CHAPTER-1

INTRODUCTION

A motion detector is a kind of security system that uses sensing ability in the

form of sensors to detect movement and this usually triggers an alarm, or some times

activate another circuit. However, motion detectors are normally used to protect

indoor areas, in this, conditions can then be controlled more closely. Detectors for

use in homes for security purpose usually detect movement in a closed space area of

little feet-by-feet. Detectors for large range warehouses can protect areas with

dimensions as large as 24mx37m. The motion detector is normally useful in places

like museums where important assets are located. As such, motion detectors can

detect break-in at vulnerable points. Such points include walls, doors windows and

other openings. Special motion detectors can protect the inside of exhibit cases where

items such as diamonds arc placed. Others can be focused on a narrow area of

coverage, somewhat like a curtain, that projected in front of a painting to detect even

the slightest touch.

Motion detector systems use a variety of methods to detect movement. Each method

has advantages and disadvantages. Motion detectors can be categorized into two

major types these are namely:

(1) Passive detectors.

(2) Active detectors.

Passive detectors are detectors which do not send out signals but merely receive

signals, such as change in temperature, change in light intensity and so on. Most

infrared detectors are passive detectors .While Active detectors are detectors which

send out waves of energy and receive waves reflected back from objects.

Any disturbance in the reflected waves caused by example a moving object will

trigger an alarm. Microwave and ultrasonic detectors are examples of active

detectors.

Man and animal or moving object produces sound. The sound is created as a result

of their physical movement, which might be low or fast movement, and also depends

on the medium that create the sound. However, these movements can be detected by

using an ultrasonic sensor. The ultrasonic sound waves are sound waves that are

above the range of human hearing and, thus, have a frequency above about

20khz.Any frequency of above 20kz is considered ultrasonic.

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In general, an ultrasonic sensor typically comprises of one or more ultrasonic

transducer which transforms electrical energy into sound and vice-versa, a casing

which encloses the ultrasonic transducer, connectors, and if possible some electronic

circuit for signal processing.

Nowadays there are numerous of the commercial ultrasonic motion detectors,

basically the main aim of this work is to design and construct a simple and cheap

ultrasonic motion detector system which is aimed at detecting the physical movement

of human, animal, or anything that moves. The design is to improve the use of sensor

I detecting motion. In general, it is aimed at reduction of the cost to design, develop

or construct an ultrasonic motion detector.

Human, animal or anything can produce sound. This sound is creating by the

physical movement whether the movement is fast or slow depends on the medium

that create the sound. Eventually these movements can be detected by using an

ultrasound sensor. Ultrasonic sound waves are sound waves that are above the range

of human hearing and, thus, have a frequency above about 20,000 hertz. Any

frequency above 20,000 hertz may be considered ultrasonic.

An ultrasonic sensor typically comprises at least one ultrasonic transducer which

transforms electrical energy into sound and, in reverse, sound into electrical energy, a

housing enclosing the ultrasonic transducer or transducers, an electrical connection

and, optionally, an electronic circuit for signal processing also enclosed in the

housing. Ultrasonic sensors have typically been used in applications such as

detecting and identifying solid objects, measuring the shape and orientation of a

work piece, detecting possible collisions between objects to avoid the collisions,

room surveillance, flow measurement, and determining a type of material by

measuring the absorption of sound.

By combining parts of electronic to the ultrasonic sensor it become an ultrasonic

motion detector. A motion detector is an electronic device that detects the physical

movement in a given area and transforms motion into an electric signal. The motion

detector may be electrically connected to devices such as security, lighting, audio 2

alarms. Motion sensors are used in a wide variety of applications. Motion detectors

are mainly used in for security systems.

Now days in the market there are many kind of ultrasonic motion detector sell,

basically this project is to design an ultrasonic motion detector use to detect physical

movement of human, animal, or anything that move. The design is to improving the

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use of sensor in detecting motion. Also to reduce the cost to built an ultrasonic

motion detector

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CHAPTER-2

Project name:-ULTRA SONIC SENSER CIRCUIT

Ultrasonic sensors use sound waves rather than light, making them ideal for stable

detection of uneven surfaces, liquids, clear objects, and objects in dirty

environments. These sensors work well for applications that require precise

measurements between stationary and moving objects.

Overview:-

Figure2.1:-Inexpensive motion detector used to control lighting

An electronic motion detector contains an optical, microwave, or acoustic sensor,

and in many cases a transmitter for illumination. However, a passive sensor only

senses a signal emitted by the moving object itself. Changes in the optical,

microwave, or acoustic field in the device's proximity are interpreted by the

electronics based on one of the technologies listed below. Most inexpensive motion

detectors can detect up to distances of at least 15 feet (5 meters). Specialized systems

are more expensive but have much longer ranges. Tomographic motion detection

systems can cover much larger areas because the radio waves are at frequencies

which penetrate most walls and obstructions, and are detected in multiple locations,

not just at the location of the transmitter.

Motion detectors have found wide use in domestic and commercial applications.

One common application is activation of automatic door openers in businesses and

public buildings. Motion sensors are also widely used in lieu of a true occupancy

sensor in activating street lights or indoor lights in walkways (such as lobbies and

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staircases). In such "Smart Lighting" systems, energy is conserved by only powering

the lights for the duration of a timer, after which the person has presumably left the

area. A motion detector may be among the sensors of a burglar alarm that is used to

alert the home owner or security service when it detects the motion of a possible

intruder. Such a detector may also trigger a security camera in order to record the

possible intrusion.

Working:-Everybody knows the speed of the sound in the dry air is around 340 m/s. Send a

short ultrasonic pulse at 40 kHz in the air, and try to listen to the echo. Of course you

won't hear anything, but with an ultrasonic sensor the back pulse can be detected. If

you know the time of the forth & back travel of the ultrasonic wave, you know the

distance, divide the distance by two and you know the range from the ultrasonic

sensor to the first obstacle in front of it.

Laser Ultrasonic Camera:-

The INL Laser Ultrasonic Camera directly images (without the need for scanning)

the surface distribution of sub nanometer ultrasonic motion at frequencies from Hz to

GHz. Ultrasonic waves form a useful nondestructive evaluation (NDE) probe for

determining physical and mechanical properties of materials and parts. The reason

for this is that ultrasonic waves or "sound" can be generated in all forms of matter:

liquids, solids and gases and exhibit information about the material in which they

travel.

Measurement of the characteristics of ultrasonic wave motion, such as wave speed,

attenuation and the presence of scattered waves from micro structural features or

flaws are used to perform NDE for quality control. Laser ultra sonic refers to the

process whereby lasers are used for both generation and detection of ultrasonic

waves in materials, thereby providing a non contacting method for performing

ultrasonic NDE. The current state of the art utilizes a pulsed laser for ultrasonic

generation through the process of thermo elastic expansion or weak ablation. The

method of detection involves interferometry of the Michelson, Fabry-Perot, and

Photorefractive (adaptive) types. Commercially available systems utilize these

interferometric methods and provide a "point and shoot" single point measurement

capability. In order to perform measurements over a large surface, the laser

generation and detection spots must be scanned in a raster fashion over the area

recording ultrasonic signals at each location

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Ultrasonic Flow meters in Waste Water Plants:-

Waste Water Treatment Plants require a large variety of instrumentation in order to

monitor and control the processes in the different stages. For the purpose of flow

metering; do electromagnetic flow meters and ultrasonic flow meters offer the

features and performance which is demanded in these applications.

Figure2.2:- Flow meters in Waste Water Plants:-

The constituent parts of an ultrasonic flow meter are a hydrostatic pressure sensor for

measuring depth, a temperature sensor, and an ultrasonic transmitter/receiver pair for

measuring water velocity. These are all controlled by a data logger, which records

data as specified from the scheme created by the user software. A single cable links

the submerged instrument to a weather-proof polycarbonate enclosure which

provides a data download point, and where the battery is stored. The enclosure has an

optional LCD display.

The flow meter is mounted on (or near) the bottom of the stream/pipe/culvert

and measures velocity and depth of the water flowing over it. Normally it is faced

upstream and reports positive flow but it is a bi-directional instrument capable of

measuring

Other:-

Ultrasonic soldering implements the principle of cavitations, producing

microscopic bubbles in molten solder, a process that removes metal oxides. Hence,

this is a case of both "binding" (soldering) and "loosening"—removing impurities

from the area to be soldered. The dairy industry, too, uses ultrasonics for both

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purposes: ultrasonic waves break up fat globules in milk, so that the fat can be mixed

together with the milk in the well-known process of homogenization. Similarly,

ultrasonic pasteurization facilitates the separation of the milk from harmful bacteria

and other microorganisms

Motion sensors

The term ‘Motion sensors’ can be used to refer to any kind of sensing system which

is used to detect motion; motion of any object or motion of human beings.

Motion sensors also called as motion detector.

Motion sensors are commonly used in security systems as triggers for automatic

lights or remote alarms and similar applications.

Types of Motion sensors:-

The way in which a motion sensor works typically depends on the type of sensor

being used, which often depends on the device that uses the sensor.

There are two basic types of motion sensors:

1) Active Sensors

2) Passive Sensors

Active Sensors:-

Active sensors emit a signal, typically an burst of (light, microwaves or sound)

waves which is reflected by the surroundings.

The reflected signal is received by the sensor and takes necessary action.

When something moves within the area of an active motion sensor, the change in

signal that is reflected to the sensor activates the system.

Passive Sensors:-

Passive Sensors are a type of motion sensor that do not emit a signal, but instead

detect infrared radiation around the sensor.

As this sensor detects temperature differences, it is well suited to detecting the

motion of people by their body temperature.

When a person or animal moves through the area, heat from the movement is

detected by the sensor, which then activates the system to which it is connected.

Ultrasonic motion sensing:-

Ultrasonic motion detectors use sound waves to detect motion. If movement is

detected, the sound wave pattern is disrupted and alarm is signaled. 7

It senses motion by analyzing sound waves in its environment.

These frequencies are generally inaudible to humans and most animals and do not

pass through objects

Figure2.3:-Ultra Sonic motion detector

Active motion sensors generate sound waves in the ultrasonic frequency range,

typically around 30 to 50 kilohertz (kHz).

When no objects are moving in the area, the pattern of sound and the time it takes to

bounce back remain the same.

If something moves, the detector senses that the level or phase of the returning

sound waves has shifted slightly.

ULTRASONIC MOTION DETECTORS;-

Generally, there exist numerous of motion detector, but of our interest is the

ultrasonic motion detectors due to its numerous advantage over other types of

detectors. For example, having fast response time and very sensitive, no physical

contact required by the object, being environmentally friendly and reliable, and

above all utilizing ultrasonic waves that are not visible and audible to human.

Ultrasonic motion detectors are electrical devices, which use ultra-sound (that is,

sound of very high frequency) to detect motion. In such a detector a transmitter emits

a sound of a frequency which is normally too high for the human ear to hear.

When a receiver picks up the sound waves that is reflected from the area under

protection, it sends it to an appropriate circuit for further action (normally an audio

circuit). In the case of motion of human or target in the space between the receiver

and transmitter, further change, or shift in the frequency of sound is a circuit in the

device detects any unusual shift in frequency, which is normally noted due to pre

defined frequency. A small shift in frequency, such as that produced by an insect or

8

rodent, is ignored. When a noticeable shift is observed, such as a large shift produced

by a moving person, the device triggers the alarm.

DESIGN ANALYSIS, TEST AND MEASUREMENTS:-

The ultrasonic motion system is built around the following subsystem.

1. A 40kHz ultrasonic frequency transmitters

2. A 40kHz ultrasonic frequency receiver

3. A modulated audible alert tone generator

4. Power supply unit

Sensor technology:-

Figure2.4:-Infrared detector mounted on circuit board, along with photo

resistive detector for visible light.

There are several motion detection technologies in wide use.

Passive infrared (PIR):-

Passive infrared sensors are sensitive to a person's skin temperature through

emitted black body radiation at mid-infrared wavelengths, in contrast to background

objects at room temperature. No energy is emitted from the sensor, thus the name

"passive infrared" (PIR). This distinguishes it from the electric eye for instance (not

usually considered a "motion detector"), in which the crossing of a person or vehicle

interrupts a visible or infrared beam.

Microwave:-

These detect motion through the principle of Doppler radar, and are similar to

a radar speed gun. A continuous wave of microwave radiation is emitted, and phase

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shifts in the reflected microwaves due to motion of an object toward (or away from)

the receiver result in aheterodyne signal at low audio frequencies.

Ultrasonic:-

An ultrasonic wave (sound at a frequency higher than a human can hear) is

emitted and reflections from nearby objects are received. Exactly as in Doppler radar,

heterodyne detection of the received field indicates motion. The detected doppler

shift is also at low audio frequencies (for walking speeds) since the

ultrasonic wavelength of around a centimeter is similar to the wavelengths used in

microwave motion detectors. One potential drawback of ultrasonic sensors is that the

sensor can be sensitive to motion in areas where coverage isn't desired, for instance,

due to reflections of sound waves around corners. 

Such extended coverage may be desirable for lighting control, where the point is

detection of any occupancy in an area. But for opening an automatic door, for

example, one would prefer a sensor selective to traffic in the path toward the door.

Tomographic motion detector:-

Tomographic motion detection systems sense disturbances to radio waves as they

pass from node to node of a mesh network. They have the ability to detect over

complete areas because they can sense through walls and obstructions.

Video camera software:-

With the proliferation of inexpensive digital cameras capable of shooting video, it is

possible to use the output of such a camera to detect motion in its field of view using

software. This solution is particularly attractive when the intention was to record video

triggered by motion detection, as no hardware beyond the camera and computer is required.

Since the observed field may be normally illuminated, this may be considered

another passive technology. However it can also be used in conjunction with near-

infrared illumination to detect motion in the "dark" (that is, with the illumination at a

wavelength not detected by the human eye)

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CHAPTER-3

ULTRASONIC MOTION DETECTORS:-

Generally, there exist numerous of motion detector, but of our interest is the

ultrasonic motion detectors due to its numerous advantage over other types of

detectors. For example, having fast response time and very sensitive, no physical

contact required by the object, being environmentally friendly and reliable, and

above all utilizing ultrasonic waves that are not visible and audible to human.

Ultrasonic motion detectors are electrical devices, which use ultra-sound (that is,

sound of very high frequency) to detect motion. In such a detector a transmitter emits

a sound of a frequency which is normally too high for the human ear to hear. When a

receiver picks up the sound waves that is reflected from the area under protection, it

sends it to an appropriate circuit for further action (normally an audio circuit).

In the case of motion of human or target in the space between the receiver and

transmitter, further change, or shift in the frequency of sound is experienced, a circuit

in the device detects any unusual shift in frequency, which is normally noted due to

predefined frequency. A small shift in frequency, such as that produced by an insect

or rodent, is ignored. When a noticeable shift is observed, such as a large shift

produced by a moving person, the device triggers the alarm.

HISTORY:-

observing Prior to World War II, sonar, the technique of sending sound waves

through water and the returning echoes to characterize submerged objects, inspired

early ultrasound investigators to explore ways to apply the concept to medical

diagnosis. In 1929 and 1935, Sokolov studied the use of ultrasonic waves in

detecting metal objects. Mulhauser, in 1931, obtained a patent for using ultrasonic

waves, using two transducers to detect flaws in solids. Firestone (1940) and Simons

(1945) developed pulsed ultrasonic testing using a pulse-echo technique.

Shortly after the close of World War II, researchers in Japan began to explore the

medical diagnostic capabilities of ultrasound. The first ultrasonic instruments used an A-

mode presentation with blips on an oscilloscope screen. That was followed by a B-mode

presentation with a two dimensional, gray scale image.

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Japan's work in ultrasound was relatively unknown in the United States and Europe

until the 1950s. Researchers then presented their findings on the use of ultrasound to detect

gallstones, breast masses, and tumors to the international medical community. Japan was

also the first country to apply Doppler ultrasound, an application of ultrasound that detects

internal moving objects such as blood coursing through the heart for cardiovascular

investigation.

Ultrasound pioneers working in the United States contributed many innovations and

important discoveries to the field during the following decades. Researchers learned to use

ultrasound to detect potential cancer and to visualize tumors in living subjects and in excised

tissue. Real-time imaging, another significant diagnostic tool for physicians, presented

ultrasound images directly on the system's CRT screen at the time of scanning.The

introduction of spectral Doppler and later color Doppler depicted blood flow in various

colors to indicate the speed and direction of the flow.

The United States also produced the earliest hand held "contact" scanner for clinical use,

the second generation of B-mode equipment, and the prototype for the first articulated-arm

hand held scanner, with 2-D images.

Figure3.1:-2D Image of Ultra Sound

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Figure3.2:-Ultra Sonic Sensor Board

How the ultrasonic sensor works:-

The ultra sonic circuit is adjusted in such a way as to stay in balance as long the

same as the output frequency of the transmitter. If there is some movement in the area

covered by the ultrasonic emission.the signal that is reflected back to the receiver

becomes distorted and the circuit is thrown out of balance. The circuit works from 9-12

VDC and can be used with batteries or a power supply.

ULTRASONIC MOTION DETECTOR:-

The ultrasonic motion detector is a project that uses an ultrasonic sensor as its base

to detect movement or moving object in small places. It is design to be a low cost

ultrasonic motion detector. The transmitter sensor use to generate signal in that area.

When the signal is block by moving or movement the receiver will gets the signal and

amplifies the signal using transistor. The transistor is use as an amplifier to the receiver

circuit.

The Led and buzzer in the circuit use to see if there is movement detect by the

sensor. The relay use to trigger another circuit when there is movement detects. The

signal generate by the sensor is about ±40khz. This is a fully hardware design project

plus it is built to be a portable ultrasonic motion detector.

The circuit consists of the following major blocks.

1.   Transmitter

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2.   Receiver

3.   Transistor Amplifier Circuit

4.   Op amp Amplifier

5.   Op amp Comparator

6.   Pi Filter

7.   Schmitt Trigger

8.   Darlington pair Amplifier

Block Diagram:-

Before starting with actual circuit design, we must first understand the basic principles

behind the technology that is used this project. The project methodology flow chart is

shown below.

The flow design of the circuit consist of

1. Finding the right transmitter and receiver sensor for the circuit.

2. Designing the amplifier/receiver circuit

3. Design the transmitter circuit

4. Using simulation to verify the design.

5. Implementation on board.

Figure3.3:-Flow Diagram of Ultrasonic Sensor

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Figure3.4:-Block Diagram of ultrasonic Sensor Circuit

Block diagram description:-

Ultrasonic sensor consist the following circuit in block diagram.

1. Amplifier circuit.

2. Hex buffer circuit

3. Sensor circuit.

Amplifier circuit:-

For the amplifier in this project, the transistor is use to act as amplifier. The basic

transistor amplifier circuit is use act as an amplifier method to amplifying. H9013 series

of transistor is use because the transistor is the general transistor use in amplifying

concept. It is a BJT type of transistor. When the receiver sensor receive signal it will

send the signal to the transistor to be amplified. In this project five transistors is use to

amplified the signal send by the receiver sensor. The type of design for the transistor is

a common emitter amplifier. Base from the design the input signal that come from the

base of transistor will be amplified and produce at the collector transistor a larger output

signal and the output will be more on positive side signal. Mean that the transistor will

amplify current from a small input current to a high output current. It is use also to

trigger the relay connected to it. Variable resistor is use to control the level of signal or

the sensitivity signal send by the receiver sensor. Mean if no setting are made by the 15

variable resistor the sensor is highly sensitive, even the air counts as a motion parts thus

we will get false trigger by the circuit.

Figure3.4:-Basic design of amplifiers

Hex buffer circuit:-

This circuit consist a buffer, crystal and transmitter sensor in it. The crystal is use to drive

the transmitter sensor into a steady frequency stability. It will ring the transmitter to

continuous transmitting frequency. A voltage applied across the crystal will cause

mechanical movement within the crystal. If an AC voltage is applied across the crystal, the

crystal will begin to vibrate. Thus in this circuit it the buffer act as a driver to make sure that

the sensor transmit the frequency. The crystal or XTAL is a 40 kHz in frequency. The buffer

or hex inverter use in the circuit is single supplies IC mean single supply needed to make it

work. It is use to change from high to low level logic conversion.

The IC is HD4069UBP hex buffer converter. The supply can be 9Vdc or 12Vdc. It is 14

pin IC. In this project the pin 1 until pin 6 uses for the transmitter sensor to drive the

frequency, the other pin use to drive transistor to supply enough current for the relay to

energize.

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Figure3.5:-Top view of HD4069UBP buffer IC.

Figure3.6:-Transmitter Circuit Design

Sensor circuit (Transmitter and Receiver):-

Use to transmit and receive signal and send to the circuit. The sensor in this

circuit is an ultrasonic sensor. The frequency generate by the sensor ±40kHz. The

transmitter and receiver must be equal in frequency to make the circuit function.

When power supply is given to the circuit, the transmitter will transform the

electrical energy to sound wave and transmit it to the air. Thus when the sound wave

or signal is blocking by something or someone, the signal will be detected by the

receiver. Crucial thing is finding the right sensor for the right circuit. Moreover the

sensor cannot be place to far from each other.

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Figure3.7:-Sensor (Transmitter and Receiver)

Ultra Sonic Detector Construction:-

The board is made of a thin insulating material clad with a thin layer of conductive

copper that is shaped in such a way as to form the necessary conductors between the

various components of the circuit. The use of a properly designed printed circuit

board is very desirable as it speeds construction up considerably and reduces the

possibility of making errors. In order to solder a component correctly you should do

the following.

Clean the component leads with a small piece of emery paper.

Bend them at the correct distance from the component’s body and insert the

component in its place on the board.

You may find sometimes a component with heavier gauge leads than usual, that are

too thick to enter in the holes of the p.c. board.

In this case use a mini drill to enlarge the holes slightly. Do not make the holes too

large as this is going to make soldering difficult afterwards.

Take the hot iron and place its tip on the component lead while holding the end of the

solder wire at the point where the lead emerges from the board. The iron tip must

touch the lead slightly above the p.c. board.

When the solder starts to melt and flow wait till it covers evenly the area around the

hole and the flux boils and gets out from underneath the solder.

The whole operation should not take more than 5 seconds. Remove the iron and

allow the solder to cool naturally without blowing on it or moving the component. If

18

everything was done properly the surface of the joint must have a bright metallic

finish and its edges should be smoothly ended on the component lead and the board

track. If the solder looks dull, cracked, or has the shape of a blob then you have made

a dry joint and you should remove the solder (with a pump or a solder wick) and redo

it.

Take care not to overheat the tracks as it is very easy to lift them from the board and

break them.

When you are soldering a sensitive component it is good practice to hold the lead

from the component side of the board with a pair of long-nose pliers to divert any

heat that could possibly damage the component.

Make sure that you do not use more solder than it is necessary as you are running the

risk of short-circuiting adjacent tracks on the board, especially if they are very close

together.

When you finish your work cut off the excess of the component leads and clean the

board thoroughly with a suitable solvent to remove all flux residues that may still

remain on it.

There are quite a few components in the circuit and you should be careful to avoid

mistakes that will be difficult to trace and repair afterwards. Solder first the pins and

the IC sockets and then following if that is possible the parts list the resistors the

trimmers and the capacitors paying particular attention to the correct orientation of

the electrolytic.

Solder then the transistors and the diodes taking care not to overheat them during

soldering. The transducers should be positioned in such a way as they do not affect

each other directly because this will reduce the efficiency of the circuit. When you

finish soldering, check your work to make sure that you have done everything

properly, and then insert the IC’s in their sockets paying attention to their correct

orientation and handling IC3 with great care as it is of the CMOS type and can be

damaged quite easily by static discharges. Do not take it out of its aluminium foil

wrapper till it is time to insert it in its socket, ground the board and your body to

discharge static electricity and then insert the IC carefully in its socket.

In the kit you will find a LED and a resistor of 560 — which will help you to make

the necessary adjustments to the circuit. Connect the resistor in series with the LED

and then connect them between point 9 of the circuit and the positive supply rail

(point1).

19

Connect the power supply across points:- 

1 (+) and 2 (-) of the p.c. board and put P1 at roughly its middle position.Turn then

P2 slowly till the LED lights when you move your fingers slightly in front of the

transducers. If you have a frequency counter then you can make a much more

accurate adjustment of the circuit.

Connect the frequency counter across the transducer and adjust P2 till the frequency

of the oscillator is exactly the same as the resonant frequency of the transducer.

Adjust then P1 for maximum sensitivity. Connecting together pins 7 & 8 on the p.c.

board will make the circuit to stay triggered till it is manually reset after an alarm.

This can be very useful if you want to know that there was an attempt to enter in the

place which are protected by the radar.

Figure3.8:-Ultra Sonic Motion Detector Circuit

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Figure3.9:-Circuit Diagram Of Ultra Sonic Motion Detector

21

CHAPTER-4

The circuit consists of the following component

1. Transmitter.

2. Receiver.

3. Transistor Amplifier Circuit.

4. Op amp Amplifier.

5. Op amp Comparator.

6. Pi Filter.

7. Schmitt Trigger.

8. Darlington pair Amplifier.

9. Resistor.

10. Capacitor.

11. IC circuit.

12. Transducer.

13. Diode.

14. Sensor (Transmitter and Receiver).

Figure4.1:-Component used in Ultrasonic sensor circuit.

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Transmitter:-

In electronics and telecommunications a transmitter or radiotransmitter is

an electronic device which, with the aid of an antenna, produces radio waves. The

transmitter itself generates a radio frequency alternating current which is applied to

the antenna. When excited by this alternating current, the antenna radiates radio

waves. In addition to their use in broadcasting, transmitters are necessary component

parts of many electronic devices that communicate by radio, such as cell

phones, wireless computer networks bluetooth enabled devices, garage door

openers, two-way radios in aircraft, ships, and spacecraft, radar sets, and navigational

beacons. The transmitter circuit consists of mainly an astable multivibrator circuit

using IC 4093.

The capacitor and resistor values are adjusted to obtain a frequency of 40 kHz which

is fed to the ultrasonic transmitter. The transmitter produces ultrasonic waves of 40

kHz frequency which travel around the room, get reflected and fall on the receiver.

U2C forms a 40 KHz oscillator. This oscillator is connected to U2D and U2E while

the inverted oscillator signal (U2B) goes to U2A and U2F. These parallel gates

provide more current and drive the ultrasonic transmitter. Note that it may take a

couple of seconds after the power is applied for the oscillator to stabilize.

Figure4.2:-Ultrasonic Transmitter.

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Receiver:- Ultrasonic Receiver which will detect the signal from the Ultrasonic

Transmitter once it bounces off from an object. The combination of these two

sensors will allow the aerial robot to detect objects in its path and maneuver around

the objects. These sensors will be attached in front of the plane.

OR

The receiver is an ultrasonic transducer. After transmission, the signal gets reflected

from the surroundings. This signal is received at the receiver transducer and is then

sent to process for the presence of motion.

Q1 and Q2 amplify the reflected 40 KHz signal picked up by the ultrasonic receiver

by 2500. Q2 is capacitively coupled to the voltage doubler formed by D1 and D2.

The rectified signal is connected to the negative input of voltage comparator U1A.

R12 (the Sensitivity potentiometer) sets the threshold voltage for U1A. When the

threshold voltage is exceeded, the open collector output of U1A goes high-

impedance. This enables the 70 Hz oscillator formed by U1B.

When this oscillator is on, the LED glows and the one-shot formed by U3 is

repeatedly triggered. The output duration of the one-shot is set by R16 and C11 and

is equal to 1.1*R16*C11 seconds. U3's output turns on Q3. As a result, K1 closes its

normally open contacts. C13 dampens the inductive kickback when K1 is turned off,

preventing the circuit from triggering due to this noise source. The unit is powered

by a 12 VDC 200mA unregulated wall transformer. U4 provides a regulated 9VDC

to power the circuit. Device pin outs are shown in Figure 2. The 40 KHz transmitter

and receiver are mounted 4" apart on a piece of perf board.

Figure4.3:-Transmitter and Receiver

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Figure4.4:-Ultrasonic Transmitter and Receiver.

Figure4.5:- Ultrasonic Receiver.

Resistor:-

A resistor is a passive two-terminal electrical component that implements electrical

resistance as a circuit element. Resistors act to reduce current flow, and, at the same

time, act to lower voltage levels within circuits. In electronic circuits resistors are

used to limit current flow, to adjust signal levels, bias active elements,

25

terminate transmission lines among other uses. In the ultrasonic sensor circuit many

resistors are used. Name of the resistor which are used in ultrasonic sensor circuit is

below.

1. R1= 180kohm

2. R2=12kohm

3. R3,R8=47kohm

4. R4=9kohm

5. R5,R6,R16=10kohm

6. R7,R10,R12,R14,R17=100kohm

7. R9,R11=1mohm

8. R13,R15=3mohm

Figure4.6:-Circuit Layout of Sensor

These are those resistor which are mainly used in ultrasonic sensor circuit.

A capacitor (originally known as a condenser) is a passive two-

terminal electrical component used to store energy electro statically in an electric

field. The forms of practical capacitors vary widely, but all contain at least

two electrical conductors (plates) separated by adi electric insulation. The conductors

can be thin films, foils or sintered beads of metal or conductive electrolyte, etc. The

non conducting dielectric acts to increase the capacitor's charge capacity.

A dielectric can be glass, ceramic, plastic film, air, vacuum, paper, mica, oxide layer

etc. Capacitors are widely used as parts of electrical circuits in many common

26

electrical devices. Name of the resistor which are used in ultrasonic sensor circuit is

below.

1. C1=10uf/16v

2. C2=47uf/16v

3. C3=4,7pf

4. C4,C7=1nf

5. C5=10nf

6. C8,C11=4,7uf/16v

7. C9=22uf/16v

8. C10=100nf

9. C12=2,2uf/16v

10. C13=3,3nf

11. C14=47nf

These are the those capacitor which is used in ultrasonic sensor.

Figure4.7:-Capacitor

IC CIRCUIT:-

An integrated circuit or monolithic integrated circuit  is a set of electronic circuit on

one small plate ("chip") of semiconductor material, normally silicon. This can be

made much smaller than a discrete circuit made from independent electronic

components. ICs can be

27

made very compact, having up to several billion transistors and other electronic

components in an area the size of a fingernail.

Figure4.8:-Block diag. of Motion Sensor Circuit

Transistor Amplifier Circuit:-

The first part of the receiver circuit consists of an amplifier section using a

BC547. The ultrasonic waves from the transmitter get reflected and fall on the

receiver. The receiver is connected to an amplifier circuit having a gain of 20. The

amplitude of waves falling on the receiver is very small, the amplifier amplifies the

noise.

Op-amp Amplifier:-

An operational amplifier ("op-amp") is a DC-coupled high-gain electronic

voltage amplifier with a differential input and, usually, a single-ended output. In this

configuration, an op-amp produces an output potential (relative to circuit ground)

that is typically hundreds of thousands of times larger than the potential difference

between its input terminals.

Operational amplifiers had their origins in analog computers, where they were

used to do mathematical operations in many linear, non-linear and frequency-

dependent circuits. The popularity of the op-amp as a building block in analog

circuits is due to its versatility. Due to negative feedback, the characteristics of an

op-amp circuit, its gain, input and output impedance, bandwidth etc. are determined

28

by external components and have little dependence on temperature coefficients or

manufacturing variations in the op-amp itself.

The LM741 series are general purpose operational amplifiers which feature

improved performance over industry standards like the LM709. They are direct,

plug-in replacements for the 709C, LM201, MC1439 and 748 in most applications.

The amplifiers offer many features which make their application nearly foolproof:

overload protection on the input and output, no latch-up when the common mode

range is exceeded, as well as freedom from oscillations.

This is the second stage of the amplifier section. This part further amplifies the

noise received by the ultrasonic receiver. This also integrate the output of the

amplifier.

The amplifier's differential inputs consist of a non-inverting input (+) with

voltage V+ and an inverting input (–) with voltage V−; ideally the op-amp amplifies

only the difference in voltage between the two, which is called the differential input

voltage. The output voltage of the op-amp Vout  is given by the equation:

Where A is the open-loop gain of the amplifier (the term "open-loop" refers to the

absence of a feedback loop from the output to the input.

Figure4.9:-Circuit diag. of Op amp

29

Figure4.10:-op-amp amplifier

Op amp Comparator:-

One input consists of the shifted, negative clipped amplified output of the Op

amp amplifier and the positive clipped amplified output. The output of the

comparator is by default high and when the positive clipped portions exceed the

negative clipped part due to noise, the Op amp inverts.

In electronics, a comparator is a device that compares two voltages or currents and

outputs a digital signal indicating which is larger. It has two analog input

terminals   and  and one binary digital output  . The output is ideally

A comparator consists of a specialized high-gain differential amplifier. They are

commonly used in devices that measure and digitize analog signals, such as analog-

to-digital converters\ (ADCs), as well as relaxation oscillators. An operational

amplifier (op-amp) has a well balanced difference input and a very high gain. This

parallels the characteristics of comparators and can be substituted in applications

with low-performance requirements.

In theory, a standard op-amp operating in open-loop configuration (without negative

feedback) may be used as a low-performance comparator. When the non-inverting

input (V+) is at a higher voltage than the inverting input (V-), the high gain of the

op-amp causes the output to saturate at the highest positive voltage it can output. 30

When the non-inverting input (V+) drops below the inverting input (V-), the output

saturates at the most negative voltage it can output. The op-amp's output voltage is

limited by the supply voltage. An op-amp operating in a linear mode with negative

feedback, using a balanced, split-voltage power supply, (powered by ± VS) has its

transfer function typically written as:  . However, this

equation may not be applicable to a comparator circuit which is non-linear and

operates open-loop (no negative feedback).

Figure4.11:-Comparator Circuit From Op amp

Pi-filter:-

The capacitor-input filter, also called pi filter due to its shape that looks like

the Greek letter pi, is a type of electronic filter. The pi-filter converts the fluctuating

ac noise into dc and feeds into the Op amp comparator.

The capacitor-input filter, also called the pi filter due to its shape that looks like

the Greek letter π, is a type of electronic filter. Filter circuits are used to remove

unwanted or undesired frequencies from a signal.

31

Figure4.12:-Pi Filter Circuit

A simple pi filter, containing a pair of capacitors, an inductor, and a load.

A typical capacitor input filter consists of a filter or reservoir capacitor C1,

connected across the rectifier output, an inductor L, in series and another filter or

smoothing capacitor, C2, connected across the load, RL. A filter of this sort is

designed for use at a particular frequency, generally fixed by the AC line frequency

and rectifier configuration. When used in this service, filter performance is often

characterized by its regulation and ripple.

The capacitor-input filter operates in three steps:-

1. The capacitor C1 offers low reactance to the AC component of the rectifier

output while it offers infinite resistance to the DC component. As a result the

capacitor shunts an appreciable amount of the AC component while the DC

component continues its journey to the inductor L.

2. The inductor L offers high reactance to the AC component but it offers almost

zero resistance to the DC component. As a result the DC component flows

through the inductor while the AC component is blocked.

3. The capacitor C2 bypasses the AC component which the inductor had failed to

block. As a result only the DC component appears across the load RL.

The component value for the inductor can be estimated as an inductance that

resonates the smoothing capacitor(s) at or below one tenth of the minimum AC

frequency in the power supplied to the filter (100 Hz from a full-wave rectifier in a

region where the power supply is 50Hz). Thus if reservoir and smoothing capacitors

of 2200 microfarads are used, a suitable minimum value for the inductor would be

that which resonates 2200 microfarads (μF) to 10 Hz, i.e. 115 mH. A larger value is

preferable provided the inductor can carry the required supply current.

32

Figure4.13:-Schmitt Trigger Circuit

Schmitt trigger:-

The next part of the receiver circuit is the Schmitt trigger.   The Schmitt trigger is

a comparator application which switches the output negative when the input passes

upward through a positive reference voltage. It then uses negative feedback to

prevent switching back to the other state until the input passes through a lower

threshold voltage, thus stabilizing the switching against rapid triggering by noise as it

passes the trigger point. In this circuit the motion caused by the object causes

distortion at the receiver output. The comparator output is by default high. When the

noise levels detected are substantially high, the comparator inverts itself and the

trigger is triggered. The output is fed to a Darlington pair.

The Schmitt trigger is a comparator application which switches the output

negative when the input passes upward through a positive reference voltage. It then

uses positive feedback of a negative voltage to prevent switching back to the other

state until the input passes through a lower threshold voltage, thus stabilizing the

switching against rapid triggering by noise as it passes the trigger point. That is, it

provides feedback which is not reversed in phase, but in this case the signal that is

being fed back is a negative signal and keeps the output driven to the negative supply

voltage until the input drops below the lower design threshold. Schmitt trigger

devices are typically used in signal conditioning applications to remove noise from

signals used in digital circuits, particularly mechanical switch bounce. They are also

used in closed loop negative feedback configurations to implement relaxation

oscillators, used in function generators and switching power supplies.

33

Fiqure4.14:-Operational Amplifier

Fiqure4.15:-schmitt trigger

34

Figure4.15:-component Circuitry of ultrasonic sensor

Darlington pair:-

This is a very high current gain section which when turned on by the trigger from

the Schmitt trigger, starts conducting and the buzzer and led goes on.

Transistors are an essential component in a sensor circuit. Usually transistors are

arranged as a pair, known as a ‘darlington pair’. It is very important that you can

identify this arrangement of transistors and state clearly why they are used.

A darlington pair is used to amplify weak signals so that they can be clearly

detected by another circuit or a computer/microprocessor.

The circuit below is a temperature sensor. When the temperature drops below zero

the LED lights. This type of system is often seen in a car and warns the driver of the

possibility of icy conditions. The two transistors are known as a darlington pair.

Without a darlington pair the circuit would probably fail.

The circuit opposite is a ‘Darlington Pair’ driver. The first transistor’s emitter feeds

into the second transistor’s base and as a result the input signal is amplified by the time

it reaches the output. The important point to remember is that the Darlington Pair is

made up of two transistors and when they are arranged as shown in the circuit they are

used to amplify weak signals

35

Figure4.16:-Darlington pair

36

CHAPTER-5

WORKING OF THE CIRCUIT:-

As it has already been stated the circuit consists of an ultrasonic transmitter and

a receiver both of which work at the same frequency.

They use ultrasonic piezoelectric transducers as output and input devices

respectively and their frequency of operation is determined by the particular devices

in use.

The transmitter is built around two NAND gates of the four found in IC3 which are

used here wired as inverters and in the particular circuit they form a multi vibrator

the output of which drives the transducer. The trimmer P2 adjusts the output

frequency of the transmitter and for greater efficiency it should be made the same as

the frequency of resonance of the transducers in use. The receiver similarly uses a

transducer to receive the signals that are reflected back to it the output of which is

amplified by the transistor TR3, and IC1 which is a 741 op-amp. The output of IC1 is

taken to the non inverting input of IC2 the amplification factor of which is adjusted

by means of P1. The circuit is adjusted in such a way as to stay in balance as long the

same as the output frequency of the transmitter.

If there is some movement in the area covered by the ultrasonic emission the signal

that is reflected back to the receiver becomes distorted and the circuit is thrown out

of balance. The output of IC2 changes abruptly and the Schmitt trigger circuit which

is built around the remaining two gates in IC3 is triggered. This drives the output

transistors TR1, 2 which in turn give a signal to the alarm system or if there is a relay

connected to the circuit, in series with the collector of TR1, it becomes activated. The

circuit works from 9-12 VDC and can be used with batteries or a power supply.

IC CIRCUIT:-

An integrated circuit or monolithic integrated circuit  is a set of electronic

circuits on one small plate ("chip") of semiconductor material, normally silicon.

This can be made much smaller than a discrete circuit made from

independent electronic components. ICs can be made very compact, having up to

several billion transistors and other electronic components in an area the size of a

fingernail. The width of each conducting line in a circuit can be made smaller and

37

smaller as the technology advances; in 2008 it dropped below 100  nanometer and

now is tens of nanometers.

Figure5.1:-Ic Circuit

PCB DESIGN:-

Figure5.2:-pcb design of ultrasonic circuit

Soldering:-

Soldering is a process in which two or more metal items are joined together by

melting and flowing a filler metal (solder) into the joint, the filler metal having a

lower melting point than the adjoining metal. Soldering differs from welding in that

soldering does not involve melting the work pieces. In brazing, the filler metal melts

at a higher temperature, but the work piece metal does not melt. In the past, nearly all

solders contained lead, but environmental concerns have increasingly dictated use

of lead-free alloys for electronics and plumbing purposes. Soldering filler materials 38

are available in many different alloys for differing applications. In electronics

assembly, the eutectic alloy of 63% tin and 37% lead (or 60/40, which is almost

identical in melting point) has been the alloy of choice. Other alloys are used for

plumbing, mechanical assembly, and other applications. Some examples of soft-

solder are tin-lead for general purposes, tin-zinc for joining aluminium, lead-silver

for strength at higher than room temperature, cadmium-silver for strength at high

temperatures, zinc-aluminium for aluminium and corrosion resistance, and tin-silver

and tin-bismuth for electronics. The purpose of flux is to facilitate the soldering

process. One of the obstacles to a successful solder joint is an impurity at the site of

the joint, for example, dirt, oil or oxidation. The impurities can be removed by

mechanical cleaning or by chemical means, but the elevated temperatures required to

melt the filler metal (the solder) encourages the work piece (and the solder) to re-

oxidize. This effect is accelerated as the soldering temperatures increase and can

completely prevent the solder from joining to the workpiece. One of the earliest

forms of flux was charcoal, which acts as a reducing agent and helps prevent

oxidation during the soldering process. Some fluxes go beyond the simple prevention

of oxidation and also provide some form of chemical cleaning (corrosion).

39

CHAPTER-6

APPLICATIONS :-

The motion detector circuit has a number of uses.

As burglar alarm : The circuit can be used as an alarm system in homes, shops

and even automobiles. The device is small, sensitive and has a low cost. This

can be used in homes and shops to guard safes and other valuables\

As a people counter device : A people counter is a device used to measure the

number and direction of people traversing a certain passage or entrance per unit

time. The resolution of the measurement is entirely dependent on the

sophistication of the technology employed. The

device is often used at the entrance of a building so that the total number of

visitors can be recorded. The motion detector can be used in daytime to count

the number of people entering a shop by attaching a counter circuit and can be

converted into a burglar alarm at night by minimum modifications.

As High Security Safe Alarm:  When integrated with a high security safe it can

trigger an alarm even in the event of a minute movement. Hence it can serve the

purpose of handling attempted robberies on high security vaults.

Motion Sensing Camera Trigger:  As the name suggests the device can be used to

trigger cameras to automatically operate the presence of motion in surroundings.

This can be used in wildlife photography and security cameras

It is used to detect flaws or cracked in metals.

It is used to detect ships, submarines, iceberg etc, in ocean.

It is used for soldering aluminium coil capacitors, aluminium wires and plates

without using any fluxes.

It is used to weld some metals which can’t be welded by electric or gas welding

It is used to cutting and drilling holes in metals.

It is used to form stable emulsion of even immiscible liquids like water and oil

or water and mercury which finds application in the preparation of photographic

films, face creams etc.

It act Like a catalytic agent and accelerate chemical reactions.

It is used to remove kidney stones and brain tumours without shedding any

blood.

40

It is used to remove broken teeth.

It is used for sterilising milk and to kill bacteria.

It is used to study the blood flow velocities in blood vessels of our body.

It is used as a diagnostic tool to detect tumours, breast cancer and also the

growth of foetus can be studied.

41