Akshay Ppt1

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ULTRASONIC distance METER

detail design specification)By-

AKSHAY JANDOO

ECE/10/106

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INTRODUCTION

My aim is to design a handy device for non-contact measurement of distance.

For measurement of shorter distance only.

Using a timer IC for better functionality.

Less cost of manufacture.

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ULTRASOUND ???

These are waves of frequency greater than20KHz.

They travel with velocity of sound & inaudible.

Because of shorter wave length they travel as

sharp beam.They undergo reflection.

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TRANSMITTER

There is a 180 degree phase shift betweenthe positive &negative terminals.

Inverters in parallelincreases thetransmission electric

power.

In the transmittersection inverter is usedfor the drive of theultrasonic sensor.

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555 OSCILLATOR

IC1 is the oscillation circuit to control thesending-out time of the ultrasonic pulse.TL=1msec & T H=64msec.IC2 is the circuit to make oscillate the

ultrasonic frequency of 40KHz.RB>RA to bring the duty of the oscillationwave close to 50%.The output of IC1 is connected with the resetterminal of IC2 through the inverter.

The ultrasonic of 40KHz is sent out for the 1millisecond and pauses for the 64 msec.

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RECIEVER

The received signal has to beamplified to sufficient gain.

The ultrasonic signal which wasreceived with the reception sensor isamplified by 1000 times (60dB) of

voltage with the operational amplifierwith two stages.

It is 100 times at the first stage(40dB) and 10 times (20dB) at the nextstage.

The circuit this time works with thesingle power supply of +9 V.The operational amplifier with the

negative feedback is used.

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DETECTOR CIRCUIT

This section includes two unites, detection circuit and signaldetector.The detection is done to detect the received ultrasonic signal. This circuit is the circuit which detects the ultrasonic whichreturned from the measurement object. The output of the detection circuit is detected using thecomparator. At the circuit this time, the operational amplifier of the singlepower supply is used instead of the comparator. The

operational amplifier amplifies and outputs the differencebetween the positive input and the negative input.

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DETECTION CIRCUIT

Detection circuit Signal detector

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DISPLAY SECTION

Display section includes led driver unit and led display unit. The measurement result is displayed in the three 7 segment

LEDs.Pnp type transistor is used for the control.4511 is the decoder which changes the binary-coded decimal

(BCD) code into the control code of the 7 segment led.

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APPLICATIONS

Used to find the range of a distant object.

The same unit can be made to detect moving objects(such as cars racing on the street) and find their rangeand speed.

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ADVANTAGES Long distance, up to 10 meters. Works with almost any surface type. Resistant to vibration, radiation, background light andnoise. Unaffected by dust, dirt or high humidity. Low cost.

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LIMITATIONS

Moderate accuracy: 0.1 to 2% of the range.

Large beam hence poor object resolution.Limited speed.Restricted target angle: requires near-perpendicularsurface.

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THANK YOU