Introduction to Ultrasonic Distance Meter Essay

2012 Words May 5th, 2011 9 Pages
ULTRA-SONIC DISTANCE METER.

Introduction to Ultrasonic Distance Meter

The project Ultrasonic Distance Meter is a very interesting and useful project for many industrial applications. In this project we have used the ultrasonic waves to measure the distance in between two points. The basic principal is based on the speed of ultrasonic waves in open air. We have used a microcontroller AT89S51 to transmit and receive ultrasonic waves through 40 KHz ultrasonic receiver and transmitters. By measuring the time required to travel the unknown distance by ultrasonic waves in air we can find out the distance between two points. The distance measured is displayed on a LCD display. The transmission & reception of ultrasonic waves is very
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This technique is often used when using the operational amplifier which needs two kinds of powers in the single power.

This IC is the low noise operational amplifier. It is used for the amplification of the received ultrasonic signal. The low noise type operational amplifier should be used because it does the about 60dB (1000times) amplification.

ENVELOPE DETECTOR

DETECTION CIRCUIT

The detection is done to detect the received ultrasonic signal. This is the half-wave rectification circuit with Shottky barrier diodes. The DC voltage according to the level of the detection signal is output to the capacitor behind the diode. The Shottky barrier diodes are used because the high frequency characteristic is good. These diodes are used to detect the received ultrasonic. The ultrasonic frequency is about 40KHz, so, the diode with the good high frequency characteristic is used.

SIGNAL DETECTOR

This circuit is the circuit which detects the ultrasonic which returned from the object. The output of the detection circuit is detected using the comparator. At the circuit this time, the operational amplifier of the single power supply is used instead of the comparator. The operational amplifier amplifies and outputs the difference between the positive input and the negative input. In case of the operational amplifier which doesn't have the negative

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