART without hardware

handshaking

Fig 5.2.3 RS232 Connector

5.3 MAX 232

35

Fig 5.3 Pin Diagram of MAX232

The MAX232 is an ic, that converts signals from an RS-232 serial port to

signals suitable for use in TTL compatible digital logic circuits. The max232 is

a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals.

5.3.1 FEATURES OF DESCRIPTION

The MAX232 device is a dual driver/receiver that Meets or Exceeds

TIA/EIA-232-F and ITU Recommendation V.28 includes a capacitive voltage

generator to supply TIA/EIA-232-F voltage levels from a single 5-V.

Operates from a Single 5-V Power Supply With supply. Each

receiver converts TIA/EIA-232-F inputs.

1.0-μF Charge-Pump Capacitors to 5-V TTL/CMOS levels.

Operates up to 120 Kbit/s typical threshold of 1.3 V, a typical

hysteresis of 0.5.

Two Drivers and Two Receivers V, and can accept ±30-V

inputs.

TTL/CMOS input levels into TIA/EIA-232-F levels.

±30-V Input Levels.

Low Supply Current: 8 mA Typical Device Information.

36

Upgrade With Improved ESD (15-kV HBM) and SOIC (16)

10.30 mm × 7.50 mm MAX232x.

0.1-μF Charge-Pump Capacitors is Available With PDIP (16)

19.30 mm × 6.35 mm.

The MAX232 device is a dual driver/receiver that includes a

capacitive voltage generator.

Supply TIA/EIA-232-F voltage levels from a single 5-V supply.

Each receiver converts TIA/EIA-232-F inputs to 5-v supply.

VTTL/CMOS levels. These receivers have a typical threshold of

1.3 V, a typical hysteresis of 0.5 V.

Accept ±30-V inputs. Each driver converts TTL/CMOS input

levels into TIA/EIA-232-F levels. The driver, receiver,

Voltage generator functions are available as cells in the Texas Instruments Lin

ASIC™ library. Outputs are protected against shorts to ground.

5.3.2 APPLICATIONS OF MAX232

TIA/EIA-232-F

Battery-Powered Systems

Terminals

Modems

Computers

5.3.3 FEATURE DESCRIPTION

5.3.3.1 POWER

The power block increases and inverts the 5V supply for the RS232 driver

using a charge pump that requires four 1-μF external capacitors.

5.3.4.2 RS232 DRIVER

Two drivers interface standard logic level to RS232 levels. Internal pull

up resistors on TIN inputs ensures a high input when the line is high impedance.

37

5.3.4.3 RS232 RECEIVER

Two receivers interface RS232 levels to standard logic levels. An open

input will result in a high output on ROUT.

5.3.4.4 VCC POWERED BY 5V

The device will be in normal operation.

5.3.4.5 VCC UNPOWERED

When MAX232 is unpowered, it can be safely connected to an active

remote RS232 device.

5.4 POWER SUPPLY MODULE

TF2, restoring electricity to the load. The transfer switch continues

to monitor utility power, and when it is restored, switches the load from the

Transformer TF2 back to the Main transformer TF1. Once the Transformer TF2

is disconnected, it goes through a cool-down routine and is automatically shut

down.

Fig 5.4 Block Diagram of Power Supply Source

Automatic mains changeover switch for uninterrupted power supply is an

integral part of the power control process, allowing smooth and immediate

38

transfer of electrical current between multiple sources and the load. Here we are

using two transformers TF1 (Main transformer) and TF2 (Backup transformer).

The transfers switch senses when utility power is interrupted, and starts up the

transformer TF2 which acts as a backup transformer. If the utility power

remains absent, the transfer switch disconnects the load from the utility and

connects it to the Transformer.

The present system is designed around two transformers. One transformer

(TF1) is used as the main supply and the other transformer (TF2) is used in the

place of the generator (for demo purpose). These two transformers are

connected with the relay which is controlled by the embedded controller. The

loads are connected to the main line (TF1) and as well as to the TF2. Initially

TF1 is connected to the load, the loads run with this power. Due to any reason

this power is interrupted, then it is identified by the controller and it

immediately switches ON to the TF2 through the relay. The controller

continuously monitors the TF1 (main line). When it finds the power on it again

switches the loads connection to the main line.

A power supply is a device that supplies electric power to an electrical

load. The term is most commonly applied to electric power converters that

convert one form of electrical energy to another, though it may also refer to

devices that convert another form of energy (mechanical, chemical, solar) to

electrical energy. A regulated power supply is one that controls the output

voltage or current to a specific value; the controlled value is held nearly

constant despite variations in either load current or the voltage supplied by the

power supply's energy source.

5.5 VOICE BANK MODULE

APR9600 was a low cost high performance sound record/play IC .Single chip,

high quality voice recording and playback solution.User friendly, Easy to use

39

operation.Non - Volatile - flash memory technology, no battery backup

required.4-8 KHz sampling rate.Can record voice with the help of on-board

microphone or via any audio input. set up to create a specific interrogation zone

which can be tightly controlled. This allows a highly defined reading area for

when tags go in and out of the interrogation zone. Mobile readers may be hand-

held or mounted on carts or vehicle.

Fig 5.5 Voice Bank Module

APR9600 is a low-cost high performance sound record/replay IC

incorporating flash analogue storage technique. Recorded sound is retained even

after power supply is removed from the module. The replayed sound exhibits

high quality with a low noise level. Sampling rate for a 60 second recording

period is 4.2 kHz that gives a sound record/replay bandwidth of 20Hz to 2.1

KHZ .

This shortens the total length of sound recording to 32 seconds. Total

sound recording time can be varied from 32 seconds to 60 seconds by changing

the value of a single resistor. The IC can operate in one of two modes: serial

40

mode and parallel mode. In serial access mode, sound can be recorded in 256

sections. In parallel access mode, sound can be recorded in 2, 4 or 8 sections.

The IC can be controlled simply using push button keys. It is also possible to

control the IC using external digital circuitry such as micro-controllers and

computers. The APR9600 has a 28 pin DIP package. Supply voltage is between

4.5V to 6.5V.

During recording and replaying, current consumption is 25 MA. In idle

mode, the current drops to 1 MA. The APR9600 experimental board is an

assembled PCB board consisting of an APR9600 IC, an electrets microphone,

support components and necessary switches to allow users to explore all

functions of the APR9600 chip. The oscillation resistor is chosen so that the

total recording period is 60 seconds with a sampling rate of 4.2 kHz. The board

measures 80mm by 55mm.

During sound recording, sound is picked up by the microphone. A

microphone pre-amplifier amplifies the voltage signal from the microphone. An

AGC circuit is included in the pre-amplifier, the extent of which is controlled by

an external capacitor and resistor. If the voltage level of a sound signal is

around 100 mV peak to- peak, the signal can be fed directly into the IC through

ANA IN pin (pin 20). The sound signal passes through a filter and a sampling

and hold circuit. The analogue voltage is then written into non-volatile flash

analogue RAMs. It has a 28 pin DIP package. Supply voltage is between 4.5V

to 6.5V. During recording and replaying, current consumption is 25 MA. In idle

mode, the current drops to 1 mA.

5.5.1 MODES OF APR9600 MODULE

5.5.1.1 PARALLEL MODE RECORDING AND REPLAYING

Record sound tracks is an example of recording 8 sound tracks. The mode

switch should have the following pattern: MSEL1=1(switched to left-hand side

41

of the mode selection switch), MSEL2=1 (left-hand side). –M8=1 (left-hand

side). RE=0 (right-hand side). The maximum length of the 8 tracks is 7.5

seconds. Press –M1 continuously and you will see BUZY LED illuminates. The

sound signal passes through a filter and a sampling and hold circuit. The

analogue voltage is then written into non-volatile flashanalogue RAMs. It has a

28 pin DIP package.

Fig 5.5.1 pin diagram of APR9600

42

The output delivered in microphone. Recording will terminate if –M1 is

released or if the recording time exceeds 7.5seconds.

Fig 5.5.1.1 APR9600 MODULE With Connector

5.5.2 SERIAL MODE RECORDING AND REPLAYING

Record sound track sequentially is an example of recording sequential

sound tracks. The mode switch should have the following pattern:

MSEL1=0(switched to right-hand side of the mode selection switch), MSEL2=0

(right-hand side). –M8=1 (left-hand side). RE=0 (right-hand side). Press CE

first to reset the sound track counter to zero. Press and hold –M1 down and you

will see BUZY LED illuminates. You can now speak to the microphone.

Recording will terminate if M1 is released or if the recording time exceeds 60

seconds (in this case you will run out the memory for your next sound track).

Press –M1 again and again to record 2nd, 3rd , 4th and other consecutive sound

tracks. Each sound track may have different lengths, but the accumulated length

of all sound tracks will not exceed 60 seconds.

43

VOICE BANK APR 9600

Voice banking is the recording of one's natural voice for the possible

eventuality of losing one's voice. Software then uses these recordings in

a speech generating device or using software on a computer so that the user may

communicate using a facsimile of their voice. Patients diagnosed with ALS will

often eventually lose their voices, so are urged to bank their voices for this

purpose.

The APR9600 device offers true single-chip voice recording,non-volatile

storage, and playback capability for 40 to 60 seconds. The device supports both

random and sequential access of multiple messages. Sample rates are user-

selectable, allowing designers to customize their design for unique quality and

storage time needs. Integrated output amplifier, microphone amplifier, and AGC

circuits greatly simplify system design.

The device is ideal for use in portable voice recorders, toys, and many

other consumer and industrial applications.APLUS integrated achieves these

high levels of storage capability by using its proprietary analog/multilevel

44

storage technology implemented in an advanced Flash non-volatile memory

process, where each memory cell can store 256 voltage levels.

This technology enables the APR9600 device to reproduce voice signals

in their natural form. It eliminates the need for encoding and compression,

which often introduce distortion.

Message Management General Description Playback and record

operations are managed by on-chip circuitry. There are several available

messaging modes depending upon desired operation. These message modes

determine message management style, message length, and external parts count.

Therefore, the designer must select the appropriate operating mode before

beginning the design. Operating modes do not affect voice quality; for

information on factors affecting quality refer to the Sampling Rate & Voice

Quality section. The device supports five message management modes (defined

by the MSEL1, MSEL2 and /M8_OPTION pins ).

Random access mode with 2, 4, or 8 fixed-duration messages Tape mode,

with multiple variable-duration messages, provides two options: - Auto rewind

– Normal Modes cannot be mixed. Switching of modes after the device has

recorded an initial message is not recommended. If modes are switched after an

initial recording has been made some unpredictable message fragments from the

previous mode may remain present, and be audible on playback, in the new

mode.These fragments will disappear after a Record operation in the newly

selected mode. the decoding necessary to choose the desired mode.

An important feature of the APR9600 Message management capabilities

is the ability to audibly prompt the user to change in the device's status through

the use of "beeps" superimposed on the device's output. This feature is enabled

by asserting a logic high level on the BE pin.

Features :

45

• Single-chip, high-quality voice recording & playback solution

- No external ICs required

- Minimum external components

• Non-volatile Flash memory technology

- No battery backup required

• User-Selectable messaging options

- Random access of multiple fixed-duration messages

- Sequential access of multiple variable-duration messages

• User-friendly, easy-to-use operation

- Programming & development systems not required

- Level-activated recording & edge-activated play back switches

• Low power consumption

- Operating current: 25 mA typical

- Standby current: 1 uA typical

- Automatic power-down

• Chip Enable pin for simple message expansion

General Description:

The APR9600 device offers true single-chip voice recording, non-volatile

storage, and playback capability for 40 to 60 seconds. The device supports both

random and sequential access of multiple messages. Sample rates are user-

selectable, allowing designers to customize their design for unique quality and

storage time needs. Integrated output amplifier, microphone amplifier, and AGC

circuits greatly simplify system design.

46

The device is ideal for use in portable voice recorders, toys, and many

other consumer and industrial applications. APLUS integrated achieves these

high levels of storage capability by using its proprietary analog/multilevel

storage technology implemented in an advanced Flash non-volatile memory

process, where each memory cell can store 256 voltage levels.

This technology enables the APR9600 device to reproduce voice signals

in their natural form. It eliminates the need for encoding and compression,

which often introduce distortion.

PIN DIAGRAM

47

APR9600 block diagram is included in order to describe the device's

internal architecture. At the left hand side of the diagram are the analog inputs.

A differential microphone amplifier, including integrated AGC, is included on-

chip for applications requiring use. The amplified microphone signals fed into

the device by connecting the ANA_OUT pin to the ANA_IN pin through an

external DC blocking capacitor. Recording can be fed directly into the ANA_IN

pin through a DC blocking capacitor, however, the connection between

ANA_IN and

ANA_OUT is still required for playback.

The next block encountered by the input signal is the internal anti-

aliasing filter. The filter automatically adjusts its response according to the

sampling frequency Selected so Shannon’s Sampling Theorem is satisfied. After

anti-aliasing filtering is accomplished the signal is ready to be clocked into the

memory array. This storage is accomplished through a combination of the and

Hold circuit and the Analog Write/Read circuit.

These circuits are clocked by either the Internal Oscillator or an external

clock source. When playback is desired the previously stored recording is

retrieved from memory, low pass filtered, and amplified as shown on the right

hand side of the diagram. The signal can be heard by connecting a speaker to

the SP+ and SP- pins. Chip-wide management is accomplished through the

device control block. The upper right hand corner. Message management is

48

provided through the message control block represented in the lower center of

the block diagram.

More detail on actual device application can be found in the Sample

Application section. More detail on sampling control can be found in the

Sample Rate and Voice Quality section. More detail on Message management

and device control can be found in the Message Management section.

CIRCUIT DIAGRAM FOR APR 9600

Functional Description of Playback Random Access Mode

On power up, the device is ready to record or playback, in any of the

enabled message segments. To playback,/CE must be set low to enable the

device and /RE must be set high to disable recording & enable playback. You

initiate playback by applying a high to low edge on the message trigger pin that

represents the message segment you intend to playback. Playback will continue

until the end of the message is reached. If a high to low edge occurs on the same

49

message trigger pin during playback, playback of the current message stops

immediately.

If a different message trigger pin pulses during playback, playback of the

current message stops immediately (indicated by one beep) and playback of the

new message segment begins. A delay equal to 8,400 cycles of he sample clock

will be encountered before the device starts playing the new message. If a

message trigger pin is held low, the selected message is played back repeatedly

as long as the trigger pin stays low. A period of silence, of duration equal to

8,400 cycles of the sampling clock, will be inserted during looping as an

indicator to the user of the transition between the end and the beginning of the

message.

Tape Mode :

Tape mode manages messages sequentially much like traditional cassette

tape recorders. Within tape mode two options exist, auto rewind and normal.

Auto rewind mode configures the device to automatically rewind to the

beginning of the message immediately following recording or playback of the

message. In tape mode, using either option, messages must be recorded or

played back sequentially, much like a traditional cassette tape recorder

Function Description of Recording in Tape Mode using the Auto Rewind

Option

On power up, the device is ready to record or playback, starting at the

first address in the memory array. To record, /CE must be set low to enable the

device and /RE must be set low to enable recording. A falling edge of the

/M1_MESSAGE pin initiates voice recording (indicated by one beep).A

subsequent rising edge of the /M1_MESSAGE pin during recording stops the

recording (also indicated by one beep).

50

If the M1_MESSAGE pin is held low beyond the end of the available

memory, recording will stop automatically (indicated by two beeps). The device

will then assert a logic low on the /M7_END pin until the /M1 Message pin is

released. The device returns to standby mode when the /M1_MESSAGE pin

goes high again.

After recording is finished the device will automatically rewind to the

beginning of the most recently recorded message and wait for the next user

input. The auto rewind function is convenient because it allows the user to

immediately playback and review the message without the need to rewind.

However, caution must be practiced because a subsequent record operation will

overwrite the last recorded message unless the user remembers to pulse the

/M2_Next pin in order to increment the device past the current message.

A subsequent falling edge on the /M1_Message pin starts a new record

operation, overwriting the previously existing message. You can preserve the

previously recorded message by using the /M2_Next input to advance to the

next available message segment.

To perform this function, the /M2_NEXT pin must be pulled low for at

least 400 cycles of the sample clock. The auto rewind mode allows the user to

record over the just recorded message simply by initiating a record sequence

without first toggling the /M2_NEXT pin To record over any other message

however requires a different sequence. You must pulse the /CE pin low once to

rewind the device to the beginning of the voice memory.

The /M2_NEXT pin must then be pulsed low for the specified number of

times to move to the start of the message you wish to overwrite. Upon arriving

at the desired message a record sequence can be initiated to overwrite the

previously recorded material. After you overwrite the message it becomes the

last available message and all previously recorded messages following this

message become inaccessible. If during a record operation all of the available

memory is used, the device will stop recording automatically,(double beep) and

51

set the /M7_END pin low for a duration equal to 1600 cycles of the sample

clock.

Playback can be initiated on this last message, but pulsing the /M2_Next

pin will put the device into an "overflow state".Once the device enters an

overflow state any subsequent pulsing of /M1_MESSAGE or /M2_NEXT will

only result in a double beep and setting of the /M7_END pin low for a duration

equal to 400 cycles of the sample clock. To proceed from this state the user

must rewind the device to the beginning of the memory array. This can be

accomplished by toggling the /CE pin low or cycling power. All inputs, except

the /CE pin,are ignored during recording.

Parameter

● Voltage: 4.5-5.5V

● Current: <40mA

● Digital Interface: 5V TTL level for UART interface and GPIO

● Analog Interface: 3.5mm mono-channel microphone connector + microphone

pin interface

● Size: 31mm x 50mm

● Recognition accuracy: 99% (under ideal environment)

Feature

● Support maximum 80 voice commands, with each voice 1500ms (one or two

words speaking)

● Maximum 7 voice commands effective at same time

● Arduino library is supplied

● Easy Control: UART/GPIO

● User-control General Pin Output

52

SPEAKERS

Digital speakers are a form of loudspeaker technology. Not to be

confused with modern digital formats and processing, they are a mature

technology, having been experimented with extensively by Bell Labs as far

back.

Function

The least significant bit drives a tiny speaker driver, of whatever physical

design is chosen; a value of "1" causes this driver to be driven full amplitude, a

value of "0" causes it to be off. This allows for high efficiency in the amplifier,

which at any time is either passing zero current, or required to drop the output

voltage by zero volts, therefore in a theoretical ideal amplifier dissipating no

power as heat at any time. The next least significant bit drives a speaker of

twice the area (most often, but not necessarily, a ring around the previous

driver), again to either full amplitude, or off. The next least significant bit drives

a speaker of twice this area, and so on.

Other approaches are possible. For example, instead of doubling the area

of the next most significant diaphragm segment, it could simply be driven so it

stroked twice as far. The digital principle of operation and attendant amplifier

efficiency benefits would remain.

Ultrasonic output

To work properly, all of the individual diaphragm elements would have to

operate cleanly at the clock frequency. The natural frequency response of the

various elements will vary with their size. This creates a DAC where the various

bits have different bandpass characteristics. Large short-term errors can be

expected.

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Since this system is converting digital signal to analog, the effect

of aliasing is unavoidable, so that the audio output is "reflected" at equal

amplitude in the frequency domain, on the other side of the sampling frequency.

One solution would be to overclock the conversion elements, introduce a digital

filter and follow them with an acoustical low pass filter. Even accounting for the

vastly lower efficiency of speaker drivers at such high frequencies, the result

was to generate an unacceptably high level of ultrasonics accompanying the

desired output.

In electronic digital to analog conversion, this is addressed by the use

of low-pass filters to eliminate the spurious upper frequencies produced. Since

these frequencies are eliminated in the electrical signal, they are not passed to

the speaker and thus ultrasonic airwaves are not generated. However, electronic

filtering is inherently unable to solve this problem with the digital loudspeaker.

The speaker elements must operate ultrasonically to avoid introducing (high

levels of) audible artifacts, and this means ultrasonic airwaves are inevitable.

Electronics can filter electrical signals, but can not remove ultrasonic

frequencies already in the air.

Efficiency

Although amplifier efficiency is good with this system, moving coil

speakers operate at relatively low efficiency in the ultrasonic frequency region.

Thus the original aim of the method is defeated. Modern speakers marketed as

'digital' are always analog speakers, in most cases driven by an analog amplifier.

The widespread use of the term 'digital' with speakers is a marketing ploy

intended to claim better suitability with 'digital' source material

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(e.g., MP3 recordings), or impute 'higher technology' than some other speaker,

and perhaps higher price. If pressed, manufacturers may claim the term means

the product is 'ready' for input from digital players; this is true of essentially all

speaker systems.

There are also a minority of Class D and Class T digital amplifier driven analog

speakers, though these are not normally found in separate computer speakers or

home stereo systems. These are common in laptops, where their higher cost is

justified by battery power savings. The speakers in such equipment are still

analog.

SOFTWARE DESCRIPTION

ARDUINO

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Arduino is a cross-platform IDE that works in conjunction with an

Arduino controller in order to write, compile and upload code to the board.The

software provides support for a wide array of Arduino boards, including

Arduino Uno, Nano, Mega, Esplora, Ethernet, Fio, Pro or Pro Mini, as well as

LilyPad Arduino.

The universal languages for Arduino are C and C++, thus the software is fit for

professionals who are familiar with these two. Features such as syntax

highlighting, automatic indentation and brace matching makes it a modern

alternative to other IDEs.Wrapped inside a streamlined interface, the software

features both the looks and the functionality that appeal to Arduino developers,

paving the way to a successful output via the debugging modules.

All of its features are hosted inside a few buttons and menus that are easy

to navigate and understand, especially for professional programmers. Also, the

built-in collection of examples might be of great help for Arduino first

timers.Provided that you’ve connected the Arduino board to the computer and

installed all the necessary drivers, one of the first steps we see fit is to choose

the model you’ll be working with using the Tools menu of the application.

Then, you can start writing the programs using the comfortable

environment that Arduino offers. The program includes a rich array of built-in

libraries such as EEPROM, Firmata, GSM, Servo, TFT, WiFI, etc, but adding

your own is also possible. Designs can be verified and compiled, with an error

log displayed in the lower part of the UI that allows you to review the code.

If the debugging process returns no errors, you can start the upload

process and have your program delivered to the board so you can proceed with

further testing.All in all, Arduino comes across as an extremely useful asset,

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providing the essentials that Arduino developers need in order to streamline the

testing process.

Arduino is an open-source computer hardware and software company,

project and user community that designs and manufacturesmicrocontroller-

based kits for building digital devices and interactive objects that can sense and

control objects in the physical world. The project is based on microcontroller

board designs, manufactured by several vendors, using various

microcontrollers. These systems provide sets of digital and analog I/O pins that

can be interfaced to various expansion boards ("shields") and other circuits.

The boards feature serial communications interfaces, including USB on

some models, for loading programs from personal computers. For programming

the microcontrollers, the Arduino project provides an integrated development

environment (IDE) based on the Processing project, which includes support for

the C and C++ programming languages.

The first Arduino was introduced in 2005, aiming to provide an

inexpensive and easy way for novices and professionals to create devices that

interact with their environment using sensors and actuators. Common examples

of such devices intended for beginner hobbyists include

simple robots, thermostats, and motion detectors. Arduino boards are available

commercially in preassembled form, or as do-it-yourself kits. The hardware

design specifications are openly available, allowing the Arduino boards to be

manufactured by anyone.

Arduino programs may be written in any programming language with a

compiler that produces binary machine code. Atmel provides a development

environment for their microcontrollers, AVR Studio and the newer Atmel

Studio. The Arduino project provides the Arduino integrated development

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environment (IDE), which is a cross-platform application written inJava. It

originated from the IDE for the Processing programming language project and

the Wiring project. It is designed to introduce programming to artists and other

newcomers unfamiliar with software development. It includes a code editor

with features such assyntax highlighting, brace matching, and automatic

indentation, and provides simple one-click mechanism for compiling and

loading programs to an Arduino board. A program written with the IDE for

Arduino is called a "sketch".

The Arduino IDE supports the C and C++ programming languages using

special rules of code organization. The Arduino IDE supplies a software

library called "Wiring" from the Wiring project, which provides many common

input and output procedures. A typical Arduino C/C++ sketch consists of two

functions that are compiled and linked with a program stub main () into an

executable cyclic program:

setup(): a function that runs once at the start of a program and that can

initialize settings.

loop(): a function called repeatedly until the board powers off.

After compilation and linking with the GNU tool chain, also included

with the IDE distribution, the Arduino IDE employs the programavrdude to

convert the executable code into a text file in hexadecimal coding that is loaded

into the Arduino board by a loader program in the board's firmware

ARDUINO BUILD PROCESS

OVERVIEW

A number of things have to happen for your Arduino code to get onto the

Arduino board. First, the Arduino environment performs some small

transformations to make sure that the code is correct C or C++ (two common

programming languages). It then gets passed to a compiler (avr-gcc), which

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turns the human readable code into machine readable instructions (or object

files). Then, your code gets combined with (linked against), the standard

Arduino libraries that provide basic functions like digitalWrite() or

Serial.print().

The result is a single Intel hex file, which contains the specific bytes that

need to be written to the program memory of the chip on the Arduino board.

This file is then uploaded to the board: transmitted over the USB or serial

connection via the bootloader already on the chip or with external programming

hardware.

Multi-file sketches

A sketch can contain multiple files (tabs). To manage them, click on the

right-facing arrow just above the scroll bar near the top of the environment.

Tabs have one of four extensions: no extension, .c, .cpp, or .h (if you provide

any other extension, the period will be converted to an underscore). When your

sketch is compiled, all tabs with no extension are concatenated together to form

the "main sketch file". Tabs with .c or .cpp extensions are compiled separately.

To use tabs with a .h extension, you need to #include it (using "double quotes"

not <angle brackets.

The Arduino environment performs a few transformations to your main

sketch file (the concatenation of all the tabs in the sketch without extensions)

before passing it to the avr-gcc compiler.First, #include "Arduino.h", or for

versions less than 1.0, #include "WProgram.h" is added to the top of your

sketch. This header file (found in <ARDUINO>/hardware/cores/<CORE>/)

includes all the defintions needed for the standard Arduino core.

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Next, the environment searches for function definitions within your main

sketch file and creates declarations (prototypes) for them. These are inserted

after any comments or pre-processor statements (#includes or #defines), but

before any other statements (including type declarations). This means that if you

want to use a custom type as a function argument, you should declare it within a

separate header file. Also, this generation isn't perfect: it won't create prototypes

for functions that have default argument values, or which are declared within a

namespace or class.

TARGETS

The Arduino environment supports multiple target boards with different

chips (currently, only AVRs), CPU speeds, or bootloaders. These are defined in

a board preferences file. Relevant variables include:

<BOARD>.name: the name to display in the Boards menu

<BOARD>.build.mcu: the microcontroller on the board (normally "atmega8" or

"atmega168").

<BOARD>.f_cpu: the clock speed at which the microcontroller operates

(normally "16000000L", or, for an ATmega168running on its internal clock,

"8000000L").

<BOARD>.core: which sub-directory of the hardware/cores/ directory to link

sketches against (normally "arduino").

Also useful is this setting in the main preferences.txt file:

build.verbose: whether or not to print debugging messages while building a

sketch (e.g. "false"). If true, will print the complete command line of each

external command executed as part of the build process.

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Note: that in Arduino 0004 and later, build.extension is unused - the main

sketch file is always treated as a .cpp file.

Build process

Sketches are compiled by avr-gcc.

The include path includes the sketch's directory, the target directory

(<ARDUINO>/hardware/core/<CORE>/) and the avr include directory

(<ARDUINO>/hardware/tools/avr/avr/include/), as well as any library

directories (in <ARDUINO>/hardware/libraries/) which contain a header file

which is included by the main sketch file.

When you verify a sketch, it is built in a temporary directory in the system temp

directory (e.g. /tmp on the Mac). When you upload it, it is built in the applet/

subdirectory of the sketch's directory (which you can access with the "Show

Sketch Folder" item in the "Sketch" menu).

The .c and .cpp files of the target are compiled and output with .o

extensions to this directory, as is the main sketch file and any other .c or .cpp

files in the sketch and any .c or .cpp files in any libraries which are #included in

the sketch. These .o files are then linked together into a static library and the

main sketch file is linked against this library. Only the parts of the library

needed for your sketch are included in the final .hex file, reducing the size of

most sketches.

The .hex file is the final output of the compilation which is then

uploaded to the board. During a "Verify" the .hex file is written to /tmp (on Mac

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and Linux) or \Documents and Settings\<USER>\Local Settings\Temp (on

Windows). During upload, it's written to the applet sub-directory of the sketch

directory (which you can open with the "Show Sketch Folder" item in the

Sketch menu).

Upload process

Sketches are uploaded by avrdude. The upload process is also controlled by

variables in the boards and main preferences files. Those in the boards file

include:

<BOARD>.upload. Protocol: the protocol that avrdude should use to talk to the

board (typically "stk500").

<BOARD>.upload. Speed: the speed (baud rate) avrdude should use when

uploading sketches (typically "19200").

<BOARD>.upload.maximum_size: the maximum size for a sketch on the board

(dependent on the chip and the size of the boot loader).

CHAPTER 7

CONCLUSION

In this project, we have described MATLab program to read printed text

on hand-held objects for assisting blind persons. In order to solve the common

62

aiming problem for blind users, we have proposed a database method to detect

the product name by using MATLab programme.The PIC16F877A

microcontroller is a family of modified hardware architecture.PIC is an

inexpensive microcontroller.In this project, we use Open CV library to process

the images so that the features for each letter could be extracted. Image

localization is then performed on the database image. Conversion to gray-scale

can be done in Open CV.

The reason we had to convert our image to gray-scale was because

thresholding could be applied to monochrome pictures only. Once the identified

label name is converted into text and converted text is displayed on display unit

connected to controller. Now converted text should be converted to voice to

hear label name as voice through earphones connected to audio jack port using

file library.In this project, we are using voice bank module APR9600 which was

a low cost high performance . We can use it for both play IC and sound record.

It is user friendly and easy to use operation. The sampling rate of voice bank is

4-8 kHz. By using this voice bank, we can record voice with the help of on-

board microphone or via any audio input.

CHAPTER 8

REFERENCE

[1] P. Viola and M. Jones. Rapid object detection using a boosted cascade of

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simple features. In CVPR, 2009.

[2] X. Chen and A. L. Yuille Detecting and Reading Text in Natural Scenes.

In CVPR, 2004.

[3] Simon M. Lucas. ICDAR 2005 text locating competition results.

Proceedings of International Conference on Document Analysis and

Recognition (ICDAR), 2005.

[4] Keechul Jung and Kwang In Kim and Anil K. Jain. Text information

extraction in images and video: a survey Pattern Recognition,2004.

[5] Ching-Tung Wu. Embedded-Text Detection and Its Application to Anti-

Spam Filtering. Master Thesis at the University of California, Santa Barbara,

2005.

[6] C_eline Mancas-Thillou, Bernard Gosselin. Natural Scene Text

Understanding.Vision Systems: Segmentation and Pattern Recognition, ISBN

978-3-902613-05-9, pp, 307-333, 2007.

[7] Yoav Freund and Robert E. Schapire. A decision-theoretic generalization

of on-line learning and an application to boosting. European Conference on

Computational Learning Theory, pp. 23-37, 2005.

[8] Robert E. Schapire and Yoav Freund and Peter Bartlett and Wee Sun Lee.

Boosting the margin: a new explanation for the activeness of voting

methods. Proc. 14th International Conference on Machine Learning, 2007.

[9] Viktor Peters. E_zientes Training ansichtsbasierter Gesichtsdetektoren.

Diplomarbeit im Fach Naturwissenschaftliche Informatik: Technische Fakultat�

Universitat Bielefeld, 2006.�

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