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With the ongoing revolution in electronics and communication where innovations are taking at the blink of the eye, it is difficult to keep the pace with the emerging trends. Excellence is an attitude that whole of human race is born with. It's the environment that makes sure that the result of this attitude is visible or not. A well planned, properly executed and evaluated minor project helps a lot in inculcating a professional attitude & practical knowledge. It provides awareness of typical approach to problem solving.
During this period, the student gets the real experience for working in the actual practical environment. Most of the theoretical knowledge that has been gained during the course of their studies is put to test here. Apart from this the students get an opportunity to experience the latest technology, which immensely helps them in building their career.
The radar which we try to develop here has an ultrasonic sensor/transducer or in other words and ultrasonic proximity detector connected with a stepper motor getting its timing pulse from a decade counter. Ultrasonic transducers are being used here. A rangefinder transmits echo signal which is then received back after hitting an object. The time delay is calculated and further analysis if implemented, can be done to locate the object in space, and also its speed of motion, distance from ground and direction of motion. 360 milliseconds are taken for the pulse transmission. Then, merely 1 millisecond is taken by the transducer to receive, detect and process the signal.
Thus, basically an ultrasonic transceiver sends a continuous wave signal I space. An object obstructs the signal and therefore an echo signal is generated which is propagated back to the receiver. The transceiver is mounted on a stepper motor which rotates by taking a step of 7.5 degree per turn. Thus a whole revolution is made and any echo is detected. The decade counter sends the signal for the stepper motor for rotation. When echo is detected, the relay circuit is set on make, and the buzzers and LEDs get the power, and thus they get activated, signaling the presence of an object in range of the radar.
Chapter-1: RFID & its Applications.
Applications of Radar
How RADAR Works
Chapter-2: Design of Ultrasonic Radar
PCB Design &Layout
Cost of Project
RADAR & Its Applications
www.wikipedia.com/radar.htmRadar is for object detection and uses electromagnetic waves to identify the range, altitude, direction. The term RADAR was is an acronym for RAdio Detection And Ranging.
A radar system uses transmitter for emitting radio waves. These on coming in contact with an obstructer, are scattered everywhere. The signal therefore is partially reflected . A slight change of wavelength (and also frequency) is present due to Doppler effect on a moving object. The returning or echo signal is normally quite weak, but it can easily be amplified by the use of modern digital electronic techniques. So therefore, the radar is then able to find the presence of an objects in its proximity. Radar can be used in quite a lot of fields like the speed of an oncoming vehicle, speed of an aeroplane, in military fields, by traffic police, for detection of precipitation, for measuring speed of ocean waves or even for measuring the speed of a cricket ball.
1.2 Applications of Radar:
This info which is provided by a radar may include the range, speed, position and other parameters of an object. So it can potentially be used in many different fields where the object positioning is required. The initial use of radar was solely for the purpose of military usage; that's for locating moving air, land, sea objects. Now, it is also being used for civilian purposes.
Radar has invaded many other fields. Meteorologists use radar to monitor precipitation. It has become the primary tool for short-term weather forecasting and to watch for severe weather such as thunderstorms,
1.3 How RADAR Works:
The Basic Idea:
www.howstuffworks.com/radar.htmHYPERLINK "http://www.howstuffworks.com/radar.htmThe"The idea behind a basic radar is quite simple: that is, a signal is sent in space, it is reflected off an object which is then received by a receiver. Radars use electromagnetic waves that is the radio waves and microwaves. This is where the name RADAR comes from (RAdio Detection And Ranging). Sound is used may also be used as a signal in devices called SONAR (SOund NAvigation Ranging). LIDAR is the newest usage, ie the Light Detection and Ranging.
Sound waves require matter to transport the energy but EM waves can do so without the presence of matter. Radio waves have wavelengths that are 10 cm and greater and microwaves have wavelengths that range from 10 cm to 1/10 of a mm.
Basic Radar System:
Fig 1- Basic Radar System
A radar system is divided into a transmitting unit, a toggle switch, an antenna(mostly parabolic), a receiving unit, a data recorder, a data processor and a display unit. Any received signals from the receiver are then sent to a data recorder for storage on a disk or tape. Later the data must be processed to be interpreted into something useful which would go on a display.
Pulse Width and Bandwidth:
Radars may be of continuous wave or pulsed type. In the pulse type of radar, waves are sent for a particular time, then a dead time is there. This dead time is the time in which no pulse is sent. The time between each pulse is called the pulse repetition time and the number of pulses transmitted in one second is called the pulse repetition frequency. Pulse width is time taken for each pulse to be transmitted. Its value is around 0.1 microsecond.
Pulse Repetition Time = 1 / Pulse Repetition Frequency
Fig 2- Pulse Repetition Time
Fig 3- Frequency Modulation
the frequency of the wave is low on the left and it slowly increases as you look right. The different frequencies of the wave will lie in a range called bandwidth. Radars use bandwidth for several reasons including resolution of a data image, memory of the radar and overuse of the transmitter.
Fig 4-Backscatter Phenomenon
EM wave upon hitting a surface, gets reflected away from surface and will be reflected back to the surface. The amount by which the waves reflect and refract depends on the properties of surface as well on the properties of the matter through which the wave was originally traveling through. This is what will happen to radar signals when they hit the surface. If the signal hits a surface that is not flat , then it gets reflected in every directions. A very small fraction of the original signal is transmitted back in the direction of the receiver. This is backscatter.
1.4 Current uses:
Introduction to RADAR Systems, Merill I. Skolnik, 3rd edition,2009 There are many other post-war civilian and scientific radar systems and applications. Only a few are noted.
1.4.1 Radar Gun:
This is a small Doppler radar which is utilized for the purpose of detecting the speed of moving objects that is the vehicles and automobiles, for regulating the traffic flow in a region. Also, this device can come in handy for measuring the speed of ocean surface waves.
1.4.2 Impulse Radar:
The pulse length decides the accuracy of range measurement by any radar - that is, shorter the pulses, greater is the precision. Another fact is that for a decided PRF, shorter the pulse frequency, greater will be power . Harmonic analysis has shown that a narrower pulse will have a wider band of frequencies which contain the energy, leading to their popular name, Wide band Radar. This is the radar type known as pulse radar.
1.4.3 Radar Astronomy:
Radio astronomy started after following WWII, many scientists were involved in the development of radar . A number of radio observatories were made during the years to follow but, because ther is additional cost and the complexity of involving transmitters and the various associated receiving equipments, and only very few were dedicated to radar astronomy. All the major radar astronomy activities have been conducted in conjunction with radio astronomy observatories.
Various spacecraft orbiting the various planets and satellites have carried radars for surface mapping; a ground-penetration radar was carried on the Mars Express mission. Radar systems on a number of aircraft and orbiting spacecraft have mapped the entire Earth for various purposes; on the Shuttle Radar Topography Mission.
The word radar is an acronym derived from the phrase RAdio Detection And Ranging and applies to electronic equipment designed for detecting and tracking objects (targets) at considerable distances. The basic principle behind radar is simple - extremely short bursts of radio energy (traveling at the speed of light) are transmitted, reflected off a target and then returned as an echo.
A radar system has a transmitter that emits radio waves. The signal is thus partly reflected back and it has a slight change of wavelength (and thus frequency) if the target is moving. .
The Radar system being developed is very low cost, basic model which can be used at homes for security purpose, safety purpose (like in cars as proximity detector) or even as a learning aid for science students. The ultrasonic frequency is harmless to humans though it might irritate the pets especially dogs as they can hear the ultrasonic range as well.
Design of Ultrasonic Radar System
www.electronickits.com/kit/complete/meas/vevm125.htmThe word radar is an acronym derived from the phrase RAdio Detection And Ranging and applies to electronic equipment designed for detecting and tracking objects (targets) at considerable distances. The basic principle behind radar is simple - extremely short bursts of radio energy (traveling at the speed of light) are transmitted, reflected off a target and then returned as an echo.
Radar makes use of a phenomenon we have all observed, that of the ECHO PRINCIPLE. To illustrate this principle, if a ship's whistle were sounded in the middle of the ocean, the sound waves would dissipate their energy as they traveled outward and at some point would disappear entirely. If, however the whistle sounded near an object such as a cliff some of the radiated sound waves would be reflected back to the ship as an echo.
The form of electromagnetic signal radiated by the radar depends upon the type of information needed about the target. Radar, as designed for marine navigation applications, is pulse modulated.
Once time and bearing are measured, these targets or echoes are calculated and displayed on the radar display. The radar display provides the operator a birds eye view of where other targets are relative to own ship.
Radar is an active device. It utilizes its own radio energy to detect and track the target. It does not depend on energy radiated by the target itself. The ability to detect a target at great distances and to locate its position with high accuracy are two of the chief attributes of the system. The radar system alerts the defence forces of any enemy object in their territory. This system can detect enemy objects with in specified range and hence alerts the forces. The system comprises of transmitter and receiver sections.
The rays which are used for transmission are Infra red rays and these rays are transmitted by IR LEDs. The IR rays travel in the air (i.e. transmission medium) and when strikes an object is reflected back and which is picked up by the receiver.
2.2 LITERATURE REVIEW:
The flow of charge through any material, encounters an opposing force similar in many respects to mechanical friction. This opposing force is called resistance of the material. It is measured in ohms. Resistors function and its coding is retrieved from N N Bhargava and Electronic club site.
Capacitors store in them charge and are used in conjunction with resistors for making timing circuits as it takes sometime for a capacitor to get charged. They act as charge tanks or charge reservoirs for supplying varying DC. They can also be used in filter circuits as they can pass AC easily but block DC.
Diodes allow electricity flow unidirectionaly. The circuit symbol arrow shows current flow direction. The diode forward biased mode, in reversed biased mode, function as a zener diode.
A voltage regulator is a circuit that supplies a regular voltage regardless of changes in load currents. Although voltage regulators can be designed using Op-Amps, it is quicker and easy to use IC voltage regulator.
2.3 Block Diagram:
The transmitter is built around timer IC 555, which is designed to operate at frequency of 38 kHz. This signal is amplified and transmitted through Ultrasonic sensor. The Ultrasonic rays are reflected and received by the Ultrasonic transceiver. The received signal is amplified by an amplifier stage, so even the weak signals can be picked up by the receiver. The amplified signal voltage is compared with a fixed threshold voltage a comparator LM311.
When the comparator output goes high because of reflection of signal from an object, a relay is energized via the relay driver. The relay contacts are used by the buzzer section to produce beep showing that an object has been detected. The relay contact switches off the bulb showing the power of in the surrounding residential areas.
2.4 Components Used :
IC1 555 timer
IC2 7805 V regulator
T1-T5, T7 BC 548 NPN transistor
BD 136 NPN transistor
LED1, LED2 RED LED
R1, R2, R9 1-kilo ohm
R3,R6 22 ohm
R13 47 Ohm
R5 100 ohm
VR1 2-kilo ohm
VR2 4.7 kilo ohm
C1, C2 0.01 micro farad
C3,C4 100 micro farad
IC4 4017 Decade counter
IC5 4069 Hex Inverter
IC6 450 Relay switch
2.5 COMPONENTS DESCRIPTION :
2.5.7 Ultrasonic sensor
tank could distort a reading.
Alternative methods for creating and detecting ultrasound include magnetostriction and capacitive actuation.
www.efymag.com2.6 Circuit Schematics:
Fig 19(a). Circuit Diagram Ultrasonic Transceiver
Fig 19(b). Circuit Diagram Ultrasonic Radar
2.8 Working Procedure:
www.efymag.com , Pradeep G. & SC Dwivedi, Dec 2006We the humans can hear sound of up to 20kHz frequency only. This proximity detector works at a frequency of 40 kHz. It uses two specially made ultrasonic transducers: One transducer emits 40kHz sound, while the other receives 40kHz sound and converts it into electrical variation of the same frequency.
Fig. 1 shows the block diagram of the ultrasonic proximity detector and
Fig. 2 shows its circuit. Mount the transducers (transmitter as well as receiver) about 5 cm apart on a piece of general-purpose PCB as shown in
Fig. 3 and connect to identical points ('a' through 'd') of the detector circuit (Fig. 2) via external wires.
The 40kHz oscillator is built around transistors T1 and T2. If there is a solid object in front of the ultrasonic transmitter module (TX1), some signals will be reflected back and sensed by the receiver transducer
(RX1). The 40kHz ultrasonic signals are converted into 40kHz electric signals by the receiver and then amplified by transistors T3 and T4.
The amplified signals are still in the inaudible range, i.e., these can't be heard. So a frequency-divider stage us ing CMOS decade counter IC4017 (IC1) is used at the output of the amplifier.
IC1 divides the input frequency by '10,' so the 40kHz signal becomes 4 kHz, which is within the audible range. The 4kHz signals are fed to op-amp IC 741
(IC2), which is wired as an earphone amplifier.
This circuit can be used as an electronic guard for the blind. Keep it (along with 9V battery) in their pocket with earphone plugged to their ear.
The transducer modules should be directed towards the walking path. If any object comes up in front or nearby , they will hear 4kHz sound through the earphone and can change their path accordingly. One thing to be noted here is that while using this device, avoid the company of your pets. The reason is that pets can hear ultrasonic sound, which will irritate them and they will bark unnecessarily.
Fig 21. PCB Layout
2.10 Cost of Project:
Misc(Solder wire, connecting wire, Connectors etc)
This radar module is a great way to provide distance feedback to any of electronic projects. Great for robotics, assembly line feedback, proximity sensor etc. This project is simple and cheap to make, and thus can be empolyed at many situations like a burglar alarm which detects unauthorized motion in its vicinity during odd hours, or in case of detecting proximity to an object for example if installed in cars, it can detect the proximity of another vehicle to it. This can come handy when the car is being parked or even on highways which can avoid any potential accident. Rather ths project can even be depicted as a scientific model for students of a RADAR in schools.
This model RADARs capabilities can be increased by attaching microcontroller which can increase its functionality by introducing additional features like speed ,velocity, direction of the object .Further, an LCD or monitor can be interfaced which can depict the object in space.