Blind Man Stick CH h

7/22/2019 Blind Man Stick CH h

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CONTENTS

1. Introduction2. Block Diagram3. Micro-Controller -At89s524. Ultrasonic Sensor & IR Sensor5. Op-Amp Lm3586. RFID Technology7. Multitone Muscical IC (Siren)8. References


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INTRODUCTION


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INTRODUCTION

Vision is the most important part of human physiology as 83% of information human being gets

from the environment is via sight. The 2011 statistics by the World Health Organization (WHO)estimates that there are 285 billion people in world with visual impairment, 39 billion of which

are blind and 246 with low vision. The traditional and oldest mobility aids for persons with

visual impairments are the walking cane (also called white cane or stick) and guide dogs. The

most important drawbacks of these aids are necessary skills and training phase, range of motion

and very little information conveyed. With the rapid advances of modern technology, both in

hardware and software front have brought potential to provide intelligent navigation capabilities.

Recently there has been a lot of Electronic Travel Aids (ETA) designed and devised to help the

blind navigate independently and safely. Also high-end technological solutions have been

introduced recently to help blind persons navigate independently. While such systems are

suitable for outdoor navigation, due to the need for line of sight access to satellites, they still

need additional components to improve on the resolution and proximity detection to prevent

collision of the blind persons with other objects and hence subject his/her life to danger.

However in comparison to other technologies many blind guidance systems use ultrasound

because of its immunity to the environmental noise. Another reason why ultrasonic is popular is

that the technology is relatively inexpensive, and also ultrasound emitters and detectors are small

enough to be carried without the need for complex circuitry.

The project is based on a theoretical model and a system concept to provide a smart electronic

aid for blind people. Apart from the conventional navigation systems, blind aid systems can be

provided a new dimension of RF-ID to identify the sitting area in office and RF module used for

find the stick along with dedicated obstacle detection circuitry incorporate ultrasonic sensor,

depth measuring circuitry helps to measure the depth in case of dealing with the stairs and on

stick vibration circuitry to inform the obstacle alert. These different units are discussed to

implement the design of a smart stick.


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COMPONENET USED

1. Microcontroller (P89v51RD2)

2. Decoder HT 12D

3. Encoder HT 12E

4. RF Module (Rx and Tx)

5. RF- ID reader

6. RF-ID Card

7. Ultrasonic Senor

8. IR Sensor

9. Temperature sensor

10. Probes

11. Multitone Musical IC


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BLOCK DIAGRAM


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BLOCKDIAGRAM


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MICRO-CONTROLLER -

AT89S52


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MICRO-CONTROLLER

INTRODUCTION

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of

in-system programmable Flash memory. The device is manufactured using Atmels high-densitynonvolatile memory technology and is compatible with the industry-standard 80C51 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 in-

system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful

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

control applications. The AT89S52 provides the following standard features: 8K bytes of Flash,

256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters,

a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and

clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode stops the

CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power-down mode saves the RAM con-tents but freezes the oscillator,

disabling all other chip functions until the next interrupt or hardware reset.


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PIN DIAGRAM


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Pin Description

1. VCC Supply voltage.

2. GND Ground.

3. Port 0

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

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

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

external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives

the code bytes during Flash programming and outputs the code bytes during program

verification.

4. Port 1 Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output

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

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

pulled low will source current (IIL) because of the internal pull-ups. In addition, P1.0 and P1.1

can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter

2 trigger input (P1.1/T2EX), respectively. Port 1 also receives the low-order address bytes during

Flash programming and verification.




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.




pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control signals

for Flash programming and verification. Port 3 also serves the functions of various special

features of the AT89S52, as shown in the following table.


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

resets the device. This pin drives high for 98 oscillator periods after the Watchdog times out. The

DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state

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

8. ALE/PROG Address Latch Enable (ALE) is an output pulse for latching the low byte of the

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

during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the

oscillator frequency and may be used for external timing or clocking purposes.

9. PSEN Program Store Enable (PSEN) is the read strobe to external program memory. When

the AT89S52 is executing code from external program memory, PSEN is activated twice each

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

memory.

10. 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 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.

11. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating

circuit.

12. XTAL2 Output from the inverting oscillator amplifier.

FEATURES OF AT89S52

Compatible with MCS

-51Products

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 10,000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines


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Three 16-bit Timer/Counters

Eight Interrupt Sources

Full Duplex UART Serial Channel

Low-power Idle and Power-down Modes

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)

Green (Halide-free) Packaging Option

ADAVANTAGES OF AT89S52

Low power High performance CMOS 8-bit microcontroller with 8kB of ISP flash memory. The device uses Atmel high-density, nonvolatile memory technology and is compatible

with the industry-standard 80C51 instruction set and pin out.

On-chip flash allows the program memory to be reprogrammed in-system or by aconventional nonvolatile memory programmer.

This powerful microcontroller is suitable for many embedded control applications.


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ULTRASONIC SENSOR & IR

SENSOR


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ULTRASONIC SENSOR

Ultrasonic sensors

Also known as transceivers when they both send and receive, but more generally called

transducers work on a principle similar to radarorsonar which evaluate attributes of a target by

interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors generate high

frequency sound waves and evaluate the echo which is received back by the sensor. Sensors

calculate the time interval between sending the signal and receiving the echo to determine the

distance to an object.

This technology can be used for measuring wind speed and direction (anemometer), tank or

channel level, and speed through air or water. For measuring speed or direction a device uses

multiple detectors and calculates the speed from the relative distances to particulates in the air or

water. To measure tank or channel level, the sensor measures the distance to the surface of the

fluid. Further applications include: humidifiers, sonar, medical ultrasonography, burglar

alarms and non-destructive testing.

Systems typically use a transducer which generates sound waves in the ultrasonic range, above

18,000 hertz, by turning electrical energy into sound, then upon receiving the echo turn the sound

waves into electrical energy which can be measured and displayed.

USES:

Medical Ultrasonic transducers. Ultrasonic sensors are used to detect movement oftargets and to measure the distance to targets in many automated factories and process
http://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Anemometerhttp://en.wikipedia.org/wiki/Humidifierhttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Medical_ultrasonographyhttp://en.wikipedia.org/wiki/Burglar_alarmshttp://en.wikipedia.org/wiki/Burglar_alarmshttp://en.wikipedia.org/wiki/Non-destructive_testinghttp://en.wikipedia.org/wiki/Automatic_factoryhttp://en.wikipedia.org/wiki/Automatic_factoryhttp://en.wikipedia.org/wiki/Non-destructive_testinghttp://en.wikipedia.org/wiki/Burglar_alarmshttp://en.wikipedia.org/wiki/Burglar_alarmshttp://en.wikipedia.org/wiki/Medical_ultrasonographyhttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Humidifierhttp://en.wikipedia.org/wiki/Anemometerhttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Radar


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plants. Sensors with an on or off digital output are available for detecting the movement

of object.

Ultrasonic sensors are used to detect movement of targets and to measure the distance totargets in many automated factories and process plants. Sensors with an on or off digital

output are available for detecting the movement of objects.

Maximum distance : 4meters Baud rate :9600 Output voltage : 5v Gives serial output

INFRARED SENSOR

An infrared sensor is an electronic device that emits and/or detects infrared radiation in order to

sense some aspect of its surroundings. Infrared sensors can measure the heat of an object, as well

as detect motion. Many of these types of sensors only measure infrared radiation, rather than

emitting it, and thus are known as passive infrared (PIR) sensors.

All objects emit some form of thermal radiation, usually in the infrared spectrum. This radiation

is invisible to our eyes, but can be detected by an infrared sensor that accepts and interprets it. In

a typical infrared sensor like a motion detector, radiation enters the front and reaches the sensor

itself at the center of the device. This part may be composed of more than one individual sensor,

each of them being made from pyro-electric materials, whether natural or artificial. These are

materials that generate an electrical voltage when heated or cooled.

These pyro-electric materials are integrated into a small circuit board. They are wired in such a

way so that when the sensor detects an increase in the heat of a small part of its field of view, it

will trigger the motion detector's alarm. It is very common for an infrared sensor to be integrated

into motion detectors like those used as part of a residential or commercial security system
http://en.wikipedia.org/wiki/Automatic_factoryhttp://www.wisegeek.com/what-is-infrared-radiation.htmhttp://www.wisegeek.com/what-is-infrared-radiation.htmhttp://www.wisegeek.com/what-is-a-motion-detector.htmhttp://www.wisegeek.org/what-is-a-circuit-board.htmhttp://www.wisegeek.org/what-is-a-circuit-board.htmhttp://www.wisegeek.com/what-is-a-motion-detector.htmhttp://www.wisegeek.com/what-is-infrared-radiation.htmhttp://www.wisegeek.com/what-is-infrared-radiation.htmhttp://en.wikipedia.org/wiki/Automatic_factory


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Infrared sensor and ultrasonic sensor both uses op-amp LM358 which act as a

comparator.

USES

A heat sensor works by using pyro-electrical materials, which emit electrical impulseswhen heated or cooled.

IR sensors can be used to detect proximity, receive communication signals and evendetect movement of a person.

The Arduino open-source electronics and embedded processor platform can be used tocontrol and monitor an infrared sensor.

IR Sensor can also be used to build speedometer.


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OP-AMP LM358

These devices consist of two independent, high-gain, frequency-compensated operational

amplifiers designed to operate from a single supply over a wide range of voltages. Operationfrom split supplies also is possible if the difference between the two supplies is 3 V to 32 V (3 V

to 26 V for the LM2904), and VCC is at least 1.5 V more positive than the input common-mode

voltage. The low supply-current drain is independent of the magnitude of the supply voltage.

Applications include transducer amplifiers, dc amplification blocks, and all the conventional

operational amplifier circuits that now can be implemented more easily in single-supply-voltage

systems. For example, these devices can be operated directly from the standard 5-V supply used

in digital systems and easily provide the required interface electronics without additional 5-V

supplies.

Features

Two internally compensated op-amps Internally frequency compensated for unity gain Large DC voltage gain: 100 dB Wide bandwidth (unity gain): 1 MHz (temperature compensated) Wide power supply range:

Single supply: 3V to 32V or dual supplies: 1.5V to 16V


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TEMPRATURE AND WATER SENSOR USES OP-AMP

In temperature detection we use the IR sensor which helps to detect fire or other heatingbody through heat.

In water sensor we use two probe which act as a conducting material and helps to detectwater.


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RFID TECHNOLOGY


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What is RFID?

RFID stands forRadio-Frequency Identification. The acronym refers to small electronic

devices that consist of a small chip and an antenna. The chip typically is capable of carrying

2,000 bytes of data or less.

The RFID device serves the same purpose as a bar code or a magnetic strip on the back of a

credit card or ATM card; it provides a unique identifier for that object. And, just as a bar code or

magnetic strip must be scanned to get the information, the RFID device must be scanned to

retrieve the identifying information.

RFID Works Better Than Barcodes

A significant advantage of RFID devices over the others mentioned above is that the RFID

device does not need to be positioned precisely relative to the scanner. We're all familiar with the

difficulty that store checkout clerks sometimes have in making sure that a barcode can be read.

And obviously, credit cards and ATM cards must be swiped through a special reader.

In contrast, RFID devices will work within a few feet (up to 20 feet for high-frequency devices)

of the scanner. For example, you could just put all of your groceries or purchases in a bag, and

set the bag on the scanner. It would be able to query all of the RFID devices and total your

purchase immediately. RFID technology has been available for more than fifty years. It has only

been recently that the ability to manufacture the RFID devices has fallen to the point where they

can be used as a "throwaway" inventory or control device. Alien Technologies recently sold 500

million RFID tags to Gillette at a cost of about ten cents per tag. One reason that it has taken so

long for RFID to come into common use is the lack of standards in the industry. Most companies

invested in RFID technology only use the tags to track items within their control; many of the

benefits of RFID come when items are tracked from company to company or from country to

country.


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RF Module (Transmitter & Receiver)

The RF module, as the name suggests, operates at Radio Frequency. The corresponding

frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data isrepresented as variations in the amplitude of carrier wave. This kind of modulation is known as

Amplitude Shift Keying (ASK).

Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals

through RF can travel through larger distances making it suitable for long range applications.

Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an

obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable

than IR transmission. RF communication uses a specific frequency unlike IR signals which are

affected by other IR emitting sources.

This RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver

(Tx/Rx) pair operates at a frequency of 433 MHZ. An RF transmitter receives serial data and

transmits it wirelessly through RF through its antenna connected at pin4. The transmission

occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an RF receiver

operating at the same frequency as that of the transmitter.

The RF module is often used along with a pair of encoder/decoder. The encoder is used for

encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E-

HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs.
http://www.engineersgarage.com/content/ht12ehttp://www.engineersgarage.com/content/ht12dhttp://www.engineersgarage.com/content/ht12dhttp://www.engineersgarage.com/content/ht12e


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Pin Diagram:

PIN DISCRIPTION

RF Transmitter

Pin No Function Name

1 Ground (0V) Ground

2 Serial data input pin Data

3 Supply voltage; 5V Vcc

4 Antenna output pin ANT

RF Receiver

Pin No Function Name

1 Ground (0V) Ground

2 Serial data output pin Data

3 Linear output pin; not connected NC



6 Ground (0V) Ground7 Ground (0V) Ground

8 Antenna input pin ANT

ENCODER (HT12E)


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Features:

Operating voltage 2.4V~5V for the HT12A 2.4V~12V for the HT12E Low power and high noise immunity CMO Technology. Low standby current: 0.1_A (typ.) at VDD=5V HT12A with a 38KHZ carrier for infrared Transmission medium Minimum transmission word Four words for the HT12E One word for the HT12A Built-in oscillator needs only 5% resistor Data code has positive polarity Minimal external components HT12A/E: 18-pin DIP/20-pin SOP package

Applications


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Built-in oscillator needs only 5% resistor Data code has positive polarity Minimal external components HT12A/E: 18-pin DIP/20-pin SOP package

Applications

Burglar alarm system Smoke and fire alarm system Garage door controllers Car door controllers Car alarm system Security system Cordless telephones Other remote control systems

RFID PASSIVE TAG

A passive tag is an RFID tag that does not contain a battery; the power is supplied by the reader.

When radio waves from the reader are encountered by a passive RFID tag, the coiled antenna

within the tag forms a magnetic field. The tag draws power from it, energizing the circuits in the

tag. The tag then sends the information encoded in the tag's memory.

The major disadvantages of a passive RFID tag are:

The tag can be read only at very short distances, typically a few feet at most. This greatlylimits the device for certain applications.

It may not be possible to include sensors that can use electricity for power.

The tag remains readable for a very long time, even after the product to which the tag is

attached has been sold and is no longer being tracked.


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MULTITONE MUSCICAL IC (Siren)

This multi-tone siren is useful for burglar alarms, reverse horns, etc. It produces five different

audio tones and is much more ear-catching than a single-tone siren. The circuit is built around

popular CMOS oscillator-cum-divider IC 4060 and small audio amplifier LM386. IC 4060 isused as the multitone generator. A 100H inductor is used at the input of IC 4060. So it

oscillates within the range of about 5MHz RF. IC 4060 itself divides RF signals into AF and

ultrasonic ranges. Audio signals of different frequencies are available at pins 1, 2, 3, 13 and 15 of

IC 4060 (IC1).

These multi-frequency signals are mixed and fed to the audio amplifier built around

IC LM386. The output of IC2 is fed to the speaker through capacitor C9. If you want louder

sound, use power amplifier TBA810 or TDA1010. Only five outputs of IC1 are used here as the

other five outputs (pins 4 through 7 and 14) produce ultrasonic signals, which are not audible.

Assemble the circuit on a general-purpose PCB and enclose in a suitable cabinet. Regulated 6V-

12V (or a battery) can be used to power the circuit.


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REFRENCES


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REFRENCES

http://www.engineersgarage.com/electronics component /at89s51- &microcontrollerdatasheet.

http://electronicsforu.com/electronicsforu/circuitarchives/view_article.asp http://www.engineersgarage.com/electronics component.
http://www.engineersgarage.com/electronicshttp://electronicsforu.com/electronicsforu/circuitarchives/view_article.asphttp://www.engineersgarage.com/electronicshttp://www.engineersgarage.com/electronicshttp://electronicsforu.com/electronicsforu/circuitarchives/view_article.asphttp://www.engineersgarage.com/electronics

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