15-03-2012, 10:44 AM
sir
i want a ppt and report for microcontroller based ultrasonic distance meter
15-03-2012, 10:44 AM
sir i want a ppt and report for microcontroller based ultrasonic distance meter
11-04-2012, 01:11 AM
Please send me this file.This file will help me with my project.
Thank you
13-08-2012, 10:03 AM
Ultrasonic Distance Meter
report on ultrasonic distance meter.docx (Size: 928.18 KB / Downloads: 143) INTRODUCTION There are several ways to measure distance without contact. One way is to use ultrasonic waves at 40 kHz for distance measurement. Ultrasonic transducers measure the amount of time taken for a pulse of sound to travel to a particular surface and return as the reflected echo. This circuit calculates the distance based on the speed of sound at 25°C ambient temperature and shows it on a 7-segment display. Using it, you can measure distance up to 2.5 metres. For this particular application, the required components are AT89C2051 microcontroller, two 40kHz ultrasonic transducers (one each for transmitter and receiver), current buffer ULN2003, operational amplifier LM324, inverter CD4049, four 7-segment displays, five transistors and some discreet components. Ultrasonic generators use piezoelectric materials such as zinc or lead zirconium tartrates or quartz crystal. The material thickness decides the resonant frequency when mounted and excited by electrodes attached on either side of it. The medical scanners used for abdomen or heart ultrasound are designed at 2.5 MHz. In this circuit, a 40kHz transducer is used for measurement in the air medium. The velocity of sound in the air is around 330 m/s at 0°C and varies with temperature. In this project, you excite the ultrasonic transmitter unit with a 40kHz pulse burst and expect an echo from the object whose distance you want to measure. It travels to the object in the air and the echo signal is picked up by another ultrasonic transducer unit (receiver), also a 40 kHz pre-tuned unit. The received signal, which is very weak, is amplified several times in the receiver circuit when seen on a CRO. Weak echoes also occur due to the signals being directly received through the side lobes. These are ignored as the real echo received alone would give the correct distance. That is why we should have a level control. Of course, the signal gets weaker if the target is farther than 2.5 metres and will need a higher pulse excitation voltage or a transducer. Here the microcontroller is used to generate 40kHz sound pulses. It reads when the echo arrives; it finds the time taken in microseconds for to-and-fro travel of sound waves. IC ULN2003 The ULN2003 is a monolithic high voltage and high current Darlington transistor arrays. It consists of seven NPN darlington pairs that features high-voltage outputs with common-cathode clamp diode for switching inductive loads. The collector-current rating of a single darlington pair is 500mA. The darlington pairs may be paralleled for higher current capability. Applications include relay drivers, hammer drivers, lamp drivers, display drivers (LED gas discharge),line drivers, and logic buffers. The ULN2003 has a 2.7kW series base resistor for each darlington pair for operation directly with TTL or 5V CMOS devices. 7-SEGMENT DISPLAY A seven-segment display (SSD), or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, and other electronic devices for displaying numerical information. The idea of the seven-segment display is quite old. In 1910, for example, a seven-segment display illuminated by incandescent bulbs was used on a power-plant boiler room signal panel. A seven segment display, as its name indicates, is composed of seven elements. Individually on or off, they can be combined to produce simplified representations of the arabic numerals. Often the seven segments are arranged in an oblique (slanted) arrangement, which aids readability. In most applications, the seven segments are of nearly uniform shape and size (usually elongated hexagons, though trapezoids and rectangles can also be used), though in the case of adding machines, the vertical segments are longer and more oddly shaped at the ends in an effort to further enhance readability. Each of the numbers 0, 6, 7 and 9 may be represented by two or more different glyphs on seven-segment displays. The seven segments are arranged as a rectangle of two vertical segments on each side with one horizontal segment on the top, middle, and bottom. Additionally, the seventh segment bisects the rectangle horizontally. There are also fourteen-segment displays and sixteen-segment displays (for full alpha numerics) however, these have mostly been replaced by dot-matrix displays. Interfacing to 7-segment display: In industrial PLC applications, one of the old, but simpler methods of displaying numeric information is to use one or more 7-Segment numeric displays connected to an output card of a PLC. Although it is possible to build such a display yourself, it is far more common to employ a pre-manufactured product such as the 4-digit panel mount unit shown at the top of this page. To correctly interface a PLC to such a display, it helps to first understand what basic electronic components are typically employed in their makeup, and how this effects our task of interfacing to, and programming such a unit... Although both LED and LCD numeric displays are readily available, and interfaced similarly, we'll concentrate on the more common LED units in the examples to follow... BCD to 7-segment decoder c/w 4-bit latch: Once 7-Segment LED displays became readily available, a simple IC known as a "BCD to 7-Segment decoder" was quickly developed to simplify their use... Binary formatted data presented to this IC's inputs results in the IC's outputs being placed into the correct state to display the equivalent numeral (0 to 9) on a 7-Segment display. Although BCD to 7-Segment decoder ICs are available without built in latches, this particular IC includes a built in 4-bit latch which we will make use of in later examples... For now the latch is set to simply allow input data to freely pass through to the decoder. Multiplexed digits: By making use of the 4-bit latches that are built into the 4511 IC, we can easily multiplex the digits if so desired... By properly controlling the state of each latch enable pin (LE) we can use the same input data lines (4 switches) to selectively write to each 7-Segment display independently... With just a minor modification to our circuit, we will be able to essentially treat each digit as a unique 4-bit memory location where BCD data of our choosing can be stored and retained... In the above schematic diagram, each display may be written to separately... First the BCD equivalent of the desired numeral (0-9) is set using the 4 data switches... If SW1 is then closed, the current BCD input data will enter the latch of the upper 4511 IC, and will be passed on to the decoder causing the numeral to displayed... if SW1 is then opened, the latch will retain the current data, but will now ignore any changes on it's inputs... The desired numeral will continue to be displayed by the upper LED display until power is lost, or SW1 is again closed and new data is allowed to enter it's latch... Implementation: Seven-segment displays may use a liquid crystal display (LCD), arrays of light-emitting diodes (LEDs), or other light-generating or controlling techniques such as cold cathode gas discharge, vacuum fluorescent, incandescent filaments, and others. For gasoline price totems and other large signs, vane displays made up of electromagnetically flipped light-reflecting segments (or "vanes") are still commonly used. An alternative to the 7-segment display in the 1950s through the 1970s was the cold-cathode, neon-lamp-like nixie tube. Starting in 1970, RCA sold a display device known as the Numitron that used incandescent filaments arranged into a seven-segment display. In a simple LED package, typically all of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common pin; this is referred to as a "common cathode" or "common anode" device. Hence a 7 segment plus decimal point package will only require nine pins (though commercial products typically contain more pins, and/or spaces where pins would go, in order to match industry standard pinouts). Integrated displays also exist, with single or multiple digits. Some of these integrated displays incorporate their own internal decoder, though most do not – each individual LED is brought out to a connecting pin as described. Multiple-digit LED displays as used in pocket calculators and similar devices used multiplexed displays to reduce the number of IC pins required to control the display. For example, all the anodes of the A segments of each digit position would be connected together and to a driver pin, while the cathodes of all segments for each digit would be connected. To operate any particular segment of any digit, the controlling integrated circuit would turn on the cathode driver for the selected digit, and the anode drivers for the desired segments; then after a short blanking interval the next digit would be selected and new segments lit, in a sequential fashion. In this manner an eight digit display with seven segments and a decimal point would require only 8 cathode drivers and 8 anode drivers, instead of sixty-four drivers and IC pins. Often in pocket calculators the digit drive lines would be used to scan the keyboard as well, providing further savings; however, pressing multiple keys at once would produce odd results on the multiplexed display. Seven segment displays can be found in patents as early as 1908 (in U.S. Patent 974,943, F W Wood invented an 8-segment display, which displayed the number 4 using a diagonal bar), but did not achieve widespread use until the advent of LEDs in the 1970s. They are sometimes even used in unsophisticated displays like cardboard "For sale" signs, where the user either applies color to pre-printed segments, or (spray)paints color through a seven-segment digit template, to compose figures such as product prices or telephone numbers. TRANSISTOR BC557 A bipolar (junction) transistor (BJT) is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons and holes. Charge flow in a BJT is due to bidirectional diffusion of charge carriers across a junction between two regions of different charge concentrations. This mode of operation is contrasted with unipolar transistors, such as field-effect transistors, in which only one carrier type is involved in charge flow due to drift. By design, most of the BJT collector current is due to the flow of charges injected from a high-concentration emitter into the base where there are minority carriers that diffuse toward the collector, and so BJTs are classified as minority-carrier devices.
22-07-2013, 08:31 PM
pls post the above requested power point presentation as soon as possible
26-07-2013, 11:37 AM
To get full information or details of ultrasonic distance meter please have a look on the pages
http://seminarprojectsshowthread.php?mode=linear&tid=68607 https://seminarproject.net/Thread-ultras...pid=164192 https://seminarproject.net/Thread-microc...pid=164193 if you again feel trouble on ultrasonic distance meter please reply in that page and ask specific fields in ultrasonic distance meter
30-08-2013, 08:27 AM
sir,i want ppt and project report of ultrasonuc distance meter
29-09-2013, 06:05 PM
send me the ppt for ultasonic distance meter using micro controller
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